CN111299569A - Chiral assembly and preparation method thereof - Google Patents
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- 239000002202 Polyethylene glycol Substances 0.000 claims description 4
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
- B22F1/102—Metallic powder coated with organic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
- B01J31/0234—Nitrogen-, phosphorus-, arsenic- or antimony-containing compounds
- B01J31/0235—Nitrogen containing compounds
- B01J31/0254—Nitrogen containing compounds on mineral substrates
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
- B01J31/0234—Nitrogen-, phosphorus-, arsenic- or antimony-containing compounds
- B01J31/0271—Nitrogen-, phosphorus-, arsenic- or antimony-containing compounds also containing elements or functional groups covered by B01J31/0201 - B01J31/0231
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- B01J35/396—
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/05—Metallic powder characterised by the size or surface area of the particles
- B22F1/054—Nanosized particles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/07—Metallic powder characterised by particles having a nanoscale microstructure
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
- B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
Abstract
The invention provides a chiral assembly and a preparation method thereof, wherein the chiral assembly comprises nanorod particles with a core-shell structure and a connecting layer, wherein the nanorod particles are arranged side by side and are of a shoulder arrangement, and the connecting layer is arranged on the surfaces of the nanorod particles with the core-shell structure; the chiral assembly body separates a chiral driving layer in a chiral assembly layer and an assembly layer in charge of assembly in space by using a space separation method, so that a chiral unit is better constructed, and more stable assembly body and PCD signals are achieved; the preparation method of the chiral assembly is simple, the raw materials are easy to obtain, the price is low, and the implementation is convenient.
Description
Technical Field
The invention belongs to the field of nano materials, and relates to a chiral assembly and a preparation method thereof.
Background
Plasmon Circular Dichroism (PCD) is capable of transferring a signal of an undetectable chiral molecule located in a deep ultraviolet region to an LSPR (localized plasmon resonance) in an ultraviolet visible region, and thus is receiving much attention.
At present, plasmon circular dichroism sources mainly comprise two types; structural plasmon circular dichroism and induced plasmon circular dichroism. The structural plasmon circular dichroism obtains a strong and stable signal by constructing a chiral assembly structure of plasmon nanoparticles, and obtains more attention compared with a weak signal for inducing PCD.
Currently, most structural PCD utilizes chiral macromolecules as templates to assemble nanoparticles into chiral structures and can achieve further enhancement by means of strong plasmon coupling between nanoparticles (Lan X, Wang Q.Self-Assembly of Chiral plasma nanostructres.Adv.Mater.2016; 28(47): 10499-. However, the template method is complex, long in time consumption and high in economic cost.
In recent years, studies on the formation of chiral assembly structures using chiral small molecules have also begun to attract attention (Hu Z, MengD, Lin F, Zhu X, Fang Z, Wu X. plasma Circular dichorism of Gold NanoparticleBased nanostructures.Adv.Opti.Mater.2019; 7(10): 1801590). For example, (Hou S, Wen T, Zhang H, Liu W, Hu X, Wang R, Hu Z, Wu X. the hybridization of chiral planar oligomers using cysteine-modified gold nanoparticles as monomers. Nano Res. 2014; 7(11) (1699) 1705) chiral thiol small molecules are added into an achiral shoulder-by-side assembly (SS) of the gold and silver nanorods, and the adsorbed chiral small molecules drive the spatial positions of the nanorods to be twisted to form the chiral assembly so as to generate PCD signals. The PCD signal g-factor can be further amplified by up to 0.065 under certain conditions, such as appropriate heat treatment of the assembly (Yan J, Hou S, JiY, Wu X.Heat-enhanced symmetry breaking in dynamic gold nanoparticles: the interface of interface control. Nanoscale.2016; 8(19): 10030-. Indicating that the formation of chiral assemblies using adsorbed chiral thiol molecules is a viable approach.
The above method has certain disadvantages in practical application. Because the chiral molecular driving source and the assembled driving source are spatially located in the same layer, the chiral molecular driving source and the assembled driving source are mutually influenced and are not easy to realize respective regulation and control; in addition, the chiral molecules are exposed in a solution environment and are easily interfered by external factors, so that PCD signals are influenced.
Therefore, it is necessary to develop a chiral assembly capable of separately controlling the chiral driving layer and the assembly layer.
Disclosure of Invention
The chiral assembly separates a chiral driving layer in a chiral assembly layer and an assembly layer in charge of assembly in space by using a space separation method, better constructs a chiral unit, achieves more stable assemblies and PCD signals, and is expected to have wide application prospect, such as being possibly used in the detection field or the catalysis field.
In order to achieve the purpose, the invention adopts the following technical scheme:
one of the purposes of the invention is to provide a chiral assembly, which comprises nanorod particles with a core-shell structure and arranged side by side, and an assembly driving layer arranged on the surfaces of the nanorod particles with the core-shell structure.
In the invention, the chiral assembly body separates the chiral driving layer in the chiral assembly layer and the assembly driving layer responsible for assembly from each other in space by using a space separation method, so that a chiral unit is better constructed, and more stable assembly body and PCD signals are achieved.
According to the invention, a metal shell layer is formed on the surface of the nanorod particles adsorbed with chiral molecules containing sulfydryl, so that the adsorbed chiral molecular layer (chiral molecules containing sulfydryl) is sandwiched between the nanorod particles and the metal shell layer, and the obtained core-shell structure of the nanorod particles with the core-shell structure does not display PCD signals; the nano-rod particles with the core-shell structure are arranged side by side, an assembly is formed under the action of a surfactant and a connecting agent, and the stable assembly with larger PCD signals can be obtained by regulating and controlling the assembly conditions.
According to the invention, a chiral driving layer is formed between the nanorod particles in the chiral assembly and the metal shell layer, and the chiral driving layer can enable the nanorods in the assembly to form torsion at a certain angle through a side-by-side assembly form, so that the chiral assembly and PCD response are obtained.
In the invention, the number of the nanorod particles with the core-shell structure, which are arranged side by side in the chiral assembly, is 2-5, preferably 2, 3, 4 or 5.
In the present invention, the side-by-side arrangement is a parallel arrangement.
In the invention, the nanorod particles with the core-shell structure comprise a core layer, a shell layer and a chiral driving layer positioned between the core layer and the shell layer.
In the invention, the core layer is made of nanorod particles.
In the present invention, the nanorod particles include gold nanorod particles.
In the present invention, the length-to-diameter ratio of the nanorod particles is 1.5-4, such as 1.5, 1.7, 1.9:1, 2.1, 2.4, 2.7, 3.1, 3.2, 3.7, 3.9, or 4, etc., preferably 3.08.
In the present invention, the chiral driving layer is bonded to the surface of the core layer.
In the invention, the material of the chiral driving layer is chiral molecules containing sulfydryl.
In the present invention, the thiol-containing chiral molecule comprises any one or a combination of at least two of cysteine, glutathione or vitamin Bt, preferably cysteine.
In the invention, when the nanorod particles are gold nanorod particles, the chiral molecules containing sulfydryl are cysteine, and the chiral driving layer and the gold nanorod particles are bonded together by Au-S bonds.
In the present invention, the material of the metal layer includes silver or a combination of silver and gold.
In the present invention, the material of the metal layer is preferably a metal having plasmon resonance properties, such as gold and/or silver.
In the present invention, the thickness of the metal layer is 7 to 9nm, for example, 7nm, 7.2nm, 7.5nm, 7.7nm, 8nm,
8.2nm, 8.5nm, 8.8nm, 9nm etc. suitable shell thickness is favorable to the transmission of chiral drive power, and the thickness when the metal level is too thick, can make the chiral drive power on inside chiral drive layer difficult to transmit out, and the thickness when the metal level is crossed lowly, and chiral molecule is more weak with the plasmon resonance of shell, can't realize big PCD signal, and to the protective properties variation of nuclear structure.
In the invention, the assembled driving layer is deposited on the surface of the nanorod particles with the core-shell structure.
In the present invention, the material of the assembly driving layer is a combination of a surfactant and a connecting agent.
In the present invention, the surfactant includes any one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, cetylpyridinium chloride or a mercapto polyethylene glycol analogue or a combination of at least two thereof.
In the present invention, the linking agent is sodium citrate.
It is a second object of the present invention to provide a method for preparing the chiral assembly according to the first object, comprising: and adding a connecting agent into the dispersion liquid of the nanorod particles with the core-shell structure for assembly to obtain the chiral assembly.
In the present invention, the dispersion of the nanorod particles with the core-shell structure is dispersed by dispersing the nanorod particles with the core-shell structure into an aqueous solution containing a surfactant.
In the present invention, the surfactant includes any one of cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC), cetylpyridinium chloride (CPC) or a mercapto-polyethylene glycol analog (PEG-SH) or a combination of at least two thereof.
In the present invention, the linking agent is sodium citrate.
In the present invention, the temperature of the assembly is 25-70 deg.C, such as 25 deg.C, 30 deg.C, 35 deg.C, 40 deg.C, 45 deg.C, 50 deg.C, 55 deg.C, 60 deg.C, 65 deg.C, 70 deg.C, etc., preferably 60 deg.C.
In the present invention, the assembling time is 10-90min, such as 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, etc., preferably 30 min.
In the invention, the preparation method of the nanorod particles with the core-shell structure comprises the following steps:
(1) and incubating the mixed solution of the nanorod particles, the surfactant and the chiral molecules containing sulfydryl to obtain incubated mixed solution.
(2) And (2) adding a metal source and a reducing agent into the incubated mixed solution obtained in the step (1) for growth to obtain the nanorod particles with the core-shell structure.
In the present invention, the concentration of the nanorod particles in the mixed solution of step (1) is 0.05-0.2nM, such as 0.05nM, 0.07nM, 0.09nM, 0.1nM, 0.12nM, 0.14nM, 0.16nM, 0.18nM, 0.20nM, etc., preferably 0.08-0.15 nM.
In the invention, the nanorod particles in the step (1) are gold nanorod particles.
In the present invention, the aspect ratio of the gold nanorod particles is 1.5 to 4, such as 1.5, 1.7, 1.9:1, 2.1, 2.4, 2.7, 3.1, 3.2, 3.7, 3.9, 4, etc., preferably 3.08.
In the invention, the thiol-containing chiral molecule in the step (1) is cysteine (Cys).
In the present invention, the concentration of the thiol-group-containing chiral molecule in the mixed solution of step (1) is 1-100. mu.M, such as 1. mu.M, 5. mu.M, 10. mu.M, 20. mu.M, 30. mu.M, 40. mu.M, 50. mu.M, 60. mu.M, 70. mu.M, 80. mu.M, 90. mu.M, 100. mu.M, etc.
In the present invention, the surfactant in step (1) is cetyltrimethylammonium bromide (CTAB).
In the present invention, the concentration of the surfactant in the mixed solution described in step (1) is 1 to 20mM, for example, 0.5mM, 1mM, 2mM, 3mM, 4mM, 5mM, 6mM, 7mM, 8mM, 9mM, 10mM, 12mM, 14mM, 16mM, 18mM, 20mM, etc., preferably 5 to 15 mM.
In the present invention, the incubation temperature in the step (1) is 20 to 40 ℃, for example, 20 ℃, 22 ℃, 25 ℃, 27 ℃, 30 ℃, 32 ℃, 35 ℃, 38 ℃, 40 ℃ and the like.
In the present invention, the incubation time in step (1) is 30-180min, such as 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 120min, 140min, 160min, 180min, etc.
In the present invention, the step (2) further comprises separating and re-dispersing the incubated mixed solution in advance.
In the invention, the separation mode comprises the step of carrying out centrifugal separation on the incubated mixed solution to obtain a lower-layer precipitate.
In the present invention, said redispersion comprises incubating the underlying precipitate redispersion in a solution containing a surfactant.
In the present invention, the incubation temperature is 20 to 40 ℃, for example, 20 ℃, 23 ℃, 25 ℃, 28 ℃, 30 ℃, 33 ℃, 35 ℃, 38 ℃, 40 ℃ and the like.
In the present invention, the incubation time is 30-180min, such as 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 120min, 140min, 160min, 180min, etc.
In the present invention, the concentration of the surfactant in the surfactant-containing solution is 1 to 20mM, for example, 1mM, 2mM, 3mM, 4mM, 5mM, 6mM, 7mM, 8mM, 9mM, 10mM, 12mM, 14mM, 16mM, 18mM, 20mM, etc., preferably 5 to 15 mM.
In the present invention, the metal source comprises a silver source or a combination of a gold source and a silver source, preferably a combination of a gold source and a silver source.
In the invention, the metal source is a combination of a gold source and a silver source, the gold source comprises chloroauric acid, and the silver source comprises silver nitrate.
In the present invention, the metal source is a combination of a gold source and a silver source, and the molar ratio of the gold source to the underlying precipitate is (0.2-1):1, for example 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, preferably (0.25-0.8): 1.
In the present invention, the metal source is a combination of a gold source and a silver source, and the molar ratio of the silver source to the underlying precipitate is (0.09: 1):1, for example, 0.09:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, and the like.
In the present invention, the reducing agent in step (2) is ascorbic acid.
In the present invention, the molar ratio of the reducing agent and the gold source in step (2) is (1.5-20):1, for example, 1.5:1, 3:1, 5:1, 8:1, 10:1, 12:1, 15:1, 17:1, 20:1, etc., preferably (1.6-16): 1.
In the present invention, the temperature for the growth in step (2) is 65 to 75 ℃, for example, 65 ℃, 66 ℃, 67 ℃, 68 ℃, 69 ℃, 70 ℃, 71 ℃, 72 ℃, 73 ℃, 74 ℃, 75 ℃ and the like.
In the present invention, the growth time in step (2) is 30-120min, such as 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.
In the invention, the step (2) further comprises the steps of carrying out centrifugal separation on the growth mixed solution obtained after growth, and removing the supernatant to obtain the lower-layer precipitate metal nanoparticles.
As a preferred technical scheme of the invention, the preparation method comprises the following steps:
(1) incubating the mixed solution of the nanorod particles, the surfactant and the chiral molecules containing the sulfydryl at the temperature of 20-40 ℃ for 30-60min to obtain an incubated mixed solution, wherein in the mixed solution, the concentration of the nanorod particles is 0.05-0.2nM, the concentration of the chiral molecules containing the sulfydryl is 1-100 mu M, and the concentration of the surfactant is 1-20 mM;
(2) centrifuging the incubated mixed solution obtained in the step (1) to obtain a lower-layer precipitate, and then dispersing the lower-layer precipitate into a 1-20mM aqueous solution containing a surfactant for incubation at 20-40 ℃ for 30-180min to obtain an incubation solution;
(3) adding a metal source and ascorbic acid into the hatching fluid obtained in the step (2), growing for 30-120min at 65-75 ℃, centrifuging, and removing supernatant to obtain nanorod particles with a core-shell structure;
(4) and (4) placing the nanorod particles with the core-shell structure obtained in the step (3) into an aqueous solution containing a surfactant for dispersion, then adding a connecting agent, and assembling at 25-70 ℃ for 10-90min to obtain the chiral assembly.
In the present invention, unless otherwise specified, the concentration unit M means mol/L, mM means mmol/L,. mu.M means. mu.mol/L, and nM means nmol/L.
Compared with the prior art, the invention has the following beneficial effects:
the chiral assembly body separates the chiral driving layer in the chiral assembly layer and the assembly layer responsible for assembly in space by using a space separation method, so that a chiral unit is better constructed, and more stable assembly body and PCD signals are achieved; the preparation method of the chiral assembly is simple, the raw materials are easy to obtain, the price is low, and the implementation is convenient.
Drawings
FIG. 1 is a schematic illustration of the preparation of rod-like core-shell nanoparticles and chiral assemblies in example 1;
wherein, 1 is gold nanorod particles, 2 is chiral molecules, 3 is a shell layer, 4 is a surfactant (CTAB), and 5 is a citrate.
FIG. 2a is the effect of ascorbic acid concentration on extinction spectra of the resulting rod-shaped core-shell nanoparticles of example 2;
FIG. 2b is a graph of the effect of ascorbic acid concentration on length and width of the rod-shaped core-shell nanoparticles prepared in example 2.
FIG. 3 is a TEM image of core-shell nanoparticles prepared in example 2 at different ascorbic acid concentrations, where (a) is ascorbic acid concentration 0.08 mM; (b) ascorbic acid concentration was 0.32 mM; (c) the ascorbic acid concentration is 0.56 mM; (d) the ascorbic acid concentration was 0.8 mM.
FIG. 4a is a CD spectrum and an extinction spectrum obtained after core-shell nanoparticles prepared in example 2 at different ascorbic acid concentrations were assembled at 60 ℃ for 30 min;
fig. 4b is a graph of the change trend of the assembly degree and the g factor in the assembly process of assembling the core-shell nanoparticles prepared in example 2 at different ascorbic acid concentrations at 60 ℃ for 30 min.
FIG. 5a is a plot of extinction spectra of core-shell nanoparticles of example 2 grown at 70 ℃ for 60min at 0.08mM ascorbic acid;
FIG. 5b is a plot of the extinction spectrum of core-shell nanoparticles of example 2 grown at 70 ℃ for 60min at 0.8mM ascorbic acid;
FIG. 5c is the change at 400nm in the extinction spectrum of example 2 during the kinetics of core-shell nanoparticle growth at 70 ℃ for 60min at ascorbic acid concentrations of 0.08 and 0.8mM, respectively;
FIG. 6a is a plot of the trend of extinction spectra of gold nanorods of example 3 after adsorption and centrifugation at different cysteine concentrations;
fig. 6b is a plot of the trend of extinction spectra for core-shell nanoparticles prepared in example 3 at different cysteine concentrations.
Fig. 7 is a TEM image of core-shell nanoparticles prepared in example 3 at different cysteine concentrations, where (a) is cysteine concentration of 1 μ M; (b) cysteine concentration was 2. mu.M; (c) cysteine concentration was 5. mu.M; (d) the cysteine concentration is 10 mu M; (e) cysteine concentration was 25. mu.M; (f) cysteine concentration is 50 μ M; (g) the cysteine concentration was 100. mu.M.
FIG. 8 is a trend graph of CD spectra and extinction spectra and a trend graph of the relationship between the degree of assembly and g-factor during the kinetics of assembling core-shell nanoparticles prepared at different cysteine concentrations for example 3 at 60 ℃ for 30min, wherein (a) is cysteine concentration of 1 μ M; (b) cysteine concentration was 2. mu.M; (c) cysteine concentration was 5. mu.M; (d) the cysteine concentration is 10 mu M; (e) cysteine concentration was 25. mu.M; (f) cysteine concentration is 50 μ M; (g) the cysteine concentration is 100 mu M; (h) the trend graph of the relation between the assembly degree change and the corresponding g factor is shown.
FIG. 9 is an extinction spectrum trend graph of core-shell nanoparticles obtained by gold nanorods of example 4 in different incubation manners of cysteine (Cys) and p-aminophenol (4-ATP), wherein S1 is Cys incubation for 3 h; s2 is Cys and 4-ATP incubated together for 3 h; s3 hatching Cys for 1.5h, adding 4-ATP, and continuing hatching for 3 h; s4 hatching for 1.5h with 4-ATP, adding Cys and hatching for 3 h; s5 is 4-ATP hatching for 3 h;
fig. 10 is a graph of the trend of CD spectrum and extinction spectrum and the trend of the relationship between assembly degree and g factor during the kinetics of assembling core-shell nanoparticles prepared in different incubation modes of cysteine and p-aminophenol at 60 ℃ for 30min according to example 4, wherein (a) is Cys incubation for 3 h; (b) cys and 4-ATP are incubated together for 3 h; (c) adding 4-ATP to incubate for 3h after Cys is incubated for 1.5 h; (d) incubating for 4-ATP for 1.5h, adding Cys, and incubating for 3 h; (e) incubating for 3h for 4-ATP; (f) the assembly degree and the corresponding g factor are related to a trend chart.
FIG. 11 is a plot of the extinction spectra of core-shell nanoparticles of different shell thicknesses prepared in example 5.
FIG. 12 is a TEM image of core-shell nanoparticles of example 5 prepared with different shell thicknesses, wherein (a) is a chloroauric acid concentration of 0.03 mM; (b) the concentration of the chloroauric acid is 0.04 mM; (c) the concentration of the chloroauric acid is 0.05 mM; (d) the concentration of the chloroauric acid is 0.06 mM; (e) the concentration of the chloroauric acid is 0.07 mM; (f) the concentration of chloroauric acid is 0.08 mM.
FIG. 13 is a CD spectrum and a trend of extinction spectrum of the core-shell nanoparticles prepared in example 5 with different shell thicknesses during the assembly process at 60 ℃ for 30min, wherein (a) is the concentration of chloroauric acid 0.03 mM; (b) the concentration of the chloroauric acid is 0.04 mM; (c) the concentration of the chloroauric acid is 0.05 mM; (d) the concentration of the chloroauric acid is 0.06 mM; (e) the concentration of the chloroauric acid is 0.07 mM; (f) the concentration of chloroauric acid is 0.08 mM.
FIG. 14a is a g-factor spectrum corresponding to a CD spectrum and an extinction spectrum of core-shell nanoparticles of different shell thicknesses prepared in example 5 after being assembled at 60 ℃ for 30 min;
FIG. 14b is a bar graph of g-factors at 600nm after core-shell nanoparticles of example 5 with different shell thicknesses are assembled at 60 ℃ for 30 min.
FIG. 15a shows the CD spectrum and extinction spectrum of the assembled core-shell nanoparticles with the optimal chiral driving layer prepared in example 6 at 30-60 deg.C;
FIG. 15b is a histogram of g-factors at 600nm for the same assembly degree after the core-shell nanoparticles with the optimal chiral driving layer prepared in example 6 were assembled at 30-60 ℃;
FIG. 16a is a CD spectrum and an extinction spectrum of the same degree of assembly of the core-shell nanoparticles with the optimal chiral driving layer prepared in example 7 at different CTAB concentrations and 30 ℃;
FIG. 16b is a graph showing the variation of the assembly degree and the g-factor of the core-shell nanoparticles with the optimal chiral driving layer prepared in example 7, after being assembled at different CTAB concentrations at 30 and 60 ℃ respectively;
FIG. 17 shows the CD spectrum and extinction spectrum of the same degree of assembly after the assembly at 30 and 60 ℃ respectively of the core-shell nanoparticles with the optimal chiral driving layer prepared in example 8 in which PEG-NH2 is added to destroy CTAB bilayer;
FIG. 18 shows the CD spectrum and the extinction spectrum of the same degree of assembly after assembly at 30 and 60 ℃ respectively, in the core-shell nanoparticle with the optimal chiral driving layer prepared in example 9, PEG-NH2 replaces CTAB bilayer;
FIG. 19a is a CD spectrum and an extinction spectrum of the same degree of assembly of core-shell nanoparticles with optimal chiral driving layer prepared in example 10, assembled at 30 and 60 ℃ respectively, with CPC replacing CTAB bilayer;
FIG. 19b is a CD spectrum and an extinction spectrum of the same degree of assembly of the core-shell nanoparticle with the optimal chiral driving layer prepared in example 10, with CPC and CTAB as surfactants, respectively, after assembly at 30 and 60 ℃;
fig. 19c is a bar graph of CD magnification at the same degree of assembly after assembly at 30 and 60 ℃ with CPC and CTAB as surfactants, respectively, in the core-shell nanoparticles with optimal chiral driving layer prepared in example 10.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
The present embodiment provides a novel method for constructing a chiral assembly, comprising the following steps:
(1) incubating a mixed solution of gold nanorods (with a length-diameter ratio of 2), a surfactant (CTAB) and cysteine at 25 ℃ for 60min to obtain an incubated mixed solution, wherein the particle concentration of the gold nanorods is 0.1nM, the surfactant concentration is 2mM, and the cysteine concentration is 2 μ M;
(2) centrifuging the incubated mixed solution obtained in the step (1) at 9500rpm for 15min, removing supernatant, adding 10mM surfactant aqueous solution into the lower precipitate, mixing, and incubating at 25 deg.C for 60min to obtain incubation solution;
(3) adding silver nitrate, chloroauric acid and ascorbic acid into the hatching fluid obtained in the step (2), and growing on the surface of the gold nanorod particles for 90min in a water bath kettle at 60 ℃ to obtain a nanoparticle solution, wherein the concentration of the silver nitrate is 10 mu M, the concentration of the chloroauric acid is 0.04mM, and the concentration of the ascorbic acid is 0.06 mM.
(4) And (3) centrifuging the nanoparticle solution obtained in the step (3) twice at the rotating speed of 9500rpm for 15min, removing the supernatant, adding a 2mM CTAB aqueous solution of a surfactant (when no special description is given, the surfactants in the assembly process are CTAB) into the lower-layer precipitate, and uniformly mixing. And adding sodium citrate at 30 ℃ for assembling to obtain the side-by-side chiral assembly.
Wherein, fig. 1 is a schematic diagram of a preparation process of a nano-particle with a rod-shaped core-shell structure and a chiral assembly; as shown in fig. 1, pre-incubating gold nanorods in a mixed solution of a surfactant and chiral molecules (cysteine) to obtain a solution containing the gold nanorods with the chiral molecules (cysteine) adsorbed on the surface, centrifuging to obtain the gold nanorods with the chiral molecules (cysteine) adsorbed on the surface, and then growing a shell layer to obtain nanoparticles with a core-shell structure; carrying out regulation and assembly on core-shell structure nanoparticles arranged in parallel in a shoulder-to-shoulder manner under the action of a surfactant (CTAB) and citric acid to obtain a chiral assembly; wherein, 1 is gold nanorod particles, 2 is chiral molecules, 3 is a shell layer, 4 is a surfactant (CTAB), and 5 is a citrate.
Example 2
In this embodiment, the influence of ascorbic acid concentration on a chiral driving source is studied, and the method relates to the regulation and control of a local hot spot in a core-shell interface region, and includes the following steps:
(1) incubating a mixed solution of gold nanorod particles (the length-diameter ratio of which is 3.08), a surfactant (CTAB) and cysteine at 30 ℃ for 30min to obtain an incubated mixed solution, wherein the particle concentration of the gold nanorod particles is 0.1nM, the concentration of the surfactant is 10mM, and the concentration of the cysteine is 2 μ M;
(2) centrifuging the incubated mixed solution obtained in the step (1) at 9500rpm for 15min, removing supernatant, adding 10mM surfactant aqueous solution into the lower precipitate, mixing, and incubating at 30 deg.C for 30min to obtain incubation solution;
(3) and (3) adding silver nitrate, chloroauric acid and ascorbic acid with different concentrations into the hatching fluid obtained in the step (2), quickly shaking, placing in a water bath kettle at 70 ℃, and growing for 60min to obtain a nanoparticle solution, wherein the concentration of the silver nitrate is 10 mu M, the concentration of the chloroauric acid is 0.05mM, and the concentration of the ascorbic acid is 0.08-0.8 mM.
(4) And (4) centrifuging the nanoparticle solution obtained in the step (3) twice at the rotating speed of 9500rpm for 15min, removing the supernatant, adding a 2mM CTAB aqueous solution serving as a surfactant into the lower-layer precipitate, and uniformly mixing. Adding sodium citrate, and assembling at 60 deg.C for 30min to obtain the chiral assembly.
The rod-like core-shell nanoparticles and assemblies thereof in this example were characterized, and the results were as follows:
the extinction spectra of the regrown particles obtained at different ascorbic acid concentrations are shown in fig. 2a (where AuNR denotes gold nanorods, Au @ Cys denotes gold nanorods surface adsorption of cysteine, and AA denotes a reducing agent ascorbic acid, and the meanings of these designations are the same as those in the following description, and are not described in detail); a size histogram for the particles as shown in FIG. 2 b; the morphology of the particles is shown in fig. 3; the above data show that different concentrations of reducing agent do not have much influence on the size morphology of the final particles. The CD and extinction spectrum of the core-shell nano-particles after being assembled for 30min at 60 ℃ are shown in figure 4 a; the dynamic change in the assembly process is analyzed, and the PCD signal is increased along with the increase of the assembly degree, so that LSPR in spectra with different assembly degrees corresponding to 5 different assembly times in the assembly process is taken as an abscissa (which can be expressed as the assembly degree), the maximum g factor corresponding to the assembly degree is taken as an ordinate (the g factor is taken as a dimensionless parameter and can be expressed as the size of chirality), thereby obtaining a line graph as shown in FIG. 4b, the influence of various factors on the g factor can be more intuitively and dynamically represented by comparing the variation trend of the line graph, and the representation mode is continuously used in the following data. Analysis of the PCD signal revealed that the higher the concentration of the reducing agent, the stronger the PCD of the assembly, and that the maximum PCD signal was obtained at a concentration of 0.8 mM. Extinction spectra of kinetics of growth of samples with 0.08mM and 0.8mM concentrations of reducing agent As shown in FIGS. 5a, 5b, and 5c, the higher the concentration of reducing agent, the faster the rate of reductive deposition of gold atoms, and therefore the concentration of reducing agent used in the examples below was 0.8 mM.
Example 3
This example studies the effect of cysteine concentration on chiral driving sources, relating to the size and spatial position of the chiral driving sources, the method comprising the steps of:
(1) incubating a mixed solution of gold nanorod particles (the length-diameter ratio is 3.08), a surfactant (CTAB) and cysteine at 30 ℃ for 30min to obtain an incubated mixed solution, wherein the particle concentration of the gold nanorod particles is 0.1nM, the concentration of the surfactant is 10mM, and the concentration of the cysteine is 1-100 μ M;
(2) centrifuging the incubated mixed solution obtained in the step (1) at 9500rpm for 15min, removing supernatant, adding 10mM aqueous solution of surfactant into the lower-layer precipitate, mixing uniformly, and incubating at 30 deg.C for 30min to obtain incubation liquid;
(3) and (3) adding silver nitrate, chloroauric acid and ascorbic acid with different concentrations into the hatching fluid obtained in the step (2), quickly shaking, placing in a 70 ℃ water bath, and growing for 60min to obtain a nanoparticle solution, wherein the concentration of the silver nitrate is 10 mu M, the concentration of the chloroauric acid is 0.05mM, and the concentration of the ascorbic acid is 0.8 mM.
(4) And (4) centrifuging the nanoparticle solution obtained in the step (3) twice at the rotating speed of 9500rpm for 15min, removing supernatant, adding a 2mM CTAB aqueous solution serving as a surfactant into the lower-layer precipitate, and uniformly mixing. Adding sodium citrate, and assembling at 60 deg.C for 30min to obtain the side-by-side nanorod chiral assembly.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
the extinction spectrums of the gold nanorods adsorbing cysteine with different concentrations and core-shell nanoparticles obtained by regrowth are shown in fig. 6a and 6b, and when the concentration of the cysteine exceeds 10 mu M, the extinction spectrums after centrifugation have trailing phenomena, which indicates that the particles are easy to weakly agglomerate; TEM representation of the morphology is shown in FIG. 7, when the concentration of cysteine is lower than 25 μ M, a tiny bulge appears at one end of the head of the core-shell particle; when the concentration is more than 25 mu M, the side edge of the core-shell particle is in a wave shape; the kinetic process of the core-shell particles assembled at 60 ℃ for 30min and the change trend graph of the g factor and the assembly degree are shown in fig. 8, and cysteine has the maximum g factor when being 5-10 mu M. Considering that too much cysteine leads to aggregation of particles, the cysteine alone in the subsequent examples was selected to be 5. mu.M.
Example 4
This example studies the effect of the integrity of the cysteine chiral lattice on the chiral driving source, relating to the effect of the chiral lattice size on PCD, the method comprising the steps of:
(1) incubating a mixed solution of gold nanorod particles (the length-diameter ratio is 3.08), a surfactant (CTAB) and cysteine at 30 ℃ for 30min to obtain an incubated mixed solution, wherein the concentration of the gold nanorod particles is 0.1nM, the concentration of the surfactant is 10mM, the concentrations of thiol molecules cysteine (Cys) and/or p-aminophenol (4-ATP) are 2 μ M respectively, the incubation sequence of two thiol molecules is changed, namely, the cysteine is incubated for 3h, the cysteine and the p-aminophenol are incubated together for 3h, the cysteine is incubated for 1.5h first, the p-aminophenol is added for incubation for 1.5h, the p-aminophenol is incubated for 1.5h first, the cysteine is added for incubation for 1.5h, and the p-aminophenol is incubated for 3 h;
(2) centrifuging the incubated mixed solution obtained in the step (1) at 9500rpm for 15min, removing supernatant, adding 10mM surfactant aqueous solution into the lower precipitate, mixing, and incubating at 30 deg.C for 30min to obtain incubation solution;
(3) and (3) adding silver nitrate, chloroauric acid and ascorbic acid with different concentrations into the hatching fluid obtained in the step (2), quickly shaking, placing in a 70 ℃ water bath, and growing for 60min to obtain a nanoparticle solution, wherein the concentration of the silver nitrate is 10 mu M, the concentration of the chloroauric acid is 0.05mM, and the concentration of the ascorbic acid is 0.8 mM.
(4) And (4) centrifuging the nanoparticle solution obtained in the step (3) twice at the rotating speed of 9500rpm for 15min, removing the supernatant, adding a 2mM CTAB aqueous solution serving as a surfactant into the lower-layer precipitate, and uniformly mixing. Adding sodium citrate, and assembling at 60 deg.C for 30min to obtain the chiral assembly.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
the extinction spectrum of the core-shell particles corresponding to the sequential incubation sequence of the chiral mercapto molecules and the achiral mercapto molecules is shown in FIG. 9; the CD and extinction spectrum of the core-shell structure in the kinetic process corresponding to the assembly of 30min at 60 ℃ are shown in figure 10, the trend graph of the corresponding g factor and the assembly degree is shown in figure 10, and a larger chiral grid can obtain a larger chiral driving force.
Example 5
In this example, the effect of the thickness of the shell layer on the chiral driving source is discussed, and the method comprises the following steps:
(1) incubating a mixed solution of gold nanorod particles (the length-diameter ratio of which is 3.08), a surfactant (CTAB) and cysteine at 30 ℃ for 30min to obtain an incubated mixed solution, wherein the particle concentration of the gold nanorod particles is 0.1nM, the concentration of the surfactant is 10mM, and the concentration of the cysteine is 5 μ M;
(2) centrifuging the incubated mixed solution obtained in the step (1) at 9500rpm for 15min, removing supernatant, adding 10mM surfactant aqueous solution into the lower precipitate, mixing, and incubating at 30 deg.C for 30min to obtain incubation solution;
(3) and (3) adding silver nitrate, chloroauric acid and ascorbic acid with different concentrations into the hatching solution obtained in the step (2), quickly shaking, placing in a water bath kettle at 70 ℃, and growing for 60min to obtain a nanoparticle solution, wherein the concentration of the silver nitrate is 10 mu M, the concentration of the chloroauric acid is 0.03-0.08 mM, and the concentration of the ascorbic acid is 0.48-0.96 mM.
(4) And (4) centrifuging the nanoparticle solution obtained in the step (3) twice at the rotating speed of 9500rpm for 15min, removing the supernatant, adding a 2mM CTAB aqueous solution serving as a surfactant into the lower-layer precipitate, and uniformly mixing. Adding sodium citrate, and assembling at 60 deg.C for 30min to obtain the chiral assembly.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
the extinction spectrum of the core-shell nano-particles with different shell thicknesses obtained by regrowth is shown in fig. 11, and as the shell thickness is increased, the blue shift degree of the core-shell particle extinction spectrum relative to the original gold rod is increased, and the absorption at 400nm is also increased; the morphology of the sample is TEM represented as shown in FIG. 12; CD and extinction spectra of the core-shell particles during the kinetic process of assembly at 60 ℃ for 30min are shown in FIG. 13, g-factor spectra corresponding to the assembly degree at 30min are shown in FIGS. 14a and 14b, and the maximum g-factor is obtained at a concentration of 0.05mM of chloroauric acid added during regrowth, and therefore, the gold source is used in the examples described later.
Example 6
This example studies the effect of assembly temperature on chiral assemblies, the method comprising the steps of:
(1) incubating a mixed solution of gold nanorod particles (the length-diameter ratio of which is 3.08), a surfactant (CTAB) and cysteine at 30 ℃ for 30min to obtain an incubated mixed solution, wherein the particle concentration of the gold nanorod particles is 0.1nM, the concentration of the surfactant is 10mM, and the concentration of the cysteine is 5 μ M;
(2) centrifuging the incubated mixed solution obtained in the step (1) at 9500rpm for 15min, removing supernatant, adding 10mM surfactant aqueous solution into the lower precipitate, mixing, and incubating at 30 deg.C for 30min to obtain incubation solution;
(3) and (3) adding silver nitrate, chloroauric acid and ascorbic acid with different concentrations into the hatching fluid obtained in the step (2), quickly shaking, placing in a 70 ℃ water bath, and growing for 60min to obtain a nanoparticle solution, wherein the concentration of the silver nitrate is 10 mu M, the concentration of the chloroauric acid is 0.05mM, and the concentration of the ascorbic acid is 0.8 mM.
(4) And (4) centrifuging the nanoparticle solution obtained in the step (3) twice at the rotating speed of 9500rpm for 15min, removing the supernatant, adding a 2mM CTAB aqueous solution serving as a surfactant into the lower-layer precipitate, and uniformly mixing. And adding sodium citrate to assemble at 30-70 ℃ to obtain the chiral assembly in side-by-side assembly.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
for the sample with CTAB as the surface ligand layer, the analysis of the dynamic process of assembly at different temperatures gave the CD and extinction spectra of the same assembly degree at different temperatures, as shown in FIG. 15a, corresponding to g at 600nmmaxThe factor spectrum is shown in FIG. 15 b. G of assemblies assembled at 60 ℃ at similar degrees of assemblymaxThe factor is slightly larger than the other assembly temperatures. Overall, the degree of assembly is a determining factor in PCD response.
Example 7
In this example, which discusses the effect of surfactant CTAB concentration on chiral assembly PCD, the method described for preparing core-shell particles was in accordance with example 6, the concentration of surfactant CTAB was adjusted to 0.5mM, 1mM, 2mM before assembly of the core-shell particles, and the core-shell particles were assembled at 30 and 60 ℃ respectively.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
the CD and extinction spectra at the same assembly degree at 30 ℃ are shown in FIG. 16a, the trend graphs of g-factor and assembly degree at 30 and 60 ℃ are shown in FIG. 16b, and at the similar assembly degree, at three CTAB concentrations, the PCD signal shows a certain temperature amplification effect
Example 8
In this example, discussing the regulation of the formation of ligand layers on the outer surface of the rod-shaped core-shell particles on the signals of the chiral assembly PCD, the method for preparing the core-shell particles is the same as that in example 6, 2.5 mu M of achiral sulfhydryl molecule cysteamine is added to the core-shell particles before the assembly, the core-shell particles are incubated at 30 ℃ for 30min, and the heads of the particles are blocked, and then 5 mu M of long-chain sulfhydryl molecule PEG-NH is added2(HS-C11-(EG)6-OCH2NH2HCl) changes the composition and structure of the CTAB bilayer of the surfactant, the core-shell particlesThe assembly was carried out at 30 and 60 ℃ respectively.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
CD and extinction spectra at the same assembly degree as shown in fig. 17, the PCD signal of the high temperature assembled sample was smaller after the CTAB bilayer was changed, indicating that the ligand layer responsible for assembly is also crucial for the influence of PCD.
Example 9
In this example, which discusses the control of the long-chain thiol ligand layer on the chiral assembly PCD, the method for preparing the core-shell particles is the same as in example 6, the core-shell particles are added with 2.5 μ M PEG-OMe (HS-C11- (EG) of long-chain thiol molecules before assembly6-OCH3) Blocking the head, adding 15 μ M PEG-NH2(HS-C11-(EG)6-OCH2NH2HCl) centrifugation to remove CTAB, and assembly of core-shell particles at 30 and 60 ℃ respectively.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
the CD and extinction spectra at the same assembly degree are shown in fig. 18, and the assembled PCD signal formed by the long-chain mercapto molecule as the surface ligand is weaker and has no PCD temperature amplification effect.
Example 10
In this example, the control of other double-layer surfactants on the chiral assembly of nanoparticles for constructing chiral driving layer separation is discussed, and the method for preparing core-shell particles is the same as that in example 6, CTAB of the core-shell particles is removed by centrifugation before assembly, and replaced with cetylpyridinium chloride (CPC), and the core-shell particles are assembled at 30 and 60 ℃.
The core-shell nanoparticles and assemblies thereof in this example were characterized with the following results:
CPC was assembled as a surfactant at 30 and 60 ℃ respectively, CD and extinction spectra at the same assembly degree are shown in fig. 19a, CPC and CTAB were assembled at 30 and 60 ℃ respectively, CD and extinction spectra at the same assembly degree are shown in fig. 19b, the magnification is shown in fig. 19c, and the assembly of surfactant CPC as a surface ligand layer had a significant PCD temperature magnification effect, and the magnification was about 4.
Comparative example 1
The comparative example provides a silver-coated gold nanorod side-by-side chiral oligomer, and the preparation method is shown in CN 107552778A.
Temperature and ion tests are carried out on the nano material obtained in the comparative example 1, and the assembly described in the comparative example 1 can not present PCD signals at high temperature; the PCD signal disappears due to the addition of metal ions; the assembly stability time is short; it can be seen from comparison between comparative example 1 and the example that the material of the example is not interfered by temperature and external metal ions, can present a stable and large PCD signal, and is easier to regulate.
Comparative example 2
The comparative example provides a gold nanorod-silica shell structure nano material, and the preparation method is shown in CN 105036070A.
The nano material obtained by the comparative example 2 is tested by an electron microscope and a spectrum, and the assembly of the comparative example 2 is disordered, is not singly assembled side by side and has low strength, and chiral molecules are positioned on the outer layer of the gold nanorod and are easily influenced and interfered in the coating process; the silicon dioxide limits the conformation of the assembly body, and the conformation can not be further optimized through additional conditions, so that a larger chiral signal is realized; as can be seen from comparison between the comparative example 2 and the example, the separation of the chiral driving layer and the assembly layer is realized in the example, the assembly process is not influenced or interfered, and an ordered side-by-side assembly body can be formed and a large PCD signal is presented; the assembled driving layer can be regulated and controlled by external means such as temperature and the like, so that PCD is further enhanced, and the method has wider application value.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.
Claims (10)
1. The chiral assembly is characterized by comprising core-shell-structured nanorod particles arranged side by side and an assembly driving layer arranged on the surfaces of the core-shell-structured nanorod particles.
2. The chiral assembly of claim 1, wherein the number of nanorod particles of core-shell structure arranged side-by-side in the chiral assembly is 2-5;
preferably, the side-by-side arrangement is a parallel arrangement;
preferably, the nanorod particles with the core-shell structure comprise a core layer, a shell layer and a chiral driving layer positioned between the core layer and the shell layer;
preferably, the core layer is made of nanorod particles;
preferably, the nanorod particles comprise gold nanorod particles;
preferably, the length-diameter ratio of the nanorod particles is 1.5-4, preferably 3.08;
preferably, the chiral driving layer is bonded on the surface of the nuclear layer;
preferably, the material of the chiral driving layer is a chiral molecule containing a mercapto group;
preferably, the thiol-containing chiral molecule comprises any one or a combination of at least two of cysteine, glutathione, or vitamin Bt, preferably cysteine;
preferably, the material of the metal layer comprises silver or a combination of silver and gold;
preferably, the thickness of the metal layer is 7-9 nm.
3. The chiral assembly of claim 1 or 2, wherein the assembly driving layer is deposited on the surface of nanorod particles with a core-shell structure;
preferably, the material of the assembly driving layer is a combination of a surfactant and a connecting agent;
preferably, the surfactant comprises any one of or a combination of at least two of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, cetylpyridinium chloride or mercapto polyethylene glycol analogues;
preferably, the linking agent comprises sodium citrate.
4. A method of preparing a chiral assembly according to any one of claims 1 to 3, comprising: and adding a connecting agent into the dispersion liquid of the nanorod particles with the core-shell structure for assembly to obtain the chiral assembly.
5. The preparation method according to claim 4, wherein the dispersion of core-shell-structured nanorod particles is dispersed by dispersing core-shell-structured nanorod particles into an aqueous solution containing a surfactant;
preferably, the surfactant comprises any one of or a combination of at least two of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, cetylpyridinium chloride or mercapto polyethylene glycol analogues;
preferably, the linking agent is sodium citrate;
preferably, the temperature of the assembly is 25-70 ℃, preferably 60 ℃;
preferably, the time of assembly is 10-90min, preferably 30 min.
6. The preparation method according to claim 4 or 5, wherein the preparation method of the nanorod particles with the core-shell structure comprises the following steps:
(1) incubating the mixed solution of the nanorod particles, the surfactant and the chiral molecules containing sulfydryl to obtain incubated mixed solution;
(2) and (2) adding a metal source and a reducing agent into the incubated mixed solution obtained in the step (1) for growth to obtain the nanorod particles with the core-shell structure.
7. The method according to claim 6, wherein the concentration of nanorod particles in the mixed solution of step (1) is 0.05-0.2nM, preferably 0.08-0.15 nM;
preferably, the nanorod particles in the step (1) are gold nanorod particles;
preferably, the length-to-diameter ratio of the gold nanorod particles is 1.5-4, preferably 3.08;
preferably, the thiol-containing chiral molecule of step (1) is cysteine;
preferably, in the mixed solution in the step (1), the concentration of the chiral molecules containing sulfydryl is 1-100 μ M;
preferably, the surfactant of step (1) is cetyl trimethyl ammonium bromide;
preferably, the concentration of the surfactant in the mixed solution in the step (1) is 1-20mM, preferably 5-15 Mm;
preferably, the incubation temperature in the step (1) is 20-40 ℃;
preferably, the incubation time in step (1) is 30-180 min.
8. The method according to claim 6 or 7, wherein the step (2) further comprises separating and re-dispersing the incubated mixed solution in advance;
preferably, the separation mode comprises the step of carrying out centrifugal separation on the incubated mixed solution to obtain a lower-layer precipitate;
preferably, said redispersing comprises incubating the lower precipitate redispersing into a solution containing a surfactant;
preferably, the incubation temperature is 20-40 ℃;
preferably, the incubation time is 30-180 min;
preferably, the surfactant concentration in the surfactant-containing solution is 1-20mM, preferably 5-15 mM;
preferably, the metal source comprises a silver source or a combination of a gold source and a silver source, preferably a combination of a gold source and a silver source;
preferably, the metal source is a combination of a gold source comprising chloroauric acid and a silver source comprising silver nitrate;
preferably, the metal source is a combination of a gold source and a silver source, and the molar ratio of the gold source to the underlying precipitate is (0.2-1):1, preferably (0.25-0.8): 1;
preferably, the metal source is a combination of a gold source and a silver source, and the molar ratio of the silver source to the underlying precipitate is (0.09-1): 1.
9. The production method according to any one of claims 6 to 8, wherein the reducing agent in step (2) is ascorbic acid;
preferably, the molar ratio of the reducing agent to the gold source in the step (2) is (1.5-20):1, preferably (1.6-16): 1;
preferably, the temperature of the growth in the step (2) is 65-75 ℃;
preferably, the growth time of the step (2) is 30-120 min;
preferably, the step (2) further comprises the steps of performing centrifugal separation on the growth mixed solution obtained after growth, and removing the supernatant to obtain the lower-layer precipitate metal nanoparticles.
10. The method according to any one of claims 4 to 9, characterized by comprising the steps of:
(1) incubating the mixed solution of the nanorod particles, the surfactant and the chiral molecules containing sulfydryl at the temperature of 20-40 ℃ for 30-180min to obtain incubated mixed solution;
(2) centrifuging the incubated mixed solution obtained in the step (1) to obtain a lower-layer precipitate, and then dispersing the lower-layer precipitate into a 1-20mM aqueous solution containing a surfactant for incubation at 20-40 ℃ for 30-180min to obtain an incubation solution;
(3) adding a metal source and ascorbic acid into the hatching fluid obtained in the step (2), growing for 30-120min at 65-75 ℃, centrifuging, and removing supernatant to obtain nanorod particles with a core-shell structure;
(4) and (4) placing the nanorod particles with the core-shell structure obtained in the step (3) into an aqueous solution containing a surfactant for dispersion, then adding a connecting agent, and assembling at 25-70 ℃ for 10-90min to obtain the chiral assembly.
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