US20100330220A1 - Directed assembly of three-dimensional structures with micron-scale features - Google Patents

Directed assembly of three-dimensional structures with micron-scale features Download PDF

Info

Publication number
US20100330220A1
US20100330220A1 US12/875,821 US87582110A US2010330220A1 US 20100330220 A1 US20100330220 A1 US 20100330220A1 US 87582110 A US87582110 A US 87582110A US 2010330220 A1 US2010330220 A1 US 2010330220A1
Authority
US
United States
Prior art keywords
ink
nozzle
deposition
polyelectrolyte
micron
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/875,821
Inventor
Gregory Gratson
Jennifer A. Lewis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Illinois
Original Assignee
University of Illinois
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Illinois filed Critical University of Illinois
Priority to US12/875,821 priority Critical patent/US20100330220A1/en
Assigned to BOARD OF TRUSTEES OF UNIVERSITY OF ILLINOIS reassignment BOARD OF TRUSTEES OF UNIVERSITY OF ILLINOIS ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GRATSON, GREGORY, LEWIS, JENNIFER A.
Publication of US20100330220A1 publication Critical patent/US20100330220A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09DCOATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00Inks
    • C09D11/02Printing inks
    • C09D11/03Printing inks characterised by features other than the chemical nature of the binder
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B33ADDITIVE MANUFACTURING TECHNOLOGY
    • B33YADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y70/00Materials specially adapted for additive manufacturing
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09DCOATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00Inks

Definitions

  • Three-dimensional structures with micron-scale features have many potential applications, for example as photonic band gap materials, tissue engineering scaffolds, biosensors, and drug delivery systems. Consequently, several assembly techniques for fabricating complex three-dimensional structures with features smaller than 100 microns have been developed, such as microfabrication, holographic lithography, two-photon polymerization and colloidal self assembly. However, all these techniques have limitations that reduce their utility.
  • Two-photon polymerization is capable of creating three-dimensional structures with sub-micron features, but from precursors that are not biocompatible.
  • Many techniques have been developed to fabricate three-dimensional photonic crystals, but they rely on expensive, complicated equipment or time-consuming procedures.
  • Colloidal self-assembly has also been utilized to make three-dimensional periodic structures, but controlling the formation of defects is difficult.
  • One fabrication technique relies on the deposition of viscoelastic colloidal inks, usually by a robotic apparatus. These inks flow through a deposition nozzle because the applied pressure shears the interparticle bonds, inducing a breakdown in the elastic modulus. The modulus recovers immediately after leaving the nozzle, and the ink solidifies to maintain its shape and span unsupported regions.
  • the particles in the ink have a mean diameter of about 1 micron, meaning that it would be impossible for the ink to flow through a 1 micron diameter deposition nozzle without clogging or jamming.
  • nanoparticle inks (mean diameter ⁇ 60 nm) also tend to jam nozzles smaller than 30 microns, limiting the applicability of viscoelastic colloidal inks to this length scale.
  • Spiders for example, derive their silk fibers from a concentrated protein biopolymer solution that solidifies as it is drawn to form an extremely strong filament.
  • the extensional flow of the solution aligns liquid crystal sheets in the polymer, and the solution gels by adding ions as it leaves the spinneret. This process was artificially recreated by the deposition of the recombinant spider silk biopolymer into a polar “deposition bath” to produce filament fibers with comparable properties.
  • the disclosure provides polyelectrolyte inks comprising a solvent, a cationic polyelectrolyte, dissolved in the solvent, and an anionic polyelectrolyte, dissolved in the solvent.
  • concentration of at least one of the polyelectrolytes in the solvent is in a semidilute regime.
  • the disclosure provides a solid filament comprising a complex of a cationic polyelectrolyte and an anionic polyelectrolyte.
  • the filament has a diameter of at most 10 microns.
  • the disclosure provides a method of making a polyelectrolyte ink comprising mixing together ingredients that comprise a solvent, a cationic polyelectrolyte, and an anionic polyelectrolyte.
  • concentration of at least one of the polyelectrolytes in the solvent is in a semidilute regime.
  • the disclosure provides a method for fabricating a filament, comprising flowing the polyelectrolyte ink through a nozzle, and contacting the ink with a deposition bath.
  • the polyelectrolyte ink gels in the deposition bath.
  • the disclosure provides a method of forming three-dimensional structure, comprising fabricating a plurality of filaments, each filament fabricated by the method set forth in the fourth aspect.
  • FIG. 2 shows the elastic modulus of the ink reacted in a water/IPA deposition bath as a function of IPA concentration in the deposition reservoir.
  • FIGS. 3A , 3 B and 3 C are electron micrographs of structures fabricated through the directed assembly of polyelectrolyte inks.
  • A Four-layer microstructure with a missing rod that may be utilized as a waveguide in a photonic crystal.
  • B Eight-layer structure with walls showing the ink's ability to form spanning and space-filling elements.
  • C Radial structure showing the inks ability to turn sharp and broad angles.
  • the present disclosure provides a method of microstructure fabrication via deposition of inks that flow through a deposition nozzle of 10 micron or less, without clogging or jamming.
  • a deposition nozzle of 10 micron or less
  • the inks solidify after leaving the nozzle.
  • the resulting microstructures have features in the micron scale and are amenable to fabrication with biocompatible materials, and are relatively easy and inexpensive to make.
  • the present disclosure includes the three-dimensional fabrication of structures with micron-scale features by making use of an ink.
  • An applied pressure forces the ink through a deposition nozzle that is attached to a moving x-y-z micropositioner, into a deposition bath that gels the ink in situ as the micropositioner moves to form a two-dimensional pattern on the substrate.
  • the nozzle then incrementally rises in the z (vertical) direction for the next layer of the pattern. This process is repeated until the desired three-dimensional structure has been created.
  • any three-dimensional structure can be defined and fabricated.
  • the inks of the present disclosure are concentrated mixtures of oppositely charged polyelectrolytes, also referred to as polyelectrolyte complexes (PEC).
  • PEC polyelectrolyte complexes
  • the PEC contains two oppositely charged polyelectrolytes (e.g. poly(acrylic acid) and poly(ethylenimine)).
  • One polyelectrolyte is preferably larger than the other, and the concentration of the larger polyelectrolyte is preferably within the semidilute regime: the concentration is above the concentration c* that separates the dilute from the semidilute concentration regime.
  • concentration is above the concentration c* that separates the dilute from the semidilute concentration regime.
  • the mixture of polyelectrolytes forms particles rather than the single phase fluid needed for the deposition of a continuous filament.
  • polymer coils strongly overlap with each other, and the mixture of electrolytes may be used for structure deposition.
  • the ink viscosity is preferably in the range that allows consistent, controllable flow at a modest applied pressure.
  • Preferred viscosity values vary between at least 0.05 Pa*sec to at most 600 Pa*sec. More preferred viscosity values are at least 0.1 Pa*sec to at most 150 Pa*sec. Yet more preferred viscosity values are at least 1 Pa*sec to at most 20 Pa*sec.
  • the ink undergoes a rapid solidification reaction when it comes in contact with the deposition bath that allows the extruded filament to maintain its shape while spanning unsupported regions of the structure.
  • polyelectrolytes examples include poly(acrylic acid), poly(ethylenimine), poly(styrene sulfonate) poly(allylamine) hydrochloride, poly(diallyldimethyl ammonium chloride), poly(4-vinyl pyridine), and cationic or anionic surfactants.
  • polystyrene resin for example polyacetylene, polyaniline, polypyrrole, polythiophene, poly(3,4 ethylenedioxythiophene) (PEDOT), NAFION® (Du Pont, Wilmington, Del.), polyphenylene vinylene, polyphenylbenzenamine, sulfonated poly-p-phenylene azobenzene dye and other organic dyes may be used, and are well suited to applications involving organic LEDs and circuits.
  • polyacetylene polyaniline
  • polypyrrole polythiophene
  • poly(3,4 ethylenedioxythiophene) PEDOT
  • NAFION® Du Pont, Wilmington, Del.
  • polyphenylene vinylene polyphenylbenzenamine
  • sulfonated poly-p-phenylene azobenzene dye and other organic dyes may be used, and are well suited to applications involving organic LEDs and circuits.
  • the parent polymers of some of these classes of polymers do not contain charged groups, however, copolymers and derivatives of these classes do; for example charged groups may be introduced through monomers containing substituents (which may be protected until after synthesis of the polymer), or by derivatizing reactive groups (such as hydroxyl groups, or electrophilic addition on phenyl rings).
  • biological electrolytes are polynucleotides, such as DNA and RNA, peptides, proteins, peptide nucleic acids, enzymes, polysaccharides such as starch and cellulose, acidic polysaccharides such as hemicelluloses (for example arabinoglucuronoxylan), basic polysaccharides such as poly-(1,4) N-acetyl-D-glucosamine (chitosan), galactans such as agarose, polyuronides such as alginic acid, carrageenans, hyaluronic acid, collagen, fibrin, proteoglycans, polylactic acid, polyglycolic acid, copolymers of organic acids, cationic lipids.
  • Biological polyelectrolytes with both positive and negative charges, for instance zwitterions such as polycarboxybetaine may also be included
  • Bioactive molecules may also be incorporated in the ink, for example charged or neutral nutrient molecules, molecular messengers such as growth stimulants, and cellular adhesion molecules.
  • Molecular probes for biomolecules such as cellular lipids or cellular membrane proteins, cellular components such as ion channels and receptors, or organelles such as mitochondria or lysosomes may also be added.
  • Smaller organic and inorganic species can also be incorporated into the inks, to amounts that do not deleteriously affect the rheological properties of the ink.
  • examples include nanoparticles, quantum dots, charge neutral polymers, organometallic precursors and biomolecules. These species may interact with the polyelectrolytes to aid in the gelation or remain inert in the ink, depending on their ionic nature.
  • many other polymers may be made into polyelectrolytes through functionalizing the polymer backbone with charged moieties, for example amino groups, sulfonate groups, and carboxylic groups.
  • the molecular weight of the larger polyelectrolyte is preferably high enough to facilitate chain overlap (preferably at least 5000 daltons) but also low enough to form a concentrated ink with a viscosity that enables flow at moderate pressures (preferably at most 100,000 daltons).
  • the concentration of the ink is preferably high to avoid deformation of the structures upon drying.
  • a typical polymer concentration ranges from at least 5% to at most 95% by weight. More preferably, the concentration varies from at least 25% to at most 75% by weight. Yet more preferably, the concentration varies from at least 35% to at most 45% by weight. Most preferable concentrations range from at least 38% to at most 42% by weight.
  • the larger polyelectrolyte and the smaller polyelectrolyte are preferably mixed together in a ratio such that one of the charge groups is in excess (usually the charge group of the larger polymer), yielding a mixture away from a stoichiometric (1:1) cationic:anionic group ratio.
  • the strong interactions between complementary polyelectrolytes may lead to the formation of kinetically stable, inhomogeneous aggregates, and the complex may form two phases, a polymer-rich aggregate and a polymer-poor fluid.
  • phase diagram can be developed relating the ratio of cationic to anionic groups as a function of overall polyelectrolyte concentration (in the chosen solvent), with the goal of determining the range for homogeneous inks. This range will be above the dilute/semidilute transition of the larger polymer and away from a stoichiometric (1:1) cationic:anionic group ratio.
  • the viscosity of the homogeneous inks increases as the polymer concentration increases and as the mixing ratio approaches 1:1. The viscosity may thus be controlled for the deposition of inks through a variety of nozzle sizes.
  • a deposition bath is selected to fabricate three-dimensional structures through a rapid solidification reaction.
  • the reaction will occur by increasing the strength of the attractions between the oppositely charged polyelectrolytes. This can be achieved, for example, through pH changes, ionic strength changes, solvent composition changes, or combinations of more than one change.
  • the reaction produces a filament that is strong enough to maintain its shape while spanning unsupported regions in the structure, but also soft enough to allow the filament to adhere to the substrate and flow through the nozzle consistently.
  • Deposition baths that induce gelation through pH changes are generally used when the polyelectrolytes contain acidic and/or basic charged groups.
  • the pH change eliminates the excess of one of the charge groups, for instance by ionizing acidic groups that are neutral at the pH of the ink. This yields a mixture with a stoichiometric (1:1) cationic:anionic group ratio that gels into a filament.
  • the pH of the deposition bath may be selected in order to induce partial dissolution of the deposited filament, while the shape is maintained.
  • the pH of the bath lowers the bond strength between the oppositely charged polyelectrolytes, leading to the dissolution.
  • the structures have a residual charge on the surface, and may be used for the adsorption of charged nanoparticles.
  • Coagulation may also be achieved through changes in solvent composition.
  • an aqueous ink may be deposited in a deposition bath containing a relatively apolar solvent such as an alcohol.
  • a relatively apolar solvent such as an alcohol.
  • the resulting drop in dielectric constant leads to an increase in the coulombic attractions between the polyelectrolytes.
  • an apolar solvent that is a poor solvent for the polyelectrolytes may be chosen, leading to increased polyelectrolyte/polyelectrolyte bonding.
  • the reaction yields a polyelectrolyte complex precipitate with a positive:negative charge ratio closer to 1:1 than in the unreacted ink, but not to the extent of the pH induced reaction.
  • the structures have a residual charge on the surface, and may be used for the adsorption of oppositely charged nanoparticles.
  • the mechanical properties of the deposited ink are dependent on the composition of the deposition bath. As illustrated in FIG. 2 , different percentages of apolar solvents generally yield filaments of varying stiffness.
  • An apparatus for depositing the ink may be manufactured by connecting a deposition nozzle with a diameter of preferably at least 0.1 microns to at most 10 microns to a micropositioner, for example a computer controlled piezoelectric micropositioner, and an ink reservoir.
  • a micropositioner for example a computer controlled piezoelectric micropositioner, and an ink reservoir.
  • These micropositioners are used in a variety of devices, such as scanning tunneling microscopes, and are commercially available. Pressure pushes the ink through the nozzle, or two or more nozzles, and the micropositioner controls the deposition pattern of the filament.
  • the nozzle (or nozzles) may be static, while the stage holding the substrate on which the microstructure is formed may be controlled by the micropositioner. In another configuration, both the nozzle and the stage may each be controlled by its own micropositioner. Multiple substrates are also possible when multiple nozzles are present.
  • the assembly of structures is then preferably performed using patterns created in a computer aided design computer program
  • the structure may be infiltrated with a high refractive index material and subsequently the PEC structure redissolved to form photonic crystals.
  • the ability of the ink to span distances renders it possible to engineer defects (for example cavities or waveguides) into the structure for functional photonic band gap materials.
  • the highly porous structures could be used for membranes that selectively allow small molecules to flow through at a faster rate.
  • screens may be prepared that do not allow cells, or cells larger than a certain size, to flow through. Screens of this type may be used, for instance, to separate smaller cells from larger cells in a blood sample. They may also be used for drug delivery systems where a range of porosities is necessary for controlled release.
  • the charged complexes may be used as tissue engineering scaffolds for cell adhesion and growth.
  • copolymers of poly(L-lactic acid) and poly(L-glycolic acid), both anionic polyelectrolytes that have been FDA approved as biodegradable polymers may be combined with one or more cationic polymers, such as chitosan, to form a biocompatible ink for tissue engineering applications.
  • cationic polymers such as chitosan
  • Nucleic acids include polynucleotides (having at least two nucleic acids), deoxyribonucleic acid (DNA), such as expressed sequence tags (ESTs), gene fragments or complementary DNA (cDNA), or intron sequences that may affect gene transcription, such as promoters, enhancers or structural elements.
  • ESTs expressed sequence tags
  • cDNA complementary DNA
  • intron sequences that may affect gene transcription, such as promoters, enhancers or structural elements.
  • the nucleic acid need not be related to a gene or gene expression, as aptamers (small nucleic acid sequences that specifically bind to a target molecule) can also be used.
  • RNA Ribonucleic acids
  • mRNA messenger RNA
  • tRNA transfer RNA
  • rRNA ribosomal RNA
  • Nucleic acids may also be modified; for example, such as substituting a nucleic acid with a non-naturally occurring one, such as inosine. Chemical modifications of nucleic acids, such as those that may confer stability or facilitated immobilization upon a substrate, may also be used.
  • PNA peptide nucleic acid
  • PNA peptide nucleic acid
  • the neutral backbone of PNAs allows for specific hybridization to DNA and RNA under conditions of low ionic strength.
  • the synthesis of PNA oligomers can be performed using standard solid phase peptide synthesis protocols.
  • Nucleic acids attached to the microstructures may be used, for example, in diagnostic and prognostic assays, gene expression arrays, pharmacogenomic assays, etc.
  • Polynucleotides may be linked to the microstructures through thiol-mediated self-assembly attachment to gold nanoparticles incorporated into the microstructures.
  • the gold may be incorporated into the microstructures either by addition to the undeposited ink mixture or by attachment to the microstructures after deposition, for example via sulfhydril groups present in the ink.
  • Polypeptides having at least two amino acid residues, may find use on or within the substrates of the application.
  • classes of polypeptides include antibodies and derivatives, protein hormones (e.g., human growth hormone and insulin), extracellular matrix molecules, such as laminin, collagen or entactin; polypeptides involved in signaling, such as phosphatases and kinases; receptors, such as dopamine receptors and hormone receptors (advantageously may be attached in the native format, or in the case of homodimers, trimers, etc., mixed with other polypeptide chains or as single chains), etc.
  • protein hormones e.g., human growth hormone and insulin
  • extracellular matrix molecules such as laminin, collagen or entactin
  • polypeptides involved in signaling such as phosphatases and kinases
  • receptors such as dopamine receptors and hormone receptors (advantageously may be attached in the native format, or in the case of homodimers, trimers, etc., mixed with other poly
  • Attaching polypeptides to the substrates of the disclosure allow for a wide variety of applications, including drug screening, diagnostic and prognostic assays, assays that resemble enzyme-linked immunosorbent assays (ELISAs), proteomic assays and even cellular adhesion studies.
  • ELISAs enzyme-linked immunosorbent assays
  • proteomic assays and even cellular adhesion studies.
  • Organic molecules also find use on the microstructures.
  • steroid hormones such as estrogen and testosterone may be attached.
  • Such couplings facilitate for screens for molecules that bind these molecules, such as antibodies or aptamers.
  • candidate small molecule antagonists or agonists may be attached to facilitate pharmaceutical screening.
  • Prions are misfolded protein aggregates that can propagate their misfolded state onto native proteins; examples include those aggregates that cause mad cow disease (bovine spongiform encephalopathy (BSE)) or Creutzfeldt-Jacob disease.
  • viruses include herpes simplex, orthopoxviruses (smallpox) or human immunodeficiency virus.
  • Bacteria that are of interest may include Vibrio cholera, Clostridium perfringens , or Bacillus anthracis (anthrax).
  • Eukaryotic cells such as those isolated as primary cultures from subjects or plants, or from cell lines (e.g., those available from the American Type Culture Collection (ATCC); Manassus, Va.), may be immobilized onto the microstructures for a variety of purposes, including screens for pharmaceuticals, investigations into cell-substrate adhesion, or for the binding of various molecules.
  • ATCC American Type Culture Collection
  • any ink that gels through a solvent change may be used to assemble three-dimensional structures from electrically, optically or biologically active polymers.
  • Inorganic structures may also be fabricated by using sol-gel precursors to produce, for example, sensors or template-free photonic band gap materials.
  • PAA carboxylate groups of poly(acrylic acid)
  • PEI poly(ethylenimine)
  • the ⁇ poly was maintained constant, and different PAA to PEI ratios yielded mixtures with varying rheological properties, as illustrated in the phase diagram of FIG. 1 .
  • the dilute-semidilute crossover concentration c* for PAA is indicated on the bottom x-axis.
  • the two-phase region consists of a dense, polymer-rich phase, and a fluid-like, polymer-poor phase, and data could not be obtained in this regime. As the ratio approaches the two-phase region, the elastic modulus and the viscosity of the mixtures increases.
  • a homogeneous, single phase was observed at mixing ratios in the PAA and PEI rich regions.
  • the charge imbalance forms a non-stoichiometric, hydrophilic complex.
  • the two-phase region, near stoichiometric mixing ratios comprises a dense, polymer-rich phase with a stoichiometric, hydrophobic complex and a fluid-like, polymer-poor phase.
  • the viscosity differences observed at different mixing ratios may be utilized to assemble structures at different length scales.
  • a lower viscosity ink may be deposited at modest applied pressures, whereas larger nozzle sizes generally require more viscous inks in order to obtain flows with controlled rates.
  • Inks prepared as described in example 1 were loaded in a deposition apparatus for microstructure fabrication.
  • the apparatus comprised a NanoCubeTM XYZ NanoPositioning System (Polytec PI, Auburn, Mass.) controlling ⁇ -Tip (World Precision Instruments, Sarasota, Fla.) deposition nozzles, and the ink was dispensed from the apparatus by a Model 800 ULTRA Dispensing System with a 3 ml ULTRA Barrel Reservoirs (EFD, Buffalo, R.I.).
  • Example 3 The experiment of Example 3 was repeated, this time using an ink with a PAA:PEI ratio of ⁇ 4.8 and a deposition bath of deionized water.
  • the pH change eliminated the excess of the groups bearing a positive charge by ionizing acidic groups that were neutral at the pH of the ink. This yielded a mixture with a nearly stoichiometric cationic:anionic group ratio that gelled into a filament (Table 1).
  • FIGS. 3A to 3C show structures fabricated with a 1 micrometer nozzle in an 83% IPA (balance water) deposition bath.
  • FIG. 3A shows an FCT structure with a missing filament in the middle that could be used as a waveguide in a photonic crystal.
  • FIG. 3B shows an 8-layer structure with walls, showing the ability to form solid structures as well as spanning elements.
  • FIG. 3C shows a radial structure with porosity at multiple length scales. The reacted complex is capable of spanning lengths much greater than the filament diameter. Waveguides and radial structures were fabricated, showing the ability to fabricate structural features with tight or broad angles.
  • the deposition occurs in a slightly acidic reservoir, partial dissolution of the complex occurs, while the shape is maintained, leading to highly porous structures with lower elasticity.
  • the structures have a residual negative charge on the surface, and may be used for the adsorption of nanoparticles.
  • the microstructures may also undergo thermal treatment and maintain their integrity.
  • the microstructures were heated at 5° C./min to 240° C. in air. The temperature was held at 240° C. for 30 minutes, and then cooled at 5° C./min.
  • the structures maintained their original shape and became harder than prior to the heating. This hardening may be due also to heat-induced inter-polyelectrolyte bond formation, for example amide bonds formed between the carboxyl groups of the PAA and the amine groups in the PEI.

Abstract

Polyelectrolyte inks comprising a solvent, a cationic polyelectrolyte dissolved in the solvent, and an anionic polyelectrolyte dissolved in the solvent, are described. The concentration of at least one of the polyelectrolytes in the solvent is in a semidilute regime.

Description

    RELATED APPLICATIONS
  • The present patent document is a divisional of U.S. patent application Ser. No. 11/560,610, which was filed on Nov. 16, 2006, which is a divisional of U.S. patent application Ser. No. 10/463,834, which was filed on Jun. 17, 2003. The preceding patent documents are hereby incorporated by reference in their entirety.
  • BACKGROUND
  • Three-dimensional structures with micron-scale features have many potential applications, for example as photonic band gap materials, tissue engineering scaffolds, biosensors, and drug delivery systems. Consequently, several assembly techniques for fabricating complex three-dimensional structures with features smaller than 100 microns have been developed, such as microfabrication, holographic lithography, two-photon polymerization and colloidal self assembly. However, all these techniques have limitations that reduce their utility.
  • Two-photon polymerization is capable of creating three-dimensional structures with sub-micron features, but from precursors that are not biocompatible. Many techniques have been developed to fabricate three-dimensional photonic crystals, but they rely on expensive, complicated equipment or time-consuming procedures. Colloidal self-assembly has also been utilized to make three-dimensional periodic structures, but controlling the formation of defects is difficult.
  • One fabrication technique relies on the deposition of viscoelastic colloidal inks, usually by a robotic apparatus. These inks flow through a deposition nozzle because the applied pressure shears the interparticle bonds, inducing a breakdown in the elastic modulus. The modulus recovers immediately after leaving the nozzle, and the ink solidifies to maintain its shape and span unsupported regions. The particles in the ink have a mean diameter of about 1 micron, meaning that it would be impossible for the ink to flow through a 1 micron diameter deposition nozzle without clogging or jamming. In practice, nanoparticle inks (mean diameter˜60 nm) also tend to jam nozzles smaller than 30 microns, limiting the applicability of viscoelastic colloidal inks to this length scale.
  • Polymeric solutions are used in nature to fabricate thin filaments. Spiders, for example, derive their silk fibers from a concentrated protein biopolymer solution that solidifies as it is drawn to form an extremely strong filament. The extensional flow of the solution aligns liquid crystal sheets in the polymer, and the solution gels by adding ions as it leaves the spinneret. This process was artificially recreated by the deposition of the recombinant spider silk biopolymer into a polar “deposition bath” to produce filament fibers with comparable properties.
  • SUMMARY
  • In a first aspect, the disclosure provides polyelectrolyte inks comprising a solvent, a cationic polyelectrolyte, dissolved in the solvent, and an anionic polyelectrolyte, dissolved in the solvent. The concentration of at least one of the polyelectrolytes in the solvent is in a semidilute regime.
  • In a second aspect, the disclosure provides a solid filament comprising a complex of a cationic polyelectrolyte and an anionic polyelectrolyte. The filament has a diameter of at most 10 microns.
  • In a third aspect, the disclosure provides a method of making a polyelectrolyte ink comprising mixing together ingredients that comprise a solvent, a cationic polyelectrolyte, and an anionic polyelectrolyte. The concentration of at least one of the polyelectrolytes in the solvent is in a semidilute regime.
  • In a fourth aspect, the disclosure provides a method for fabricating a filament, comprising flowing the polyelectrolyte ink through a nozzle, and contacting the ink with a deposition bath. The polyelectrolyte ink gels in the deposition bath.
  • In a fifth aspect, the disclosure provides a method of forming three-dimensional structure, comprising fabricating a plurality of filaments, each filament fabricated by the method set forth in the fourth aspect.
  • DESCRIPTION OF THE DRAWINGS
  • FIG. 1 shows viscosity and elastic modulus of polyelectrolyte mixtures as a function of the mixing ratio of ionizable groups at a constant polymer volume fraction (Φpoly=0.4).
  • FIG. 2 shows the elastic modulus of the ink reacted in a water/IPA deposition bath as a function of IPA concentration in the deposition reservoir.
  • FIGS. 3A, 3B and 3C are electron micrographs of structures fabricated through the directed assembly of polyelectrolyte inks. (A) Four-layer microstructure with a missing rod that may be utilized as a waveguide in a photonic crystal. (B) Eight-layer structure with walls showing the ink's ability to form spanning and space-filling elements. (C) Radial structure showing the inks ability to turn sharp and broad angles.
  • DETAILED DESCRIPTION
  • The present disclosure provides a method of microstructure fabrication via deposition of inks that flow through a deposition nozzle of 10 micron or less, without clogging or jamming. When deposited in a deposition bath the inks solidify after leaving the nozzle. The resulting microstructures have features in the micron scale and are amenable to fabrication with biocompatible materials, and are relatively easy and inexpensive to make.
  • The present disclosure includes the three-dimensional fabrication of structures with micron-scale features by making use of an ink. An applied pressure forces the ink through a deposition nozzle that is attached to a moving x-y-z micropositioner, into a deposition bath that gels the ink in situ as the micropositioner moves to form a two-dimensional pattern on the substrate. The nozzle then incrementally rises in the z (vertical) direction for the next layer of the pattern. This process is repeated until the desired three-dimensional structure has been created. With this technique, any three-dimensional structure can be defined and fabricated.
  • The inks of the present disclosure are concentrated mixtures of oppositely charged polyelectrolytes, also referred to as polyelectrolyte complexes (PEC). The PEC contains two oppositely charged polyelectrolytes (e.g. poly(acrylic acid) and poly(ethylenimine)). One polyelectrolyte is preferably larger than the other, and the concentration of the larger polyelectrolyte is preferably within the semidilute regime: the concentration is above the concentration c* that separates the dilute from the semidilute concentration regime. Below c*, in the dilute regime, the mixture of polyelectrolytes forms particles rather than the single phase fluid needed for the deposition of a continuous filament. Above c*, in the semidilute regime, polymer coils strongly overlap with each other, and the mixture of electrolytes may be used for structure deposition.
  • The ink viscosity is preferably in the range that allows consistent, controllable flow at a modest applied pressure. Preferred viscosity values vary between at least 0.05 Pa*sec to at most 600 Pa*sec. More preferred viscosity values are at least 0.1 Pa*sec to at most 150 Pa*sec. Yet more preferred viscosity values are at least 1 Pa*sec to at most 20 Pa*sec. Moreover, the ink undergoes a rapid solidification reaction when it comes in contact with the deposition bath that allows the extruded filament to maintain its shape while spanning unsupported regions of the structure.
  • Examples of polyelectrolytes that may be used in PEC are poly(acrylic acid), poly(ethylenimine), poly(styrene sulfonate) poly(allylamine) hydrochloride, poly(diallyldimethyl ammonium chloride), poly(4-vinyl pyridine), and cationic or anionic surfactants. Electrically or optically active classes of polymers, for example polyacetylene, polyaniline, polypyrrole, polythiophene, poly(3,4 ethylenedioxythiophene) (PEDOT), NAFION® (Du Pont, Wilmington, Del.), polyphenylene vinylene, polyphenylbenzenamine, sulfonated poly-p-phenylene azobenzene dye and other organic dyes may be used, and are well suited to applications involving organic LEDs and circuits. The parent polymers of some of these classes of polymers do not contain charged groups, however, copolymers and derivatives of these classes do; for example charged groups may be introduced through monomers containing substituents (which may be protected until after synthesis of the polymer), or by derivatizing reactive groups (such as hydroxyl groups, or electrophilic addition on phenyl rings).
  • For biochemical, molecular biological and biomedical applications, such as biocatalysis, gene manipulation and tissue engineering, biological electrolytes may be used. Example biological polyelectrolytes are polynucleotides, such as DNA and RNA, peptides, proteins, peptide nucleic acids, enzymes, polysaccharides such as starch and cellulose, acidic polysaccharides such as hemicelluloses (for example arabinoglucuronoxylan), basic polysaccharides such as poly-(1,4) N-acetyl-D-glucosamine (chitosan), galactans such as agarose, polyuronides such as alginic acid, carrageenans, hyaluronic acid, collagen, fibrin, proteoglycans, polylactic acid, polyglycolic acid, copolymers of organic acids, cationic lipids. Biological polyelectrolytes with both positive and negative charges, for instance zwitterions such as polycarboxybetaine, may also be included in the ink compositions.
  • Bioactive molecules may also be incorporated in the ink, for example charged or neutral nutrient molecules, molecular messengers such as growth stimulants, and cellular adhesion molecules. Molecular probes for biomolecules such as cellular lipids or cellular membrane proteins, cellular components such as ion channels and receptors, or organelles such as mitochondria or lysosomes may also be added.
  • Smaller organic and inorganic species can also be incorporated into the inks, to amounts that do not deleteriously affect the rheological properties of the ink. Examples include nanoparticles, quantum dots, charge neutral polymers, organometallic precursors and biomolecules. These species may interact with the polyelectrolytes to aid in the gelation or remain inert in the ink, depending on their ionic nature. Also, many other polymers may be made into polyelectrolytes through functionalizing the polymer backbone with charged moieties, for example amino groups, sulfonate groups, and carboxylic groups.
  • The molecular weight of the larger polyelectrolyte is preferably high enough to facilitate chain overlap (preferably at least 5000 daltons) but also low enough to form a concentrated ink with a viscosity that enables flow at moderate pressures (preferably at most 100,000 daltons). The concentration of the ink is preferably high to avoid deformation of the structures upon drying. A typical polymer concentration ranges from at least 5% to at most 95% by weight. More preferably, the concentration varies from at least 25% to at most 75% by weight. Yet more preferably, the concentration varies from at least 35% to at most 45% by weight. Most preferable concentrations range from at least 38% to at most 42% by weight.
  • The larger polyelectrolyte and the smaller polyelectrolyte are preferably mixed together in a ratio such that one of the charge groups is in excess (usually the charge group of the larger polymer), yielding a mixture away from a stoichiometric (1:1) cationic:anionic group ratio. In the vicinity of this ratio, the strong interactions between complementary polyelectrolytes may lead to the formation of kinetically stable, inhomogeneous aggregates, and the complex may form two phases, a polymer-rich aggregate and a polymer-poor fluid.
  • Once the polyelectrolytes and solvent have been chosen, a phase diagram can be developed relating the ratio of cationic to anionic groups as a function of overall polyelectrolyte concentration (in the chosen solvent), with the goal of determining the range for homogeneous inks. This range will be above the dilute/semidilute transition of the larger polymer and away from a stoichiometric (1:1) cationic:anionic group ratio. The viscosity of the homogeneous inks increases as the polymer concentration increases and as the mixing ratio approaches 1:1. The viscosity may thus be controlled for the deposition of inks through a variety of nozzle sizes.
  • A deposition bath is selected to fabricate three-dimensional structures through a rapid solidification reaction. In these polyelectrolyte inks, the reaction will occur by increasing the strength of the attractions between the oppositely charged polyelectrolytes. This can be achieved, for example, through pH changes, ionic strength changes, solvent composition changes, or combinations of more than one change. The reaction produces a filament that is strong enough to maintain its shape while spanning unsupported regions in the structure, but also soft enough to allow the filament to adhere to the substrate and flow through the nozzle consistently.
  • Deposition baths that induce gelation through pH changes are generally used when the polyelectrolytes contain acidic and/or basic charged groups. The pH change eliminates the excess of one of the charge groups, for instance by ionizing acidic groups that are neutral at the pH of the ink. This yields a mixture with a stoichiometric (1:1) cationic:anionic group ratio that gels into a filament.
  • In addition, the pH of the deposition bath may be selected in order to induce partial dissolution of the deposited filament, while the shape is maintained. The pH of the bath lowers the bond strength between the oppositely charged polyelectrolytes, leading to the dissolution. The structures have a residual charge on the surface, and may be used for the adsorption of charged nanoparticles.
  • Coagulation may also be achieved through changes in solvent composition. For example, an aqueous ink may be deposited in a deposition bath containing a relatively apolar solvent such as an alcohol. The resulting drop in dielectric constant leads to an increase in the coulombic attractions between the polyelectrolytes. Also, an apolar solvent that is a poor solvent for the polyelectrolytes may be chosen, leading to increased polyelectrolyte/polyelectrolyte bonding. The reaction yields a polyelectrolyte complex precipitate with a positive:negative charge ratio closer to 1:1 than in the unreacted ink, but not to the extent of the pH induced reaction. The structures have a residual charge on the surface, and may be used for the adsorption of oppositely charged nanoparticles.
  • Moreover, the mechanical properties of the deposited ink are dependent on the composition of the deposition bath. As illustrated in FIG. 2, different percentages of apolar solvents generally yield filaments of varying stiffness.
  • An apparatus for depositing the ink may be manufactured by connecting a deposition nozzle with a diameter of preferably at least 0.1 microns to at most 10 microns to a micropositioner, for example a computer controlled piezoelectric micropositioner, and an ink reservoir. These micropositioners are used in a variety of devices, such as scanning tunneling microscopes, and are commercially available. Pressure pushes the ink through the nozzle, or two or more nozzles, and the micropositioner controls the deposition pattern of the filament. Alternatively, the nozzle (or nozzles) may be static, while the stage holding the substrate on which the microstructure is formed may be controlled by the micropositioner. In another configuration, both the nozzle and the stage may each be controlled by its own micropositioner. Multiple substrates are also possible when multiple nozzles are present. The assembly of structures is then preferably performed using patterns created in a computer aided design computer program coupled to the micropositioner.
  • There are many applications for solid PEC structures fabricated with these materials and methods. The structure may be infiltrated with a high refractive index material and subsequently the PEC structure redissolved to form photonic crystals. The ability of the ink to span distances renders it possible to engineer defects (for example cavities or waveguides) into the structure for functional photonic band gap materials. The highly porous structures could be used for membranes that selectively allow small molecules to flow through at a faster rate. Also, screens may be prepared that do not allow cells, or cells larger than a certain size, to flow through. Screens of this type may be used, for instance, to separate smaller cells from larger cells in a blood sample. They may also be used for drug delivery systems where a range of porosities is necessary for controlled release.
  • The charged complexes may be used as tissue engineering scaffolds for cell adhesion and growth. For instance, copolymers of poly(L-lactic acid) and poly(L-glycolic acid), both anionic polyelectrolytes that have been FDA approved as biodegradable polymers, may be combined with one or more cationic polymers, such as chitosan, to form a biocompatible ink for tissue engineering applications. To promote cell growth throughout the structure, proteins and sugars may be added to the ink to be released as the polyelectrolytes dissolve.
  • Biologically interesting molecules may also be attached to the microstructures. Examples of these molecules include nucleic acids, polypeptides and other organic molecules. Nucleic acids include polynucleotides (having at least two nucleic acids), deoxyribonucleic acid (DNA), such as expressed sequence tags (ESTs), gene fragments or complementary DNA (cDNA), or intron sequences that may affect gene transcription, such as promoters, enhancers or structural elements. However, the nucleic acid need not be related to a gene or gene expression, as aptamers (small nucleic acid sequences that specifically bind to a target molecule) can also be used. Ribonucleic acids (RNA) may also be used, such as messenger RNA (mRNA), transfer RNA (tRNA) or ribosomal RNA (rRNA). Nucleic acids may also be modified; for example, such as substituting a nucleic acid with a non-naturally occurring one, such as inosine. Chemical modifications of nucleic acids, such as those that may confer stability or facilitated immobilization upon a substrate, may also be used. Another example of a modified nucleic acid is a peptide nucleic acid (PNA), which is a nucleic acid mimic (e.g., DNA mimic) in that the deoxyribose phosphate backbone is replaced by a pseudopeptide backbone and only the four natural nucleobases are retained. The neutral backbone of PNAs allows for specific hybridization to DNA and RNA under conditions of low ionic strength. The synthesis of PNA oligomers can be performed using standard solid phase peptide synthesis protocols. Nucleic acids attached to the microstructures may be used, for example, in diagnostic and prognostic assays, gene expression arrays, pharmacogenomic assays, etc.
  • Polynucleotides may be linked to the microstructures through thiol-mediated self-assembly attachment to gold nanoparticles incorporated into the microstructures. The gold may be incorporated into the microstructures either by addition to the undeposited ink mixture or by attachment to the microstructures after deposition, for example via sulfhydril groups present in the ink.
  • Polypeptides, having at least two amino acid residues, may find use on or within the substrates of the application. Examples of classes of polypeptides include antibodies and derivatives, protein hormones (e.g., human growth hormone and insulin), extracellular matrix molecules, such as laminin, collagen or entactin; polypeptides involved in signaling, such as phosphatases and kinases; receptors, such as dopamine receptors and hormone receptors (advantageously may be attached in the native format, or in the case of homodimers, trimers, etc., mixed with other polypeptide chains or as single chains), etc. Attaching polypeptides to the substrates of the disclosure allow for a wide variety of applications, including drug screening, diagnostic and prognostic assays, assays that resemble enzyme-linked immunosorbent assays (ELISAs), proteomic assays and even cellular adhesion studies.
  • Organic molecules also find use on the microstructures. For example, steroid hormones, such as estrogen and testosterone may be attached. Such couplings facilitate for screens for molecules that bind these molecules, such as antibodies or aptamers. Likewise, candidate small molecule antagonists or agonists may be attached to facilitate pharmaceutical screening.
  • Entities such as prions, viruses, bacteria, and eukaryotic cells may also be attached. Prions are misfolded protein aggregates that can propagate their misfolded state onto native proteins; examples include those aggregates that cause mad cow disease (bovine spongiform encephalopathy (BSE)) or Creutzfeldt-Jacob disease. Examples of viruses include herpes simplex, orthopoxviruses (smallpox) or human immunodeficiency virus. Bacteria that are of interest may include Vibrio cholera, Clostridium perfringens, or Bacillus anthracis (anthrax). Eukaryotic cells, such as those isolated as primary cultures from subjects or plants, or from cell lines (e.g., those available from the American Type Culture Collection (ATCC); Manassus, Va.), may be immobilized onto the microstructures for a variety of purposes, including screens for pharmaceuticals, investigations into cell-substrate adhesion, or for the binding of various molecules.
  • Any ink that gels through a solvent change may be used to assemble three-dimensional structures from electrically, optically or biologically active polymers. Inorganic structures may also be fabricated by using sol-gel precursors to produce, for example, sensors or template-free photonic band gap materials.
  • EXAMPLES 1) Ink Mixtures
  • A linear polyacid, poly(acrylic acid) (MW˜10,000) and a highly branched polybase, poly(ethylenimine) were combined in an aqueous solvent, yielding solutions with a polymer fraction Φpoly=0.4. When these polyions were combined, the carboxylate groups of poly(acrylic acid) (PAA) form ionic bonds to the amine groups of poly(ethylenimine) (PEI). The polymers were initially mixed under mildly acidic conditions (pH˜3.6), where the partial charge on the PAA let only a fraction of the potentially ionizable groups participate in complexation. The Φpoly was maintained constant, and different PAA to PEI ratios yielded mixtures with varying rheological properties, as illustrated in the phase diagram of FIG. 1. In this figure, the values on the left and the right y-axes indicate values for pure PAA and pure PEI at Φpoly=0.4 The dilute-semidilute crossover concentration c* for PAA is indicated on the bottom x-axis. The two-phase region consists of a dense, polymer-rich phase, and a fluid-like, polymer-poor phase, and data could not be obtained in this regime. As the ratio approaches the two-phase region, the elastic modulus and the viscosity of the mixtures increases.
  • A homogeneous, single phase was observed at mixing ratios in the PAA and PEI rich regions. The charge imbalance forms a non-stoichiometric, hydrophilic complex. The two-phase region, near stoichiometric mixing ratios, comprises a dense, polymer-rich phase with a stoichiometric, hydrophobic complex and a fluid-like, polymer-poor phase.
  • The viscosity differences observed at different mixing ratios may be utilized to assemble structures at different length scales. At small nozzle sizes, a lower viscosity ink may be deposited at modest applied pressures, whereas larger nozzle sizes generally require more viscous inks in order to obtain flows with controlled rates.
  • 2) Ink Deposition Apparatus
  • Inks prepared as described in example 1 were loaded in a deposition apparatus for microstructure fabrication. The apparatus comprised a NanoCube™ XYZ NanoPositioning System (Polytec PI, Auburn, Mass.) controlling μ-Tip (World Precision Instruments, Sarasota, Fla.) deposition nozzles, and the ink was dispensed from the apparatus by a Model 800 ULTRA Dispensing System with a 3 ml ULTRA Barrel Reservoirs (EFD, Providence, R.I.).
  • 3) Fabrication of Structures in an Isopropanol and Water
  • An ink prepared according to the procedure of example 1, with a Φpoly=0.4, a PAA:PEI ratio of 5.7:1, was deposited, at a velocity of 20 microns/second and through a 1 micron nozzle, in a deposition bath containing a mixture of isopropanol (IPA) and water. The gelation occurs due to a decrease in solvent quality for the polyelectrolytes and an increase in the coulombic attractions between the ionizable groups, yielding a reacted ink filament. NMR spectroscopic data (not shown) showed no discernable difference in the types of bonds in the reacted and unreacted complexes, indicating that the reaction only causes a change in the number and strength of the bonds. The mechanical properties of the reacted ink were highly dependent on the deposition bath, as illustrated in FIG. 2.
  • 4) Fabrication of Structures in a Water Deposition Bath
  • The experiment of Example 3 was repeated, this time using an ink with a PAA:PEI ratio of ˜4.8 and a deposition bath of deionized water. The pH change eliminated the excess of the groups bearing a positive charge by ionizing acidic groups that were neutral at the pH of the ink. This yielded a mixture with a nearly stoichiometric cationic:anionic group ratio that gelled into a filament (Table 1).
  • TABLE 1
    (−:+) charge
    Polyelectrolyte Carbon Hydrogen Nitrogen ratio
    PAA 39.48  4.80 NA
    PEI 52.04 11.78 31.68 NA
    Unreacted PEC 40.12  5.21  2.27 4.8:1
    Reacted PEC 41.92  5.58  2.90 1.1:1
  • 4) Microstructures
  • FIGS. 3A to 3C show structures fabricated with a 1 micrometer nozzle in an 83% IPA (balance water) deposition bath. FIG. 3A shows an FCT structure with a missing filament in the middle that could be used as a waveguide in a photonic crystal. FIG. 3B shows an 8-layer structure with walls, showing the ability to form solid structures as well as spanning elements. FIG. 3C shows a radial structure with porosity at multiple length scales. The reacted complex is capable of spanning lengths much greater than the filament diameter. Waveguides and radial structures were fabricated, showing the ability to fabricate structural features with tight or broad angles. Periodic structures with different feature sizes were also fabricated, wherein the feature size of a structure is the diameter of its thinnest filament, obtained with different nozzles and inks (Φpoly=0.4 and PAA:PEI ratio˜5.7:1; Φpoly=0.4 and PAA:PEI ratio˜5:1; Φpoly=0.43 and PAA:PEI ratio˜2:1).
  • If the deposition occurs in a slightly acidic reservoir, partial dissolution of the complex occurs, while the shape is maintained, leading to highly porous structures with lower elasticity. The structures have a residual negative charge on the surface, and may be used for the adsorption of nanoparticles.
  • The microstructures may also undergo thermal treatment and maintain their integrity. For example, the microstructures were heated at 5° C./min to 240° C. in air. The temperature was held at 240° C. for 30 minutes, and then cooled at 5° C./min. The structures maintained their original shape and became harder than prior to the heating. This hardening may be due also to heat-induced inter-polyelectrolyte bond formation, for example amide bonds formed between the carboxyl groups of the PAA and the amine groups in the PEI.

Claims (13)

1. An apparatus for the fabrication of microstructures, the apparatus comprising:
(1) a nozzle comprising an opening having a diameter of at most 10 microns;
(2) a stage below the nozzle for supporting a substrate;
(3) a micropositioner operably connected to at least one of the nozzle and the stage; and
(4) an ink reservoir in fluid communication with the nozzle.
2. The apparatus of claim 1, further comprising a pressure dispensing system operably connected to the ink reservoir.
3. The apparatus of claim 1, wherein the micropositioner is a computer-controlled micropositioner.
4. The apparatus of claim 1, wherein the opening of the nozzle has a diameter of at most 1 micron.
5. The apparatus of claim 1, wherein the opening of the nozzle has a diameter of at least 0.1 micron.
6. The apparatus of claim 1, further comprising a plurality of nozzles.
7. The apparatus of claim 6, further comprising a plurality of substrates on the stage.
8. The apparatus of claim 1, further comprising a substrate on the stage, the substrate comprising a deposition bath.
9. The apparatus of claim 8, wherein the deposition bath is configured to induce gelation of an ink flowed through the nozzle.
10. The apparatus of claim 8, wherein the deposition bath comprises an aqueous solvent.
11. The apparatus of claim 8, wherein the deposition bath comprises an apolar solvent.
12. The apparatus of claim 11, wherein the apolar solvent comprises an alcohol.
13. The apparatus of claim 12, wherein the deposition bath comprises a mixture of isopropyl alcohol and water.
US12/875,821 2003-06-17 2010-09-03 Directed assembly of three-dimensional structures with micron-scale features Abandoned US20100330220A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/875,821 US20100330220A1 (en) 2003-06-17 2010-09-03 Directed assembly of three-dimensional structures with micron-scale features

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/463,834 US7141617B2 (en) 2003-06-17 2003-06-17 Directed assembly of three-dimensional structures with micron-scale features
US11/560,610 US7790061B2 (en) 2003-06-17 2006-11-16 Directed assembly of three-dimensional structures with micron-scale features
US12/875,821 US20100330220A1 (en) 2003-06-17 2010-09-03 Directed assembly of three-dimensional structures with micron-scale features

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US11/560,610 Division US7790061B2 (en) 2003-06-17 2006-11-16 Directed assembly of three-dimensional structures with micron-scale features

Publications (1)

Publication Number Publication Date
US20100330220A1 true US20100330220A1 (en) 2010-12-30

Family

ID=33551382

Family Applications (3)

Application Number Title Priority Date Filing Date
US10/463,834 Expired - Fee Related US7141617B2 (en) 2003-06-17 2003-06-17 Directed assembly of three-dimensional structures with micron-scale features
US11/560,610 Expired - Fee Related US7790061B2 (en) 2003-06-17 2006-11-16 Directed assembly of three-dimensional structures with micron-scale features
US12/875,821 Abandoned US20100330220A1 (en) 2003-06-17 2010-09-03 Directed assembly of three-dimensional structures with micron-scale features

Family Applications Before (2)

Application Number Title Priority Date Filing Date
US10/463,834 Expired - Fee Related US7141617B2 (en) 2003-06-17 2003-06-17 Directed assembly of three-dimensional structures with micron-scale features
US11/560,610 Expired - Fee Related US7790061B2 (en) 2003-06-17 2006-11-16 Directed assembly of three-dimensional structures with micron-scale features

Country Status (5)

Country Link
US (3) US7141617B2 (en)
CN (1) CN1826393A (en)
DE (1) DE112004001096B4 (en)
GB (1) GB2418918B (en)
WO (1) WO2005000977A2 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060198959A1 (en) * 2003-07-31 2006-09-07 Kazuhiro Murata Method of producing a three-dimensional structure and fine three-dimensional structure
US9643358B2 (en) 2011-07-01 2017-05-09 The Board Of Trustees Of The University Of Illinois Multinozzle deposition system for direct write applications
US10117968B2 (en) 2013-11-05 2018-11-06 President And Fellows Of Harvard College Method of printing a tissue construct with embedded vasculature
US10151649B2 (en) 2013-11-18 2018-12-11 President And Fellows Of Harvard College Printed stretchable strain sensor
US10462907B2 (en) 2013-06-24 2019-10-29 President And Fellows Of Harvard College Printed three-dimensional (3D) functional part and method of making
US10597545B2 (en) 2015-05-18 2020-03-24 President And Fellows Of Harvard College Foam ink composition and 3D printed hierarchical porous structure
US11207831B2 (en) 2016-12-08 2021-12-28 President And Fellows Of Harvard College 3D printed core-shell filament and method of 3D printing a core-shell filament
US11492547B2 (en) 2020-06-04 2022-11-08 UbiQD, Inc. Low-PH nanoparticles and ligands

Families Citing this family (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030091647A1 (en) * 2001-11-15 2003-05-15 Lewis Jennifer A. Controlled dispersion of colloidal suspensions via nanoparticle additions
US20040226620A1 (en) 2002-09-26 2004-11-18 Daniel Therriault Microcapillary networks
US7141617B2 (en) 2003-06-17 2006-11-28 The Board Of Trustees Of The University Of Illinois Directed assembly of three-dimensional structures with micron-scale features
WO2006101453A1 (en) * 2005-03-22 2006-09-28 Agency For Science, Technology And Research Scaffold and method of forming scaffold by entangling fibres
US9327538B2 (en) 2006-01-05 2016-05-03 Ppg Industries Ohio, Inc. Bragg diffracting security markers
US7625515B2 (en) * 2006-06-19 2009-12-01 Iowa State University Research Foundation, Inc. Fabrication of layer-by-layer photonic crystals using two polymer microtransfer molding
US20080231184A1 (en) * 2006-06-19 2008-09-25 Iowa State University Research Foundation, Inc. Higher efficiency incandescent lighting using photon recycling
US7545209B2 (en) * 2006-09-07 2009-06-09 National Semiconductor Corporation Gain adjustment for programmable gain amplifiers
KR20080060744A (en) * 2006-12-27 2008-07-02 한국조폐공사 Ink containing pna and method for identifying the same
US8895111B2 (en) 2007-03-14 2014-11-25 Kimberly-Clark Worldwide, Inc. Substrates having improved ink adhesion and oil crockfastness
US7956102B2 (en) * 2007-04-09 2011-06-07 The Board Of Trustees Of The University Of Illinois Sol-gel inks
US20090101278A1 (en) * 2007-10-17 2009-04-23 Louis Laberge-Lebel Methods for preparing freeform three-dimensional structures
US20090221736A1 (en) * 2008-02-29 2009-09-03 Mccurry Charles Douglas Water-based ink composition for improved crockfastness
US8216666B2 (en) 2008-02-29 2012-07-10 The Procter & Gamble Company Substrates having improved crockfastness
US7922939B2 (en) 2008-10-03 2011-04-12 The Board Of Trustees Of The University Of Illinois Metal nanoparticle inks
US8187500B2 (en) 2008-10-17 2012-05-29 The Board Of Trustees Of The University Of Illinois Biphasic inks
US9400219B2 (en) * 2009-05-19 2016-07-26 Iowa State University Research Foundation, Inc. Metallic layer-by-layer photonic crystals for linearly-polarized thermal emission and thermophotovoltaic device including same
WO2011119607A2 (en) * 2010-03-24 2011-09-29 The Board Of Trustees Of The University Of Illinois Viscoelastic ink for direct writing of hydrogel structures
US9474269B2 (en) 2010-03-29 2016-10-25 The Clorox Company Aqueous compositions comprising associative polyelectrolyte complexes (PEC)
US20110236582A1 (en) 2010-03-29 2011-09-29 Scheuing David R Polyelectrolyte Complexes
US9309435B2 (en) 2010-03-29 2016-04-12 The Clorox Company Precursor polyelectrolyte complexes compositions comprising oxidants
JP2013060570A (en) * 2010-10-28 2013-04-04 Kao Corp Modified polyuronic acid or its salt
US8742406B1 (en) 2011-02-16 2014-06-03 Iowa State University Research Foundation, Inc. Soft lithography microlens fabrication and array for enhanced light extraction from organic light emitting diodes (OLEDs)
US8975220B1 (en) 2014-08-11 2015-03-10 The Clorox Company Hypohalite compositions comprising a cationic polymer
JP2016098313A (en) * 2014-11-21 2016-05-30 セイコーエプソン株式会社 Cellulose-based material, liquid composition, molded object, and method for manufacturing molded object
US9570385B2 (en) 2015-01-22 2017-02-14 Invensas Corporation Method for fabrication of interconnection circuitry with electrically conductive features passing through a support and comprising core portions formed using nanoparticle-containing inks
JP6582485B2 (en) 2015-03-27 2019-10-02 セイコーエプソン株式会社 Composition, method for producing shaped article, and shaped article
JP2016188283A (en) 2015-03-30 2016-11-04 セイコーエプソン株式会社 Composition set, method for manufacturing molded object and molded object
US10394202B2 (en) 2015-08-21 2019-08-27 Voxel8, Inc. 3D printer calibration and control
CN105315792B (en) * 2015-11-18 2020-01-10 Tcl集团股份有限公司 Quantum dot printing ink, preparation method thereof and quantum dot light-emitting diode
US20180251649A1 (en) * 2015-11-30 2018-09-06 President And Fellows Of Harvard College Hydrogel composite ink formulation and method of 4d printing a hydrogel composite structure
JP7358340B2 (en) 2017-05-26 2023-10-10 インフィニット・マテリアル・ソリューションズ,エルエルシー Water-soluble polymer composition
CN107706318B (en) * 2017-10-16 2020-06-26 深圳市华星光电半导体显示技术有限公司 Electronic transmission layer ink-jet printing ink and preparation method thereof
CN107974131B (en) * 2017-11-16 2021-01-12 华南师范大学 Carbon dot ink and preparation method and application thereof
WO2019226695A1 (en) * 2018-05-21 2019-11-28 Virginia Polytechnic Institute And State University Selective deposition of materials for composite structures via additive manufacturing
US20220134301A1 (en) * 2019-03-12 2022-05-05 Ohio State Innovation Foundation Ph-sensitive capsule and release system
US11787117B2 (en) * 2020-04-23 2023-10-17 Rtx Corporation Fabricating ceramic structures
US20230287224A1 (en) * 2020-07-29 2023-09-14 Ohio State Innovation Foundation pH-SENSITIVE CAPSULE AND RELEASE SYSTEM
CN112768611A (en) * 2021-01-11 2021-05-07 陈云 Preparation method of trans-organic-inorganic hybrid perovskite solar cell

Citations (98)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2892797A (en) * 1956-02-17 1959-06-30 Du Pont Process for modifying the properties of a silica sol and product thereof
US3878034A (en) * 1970-06-25 1975-04-15 Du Pont Refractory laminate based on negative sol or silicate and positive sol
US4137217A (en) * 1972-07-01 1979-01-30 Eishun Tsuchida Polyion complex and method for preparing the same
US4181532A (en) * 1975-10-22 1980-01-01 United Kingdom Atomic Energy Authority Production of colloidal dispersions
US4410457A (en) * 1981-05-11 1983-10-18 Sumitomo Chemical Co., Ltd. Conductive paste
US4426356A (en) * 1982-09-30 1984-01-17 E. I. Du Pont De Nemours And Company Method for making capacitors with noble metal electrodes
US4446174A (en) * 1979-04-27 1984-05-01 Fuiji Photo Film Company, Ltd. Method of ink-jet recording
US4471100A (en) * 1981-01-16 1984-09-11 Nippon Shokubai Kagaku Kogyo Co., Ltd. Copolymer and method for manufacture thereof
US4818614A (en) * 1985-07-29 1989-04-04 Shiseido Company Ltd. Modified powder
US4946904A (en) * 1987-05-15 1990-08-07 Nippon Oil And Fats Co., Ltd. Additives for cement
US5021596A (en) * 1988-02-25 1991-06-04 Huels Troisdorf Aktiengesellschaft Zirconium chelates, their preparation, and their use in printing inks
US5059266A (en) * 1989-05-23 1991-10-22 Brother Kogyo Kabushiki Kaisha Apparatus and method for forming three-dimensional article
US5100984A (en) * 1989-05-17 1992-03-31 Sika Ag Vorm. Kaspar Winkler & Co. Water-soluble copolymers, a process for their preparation and their use as fluidizers in suspensions of solid matter
US5147841A (en) * 1990-11-23 1992-09-15 The United States Of America As Represented By The United States Department Of Energy Method for the preparation of metal colloids in inverse micelles and product preferred by the method
US5196199A (en) * 1990-12-14 1993-03-23 Fuisz Technologies Ltd. Hydrophilic form of perfluoro compounds and method of manufacture
US5237017A (en) * 1989-12-27 1993-08-17 Kuraray Co., Ltd. Process for producing imidized acrylic resins
US5238625A (en) * 1991-04-12 1993-08-24 Colloid Research Institute Process for preparing zirconia sols and/or zirconia forms
US5284894A (en) * 1990-02-22 1994-02-08 Basf Corporation Low-foaming latexes for use in printing ink formulations
US5344487A (en) * 1992-02-12 1994-09-06 Whalen Shaw Michael Layered composite pigments and method of making same
US5393343A (en) * 1993-09-29 1995-02-28 W. R. Grace & Co.-Conn. Cement and cement composition having improved rheological properties
US5416071A (en) * 1991-03-12 1995-05-16 Takeda Chemical Industries, Ltd. Water-soluble composition for sustained-release containing epo and hyaluronic acid
US5424466A (en) * 1992-09-25 1995-06-13 Institut Francais Du Petrole Improved process for the production of esters from fatty substances having a natural origin
US5424467A (en) * 1993-07-14 1995-06-13 Idaho Research Foundation Method for purifying alcohol esters
US5424364A (en) * 1994-05-17 1995-06-13 E. I. Du Pont De Nemours & Company Comb pigment dispersants
US5424477A (en) * 1991-04-24 1995-06-13 Mitsui Toatsu Chemicals Incorporated Preparation process of α-aspartyl-L-phenylalanine methyl ester
US5424362A (en) * 1993-04-28 1995-06-13 The Dow Chemical Company Paintable olefinic interpolymer compositions
US5429761A (en) * 1994-04-14 1995-07-04 The Lubrizol Corporation Carbonated electrorheological particles
US5516836A (en) * 1992-04-16 1996-05-14 Huels Aktiengesellschaft Method of producing aqueous polymer dispersions
US5545280A (en) * 1992-01-16 1996-08-13 Minnesota Mining And Manufacturing Company Method of selectively applying adhesive to protrusions on a substrate
US5556460A (en) * 1995-09-18 1996-09-17 W.R. Grace & Co.-Conn. Drying shrinkage cement admixture
US5597871A (en) * 1994-09-02 1997-01-28 Roehm Gmbh Chemische Fabrik Comb polymers
US5607892A (en) * 1993-02-10 1997-03-04 Rhone-Poulenc Chimie Zirconium/cerium mixed oxide catalyst/catalyst support compositions having high/stable specific surfaces
US5643247A (en) * 1993-01-21 1997-07-01 Mayo Foundation For Medical Education And Research Microparticle switching devices for use in implantable reservoirs
US5646200A (en) * 1994-06-22 1997-07-08 Tioxide Specialties Limited Compositions containing zirconium compounds
US5651986A (en) * 1994-08-02 1997-07-29 Massachusetts Institute Of Technology Controlled local delivery of chemotherapeutic agents for treating solid tumors
US5654006A (en) * 1993-02-12 1997-08-05 Mayo Foundation For Medical Education And Research Condensed-phase microparticle composition and method
US5665158A (en) * 1995-07-24 1997-09-09 W. R. Grace & Co.-Conn. Cement admixture product
US5753261A (en) * 1993-02-12 1998-05-19 Access Pharmaceuticals, Inc. Lipid-coated condensed-phase microparticle composition
US5783136A (en) * 1996-09-09 1998-07-21 Ford Global Technologies, Inc. Method of preparing a stereolithographically produced prototype for experimental stress analysis
US5800922A (en) * 1995-05-30 1998-09-01 Aluminum Company Of America Method of making a gelation-resistant alumina
US5883196A (en) * 1995-05-24 1999-03-16 Basf Aktiengesellschaft Preparation of polyalkenylsuccinic acid derivatives and their use as fuel and lubricant additives
US5891313A (en) * 1993-11-23 1999-04-06 The Perkin-Elmer Corp. Entrapment of nucleic acid sequencing template in sample mixtures by entangled polymer networks
US5957828A (en) * 1996-08-28 1999-09-28 Mitsui Mining And Smelting Co., Ltd. Silver sol, preparation thereof, coating material for forming transparent conductive film and transparent conductive film
US6015781A (en) * 1996-04-16 2000-01-18 The Procter & Gamble Company Detergent compositions containing selected mid-chain branched surfactants
US6020303A (en) * 1996-04-16 2000-02-01 The Procter & Gamble Company Mid-chain branched surfactants
US6027326A (en) * 1997-10-28 2000-02-22 Sandia Corporation Freeforming objects with low-binder slurry
US6060443A (en) * 1996-04-16 2000-05-09 The Procter & Gamble Company Mid-chain branched alkyl sulfate surfactants
US6080216A (en) * 1998-04-22 2000-06-27 3M Innovative Properties Company Layered alumina-based abrasive grit, abrasive products, and methods
US6093856A (en) * 1996-11-26 2000-07-25 The Procter & Gamble Company Polyoxyalkylene surfactants
US6103868A (en) * 1996-12-27 2000-08-15 The Regents Of The University Of California Organically-functionalized monodisperse nanocrystals of metals
US6107409A (en) * 1998-05-06 2000-08-22 Bridgestone Corporation Gels derived from extending grafted comb polymers and polypropylene via a solution synthesis
US6165406A (en) * 1999-05-27 2000-12-26 Nanotek Instruments, Inc. 3-D color model making apparatus and process
US6167910B1 (en) * 1998-01-20 2001-01-02 Caliper Technologies Corp. Multi-layer microfluidic devices
US6207749B1 (en) * 1998-04-13 2001-03-27 Massachusetts Institute Of Technology Comb copolymers for regulating cell-surface interactions
US6211249B1 (en) * 1997-07-11 2001-04-03 Life Medical Sciences, Inc. Polyester polyether block copolymers
US6228217B1 (en) * 1995-01-13 2001-05-08 Hercules Incorporated Strength of paper made from pulp containing surface active, carboxyl compounds
US6228829B1 (en) * 1997-10-14 2001-05-08 The Procter & Gamble Company Granular detergent compositions comprising mid-chain branched surfactants
US6242406B1 (en) * 1997-10-10 2001-06-05 The Procter & Gamble Company Mid-chain branched surfactants with cellulose derivatives
US6258161B1 (en) * 1998-11-04 2001-07-10 W. R. Grace & Co.-Conn. Masonry blocks and masonry concrete admixture for improved freeze-thaw durability
US6262129B1 (en) * 1998-07-31 2001-07-17 International Business Machines Corporation Method for producing nanoparticles of transition metals
US6277191B1 (en) * 1998-06-18 2001-08-21 W. R. Grace & Co.-Conn. Air entrainment with polyoxyalkylene copolymers for concrete treated with oxyalkylene SRA
WO2001078968A1 (en) * 2000-04-17 2001-10-25 Envision Technologies Gmbh Device and method for the production of three-dimensional objects
US20020016387A1 (en) * 2000-05-30 2002-02-07 Jialin Shen Material system for use in three dimensional printing
US20020015846A1 (en) * 1997-11-19 2002-02-07 Basf Aktiengesellschaft Multicomponent superabsorbent fibers
US6379974B1 (en) * 1996-11-19 2002-04-30 Caliper Technologies Corp. Microfluidic systems
US6395804B1 (en) * 1998-12-18 2002-05-28 3M Innovative Properties Company Polyelectrolyte dispersants for hydrophobic particles in water-based systems
US20020079601A1 (en) * 1996-12-20 2002-06-27 Z Corporation Method and apparatus for prototyping a three-dimensional object
US6436167B1 (en) * 1996-05-13 2002-08-20 The United States Of America As Represented By The Secretary Of The Navy Synthesis of nanostructured composite particles using a polyol process
WO2002064354A1 (en) * 2001-02-15 2002-08-22 Vantico Gmbh Three-dimensional structured printing
US6441054B1 (en) * 2000-03-02 2002-08-27 W.R. Grace & Co.-Conn Air management in cementitious mixtures having plasticizer and a clay-activity modifying agent
US20020121229A1 (en) * 1997-06-25 2002-09-05 W.R. Grace & Co.-Conn. Admixture composition for optimizing EO/PO plasticizer addition
US6451433B1 (en) * 1998-09-14 2002-09-17 Mitsubishi Materials Corporation Fine metal particle-dispersion solution and conductive film using the same
US6517199B1 (en) * 1999-11-12 2003-02-11 Canon Kabushiki Kaisha Liquid composition, ink set, colored area formation on recording medium, and ink-jet recording apparatus
US20030032727A1 (en) * 2001-07-09 2003-02-13 Sridevi Narayan-Sarathy Comb-shaped polymers having anionic functionality
US20030091647A1 (en) * 2001-11-15 2003-05-15 Lewis Jennifer A. Controlled dispersion of colloidal suspensions via nanoparticle additions
US6572673B2 (en) * 2001-06-08 2003-06-03 Chang Chun Petrochemical Co., Ltd. Process for preparing noble metal nanoparticles
US6596545B1 (en) * 1998-07-14 2003-07-22 Zyomyx, Inc. Microdevices for screening biomolecules
US6595232B2 (en) * 2001-09-28 2003-07-22 Corning, Incorporated Microfluidic device and manufacture thereof
US6599647B2 (en) * 2000-12-27 2003-07-29 Ngk Insulators, Ltd. Joined insulator body
US20030162004A1 (en) * 2001-12-17 2003-08-28 Mirkin Chard A. Patterning of solid state features by direct write nanolithographic printing
US20030177690A1 (en) * 2000-09-07 2003-09-25 Lars Wittkowski Vinylamine compounds
US6673285B2 (en) * 2000-05-12 2004-01-06 The Regents Of The University Of Michigan Reverse fabrication of porous materials
US20040076822A1 (en) * 2002-05-29 2004-04-22 Anand Jagota Fibrillar microstructure for conformal contact and adhesion
US20040096469A1 (en) * 2002-11-14 2004-05-20 Lewis Jennifer A. Controlled dispersion of colloidal suspensions by comb polymers
US6746510B2 (en) * 2001-04-02 2004-06-08 The United States Of America As Represented By The Secretary Of The Navy Processing of nanocrystalline metallic powders and coatings using the polyol process
US20040161544A1 (en) * 2003-01-09 2004-08-19 Kasperchik Vladek P. Freeform fabrication low density material systems
US20050004261A1 (en) * 2003-04-07 2005-01-06 Seiko Epson Corporation Aqueous ink composition and method of manufacturing the same
US6861205B2 (en) * 2002-02-06 2005-03-01 Battelle Memorial Institute Three dimensional microstructures and method of making
US6878184B1 (en) * 2002-08-09 2005-04-12 Kovio, Inc. Nanoparticle synthesis and the formation of inks therefrom
US6929675B1 (en) * 2003-04-24 2005-08-16 Sandia Corporation Synthesis metal nanoparticle
US6936746B2 (en) * 2000-01-27 2005-08-30 Paul Hartmann Ag Polyelectrolyte solid system, method for the production thereof and a wound dressing
US20050189520A1 (en) * 2004-03-01 2005-09-01 Sumitomo Electric Industries, Ltd. Metallic colloidal solution and inkjet-use metallic ink
US20050196605A1 (en) * 2004-03-08 2005-09-08 Ecology Coatings, Inc. Environmentally friendly coating compositions for coating metal objects, coated objects therefrom, and methods, processes and assemblages for coating thereof
US6942825B2 (en) * 2001-10-31 2005-09-13 Fujikura Kasei Co., Ltd. Silver compound paste
US7081322B2 (en) * 2003-03-27 2006-07-25 Kodak Graphics Communications Canada Company Nanopastes as ink-jet compositions for printing plates
US7160525B1 (en) * 2003-10-14 2007-01-09 The Board Of Trustees Of The University Of Arkansas Monodisperse noble metal nanocrystals
US7198736B2 (en) * 2004-03-03 2007-04-03 Sumitomo Electric Industries, Ltd. Conductive silver paste and conductive film formed using the same
US20070172588A1 (en) * 2002-09-26 2007-07-26 Daniel Therriault Microcapillary networks

Family Cites Families (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3546142A (en) * 1967-01-19 1970-12-08 Amicon Corp Polyelectrolyte structures
DE2052749C3 (en) 1970-10-28 1974-09-12 Deutsche Gold- Und Silber-Scheideanstalt Vormals Roessler, 6000 Frankfurt Process for the production of ductile gold and ductile gold alloys with high hardness and high-temperature tensile strength
JPS53106682A (en) 1977-03-01 1978-09-16 Hitachi Ltd Supporting method for hydrated metal oxide on carrier
US4414354A (en) 1977-06-16 1983-11-08 Monsanto Company Aqueous polymeric latex coating compositions, products produced thereby, methods for preparing such compositions, and methods for using such compositions
AU534964B2 (en) 1980-11-05 1984-02-23 Square D Company Contact material and method of making
JPS57201700A (en) 1981-03-03 1982-12-10 Shii Fuitsushiyaa Pooru Ball pen marking tool and its ink composition
IE54772B1 (en) 1982-05-14 1990-01-31 Johnson Matthey Plc Compositions comprising inorganic particles
JPH0725689B2 (en) 1986-10-07 1995-03-22 中外製薬株式会社 Sustained-release preparation containing granulocyte colony-stimulating factor
US4960465A (en) 1986-12-09 1990-10-02 W. R. Grace & Co. Hydraulic cement additives and hydraulic cement compositions containing same
KR0159921B1 (en) * 1988-10-03 1999-01-15 마이클 비. 키한 A composition comprising cathionic and anionic polymer process thereof
DK168738B1 (en) 1991-04-30 1994-05-30 Topsoe Haldor As Ceramic binder, manufacture and use thereof
US5965194A (en) 1992-01-10 1999-10-12 Imation Corp. Magnetic recording media prepared from magnetic particles having an extremely thin, continuous, amorphous, aluminum hydrous oxide coating
AT399340B (en) 1993-02-01 1995-04-25 Chemie Linz Gmbh COPOLYMERS BASED ON MALEINIC ACID DERIVATIVES AND VINYL MONOMERS, THEIR PRODUCTION AND USE
US5820879A (en) 1993-02-12 1998-10-13 Access Pharmaceuticals, Inc. Method of delivering a lipid-coated condensed-phase microparticle composition
GB9407246D0 (en) 1994-04-13 1994-06-08 Sandoz Ltd Improvements in or relating to organic compounds
SE505386C2 (en) * 1995-11-29 1997-08-18 Akzo Nobel Surface Chem Polyelektrolytkomposition
EG22088A (en) 1996-04-16 2002-07-31 Procter & Gamble Alkoxylated sulfates
MA25183A1 (en) 1996-05-17 2001-07-02 Arthur Jacques Kami Christiaan DETERGENT COMPOSITIONS
US5958858A (en) 1996-06-28 1999-09-28 The Procter & Gamble Company Low anionic surfactant detergent compositions
US5711958A (en) 1996-07-11 1998-01-27 Life Medical Sciences, Inc. Methods for reducing or eliminating post-surgical adhesion formation
US6465257B1 (en) 1996-11-19 2002-10-15 Caliper Technologies Corp. Microfluidic systems
JP2001509127A (en) 1997-01-21 2001-07-10 ダブリユ・アール・グレイス・アンド・カンパニー・コネテイカツト Emulsified comb polymer and defoamer composition and method for preparing the same
US5780525A (en) 1997-02-14 1998-07-14 Reliance Electric Industrial Company Photocurable composition for electrical insulation
US6133227A (en) 1997-06-23 2000-10-17 The Procter & Gamble Company Enzymatic detergent compositions
US6127094A (en) 1997-10-02 2000-10-03 Napp Systems Inc. Acrylate copolymer-containing water-developable photosensitive resins and printing plates prepared therefrom
CN1297462A (en) 1998-03-07 2001-05-30 贝耶尔德夫公司 Sulfonated comb polymers and preparations, especially hair cosmetic preparations based on such sulfonated comb polymers
US6613234B2 (en) 1998-04-06 2003-09-02 Ciphergen Biosystems, Inc. Large pore volume composite mineral oxide beads, their preparation and their applications for adsorption and chromatography
US6602994B1 (en) 1999-02-10 2003-08-05 Hercules Incorporated Derivatized microfibrillar polysaccharide
JP2001269859A (en) 2000-03-27 2001-10-02 Jsr Corp Aqueous dispersing element for polishing chemical machine
EP1276824A4 (en) 2000-04-21 2005-03-16 Stc Unm Prototyping of patterned functional nanostructures
US6645432B1 (en) 2000-05-25 2003-11-11 President & Fellows Of Harvard College Microfluidic systems including three-dimensionally arrayed channel networks
EP1339777A2 (en) 2000-09-11 2003-09-03 Massachusetts Institute Of Technology Graft copolymers, methods for grafting hydrophilic chains onto hydrophobic polymers, and articles thereof
US6418968B1 (en) 2001-04-20 2002-07-16 Nanostream, Inc. Porous microfluidic valves
US6656410B2 (en) 2001-06-22 2003-12-02 3D Systems, Inc. Recoating system for using high viscosity build materials in solid freeform fabrication
US6645444B2 (en) 2001-06-29 2003-11-11 Nanospin Solutions Metal nanocrystals and synthesis thereof
KR100746067B1 (en) 2002-11-13 2007-08-03 닛뽕소다 가부시키가이샤 Dispersoid having metal-oxygen bond, metal oxide film, and monomolecular film
US6974493B2 (en) 2002-11-26 2005-12-13 Honda Motor Co., Ltd. Method for synthesis of metal nanoparticles
US7141617B2 (en) 2003-06-17 2006-11-28 The Board Of Trustees Of The University Of Illinois Directed assembly of three-dimensional structures with micron-scale features
KR100539392B1 (en) * 2003-08-12 2005-12-27 (주)해은켐텍 The Polyelectrolyte composition for humidity sensor, Polyelectrolyte ink and preparation method of Polyelectrolyte membrane for humidity sensor by inkjet printing
US7956102B2 (en) 2007-04-09 2011-06-07 The Board Of Trustees Of The University Of Illinois Sol-gel inks

Patent Citations (103)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2892797A (en) * 1956-02-17 1959-06-30 Du Pont Process for modifying the properties of a silica sol and product thereof
US3878034A (en) * 1970-06-25 1975-04-15 Du Pont Refractory laminate based on negative sol or silicate and positive sol
US4137217A (en) * 1972-07-01 1979-01-30 Eishun Tsuchida Polyion complex and method for preparing the same
US4181532A (en) * 1975-10-22 1980-01-01 United Kingdom Atomic Energy Authority Production of colloidal dispersions
US4446174A (en) * 1979-04-27 1984-05-01 Fuiji Photo Film Company, Ltd. Method of ink-jet recording
US4471100A (en) * 1981-01-16 1984-09-11 Nippon Shokubai Kagaku Kogyo Co., Ltd. Copolymer and method for manufacture thereof
US4410457A (en) * 1981-05-11 1983-10-18 Sumitomo Chemical Co., Ltd. Conductive paste
US4426356A (en) * 1982-09-30 1984-01-17 E. I. Du Pont De Nemours And Company Method for making capacitors with noble metal electrodes
US4818614A (en) * 1985-07-29 1989-04-04 Shiseido Company Ltd. Modified powder
US4946904A (en) * 1987-05-15 1990-08-07 Nippon Oil And Fats Co., Ltd. Additives for cement
US5021596A (en) * 1988-02-25 1991-06-04 Huels Troisdorf Aktiengesellschaft Zirconium chelates, their preparation, and their use in printing inks
US5100984A (en) * 1989-05-17 1992-03-31 Sika Ag Vorm. Kaspar Winkler & Co. Water-soluble copolymers, a process for their preparation and their use as fluidizers in suspensions of solid matter
US5059266A (en) * 1989-05-23 1991-10-22 Brother Kogyo Kabushiki Kaisha Apparatus and method for forming three-dimensional article
US5237017A (en) * 1989-12-27 1993-08-17 Kuraray Co., Ltd. Process for producing imidized acrylic resins
US5284894A (en) * 1990-02-22 1994-02-08 Basf Corporation Low-foaming latexes for use in printing ink formulations
US5147841A (en) * 1990-11-23 1992-09-15 The United States Of America As Represented By The United States Department Of Energy Method for the preparation of metal colloids in inverse micelles and product preferred by the method
US5196199A (en) * 1990-12-14 1993-03-23 Fuisz Technologies Ltd. Hydrophilic form of perfluoro compounds and method of manufacture
US5416071A (en) * 1991-03-12 1995-05-16 Takeda Chemical Industries, Ltd. Water-soluble composition for sustained-release containing epo and hyaluronic acid
US5238625A (en) * 1991-04-12 1993-08-24 Colloid Research Institute Process for preparing zirconia sols and/or zirconia forms
US5424477A (en) * 1991-04-24 1995-06-13 Mitsui Toatsu Chemicals Incorporated Preparation process of α-aspartyl-L-phenylalanine methyl ester
US5545280A (en) * 1992-01-16 1996-08-13 Minnesota Mining And Manufacturing Company Method of selectively applying adhesive to protrusions on a substrate
US5344487A (en) * 1992-02-12 1994-09-06 Whalen Shaw Michael Layered composite pigments and method of making same
US5516836A (en) * 1992-04-16 1996-05-14 Huels Aktiengesellschaft Method of producing aqueous polymer dispersions
US5424466A (en) * 1992-09-25 1995-06-13 Institut Francais Du Petrole Improved process for the production of esters from fatty substances having a natural origin
US5643247A (en) * 1993-01-21 1997-07-01 Mayo Foundation For Medical Education And Research Microparticle switching devices for use in implantable reservoirs
US5607892A (en) * 1993-02-10 1997-03-04 Rhone-Poulenc Chimie Zirconium/cerium mixed oxide catalyst/catalyst support compositions having high/stable specific surfaces
US5811124A (en) * 1993-02-12 1998-09-22 Mayo Foundation For Medical Education And Research Microparticles with high drug loading
US5753261A (en) * 1993-02-12 1998-05-19 Access Pharmaceuticals, Inc. Lipid-coated condensed-phase microparticle composition
US5654006A (en) * 1993-02-12 1997-08-05 Mayo Foundation For Medical Education And Research Condensed-phase microparticle composition and method
US5424362A (en) * 1993-04-28 1995-06-13 The Dow Chemical Company Paintable olefinic interpolymer compositions
US5424467A (en) * 1993-07-14 1995-06-13 Idaho Research Foundation Method for purifying alcohol esters
US5393343A (en) * 1993-09-29 1995-02-28 W. R. Grace & Co.-Conn. Cement and cement composition having improved rheological properties
US6051636A (en) * 1993-11-23 2000-04-18 The Perkin-Elmer Corporation Entrapment of nucleic acid sequencing template in sample mixtures by entangled polymer networks
US5891313A (en) * 1993-11-23 1999-04-06 The Perkin-Elmer Corp. Entrapment of nucleic acid sequencing template in sample mixtures by entangled polymer networks
US5429761A (en) * 1994-04-14 1995-07-04 The Lubrizol Corporation Carbonated electrorheological particles
US5424364A (en) * 1994-05-17 1995-06-13 E. I. Du Pont De Nemours & Company Comb pigment dispersants
US5646200A (en) * 1994-06-22 1997-07-08 Tioxide Specialties Limited Compositions containing zirconium compounds
US5651986A (en) * 1994-08-02 1997-07-29 Massachusetts Institute Of Technology Controlled local delivery of chemotherapeutic agents for treating solid tumors
US5597871A (en) * 1994-09-02 1997-01-28 Roehm Gmbh Chemische Fabrik Comb polymers
US6228217B1 (en) * 1995-01-13 2001-05-08 Hercules Incorporated Strength of paper made from pulp containing surface active, carboxyl compounds
US5883196A (en) * 1995-05-24 1999-03-16 Basf Aktiengesellschaft Preparation of polyalkenylsuccinic acid derivatives and their use as fuel and lubricant additives
US5800922A (en) * 1995-05-30 1998-09-01 Aluminum Company Of America Method of making a gelation-resistant alumina
US5665158A (en) * 1995-07-24 1997-09-09 W. R. Grace & Co.-Conn. Cement admixture product
US5556460A (en) * 1995-09-18 1996-09-17 W.R. Grace & Co.-Conn. Drying shrinkage cement admixture
US6060443A (en) * 1996-04-16 2000-05-09 The Procter & Gamble Company Mid-chain branched alkyl sulfate surfactants
US6015781A (en) * 1996-04-16 2000-01-18 The Procter & Gamble Company Detergent compositions containing selected mid-chain branched surfactants
US6020303A (en) * 1996-04-16 2000-02-01 The Procter & Gamble Company Mid-chain branched surfactants
US6436167B1 (en) * 1996-05-13 2002-08-20 The United States Of America As Represented By The Secretary Of The Navy Synthesis of nanostructured composite particles using a polyol process
US5957828A (en) * 1996-08-28 1999-09-28 Mitsui Mining And Smelting Co., Ltd. Silver sol, preparation thereof, coating material for forming transparent conductive film and transparent conductive film
US5783136A (en) * 1996-09-09 1998-07-21 Ford Global Technologies, Inc. Method of preparing a stereolithographically produced prototype for experimental stress analysis
US6379974B1 (en) * 1996-11-19 2002-04-30 Caliper Technologies Corp. Microfluidic systems
US6093856A (en) * 1996-11-26 2000-07-25 The Procter & Gamble Company Polyoxyalkylene surfactants
US20020079601A1 (en) * 1996-12-20 2002-06-27 Z Corporation Method and apparatus for prototyping a three-dimensional object
US6103868A (en) * 1996-12-27 2000-08-15 The Regents Of The University Of California Organically-functionalized monodisperse nanocrystals of metals
US20020121229A1 (en) * 1997-06-25 2002-09-05 W.R. Grace & Co.-Conn. Admixture composition for optimizing EO/PO plasticizer addition
US6211249B1 (en) * 1997-07-11 2001-04-03 Life Medical Sciences, Inc. Polyester polyether block copolymers
US6242406B1 (en) * 1997-10-10 2001-06-05 The Procter & Gamble Company Mid-chain branched surfactants with cellulose derivatives
US6228829B1 (en) * 1997-10-14 2001-05-08 The Procter & Gamble Company Granular detergent compositions comprising mid-chain branched surfactants
US6027326A (en) * 1997-10-28 2000-02-22 Sandia Corporation Freeforming objects with low-binder slurry
US20020015846A1 (en) * 1997-11-19 2002-02-07 Basf Aktiengesellschaft Multicomponent superabsorbent fibers
US6167910B1 (en) * 1998-01-20 2001-01-02 Caliper Technologies Corp. Multi-layer microfluidic devices
US6207749B1 (en) * 1998-04-13 2001-03-27 Massachusetts Institute Of Technology Comb copolymers for regulating cell-surface interactions
US6080216A (en) * 1998-04-22 2000-06-27 3M Innovative Properties Company Layered alumina-based abrasive grit, abrasive products, and methods
US6107409A (en) * 1998-05-06 2000-08-22 Bridgestone Corporation Gels derived from extending grafted comb polymers and polypropylene via a solution synthesis
US6277191B1 (en) * 1998-06-18 2001-08-21 W. R. Grace & Co.-Conn. Air entrainment with polyoxyalkylene copolymers for concrete treated with oxyalkylene SRA
US6596545B1 (en) * 1998-07-14 2003-07-22 Zyomyx, Inc. Microdevices for screening biomolecules
US6262129B1 (en) * 1998-07-31 2001-07-17 International Business Machines Corporation Method for producing nanoparticles of transition metals
US6451433B1 (en) * 1998-09-14 2002-09-17 Mitsubishi Materials Corporation Fine metal particle-dispersion solution and conductive film using the same
US6258161B1 (en) * 1998-11-04 2001-07-10 W. R. Grace & Co.-Conn. Masonry blocks and masonry concrete admixture for improved freeze-thaw durability
US6395804B1 (en) * 1998-12-18 2002-05-28 3M Innovative Properties Company Polyelectrolyte dispersants for hydrophobic particles in water-based systems
US6165406A (en) * 1999-05-27 2000-12-26 Nanotek Instruments, Inc. 3-D color model making apparatus and process
US6517199B1 (en) * 1999-11-12 2003-02-11 Canon Kabushiki Kaisha Liquid composition, ink set, colored area formation on recording medium, and ink-jet recording apparatus
US6936746B2 (en) * 2000-01-27 2005-08-30 Paul Hartmann Ag Polyelectrolyte solid system, method for the production thereof and a wound dressing
US6441054B1 (en) * 2000-03-02 2002-08-27 W.R. Grace & Co.-Conn Air management in cementitious mixtures having plasticizer and a clay-activity modifying agent
US20030090034A1 (en) * 2000-04-17 2003-05-15 Muelhaupt Rolf Device and method for the production of three-dimensional objects
WO2001078968A1 (en) * 2000-04-17 2001-10-25 Envision Technologies Gmbh Device and method for the production of three-dimensional objects
US6673285B2 (en) * 2000-05-12 2004-01-06 The Regents Of The University Of Michigan Reverse fabrication of porous materials
US20020016387A1 (en) * 2000-05-30 2002-02-07 Jialin Shen Material system for use in three dimensional printing
US20030177690A1 (en) * 2000-09-07 2003-09-25 Lars Wittkowski Vinylamine compounds
US6599647B2 (en) * 2000-12-27 2003-07-29 Ngk Insulators, Ltd. Joined insulator body
WO2002064354A1 (en) * 2001-02-15 2002-08-22 Vantico Gmbh Three-dimensional structured printing
US6746510B2 (en) * 2001-04-02 2004-06-08 The United States Of America As Represented By The Secretary Of The Navy Processing of nanocrystalline metallic powders and coatings using the polyol process
US6572673B2 (en) * 2001-06-08 2003-06-03 Chang Chun Petrochemical Co., Ltd. Process for preparing noble metal nanoparticles
US20030032727A1 (en) * 2001-07-09 2003-02-13 Sridevi Narayan-Sarathy Comb-shaped polymers having anionic functionality
US6595232B2 (en) * 2001-09-28 2003-07-22 Corning, Incorporated Microfluidic device and manufacture thereof
US6942825B2 (en) * 2001-10-31 2005-09-13 Fujikura Kasei Co., Ltd. Silver compound paste
US20030091647A1 (en) * 2001-11-15 2003-05-15 Lewis Jennifer A. Controlled dispersion of colloidal suspensions via nanoparticle additions
US20030162004A1 (en) * 2001-12-17 2003-08-28 Mirkin Chard A. Patterning of solid state features by direct write nanolithographic printing
US6861205B2 (en) * 2002-02-06 2005-03-01 Battelle Memorial Institute Three dimensional microstructures and method of making
US20040076822A1 (en) * 2002-05-29 2004-04-22 Anand Jagota Fibrillar microstructure for conformal contact and adhesion
US6878184B1 (en) * 2002-08-09 2005-04-12 Kovio, Inc. Nanoparticle synthesis and the formation of inks therefrom
US20090000678A1 (en) * 2002-09-26 2009-01-01 Daniel Therriault Microcapillary networks
US20070172588A1 (en) * 2002-09-26 2007-07-26 Daniel Therriault Microcapillary networks
US20040096469A1 (en) * 2002-11-14 2004-05-20 Lewis Jennifer A. Controlled dispersion of colloidal suspensions by comb polymers
US7053125B2 (en) * 2002-11-14 2006-05-30 The Board Of Trustees Of The University Of Illinois Controlled dispersion of colloidal suspension by comb polymers
US20040161544A1 (en) * 2003-01-09 2004-08-19 Kasperchik Vladek P. Freeform fabrication low density material systems
US7081322B2 (en) * 2003-03-27 2006-07-25 Kodak Graphics Communications Canada Company Nanopastes as ink-jet compositions for printing plates
US20050004261A1 (en) * 2003-04-07 2005-01-06 Seiko Epson Corporation Aqueous ink composition and method of manufacturing the same
US6929675B1 (en) * 2003-04-24 2005-08-16 Sandia Corporation Synthesis metal nanoparticle
US7160525B1 (en) * 2003-10-14 2007-01-09 The Board Of Trustees Of The University Of Arkansas Monodisperse noble metal nanocrystals
US20050189520A1 (en) * 2004-03-01 2005-09-01 Sumitomo Electric Industries, Ltd. Metallic colloidal solution and inkjet-use metallic ink
US7198736B2 (en) * 2004-03-03 2007-04-03 Sumitomo Electric Industries, Ltd. Conductive silver paste and conductive film formed using the same
US20050196605A1 (en) * 2004-03-08 2005-09-08 Ecology Coatings, Inc. Environmentally friendly coating compositions for coating metal objects, coated objects therefrom, and methods, processes and assemblages for coating thereof

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
J. Jiyou Guo and Jennifer A. Lewis; Aggregration Effects on the Compressive Flow Properties and Drying Behavior of Colloidal Silica Suspensions; 1999; Journal of the American Ceramic Society; Volume 82 No. 9; Page 2347 *
Sherry L. Morissette and Jennifer A. Lewis; Solid Freeform Fabrication of Aqueous Alumina-Poly(vinyl alcohol) Gelcasting Suspensions; 2000; Journal of the American Ceramic Society; Volume 82 No. 10; Pages 2409-2411 *
Smay et al.; Directed Colloidal Assembly of 3D Periodic Structures; 2002; Advanced Materials; Volume 14 No.18; Pages 1279-1281 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060198959A1 (en) * 2003-07-31 2006-09-07 Kazuhiro Murata Method of producing a three-dimensional structure and fine three-dimensional structure
US8021593B2 (en) * 2003-07-31 2011-09-20 Sijtechnology, Inc. Method of producing a three-dimensional structure and fine three-dimensional structure
US9643358B2 (en) 2011-07-01 2017-05-09 The Board Of Trustees Of The University Of Illinois Multinozzle deposition system for direct write applications
US10462907B2 (en) 2013-06-24 2019-10-29 President And Fellows Of Harvard College Printed three-dimensional (3D) functional part and method of making
US10117968B2 (en) 2013-11-05 2018-11-06 President And Fellows Of Harvard College Method of printing a tissue construct with embedded vasculature
US10151649B2 (en) 2013-11-18 2018-12-11 President And Fellows Of Harvard College Printed stretchable strain sensor
US10612986B2 (en) 2013-11-18 2020-04-07 President And Fellows Of Harvard College Printed stretchable strain sensor
US10597545B2 (en) 2015-05-18 2020-03-24 President And Fellows Of Harvard College Foam ink composition and 3D printed hierarchical porous structure
US11207831B2 (en) 2016-12-08 2021-12-28 President And Fellows Of Harvard College 3D printed core-shell filament and method of 3D printing a core-shell filament
US11492547B2 (en) 2020-06-04 2022-11-08 UbiQD, Inc. Low-PH nanoparticles and ligands

Also Published As

Publication number Publication date
WO2005000977A3 (en) 2005-03-31
CN1826393A (en) 2006-08-30
US7790061B2 (en) 2010-09-07
DE112004001096B4 (en) 2017-11-02
US7141617B2 (en) 2006-11-28
DE112004001096T5 (en) 2006-10-26
GB2418918A (en) 2006-04-12
US20070228335A1 (en) 2007-10-04
WO2005000977A2 (en) 2005-01-06
US20060235105A1 (en) 2006-10-19
GB0525788D0 (en) 2006-01-25
GB2418918B (en) 2008-07-09

Similar Documents

Publication Publication Date Title
US7790061B2 (en) Directed assembly of three-dimensional structures with micron-scale features
Zheng et al. Polymer nano-and microspheres with bumpy and chain-segregated surfaces
Wan et al. Fibers by interfacial polyelectrolyte complexation–processes, materials and applications
Dankers et al. A modular and supramolecular approach to bioactive scaffolds for tissue engineering
Chronakis et al. Generation of molecular recognition sites in electrospun polymer nanofibers via molecular imprinting
Varga et al. Effect of cross-link density on the internal structure of poly (N-isopropylacrylamide) microgels
Ke et al. Controllable construction of carbohydrate microarrays by site-directed grafting on self-organized porous films
Subramanian et al. Preparation and evaluation of the electrospun chitosan/PEO fibers for potential applications in cartilage tissue engineering
Petrov et al. Base− acid equilibria in polyelectrolyte systems: From weak polyelectrolytes to interpolyelectrolyte complexes and multilayered polyelectrolyte shells
Dakhara et al. Polyelectrolyte Complex: A Pharmaceutical Review.
Chen et al. Fabrication of polymer nanopeapods in the nanopores of anodic aluminum oxide templates using a double-solution wetting method
Cutright et al. Surface‐bound microgels for separation, sensing, and biomedical applications
Vitale et al. Tuning porosity and functionality of electrospun rubber nanofiber mats by photo-crosslinking
Cui et al. Wet‐spinning of biocompatible core–shell polyelectrolyte complex fibers for tissue engineering
Kalaoglu-Altan et al. Reactive and ‘clickable’electrospun polymeric nanofibers
Otoni et al. Charge matters: electrostatic complexation as a green approach to assemble advanced functional materials
Penfold et al. Layer-by-layer self-assembly of polyelectrolytic block copolymer worms on a planar substrate
Ferrara et al. Aqueous processed biopolymer interfaces for single-cell microarrays
Meyer et al. Chitosan-coated wires: conferring electrical properties to chitosan fibers
Teixeira Jr et al. Nucleo-copolymers: oligonucleotide-based amphiphilic diblock copolymers
Zhang et al. Dynamic hydrogels based on double imine connections and application for delivery of fluorouracil
Zhang et al. Bioactive galactose-branched polyelectrolyte multilayers and microcapsules: self-assembly, characterization, and biospecific lectin adsorption
CN113083172A (en) Nucleic acid hydrogel with improved mechanical properties and preparation method and application thereof
Kim et al. Fabrication of biomimetic bundled gel fibres using dynamic microfluidic gelation of phase-separated polymer solutions
Choi et al. Methods and applications of biomolecular surface coatings on individual cells

Legal Events

Date Code Title Description
AS Assignment

Owner name: BOARD OF TRUSTEES OF UNIVERSITY OF ILLINOIS, ILLIN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GRATSON, GREGORY;LEWIS, JENNIFER A.;REEL/FRAME:024954/0232

Effective date: 20030930

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION