CN114082971A

CN114082971A - Preparation method and application of chiral metal nano spiral fiber array

Info

Publication number: CN114082971A
Application number: CN202010777042.1A
Authority: CN
Inventors: 车顺爱; 杨普; 韩光
Original assignee: Haining Ruichuang New Materials Co ltd; Shanghai Jiao Tong University
Current assignee: Haining Ruichuang New Materials Co ltd; Shanghai Jiao Tong University
Priority date: 2020-08-05
Filing date: 2020-08-05
Publication date: 2022-02-25

Abstract

The invention provides a preparation method and application of a chiral metal nano-spiral fiber array, including the following steps: step S1, put the substrate in a hydroxylation reagent, and then take it out for washing to obtain a hydroxylated substrate; step S2, remove the hydroxyl group The silylated substrate is placed in the aminosilylation reagent, and then taken out and washed to obtain an aminosilylated substrate; in step S3, the aminosilylated substrate is immersed in a solution containing metal species so that the metal species is loaded to obtain a metal species-loaded substrate; Step S4, placing the metal seed-loaded substrate into a mixed solution containing a metal source and an inducer, and performing an electrodeposition reaction to grow a metal nano-spiral fiber array on the metal-seeded substrate; Step S5, removing residues in the metal nano-spiral fiber array inducer. The preparation method of the invention is simple and feasible, can save raw materials, and the product has obvious chirality and is widely used. The present invention can also be applied to distinguish different enantiomers of chiral molecules.

Description

Preparation method and application of chiral metal nano spiral fiber array

Technical Field

The invention relates to the field of metal nano materials, in particular to a preparation method and application of a Chiral metal nano spiral fiber array (CANAs).

Background

The metal nano material has high electron density, dielectric property and catalytic capability, can be combined with various biological macromolecules and does not influence the biological activity, so the metal nano material has wide application in the fields of analysis and detection, biosensing, disease treatment and the like.

At present, various metal nanomaterials with different morphologies, including metal nanomaterials with chiral characteristics, have been synthesized by physical methods or chemical methods. The physical method is to control the morphology of the metal material by glancing angle deposition and the like, and the chemical method is to change the morphology of the metal material by introducing a template.

However, the physical method has a problem that fine structure control is difficult to perform, and the chemical method has problems that a material structure is difficult to control, a material chiral structure cannot be reserved after a template is removed, and the like, so that the application of the existing chiral metal material is limited. In addition, a large amount of solution containing metal or metal ions is usually required in the chemical method, and the solution has high cost and is easy to pollute the environment, so that the overall preparation cost is increased, the industrial application is not facilitated, and the environmental protection is also not facilitated.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for preparing a chiral metal nanospiral fiber array that can achieve fine structure control and does not leave any organic matter such as a template.

The invention provides a preparation method of a chiral metal nano spiral fiber array, which is characterized by comprising the following steps: step S1, placing the substrate into a hydroxylation reagent for standing, taking out and washing to obtain a hydroxylated substrate; step S2, putting the hydroxylated substrate into an amino silanization reagent for standing, taking out and washing to obtain an amino silanization substrate; step S3, placing the amino silanization substrate into a solution containing metal seeds to be soaked so as to load the metal seeds, and obtaining a loaded metal seed substrate; step S4, putting the load metal seed substrate into a mixed solution containing a metal source and an inducer, and reacting by using an electro-deposition device under preset time and preset voltage, so as to grow a metal nano spiral fiber array on the load metal seed substrate; and step S5, removing the residual inducer in the metal nano spiral fiber array, wherein the inducer is a chiral inducer.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: wherein, the hydroxylation reagent is a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: wherein, the metal species in the step S3 is one or a mixture of gold species and silver species; in step S4, the metal source is one of gold species and silver species or a mixture of the two.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: in step S4, the mixed solution further contains a stabilizer, preferably a thiol-containing compound.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: wherein the stabilizer is 4-mercaptobenzoic acid.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: wherein, the chiral inducer is a chiral organic micromolecule or macromolecule containing functional groups.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: in step S4, the electrodeposition apparatus is a multi-electrode system, and the working electrode of the multi-electrode system is a metal seed supporting substrate.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: wherein the preset time in the step S4 is 5 min-30 min.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: wherein, the preset voltage of the step S4 is-0.4V-0.1V.

The preparation method of the chiral metal nano spiral fiber array provided by the invention can also have the following characteristics: wherein, the method for removing the residual inducer in the metal nano spiral fiber array in the step S5 is to soak the metal nano spiral fiber array in NaBH₄Solution, electrochemical oxidation, or chemical ligand exchange. Specifically, in the electrochemical oxidation method, an electrochemical CV cycle is used for 900 cycles in a 0.1mol/L NaOH solution, and the residual inducer is consumed by oxidation-reduction reaction.

The invention also provides an application of the chiral metal nano spiral fiber array in chiral molecule detection, which has the following characteristics: the chiral metal nano spiral fiber array is matched with a Raman spectrometer for use so as to detect chiral compounds, wherein the chiral metal nano spiral fiber array is prepared by any one of the preparation methods of the chiral metal nano spiral fiber array.

Action and Effect of the invention

According to the preparation method of the chiral metal nano-spiral fiber array, hydroxylation, amino silanization and gold seed loading are sequentially carried out on the substrate, and then the chiral metal nano-spiral fiber array is grown through electrochemical deposition reaction, so that the chiral metal nano-spiral fiber array which is orderly arranged can be obtained. In the invention, the chiral inducer is adopted to carry out chiral induction on the growth process of the nano-fiber, so that the metal material forms a chiral morphological structure, and the chiral inducer enables the metal material to be spontaneously assembled into a chiral structure in an induction mode, so that the chiral structure can be retained after being removed. In addition, in the invention, because the chiral metal nano spiral fiber array is prepared by adopting an electrochemical deposition method, the used growth solution can be recycled, so that the use of raw materials can be greatly reduced, the cost can be reduced, the method is more suitable for industrial production, and the method is more environment-friendly.

In addition, the invention also provides an application of the chiral metal nano spiral fiber array in detecting chiral compounds, and the chiral metal nano spiral fiber array can be used as a substrate material for carrying out specific Raman scattering signal enhancement on the chiral compounds during Raman scattering detection, so that the enhancement degrees of antipodes are different, and the content ratio of the antipodes can be calculated through the characteristic peak intensity in Raman spectrum. The chiral metal nano spiral fiber array can be combined with a common Raman spectrometer to realize the detection of the chiral compound, and has the advantages of low cost, simple operation, small interference, accurate result, simple operation, wide application and the like.

Drawings

FIG. 1 is a flow chart of the preparation of chiral metal nano-helical fiber array of the present invention;

FIG. 2 is a scanning electron micrograph of an L-shaped gold nano spiral fiber array prepared in example 1 of the present invention;

FIG. 3 is a high-power scanning electron micrograph of an L-shaped gold nano spiral fiber array prepared in example 1 of the present invention;

FIG. 4 is a low-power transmission electron micrograph of an L-shaped gold nano spiral fiber array prepared in example 1 of the present invention;

FIG. 5 is a high-power transmission electron micrograph of an L-shaped gold nano spiral fiber array prepared in example 1 of the present invention;

FIG. 6 is a high power transmission electron micrograph of a single fiber of an L-shaped gold nano spiral fiber array prepared in example 1 of the present invention;

FIG. 7 is circular dichroism spectra of an L-type gold nano-spiral fiber array prepared in example 1 and an R-type gold nano-spiral fiber array prepared in example 2;

FIG. 8 is a scanning electron micrograph of an array of gold nanofibers made using a hydroxylated substrate of comparative example 1;

FIG. 9 is a high-power scanning electron micrograph of an array of gold nanofibers made using a hydroxylated substrate in comparative example 1;

fig. 10 is a low-power scanning electron micrograph of a gold nanofiber array prepared using an amino silanized substrate in comparative example 2;

fig. 11 is a high-power scanning electron micrograph of a gold nanofiber array prepared using an amino silanized substrate in comparative example 2;

FIG. 12 is a scanning electron micrograph of a chiral gold nano spiral fiber array prepared at a deposition voltage of-0.4V in example 3 of the present invention;

FIG. 13 is a scanning electron micrograph of a chiral gold nano spiral fiber array prepared at a deposition voltage of-0.3V in example 4 of the present invention;

FIG. 14 is a scanning electron micrograph of a material obtained at a deposition voltage of-0.1V in example 5 of the present invention;

FIG. 15 is a scanning electron micrograph of a material obtained in comparative example 3 at a deposition voltage of 0.1V;

FIG. 16 is a scanning electron micrograph of a material obtained in comparative example 4 at a deposition voltage of 0.2V;

FIG. 17 is a scanning electron micrograph of a material obtained in comparative example 5 at a deposition voltage of 0.3V;

FIG. 18 is a scanning electron micrograph of a material obtained in comparative example 6 at a deposition voltage of 0.4V;

FIG. 19 is a scanning electron microscope photomicrograph of 9 sets of chiral gold nano spiral fiber arrays obtained by 9 cycles in example 6 of the present invention;

FIG. 20 is a scanning electron micrograph of a chiral Au-Ag nanospiral fiber array prepared in example 7 according to the present invention;

FIG. 21 is a Raman spectrum of L/D proline detected by using chiral gold nano-helical fiber array in the test example of the present invention.

Detailed Description

FIG. 1 is a flow chart of the preparation of the chiral metal nano-helical fiber array of the present invention.

As shown in fig. 1, the preparation method of the chiral metal nano spiral fiber array of the present invention comprises the following steps:

step S1, placing the substrate into a hydroxylation reagent for standing, taking out and washing to obtain a hydroxylated substrate;

step S2, putting the hydroxylated substrate into an amino silanization reagent for standing, taking out and washing to obtain an amino silanization substrate;

step S3, placing the amino silanization substrate into a solution containing metal seeds to be soaked so as to load the metal seeds, and obtaining a loaded metal seed substrate;

step S4, putting the load metal seed substrate into a mixed solution containing a metal source and an inducer, and reacting by using an electro-deposition device under preset time and preset voltage, so as to grow a metal nano spiral fiber array on the load metal seed substrate;

and step S5, removing the residual inducer in the metal nano spiral fiber array, wherein the inducer is a chiral inducer.

In order to make the technical means, the creation features, the achievement purposes and the effects of the invention easy to understand, the invention is specifically described below by combining the embodiment and the attached drawings.

In the following examples, the main component sources are:

an N-type conductive silicon substrate (model #905301, diameter 100mm, thickness 510-.

< example 1>

The embodiment provides a preparation method of a chiral metal nano spiral fiber array, which specifically comprises the following steps:

step S1, the N-type conductive silicon substrate is cleaned in advance, and the manner of cleaning in advance is as follows: firstly, cutting an N-type conductive silicon substrate into the size of 1x2cm, then respectively placing the N-type conductive silicon substrate in acetone, ethanol and deionized water for 30min by ultrasonic waves, and cleaning the solvent on the surface of the N-type conductive silicon substrate by using ultrapure water when the cleaning solvent is replaced each time; putting the cleaned N-type conductive silicon substrate into a mixed solution containing 15mL of 95-98% concentrated sulfuric acid and 15mL of 30% hydrogen peroxide (the volume ratio of the concentrated sulfuric acid to the hydrogen peroxide is 1:1), heating in a water bath at 60 ℃ for 2h, carrying out ultrasonic treatment for 30min, taking out, and washing with deionized water for three times to obtain a hydroxylated substrate;

step S2, soaking the hydroxylated substrate in 5 mmol/L3-aminopropyl trimethoxy silane solution, standing for 2h, performing ultrasonic treatment for 30min, taking out, and washing with deionized water for three times to obtain an amino silanized substrate;

step S3, placing the amino silanization substrate into a solution containing gold seeds to be soaked for 2 hours to enable the amino silanization substrate to be loaded with the gold seeds, and obtaining a gold seed loaded substrate; wherein the gold seed solution is 10mL2.5x10^-4mol/L trisodium citrate solution and 10mL2.5X10^-4mol/L HAuCl₄Mixed solution of the solutions 600. mu.L of 0.1M NaBH at room temperature₄Reducing to form gold species.

Step S4, placing the substrate loaded with gold seeds into a growth solution (the growth solution is a mixed solution consisting of 1.2mL of ethanol, 1.75mL of water, 100 mu L of 100mmol/L N-acetyl-L cysteine, 600 mu L of 4-mercaptobenzoic acid and 375 mu L of 100mmol/L chloroauric acid solution), performing electrodeposition reaction in a three-electrode system, wherein the working electrode is the substrate loaded with gold seeds, the reference electrode is an Ag/AgCl electrode, the counter electrode is a carbon rod, the deposition voltage is-0.2V, the preset time is 11min, taking out the substrate after the reaction is finished, soaking the substrate in absolute ethanol for 10min, repeating the steps twice, soaking the substrate in deionized water for 10min, and finally performing vacuum drying to obtain the gold nano spiral fiber array substrate with the residual inducer;

step S5, soaking the metal nano spiral fiber array substrate with the residual inducer in 0.001mol/L NaBH₄And (3) circulating for 900 circles in the solution for 1 hour or in 0.1mol/L NaOH solution by using electrochemical CV, allowing the solution to generate redox reaction for consumption, and removing residual organic inducer to obtain the L-type gold nano spiral fiber array.

Fig. 2 is a low-power scanning electron microscope photograph of the L-type gold nano spiral fiber array prepared in example 1 of the present invention, fig. 3 is a high-power scanning electron microscope photograph of the L-type gold nano spiral fiber array prepared in example 1 of the present invention, fig. 4 is a low-power transmission electron microscope photograph of the L-type gold nano spiral fiber array prepared in example 1 of the present invention, and fig. 5 is a high-power transmission electron microscope photograph of the L-type gold nano spiral fiber array prepared in example 1 of the present invention.

As shown in fig. 2 to 5, the L-shaped gold nano spiral fiber array prepared in example 1 is composed of single-stranded gold nano spiral fibers arranged in order, each gold nano spiral fiber has a length of about 900nm and a diameter of about 7 nm.

FIG. 6 is a high-power transmission electron microscope photograph of a single fiber of an L-type gold nano spiral fiber array prepared in example 1 of the present invention.

As shown in FIG. 6, the pitch of the fiber in the L-type gold nano spiral fiber array prepared in example 1 was about 45 nm.

< example 2>

This example provides a preparation method of a chiral metal nano spiral fiber array, which has substantially the same process as example 1, except that N-acetyl-D-cysteine is used as the inducing agent in step S4, and finally an R-type gold nano spiral fiber array is obtained.

FIG. 7 is circular dichroism spectra of L-type gold nano-spiral fiber array prepared in example 1 and R-type gold nano-spiral fiber array prepared in example 2.

In FIG. 7, L-CANAs is an L-type gold nano-spiral fiber array, and R-CANAs is an R-type gold nano-spiral fiber array.

As shown in fig. 7, the L-type gold nanospiral fiber array and the R-type gold nanospiral fiber array have distinct circular dichroism, indicating that the two have opposite chirality.

< comparative example 1>

The comparative example used a hydroxylated substrate directly as the working electrode to prepare a gold nanofiber array, and the specific process was as follows:

putting a hydroxylated substrate into a growth solution (the growth solution is the same as that in example 1), carrying out an electrodeposition reaction in a three-electrode system, wherein the working electrode is the hydroxylated substrate, the reference electrode is an Ag/AgCl electrode, the counter electrode is a carbon rod, the deposition voltage is-0.2V, the preset time is 11min, taking out the hydroxylated substrate after the reaction is finished, soaking the hydroxylated substrate in absolute ethyl alcohol for 10min, repeating the soaking for two times, then soaking the hydroxylated substrate in deionized water for 10min, and really soaking the hydroxylated substrate in the deionized water for 10minAfter air drying, soaking in 0.001mol/L NaBH₄And (5) removing the residual organic inducer in the solution for 1h to obtain the gold nanofiber array prepared by using the hydroxylated substrate.

Among them, the method for preparing the hydroxylated substrate was the same as that of example 1.

Fig. 8 is a low-power scanning electron micrograph of the gold nanofiber array prepared using the hydroxylated substrate in comparative example 1, and fig. 9 is a high-power scanning electron micrograph of the gold nanofiber array prepared using the hydroxylated substrate in comparative example 1.

As shown in fig. 8 and 9, when the hydroxylated substrate is directly used as the working electrode, the aligned gold nanofiber array is not obtained, but the bottom of the substrate has some wound nanowires, and the top is a random accumulation of blocks.

The gold nanofiber prepared under the condition has no circular dichroism through detection.

< comparative example 2>

The present comparative example, which was substantially the same as comparative example 1 except that the working electrode was an amino silanized substrate, prepared a gold nanofiber array using the amino silanized substrate directly as the working electrode. The method for producing the aminosilane substrate was the same as that used in example 1.

Fig. 10 is a low-power scanning electron micrograph of the gold nanofiber array prepared using the aminosilylated substrate in comparative example 2, and fig. 11 is a high-power scanning electron micrograph of the gold nanofiber array prepared using the aminosilylated substrate in comparative example 2.

As shown in fig. 10 and 11, when the substrate with the amino silane group is directly used as the working electrode, an array of aligned gold nanofibers can be formed, the diameter of the nanofibers is about 25nm, but the head is significantly aggregated.

Examples effects and effects

According to the methods of preparing chiral metal nano-helical fiber arrays according to embodiments 1 and 2, since hydroxylation, amino-silanization, and gold species loading are sequentially performed on an N-type conductive silicon substrate, and then the chiral gold nano-helical fiber array is grown through an electrochemical deposition reaction, the chiral gold nano-helical fiber array arranged in order can be obtained. Whereas in comparative examples 1 and 2, when the growth was directly performed using the hydroxylated substrate and the aminosilane substrate as the working electrodes, the chiral metal nano-helical fiber array having circular dichroism was not obtained.

In the preparation methods of example 1 and example 2, the chiral inducer is used to induce chirality in the growth process of the nanofibers, so that the metal material forms a chiral morphological structure, and the chiral inducer spontaneously assembles to form a chiral structure by an inducing manner, so that the chiral structure can be maintained after removal.

In addition, in example 1 and example 2, since NaBH was used after the completion of the growth of the chiral gold nano-helical fiber array₄The residual organic inducer is removed by the solution, so that the falling-off of the film (namely the gold nano spiral fiber array) on the substrate can be effectively reduced in the process of removing the residual organic inducer, and the integrity of the spiral fiber array is ensured while the interference of the organic inducer is removed.

< example 3>

This example is an experiment of chiral metal nanospiral fiber arrays prepared at different deposition voltages. The manufacturing process of this example is substantially the same as that of example 1, except that the deposition voltage of step S4 is different: in this example, the deposition voltage was-0.4V. The method comprises the following specific steps:

and step S4, putting the prepared substrate loaded with the gold seeds into a growth solution, carrying out electrodeposition reaction in a three-electrode system, wherein the working electrode is the substrate loaded with the gold seeds, the reference electrode is an Ag/AgCl electrode, the counter electrode is a carbon rod, the deposition voltage is-0.4V, the preset time is 11min, taking out the substrate after the reaction is finished, soaking the substrate in ethanol for 10min, repeating the steps for two times, soaking the substrate in deionized water for 10min, and carrying out vacuum drying.

FIG. 12 is a scanning electron micrograph of a chiral Au nano spiral fiber array prepared at a deposition voltage of-0.4V in example 3 of the present invention.

As shown in fig. 12, when the deposition voltage is-0.4V, a chiral gold nano-spiral fiber array can be formed, the length of each corresponding gold nano-spiral fiber is about 800nm, the diameter is about 13-15nm, and the top of the nano-wire is wound.

< example 4>

This example is an experiment of chiral metal nanospiral fiber arrays prepared at different deposition voltages. The manufacturing process of this example is substantially the same as that of example 3, except that the deposition voltage of step S4 is different: in this example, the deposition voltage was-0.3V.

FIG. 13 is a scanning electron micrograph of a chiral Au nano spiral fiber array prepared at a deposition voltage of-0.3V in example 4 of the present invention.

As shown in fig. 13, an array of chiral gold nanospiral fibers can be formed at a deposition voltage of-0.3V, with each corresponding gold nanospiral fiber having a length of about 500nm and a diameter of about 20nm, and with a severe aggregation of spherical particles at the top of the nanowires, which may be strongly related to the size of the gold species.

< example 5>

This example is an experiment of chiral metal nanospiral fiber arrays prepared at different deposition voltages. The manufacturing process of this example is substantially the same as that of example 3, except that the deposition voltage of step S4 is different: in this example, the deposition voltage was-0.1V.

FIG. 14 is a scanning electron micrograph of a chiral Au nano spiral fiber array prepared at a deposition voltage of-0.1V in example 5 of the present invention.

As shown in FIG. 14, when the deposition voltage is-0.1V, an array of gold nano-spiral fibers can be formed, the length of each corresponding gold nano-spiral fiber is about 500-600nm, the diameter is about 8-10nm, and the nanowires are intertwined with each other, and also many aggregates are present at the top of the nanowires.

< comparative example 3>

This comparative example is substantially the same as example 3, differing only in the deposition voltage of step S4: the deposition voltage in this comparative example was 0.1V.

FIG. 15 is a low-power scanning electron micrograph of the chiral gold nano spiral fiber array obtained in comparative example 3 at a deposition voltage of 0.1V.

As shown in fig. 15, when the deposition voltage is 0.1V, an array of gold nano-spiral fibers can be formed, the length of each corresponding gold nano-spiral fiber is about 700-800nm, the diameter is about 15nm, and the nanowires are intertwined with each other, and also a plurality of aggregates are present on the top of the nanowires.

< comparative example 4>

This comparative example is substantially the same as example 3, differing only in the deposition voltage of step S4: the deposition voltage in this comparative example was 0.2V. At this deposition voltage, no chiral gold nano-helical fiber array was finally formed on the substrate.

FIG. 16 is a scanning electron micrograph of a material obtained in comparative example 4 at a deposition voltage of 0.2V.

As shown in fig. 16, the chiral gold nano spiral fiber array cannot be formed at the deposition voltage, but particles are formed to be connected with each other in a spherical packing manner and are relatively sparse.

< comparative example 5>

This comparative example is substantially the same as example 3, differing only in the deposition voltage of step S4: the deposition voltage in this comparative example was 0.3V. At this deposition voltage, no chiral gold nano-helical fiber array was finally formed on the substrate.

FIG. 17 is a scanning electron micrograph of a material obtained in comparative example 5 at a deposition voltage of 0.3V.

As shown in fig. 17, the chiral gold nanospiral fiber array could not be formed at this deposition voltage, resulting in a morphology similar to that of fig. 16 in comparative example 4.

< comparative example 6>

This comparative example is substantially the same as example 3, differing only in the deposition voltage of step S4: the deposition voltage in this comparative example was 0.4V. At this deposition voltage, no chiral gold nano-helical fiber array was finally formed on the substrate.

FIG. 18 is a scanning electron micrograph of a material obtained in comparative example 6 at a deposition voltage of 0.4V.

As shown in fig. 18, the chiral gold nanospiral fiber array could not be formed at this deposition voltage, again forming a morphology similar to that of fig. 16 in comparative example 4. .

Examples effects and effects

According to the preparation methods of the chiral metal nano spiral fiber arrays related to the above embodiments 3 to 5, since the deposition voltage is controlled to be-0.4V to 0.4V during the preparation process, the chiral gold nano spiral fiber arrays can be obtained in the embodiments 3 to 5 and the comparative example 3, and the chiral gold nano spiral fiber arrays are more neat and dense. In contrast, the deposition voltages in comparative examples 4 to 6 were 0.2V, 0.3V, and 0.4V, respectively, and the chiral metal nano-helical fiber array could not be obtained under these three deposition voltage conditions.

< example 6>

This example is an experiment of preparing a chiral metal nanospiral fiber array by cyclic electrodeposition reaction in the same growth solution. The preparation process of this example is substantially the same as that of example 3, except that this example employs a preparation method of circulating electrochemical deposition for 9 times under the same conditions in the same growth solution to obtain 9 sets of chiral gold nano spiral fiber arrays. That is, after the completion of step S4, the used growth solution was placed again on the other gold seed-loaded substrate obtained in step S3, and the electrochemical deposition was repeated using the growth solution for 9 times in total.

FIG. 19 is a scanning electron micrograph of 9 sets of chiral Au nano spiral fiber arrays obtained by 9 cycles in example 6 of the present invention.

As shown in fig. 19, the shapes of the L-type gold nano spiral fiber arrays obtained by using the same growth solution repeatedly for 9 times under the same deposition conditions are similar, and each gold nano spiral fiber has a length of about 800-900nm and a diameter of about 8 nm.

All gold nanospiral fiber arrays prepared in this example were also tested to have a pronounced circular dichroism similar to the L-type gold nanospiral fiber array of example 1.

Examples effects and effects

According to the preparation method of the chiral metal nano spiral fiber array related to the embodiment 6, the well-arranged chiral gold nano spiral fiber array can still be obtained by circulating the electrodeposition reaction for 9 times under the same growth solution, so that the growth solution in the electrodeposition reaction can be repeatedly utilized, the use of raw materials is saved compared with the prior art, the cost is reduced, and the preparation method is more suitable for industrial production.

< example 7>

This example is an experiment of chiral metal nano-spiral fiber arrays prepared from different metal sources, specifically, a preparation experiment of chiral gold-silver nano-spiral fiber arrays, the preparation process is basically the same as that in example 1, except that a gold-silver mixed metal source is used in step S4, specifically, the following:

step S4, the prepared gold seed-loaded substrate is placed into a growth solution (the growth solution is a mixed solution consisting of 1.2mL of ethanol, 1.75mL of water, 100 muL of 100mmol/L N-acetyl-L cysteine, 600 muL of 4-mercaptobenzoic acid, 287 muL of 100mmol/L chloroauric acid solution and 94 muL of 100mmol/L silver nitrate solution), electrodeposition reaction is carried out in a three-electrode system, wherein a working electrode is the gold seed-loaded substrate, a reference electrode is a saturated calomel electrode, a counter electrode is a carbon rod, the deposition voltage is-0.22V, the preset time is 11min, the substrate is taken out after the reaction is finished, the substrate is soaked in ethanol for 10min and repeated twice, then the substrate is soaked in deionized water for 10min, and vacuum drying is carried out.

FIG. 20 is a scanning electron micrograph of the chiral Au-Ag nanospiral fiber array prepared in example 7.

As shown in fig. 20, the chiral gold-silver nano spiral fiber array of the present embodiment also exhibits a regularly arranged spiral fiber morphology, but the head of the nano fiber has an aggregation phenomenon, which indicates that the electrodeposition growth reaction using the mixed metal source can also obtain the corresponding spiral fiber array material. In addition, the chiral gold-silver nano spiral fiber array also has obvious circular dichroism through detection.

Examples effects and effects

According to the method for preparing the chiral metal nano-spiral fiber array in embodiment 7, since the gold-silver mixed metal source is used in the electrochemical deposition, and the corresponding chiral gold-silver nano-spiral fiber array can be prepared, in the invention, a plurality of metal sources can be used for the growth of the chiral metal nano-spiral fiber array to prepare the corresponding mixed chiral metal nano-spiral fiber array, so that the method of the invention can be used for preparing various chiral metal nano-spiral fiber arrays with wide application of products.

< test example >

Chiral molecular detection assay

In the present test example, chirality of proline was detected using an L-type gold nano-helical fiber array prepared as in example 1 as a substrate.

The specific steps of the test are as follows: cutting the substrate into the size of 1mm multiplied by 1mm, uniformly dripping 20 mu L0.1M L-proline or D-proline on the substrate, naturally drying at room temperature, and performing chiral molecule detection under the Raman spectrum of a 532nm laser.

The test results are shown in fig. 21.

As shown in fig. 21, the L-type gold nano-spiral fiber array prepared in example 1 can enhance the raman signal of L-proline, but cannot enhance the raman signal of D-proline, so that the raman signal of D-proline is very weak, and thus the chiral nano-gold film prepared by the present invention can be used to distinguish corresponding enantiomers. In addition, through further tests, the aforementioned enhancement effect also conforms to the linear rule, so that the chiral compounds containing different enantiomers can be quantitatively detected, and the specific principle and process of the detection are described in the chinese patents CN201811479013.6 and CN201811479015.5 which have been previously applied by the applicant, and are not described herein again.

Therefore, the chiral metal nano spiral fiber array can be combined with a common Raman spectrometer to realize the detection of the chiral compound, and has the advantages of low cost, simple operation, small interference, accurate result, simple operation, wide application and the like.

The test examples are merely illustrative of specific embodiments of the present invention, and the substrate material for detecting chiral compounds and the chiral compounds to be detected according to the present invention are not limited to the ranges described in the test examples.

In the test example, the L-type gold nano spiral fiber array prepared in example 1 was used as the substrate material, however, in the present invention, the substrate material may also be other chiral metal nano spiral fiber arrays prepared according to the method of the present invention, such as D-type gold nano spiral fiber array or chiral gold-silver nano spiral fiber array prepared in other examples.

Claims

1. A preparation method of a chiral metal nano spiral fiber array is characterized by comprising the following steps:

step S2, placing the hydroxylated substrate into an amino silanization reagent for standing, taking out and washing to obtain an amino silanization substrate;

step S4, putting the load metal seed substrate into a mixed solution containing a metal source and an inducer, and reacting by using an electrodeposition device under preset time and preset voltage so as to grow a metal nano spiral fiber array on the load metal seed substrate;

step S5, removing the residual inducer in the metal nano spiral fiber array,

wherein the inducer is a chiral inducer.

2. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein the hydroxylation reagent is a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

3. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein, the metal seeds in the step S3 are one or a mixture of gold seeds and silver seeds;

in step S4, the metal source is one of gold species, silver species or a mixture of both.

4. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein, the mixed solution in the step S4 further contains a stabilizer.

5. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein, the chiral inducer is a chiral organic micromolecule or macromolecule containing functional groups.

6. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein the electrodeposition apparatus in the step S4 is a multi-electrode system,

the working electrode of the multi-electrode system is the supported metal seed substrate.

7. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein the predetermined time in the step S4 is 5min to 30 min.

8. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein, the predetermined voltage in the step S4 is-0.4V-0.1V.

9. The method for preparing the chiral metal nanospiral fiber array of claim 1, wherein:

wherein, the step S5 of removing the residual inducer in the metal nano spiral fiber array is to soak the metal nano spiral fiber array in NaBH₄Solution, electrochemical oxidation reaction or chemical ligand exchange method.

10. An application of a chiral metal nano spiral fiber array in chiral compound detection is characterized in that the chiral metal nano spiral fiber array is matched with a Raman spectrometer for use so as to detect a chiral compound,

wherein the chiral metal nano-spiral fiber array is prepared by the method for preparing the chiral metal nano-spiral fiber array according to any one of claims 1 to 9.