CN110625933A

CN110625933A - Method for in-situ construction of composite flexible micro-nano device based on laser direct writing technology

Info

Publication number: CN110625933A
Application number: CN201910804001.4A
Authority: CN
Inventors: 吴苏州; 杨高洁; 李晓云
Original assignee: SHENZHEN JINGLAI NEW MATERIAL TECHNOLOGY Co Ltd
Current assignee: SHENZHEN JINGLAI NEW MATERIAL TECHNOLOGY Co Ltd
Priority date: 2019-08-28
Filing date: 2019-08-28
Publication date: 2019-12-31
Anticipated expiration: 2039-08-28
Also published as: CN110625933B

Abstract

The invention relates to the field of micro-nano device technology and laser micro-manufacturing, and mainly relates to a method for constructing a composite flexible micro-nano device in situ based on a laser direct writing technology. According to the principle that different fluorescent molecules are excited by different electron transitions and the intensity of pulse laser is different, a novel method for constructing different structural domains of a composite micro-nano device in situ in a flexible material by utilizing a two-photon laser direct writing technology is adopted, two types of fluorophore solutions with different active groups are respectively used for processing hydrogel, and high-energy and low-energy two-photon pulse laser excitation is respectively carried out according to designed micro patterns so as to polymerize on a hydrogel substrate; and then, processing the micro-pattern by using two nano materials which can be respectively combined with the groups, so that the micro-pattern is specifically and selectively combined in different areas, and then, dehydrating and reducing the micro-pattern to form a micro-nano composite device structure. The method can construct the composite flexible micro-nano device in one step, and has the advantages of simple process, high forming efficiency, high processing fineness and wide application prospect.

Description

Method for in-situ construction of composite flexible micro-nano device based on laser direct writing technology

Technical Field

The invention belongs to the fields of micro-nano device technology and laser micro-manufacturing, and relates to a method for constructing a composite flexible micro-nano device in situ based on a laser direct writing technology.

Background

The metal material with the special micro-nano structure can show important application prospects in the fields of metamaterials, electronic devices, nano-photonic devices, catalysis and the like by virtue of unique optical and electrical properties of the metal material. At present, the controllable preparation method of the metal micro-nano structure comprises chemical synthesis, self-assembly, photoetching, focused ion beam processing, 3D printing and the like. However, these processing methods also have some disadvantages in controllable preparation and integration, fineness, multi-material complex structure, and the like, and face huge challenges.

At present, a multiphoton femtosecond pulse laser direct writing technology is used as an advanced three-dimensional micro-nano manufacturing and processing means, controllable processing of three-dimensional micro-nano structures of various materials is realized, and the unique advantages of easiness in integration, no mask, designability of any shape, high resolution, capability of obtaining micro-nano scale processing resolution in an ultrafast process and the like are displayed. The rapid development of the femtosecond laser direct writing technology promotes the preparation of the functional metal micro-nano device, and the device is rapidly developed and widely applied in the fields of bioengineering, aerospace, national defense and the like in recent years.

However, until now, the multiphoton femtosecond pulse laser direct writing technology can process only a single material at a time or simply mix two materials and then process them, and it is difficult to realize fine manufacture of two or more different materials in a single processing process. If various complex device units can be quickly constructed on a micro-nano scale, the method has great application value in the fields of development of optoelectronic devices, nano elements, sensors, biomedicine and the like.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for constructing a composite flexible micro-nano device in situ based on a laser direct writing technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for constructing a composite flexible micro-nano device in situ based on a laser direct writing technology is characterized in that the composite flexible micro-nano device is formed by printing a micro structure area capable of polymerizing different nano particles and high molecular components in a flexible substrate by utilizing a two-photon laser direct writing technology.

The method for constructing the composite flexible micro-nano device in situ based on the laser direct writing technology is characterized by comprising the following specific steps of:

(1) preparation of hydrogel substrate flexible material: mixing the hydrogel precursor solution with a cross-linking agent, a catalyst and an initiator, placing the mixture at the temperature of 10-37 ℃ to form gel, and placing the gel in pure water to expand to be several times of volume;

(2) preparing a model file of a structural region combined by different materials through drawing software, and importing the model file into imaging software;

(3) 3D two-photon laser printing for the first time: placing the expanded hydrogel in a high-excitation-state functional fluorophore solution for 1 hour to enable the dye to completely permeate into the hydrogel, then placing the hydrogel on a femtosecond laser two-photon processing platform, controlling the platform to move by using software, and combining the first fluorophore molecules on a hydrogel framework by using a high laser intensity and using 780nm wavelength femtosecond laser as a light source and 128mW laser power to design a 3D structure by using a two-photon laser direct writing technology;

(4) and 3D two-photon laser printing for the second time: after the hydrogel is continuously treated by the functional fluorophore solution in the low excitation state for 30 minutes, the designed pattern is printed on the substrate by femtosecond laser with 780nm wavelength by using a two-photon laser direct writing technology, and the second fluorophore molecule is combined on the hydrogel framework with low laser intensity;

(5) washing hydrogel with pure water for multiple times to remove residual fluorophore molecules, sequentially adding high molecules or nanoparticles capable of reacting with the active groups of the fluorophore molecules, and incubating for 1-3 hr to selectively combine different particles in situ;

(6) and then washing the hydrogel for multiple times by using pure water to remove residual high molecules or nano particles, immersing the hydrogel in an acid solution by utilizing heterogeneous isotropy, shrinking, drying and dehydrating to obtain a concentrated and polymerized nano particle micro-nano pattern structure, wherein the concentrated and polymerized nano particle micro-nano pattern structure can be used for connecting a composite flexible micro-nano device between electrodes.

In the above scheme, the hydrogel precursor solution described in step (1) is a mixed solution of acrylamide, sodium acrylate, sodium chloride, PBS and pure water, wherein the sodium chloride concentration is 2M, and a mixed solution in which 2mL of 10 × PBS and 3.5mL of pure water are uniformly mixed, wherein the acrylamide and the sodium acrylate concentration is 1-30%, and the mass ratio is 1: 5-5: 1; or natural polymer hydrogel solution such as methyl propylene sodium hyaluronate, collagen, fibroin, gelatin, etc.; the concentration is 5-20% (w/v).

In the above scheme, the cross-linking agent in step (1) is N, N' -methylenebisacrylamide, and the concentration of the cross-linking agent in the mixed solution is 0.01-1% (w/w); the catalyst is ammonium persulfate, and the concentration of the ammonium persulfate in the mixed solution is 0.1-0.5% (w/w); initiator tetramethylethylenediamine, the concentration of which in the mixed solution is 0.1-0.5% (v/v).

In the above scheme, the high excited state functional fluorophore in step (3) is activated NH₂One of the aflame, Azide, DBCO, SH, Biotin-AFdye, Cy5 fluorophore molecules, or Biotin-4-fluorochein; fluorophore concentration of 100. mu.M-200. mu.M;

in the above scheme, the functional fluorophore with low excited state in step (4) is NH-carrying₂One of Fluorescein, Cy3, Melamine-, Azide-, DBCO-, SH-; fluorophore concentration 500. mu.M-2 mM;

in the scheme, the high laser intensity in the step (3) is within the range of 12-20% of the output laser intensity; the low laser intensity in the step (4) is within the range of 5-9% of the output laser intensity, so that the functional fluorophore with a high excitation state for the first printing cannot be excited during the second laser printing;

in the above scheme, the polymer or nanoparticle in step (5) is two of antibody, protein, DNA, or nanoparticles such as graphene, CNT, Qdots, nanogold, nanosilver, etc., and has corresponding structural units capable of reacting with the active group of fluorophore molecule, i.e. NHS-, SH-, DBCO-, Azide-, Melamine-, Streptavidin-;

in the scheme, the acidic solution in the step (6) is one of hydrochloric acid, acetic acid and citric acid, and the concentration is 0.5-1M.

The invention has the following beneficial effects: (1) according to the in-situ construction composite flexible micro-nano device based on the laser direct writing technology, two micro-pattern structures made of completely different materials can be formed in situ at one time only by simply adjusting the intensity of two-photon laser, the crosstalk among material patterns is small, and the selective combination of different materials in different areas can be perfectly achieved; (2) the forming process is simple, the forming can be directly carried out without a mask or a die, the forming efficiency is high, and the processing fineness can reach the micro-nano scale; (3) the method for constructing the composite flexible micro-nano device in situ can quickly form micro-nano device units with different materials and different properties on the flexible substrate, has small limitation on the used materials, and has huge application prospect in the aspects of developing complex flexible photoelectronic devices, nano elements, biosensors and the like.

Drawings

Fig. 1 is a fluorescence image of a composite pattern of Qdot and nanogold constructed in example 1 of the present invention, demonstrating that two materials can be successfully and selectively bound at different sites, and that two materials can be bound at overlapping sites.

Fig. 2 is a fluorescence diagram of the graphene and nano-silicon composite micro-nano device unit prepared in situ in example 2.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.

Example 1

An in-situ constructed composite micro-nano structure unit based on a laser direct writing technology can be prepared by the following method:

(1) preparing a hydrogel precursor solution, namely uniformly mixing 3.5g of sodium acrylate, 1g of acrylamide, 3mg of N, N' -methylene bisacrylamide, 8mL of 2M sodium chloride, 2mL of 10xPBS and 3.5mL of pure water; then 1mL of the precursor solution is taken and mixed with 20 mu L of 10% (v/v) tetramethylethylenediamine and 20 mu L of 10% (w/v) ammonium persulfate, the mixture is placed at 37 ℃ to react for 1 hour to form gel, and the gel is placed in pure water to swell;

(2) cutting the expanded hydrogel into square blocks with the side length of 2cm, placing the square blocks in a Biotin-4-fluoroescein solution with the concentration of 200 mu M for 1 hour, placing the square blocks on a femtosecond laser two-photon processing platform, controlling the platform to move by using software, taking a femtosecond laser with the wavelength of 780nm as a light source according to a designed square structure, taking the femtosecond laser as the light source, and printing fluorophore molecules on a hydrogel framework, wherein the femtosecond laser has the excitation light intensity of 16%;

(3) then, directly covering 500 mu M of Cy3-amine fluorescent solution on the surface of the hydrogel, after the fluorescent solution completely infiltrates into the hydrogel for 30 minutes, carrying out femtosecond laser with 780nm wavelength on the designed circular pattern, wherein the excitation light intensity is 7%, and combining the second fluorophore molecules on the hydrogel framework;

(4) after the hydrogel is washed by pure water for multiple times to remove residual fluorophore molecules, 3 mu g/mL of nanogold-streptavidin is added and incubated for 3 hours; washing with pure water for several times to remove residual nanoparticles, immersing the hydrogel in 10 μ g/mL biotin-NHS, and incubating for 3 hours; after washing with purified water several times, the cells were incubated in Qdot705-streptavidin at 10. mu.g/mL for 3 hours.

(5) And washing the hydrogel with pure water for multiple times, then putting the hydrogel into a 0.5M citric acid solution for shrinkage, drying and dehydrating to obtain the concentrated and polymerized Qdot and nanogold composite micro-nano pattern structure.

(6) The binding sites of the nanoparticles on the hydrogel substrate were observed under a confocal fluorescence microscope, and the results are shown in fig. 1, which demonstrates that two nanoparticles can be successfully and selectively bound to different regions and two materials can be bound to the overlapping sites.

Example 2

An in-situ constructed composite flexible micro-nano device unit based on a laser direct writing technology can be prepared by the following method:

(1) mixing methacrylated hyaluronic acid with 3mg of N, N' -methylenebisacrylamide, 8mL of 2M sodium chloride, 2mL of 10xPBS and 9.2mL of pure water at a concentration of 5% (w/v); then 1mL of the precursor solution is taken and mixed with 20 mu L of 10% (v/v) tetramethylethylenediamine and 20 mu L of 10% (w/v) ammonium persulfate, the mixture is placed at 37 ℃ to react for 1 hour to form gel, and the gel is placed in pure water to swell;

(2) cutting the expanded hydrogel into square blocks with the side length of 2cm, placing the square blocks in AFdye-azide solution with the concentration of 100 mu M for 1 hour, placing the square blocks on a femtosecond laser two-photon processing platform, controlling the platform to move by using software, taking femtosecond laser with the wavelength of 780nm as a light source according to a designed comb-shaped structure, and printing fluorophore molecules on a hydrogel framework, wherein the femtosecond laser with the wavelength of 780nm is used as the light source, and the excitation light intensity is 14%;

(3) then directly covering 1mM fluoroescein-amino fluorescent solution on the surface of the hydrogel, taking 780nm wavelength femtosecond laser as a light source for the designed anti-comb pattern after the fluorescent solution completely permeates into the hydrogel for 30 minutes, wherein the excitation light intensity is 6%, and combining the second fluorophore molecule on the hydrogel framework;

(4) after the hydrogel was washed with pure water several times to remove residual fluorophore molecules, 5. mu.g/ml of graphene-NHS was added and incubated for 3 hours; washing with pure water for several times to remove residual nanoparticles, immersing the hydrogel in 10 μ g/ml biotin-DBCO, and incubating for 3 hours; after washing with pure water several times, the cells were incubated in 3. mu.g/ml of nano-silicon-streptavidin-503 for 3 hours.

(5) And washing the hydrogel with pure water for multiple times, then putting the hydrogel into 0.1MHCl solution for shrinkage, drying and dehydrating to obtain the concentrated and polymerized graphene and nano silicon composite micro-nano pattern structure.

(6) And (3) placing the sample under a confocal fluorescence microscope to observe the binding sites of the nanoparticles on the hydrogel substrate, and forming flexible composite micro-nano device units which can be connected to two ends of the electrode as shown in figure 2.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and not to limit the protection scope of the present invention accordingly. All equivalent changes or modifications made in accordance with the spirit of the present disclosure are intended to be covered by the scope of the present disclosure.

Claims

1. A method for constructing a composite flexible micro-nano device in situ based on a laser direct writing technology is characterized in that the composite flexible micro-nano device is formed by printing a micro structure area capable of polymerizing different nano particles and high molecular components in a flexible substrate by utilizing a two-photon laser direct writing technology.

2. The method for constructing the composite flexible micro-nano device in situ based on the laser direct writing technology according to claim 1 is characterized by comprising the following specific steps:

(1) preparation of hydrogel substrate flexible material: mixing the hydrogel precursor solution with a cross-linking agent, a catalyst and an initiator, placing the mixture at 10-37 ℃ to form gel, and placing the gel in pure water to expand to be several times of volume;

(3) 3D two-photon laser printing for the first time: placing the expanded hydrogel in a high-excitation-state functional fluorophore solution to enable the dye to completely permeate into the hydrogel, then placing the hydrogel on a femtosecond laser two-photon processing platform, controlling the platform to move by using software, using a two-photon laser direct writing technology to design a 3D structure, using 780nm wavelength femtosecond laser as a light source, and combining first fluorophore molecules on a hydrogel framework with high laser intensity;

(4) and 3D two-photon laser printing for the second time: after the hydrogel is continuously treated by the functional fluorophore solution in the low excitation state for a period of time, the designed pattern is printed on the substrate by femtosecond laser with 780nm wavelength by using a two-photon laser direct writing technology, and the second fluorophore molecule is combined on the hydrogel framework with low laser intensity;

3. The method according to claim 2, wherein the hydrogel precursor solution in step (1) is a mixed solution of acrylamide, sodium acrylate, sodium chloride, PBS and pure water; or natural polymer hydrogel solution such as methyl propylene sodium hyaluronate, collagen, fibroin, gelatin, etc. with concentration of 5-20% (w/v).

4. The method according to claim 2, wherein the crosslinking agent in the step (1) is N, N' -methylenebisacrylamide in a concentration of 0.01 to 1% (w/w) in the mixed solution; the catalyst is ammonium persulfate, and the concentration of the ammonium persulfate in the mixed solution is 0.1-0.5% (w/w); initiator tetramethylethylenediamine, the concentration of which in the mixed solution is 0.1-0.5% (v/v).

5. The method according to claim 2, wherein the high excited state functional fluorophore in step (3) is activated NH₂One of the aflame, Azide, DBCO, SH, Biotin-AFdye, Cy5 fluorophore molecules, or Biotin-4-fluorochein; the fluorophore concentration was 100. mu.M-200. mu.M.

6. The method according to claim 2, wherein the low excited state in the step (4)The functional fluorophore is NH-bearing₂One of Fluorescein, Cy3, Melamine-, Azide-, DBCO-, SH-; the fluorophore concentration was 500. mu.M-2 mM.

7. The method according to claim 2, wherein the high laser intensity in step (3) is in the range of 12-20% of the output laser intensity; and (4) reducing the laser intensity in the step (4), wherein the light intensity range of the output laser is 5-9%.

8. The method according to claim 2, wherein the polymer or nanoparticle in step (5) is antibody, protein, DNA, or two kinds of nanoparticles selected from graphene, CNT, Qdots, nanogold, nanosilver, etc., and has a corresponding structural unit capable of reacting with the active group of the fluorophore molecule, i.e., NHS-, SH-, DBCO-, Azide-, Melamine-, Streptavidin-.

9. The method according to claim 2, wherein the acidic solution in step (6) is one of hydrochloric acid, acetic acid and citric acid, and the concentration is 0.5-1M.

10. The method according to claim 2, wherein in the step (3), the swollen hydrogel is placed in the high-excited-state functional fluorophore solution for 1 hour, the laser power is 128mW, and the hydrogel is treated with the low-excited-state functional fluorophore solution for 30 minutes.