WO2020113724A1

WO2020113724A1 - Method for preparing chiral metal nano spiral fiber array

Info

Publication number: WO2020113724A1
Application number: PCT/CN2018/124281
Authority: WO
Inventors: 车顺爱; 刘泽栖; 段瑛滢
Original assignee: 同济大学
Priority date: 2018-12-05
Filing date: 2018-12-27
Publication date: 2020-06-11
Also published as: CN111266598A; CN111266598B

Abstract

Provided is a method for preparing a chiral metal nano spiral fiber array capable of achieving fine structure regulation and not leaving organic matter such as templates; the method for preparation comprises the following steps: step S1: placing a substrate into an aminosilanization reagent and letting it stand for a period of time, then taking it out and washing it; step S2: immersing the substrate washed in step S1 in a solution containing a metal seed so as to load a metal seed; step S3: placing the substrate carrying the metal seed into a mixed solution containing a metal source and an inducer, and adding a reducing agent to perform a growth reaction for a predetermined time, thereby growing a metal spiral fiber array on the substrate; step S4: removing the remaining inducer from the metal spiral fiber array, the inducer being a chiral inducer.

Description

Method for preparing chiral metal nano spiral fiber array

Technical field

The invention relates to a method for preparing a chiral metal nano-spiral fiber array.

Background technique

Metal nanomaterials have high electron density, dielectric properties, and catalytic capabilities. They have the advantage of being able to combine with a variety of biological macromolecules without affecting biological activity. Therefore, they have a wide range of applications in the fields of analytical detection, biosensing, and disease treatment.

At present, people have synthesized metal nanomaterials of various morphologies through physical methods or chemical methods, including metal nanomaterials with chiral characteristics. Among them, 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 the problem that it is difficult to control the fine structure, and the chemical method has the problem that the chiral structure of the material cannot be retained after removing the template, which limits the application of the existing chiral metal materials.

Summary of the invention

The purpose of the present invention is to solve the above problems and provide a method for preparing a chiral metal nano-spiral fiber array that can achieve fine structure control without leaving organic materials such as templates. The preparation method includes the following steps: Step S1. Put it in an aminosilylation reagent for a period of time and then take it out and wash it; Step S2, soak the substrate washed in step S1 in a solution containing metal species so as to support the metal species; Step S3, place the substrate loaded with metal species Into a mixed solution containing a metal source and an inducer, adding a reducing agent to perform a growth reaction for a predetermined time, thereby allowing the metal spiral fiber array to grow on the substrate; step S4, removing the residual inducer in the metal spiral fiber array, wherein the inducer It is a chiral inducer.

The preparation method of the chiral metal nano-spiral fiber array provided by the present invention may also have such technical features, wherein the mixed solution in step S3 further contains a stabilizer, the stabilizer is 4-mercaptobenzoic acid, and the content is 2mM-8mM .

The preparation method of the chiral metal nanospiral fiber array provided by the present invention may also have such technical characteristics, wherein the metal species in step S2 is one of gold species, silver species, or a mixture of the two, in step S3 The source of metal is one of gold source and silver source or a mixture of both.

The preparation method of the chiral metal nanospiral fiber array provided by the present invention may also have such technical characteristics, wherein the chiral inducer is a thiol-containing chiral compound or a thiol-containing protein.

The preparation method of the chiral metal nanospiral fiber array provided by the present invention may also have such technical characteristics, wherein the chiral compound containing a thiol group is N-acetyl-L-cysteine or N-acetyl-D-semi Cystine, a protein containing sulfhydryl groups, is trypsin or chymotrypsin.

The preparation method of the chiral metal nano-spiral fiber array provided by the present invention may also have such technical characteristics, wherein, in step S4, the residual inducer in the metal spiral fiber array substrate is removed by an electrochemical method, and the electrochemical method is cyclic volt Anfa.

The preparation method of the chiral metal nano-spiral fiber array provided by the present invention may also have such technical characteristics, wherein the reducing agent in step S3 is ascorbic acid.

The preparation method of the chiral metal nano-spiral fiber array provided by the present invention may also have such technical characteristics, wherein, in step S3, the predetermined time is 5 minutes to 30 minutes.

The preparation method of the chiral metal nano-spiral fiber array provided by the present invention may also have such technical characteristics, wherein the substrate is a silicon substrate or a quartz substrate.

The preparation method of the chiral metal nano-spiral fiber array provided by the present invention may also have such technical characteristics, wherein the substrate is a pre-cleaned substrate, and the pre-cleaning method is: placing the substrate into a solution containing concentrated sulfuric acid and peroxide The hydrogen mixed solution is heated, sonicated, and then taken out and washed with deionized water.

Invention function and effect

According to the preparation method of the chiral metal nanospiral fiber array provided by the present invention, since the chiral inducer is used to induce the chiral growth of the nanofibers, the metal material is formed into a chiral morphological structure, and, due to the The chiral inducer allows metal materials to assemble spontaneously to form chiral structures by induction, so that the chiral structures can be retained after being removed. Compared with the chiral metal material that loses chirality after removing the template in the prior art, the preparation method of the metal nanohelical fiber array of the present invention has the advantages of simple process, low cost, and wide application of products.

BRIEF DESCRIPTION

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

2 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array according to Embodiment 1 of the present invention;

3 is a high-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array according to Example 1 of the present invention; FIG. 4 is a low-power transmission electron microscope photograph of an L-shaped gold nanohelical fiber array according to Example 1 of the present invention;

5 is a high-power transmission electron microscope photograph of an L-shaped gold nanohelical fiber array according to Example 1 of the present invention;

6 is a circular dichroism spectrum of the gold nanohelical fiber array in the first embodiment of the present invention;

7 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with an amount of 4-mercaptobenzoic acid of 3.45 mM in Example 2 of the present invention;

8 is a high-magnification scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with a 4-mercaptobenzoic acid dosage of 3.45 mM according to Example 2 of the present invention;

9 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with a 4-mercaptobenzoic acid dosage of 4.14 mM according to Example 2 of the present invention;

10 is a high-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with a 4-mercaptobenzoic acid dosage of 4.14 mM in Example 2 of the present invention;

11 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with an amount of 4-mercaptobenzoic acid of 2.76 mM in Example 2 of the present invention;

12 is a high-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with an amount of 4-mercaptobenzoic acid of 2.76 mM in Example 2 of the present invention;

13 is a low-power scanning electron microscope photograph of a comparative example of the gold nanofiber array of the present invention;

14 is a high-power scanning electron microscope photograph of a gold nanofiber array of a comparative example of the present invention.

detailed description

The specific embodiments of the present invention will be described below with reference to the drawings.

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

As shown in FIG. 1, the preparation method of the metal nanospiral fiber array of the present invention specifically includes the following steps:

In step S1, the substrate is placed in an aminosilylation reagent and allowed to stand for a period of time, then taken out and washed;

Step S2, soaking the substrate washed in step S1 in a solution containing metal species to load the metal species;

Step S3, the substrate loaded with the metal species is put into a mixed solution containing a metal source and an inducer, and a reducing agent is added to perform a growth reaction for a predetermined time, so that the metal spiral fiber array is grown on the substrate to obtain a metal spiral fiber array substrate, wherein The inducer is a chiral inducer;

Step S4: Remove the inducer remaining in the metal spiral fiber array substrate.

This example is the preparation of a gold nanospiral fiber array. Specifically, in the above process, the substrate used in step S1 is a pre-cleaned silicon substrate. The pre-cleaning method is: placing the silicon substrate into a solution containing concentrated sulfuric acid and hydrogen peroxide (the volume ratio of concentrated sulfuric acid to hydrogen peroxide is 3:1) The mixed solution is heated at 60°C for 2 hours, sonicated for another half hour, and then taken out and washed three times with deionized water.

The aminosilylation reagent used in step S1 is a 5 mM 3-aminopropyltriethoxysilane solution, and the standing time is 2 hours.

The metal species in step S2 is a gold species, and the soaking time is 2 hours.

The metal source of step S3 is chloroauric acid, the inducer is chiral inducer N-acetyl-L-cysteine, and the reducing agent is ascorbic acid. Specifically, the mixed solution of the inducer and the reducing agent contains 3.45 mM chiral inducer (N-acetyl-L-cysteine or N-acetyl-D-cysteine), 2.76 mM 4-mercaptobenzoic acid , 8.62mM chloroauric acid and 20.69mM ascorbic acid.

The growth reaction in step S3 is allowed to stand at room temperature, and the predetermined reaction time is 15 minutes. In addition, in step S3, the metal spiral fiber array substrate is obtained, washed with absolute ethanol three times, and then dried.

In step S4, the residual inducer is removed by an electrochemical method, specifically cyclic voltammetry.

In this example, N-acetyl-L cysteine was used as an inducer to prepare an L-shaped gold nanohelical fiber array, and N-acetyl-D-cysteine was also used as an inducer to prepare an R-shaped gold nanometer Spiral fiber array.

FIG. 2 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array according to Embodiment 1 of the present invention, FIG. 3 is a high-power scanning electron microscope photograph of an L-shaped gold nanospiral fiber array according to Embodiment 1 of the present invention, and FIG. 4 is the present invention Low magnification transmission electron microscope photograph of the L-shaped gold nanohelical fiber array of Example 1, FIG. 5 is a high magnification transmission electron microscope photograph of the L-shaped gold nanohelical fiber array of Example 1 of the present invention.

It can be seen from FIGS. 2 to 5 that the gold nanohelical fiber array prepared in this example is composed of single-stranded gold nanohelical fibers arranged neatly, and each gold nanohelical fiber has a diameter of about 10 nm. It is estimated that the pitch of each gold nanospiral fiber is about 50nm.

FIG. 6 is a circular dichroism spectrum of the gold nanospiral fiber array in Example 1 of the present invention. In Figure 6, L-Au NHWs are L-shaped gold nanospiral fiber arrays, and R-Au NHWs are R-shaped gold nanospiral fiber arrays.

As shown in Fig. 6, the L-shaped gold nanospiral fiber array and the R-shaped gold nanospiral fiber array have obvious circular dichroism, indicating that the two have opposite chirality.

This example is an experiment of gold nanospiral fiber arrays prepared under different conditions.

A total of three gold nanospiral fiber arrays were prepared in this embodiment. The preparation process of the three kinds of gold nanohelical fiber arrays is the same as that in the first embodiment, but the conditions are different. The details are as follows:

The first one: the amount of 4-mercaptobenzoic acid in step S3 is changed to 3.45mM;

Second: the amount of 4-mercaptobenzoic acid in step S3 is changed to 4.14mM;

Third: N-acetyl L-cysteine is used in step S3, and the dosage is changed to 2.76mM.

7 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with an amount of 4-mercaptobenzoic acid of 3.45 mM in Example 2 of the present invention, and FIG. 8 is an amount of 4-mercaptobenzoic acid in Example 2 of the present invention with an amount of 3.45 High magnification scanning electron micrograph of mM L-shaped gold nanohelical fiber array.

As shown in FIGS. 7 and 8, when the amount of 4-mercaptobenzoic acid is 3.45 mM, the diameter of each gold nanohelical fiber is about 12 nm, and the pitch of each gold nanohelical fiber is about 60 nm.

9 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with a 4-mercaptobenzoic acid dosage of 4.14 mM in Example 2 of the present invention, and FIG. 10 is a 4-mercaptobenzoic acid dosage of 4.14 in Example 2 of the present invention High magnification scanning electron micrograph of mM L-shaped gold nanohelical fiber array.

As shown in FIGS. 9 and 10, when the amount of 4-mercaptobenzoic acid is 4.14 mM, the diameter of each gold nanohelical fiber is about 15 nm, and the pitch of each gold nanohelical fiber is about 75 nm.

11 is a low-power scanning electron microscope photograph of an L-shaped gold nanohelical fiber array with an amount of 2.76 mM 4-mercaptobenzoic acid in Example 2 of the present invention, and FIG. 12 is an amount of 4-mercaptobenzoic acid in Example 2 of the present invention with 2.76 mM High magnification scanning electron micrograph of mM L-shaped gold nanohelical fiber array.

As shown in FIGS. 11 and 12, when the amount of 4-mercaptobenzoic acid is 2.76 mM, the diameter of each gold nanohelical fiber is about 7 nm, and the pitch of each gold nanohelical fiber is about 35 nm.

After testing, the three types of gold nanohelical fiber arrays prepared in this example also have obvious circular dichroism similar to the gold nanohelical fiber arrays in Example 1.

This embodiment is an experiment of a metal nanospiral fiber array prepared by different metal sources, specifically a gold-silver nanospiral fiber array preparation experiment.

In this embodiment, the first four steps of the method for preparing the gold-silver nanospiral fiber array are the same as steps S1 to S3 of the embodiment. The difference is that the growth reaction in step S3 also includes a silver growth step, as follows:

The gold nanospiral fiber array obtained by the growth reaction was placed in a solution containing 5 mM silver nitrate and 10 mM ascorbic acid, and left to react for 5 minutes, taken out, washed with ethanol three times, and dried to obtain a gold-silver nanospiral fiber array.

Then, the dried gold-silver nanospiral fiber array is subjected to an organic matter removal operation to obtain a chiral gold-silver nanospiral fiber array.

The electron-microscope scanning test shows that the gold-silver nanospiral fiber array of this embodiment also exhibits neatly arranged spiral fiber morphology, indicating that the stepwise growth reaction using a mixed metal source can also obtain the corresponding spiral fiber array material. In addition, the gold-silver nanospiral fiber array also has obvious circular dichroism.

This comparative example is an experiment for preparing a gold nanofiber array without using the inducer of the embodiment. That is, in the preparation process of this comparative example, no inducer is added to the mixed solution in step S3.

FIG. 13 is a low-power scanning electron microscope photograph of a gold nanofiber array of a comparative example of the present invention, and FIG. 14 is a high-power scanning electron microscope photograph of a gold nanofiber array of a comparative example of the present invention.

As shown in FIG. 13 and FIG. 14, when the chiral inducer is not used, the diameter of the nanofibers in the prepared gold nanofiber array is about 10 nm, but they do not have obvious spiral morphology. In addition, this gold nanofiber array also does not have circular dichroism.

Example function and effect

It can be seen from the above examples that the chiral inducer is used to induce the chiral growth of the nanofibers, so that the metal material is formed into a chiral morphological structure, and after the chiral inducer is removed The chiral structure is preserved, so the metal nanospiral fiber array prepared by the chiral structure can be applied to the fields of chiral catalysis and chiral recognition. In general, the preparation method of the metal nanohelical fiber array of the present invention has the advantages of simple synthesis, low cost, and wide application of products.

Since 4-mercaptobenzoic acid with a content of 2 mM to 8 mM is used as a stabilizer in the above preparation process, the fibrous morphology formed by the metal material can be more stable. Meanwhile, referring to Example 2, the amount of stabilizer (ie, 4-mercaptobenzoic acid) added is positively correlated with the diameter and pitch of the gold nanohelix, so adjusting the amount of stabilizer added can adjust the morphology of the helix.

Since the inducer is N-acetyl-L-cysteine or N-acetyl-D-cysteine, it can make the metal material twist in the process of forming fibers, and finally obtain a spiral fiber morphology. In addition, due to the use of electrochemical methods to remove residual organic matter, it can effectively remove the inducer and allow the spiral fiber shape of the metal material to be retained, and it will not be interfered by residual organic matter in applications such as chiral catalysis and chiral recognition.

The above examples are only used to illustrate specific embodiments of the present invention, and the preparation method of the present invention is not limited to the description scope of the above examples.

For example, in the embodiment, the inducer uses N-acetyl-L-cysteine or N-acetyl-D-cysteine, but in the present invention, the inducer may also use other thiol-containing chiral compounds Or thiol-containing proteins, such as trypsin or chymotrypsin.

In the embodiments, the aminosilylation reagent is 3-aminopropyltriethoxysilane, but in the present invention, the aminosilylation reagent may also be 3-aminopropyltrimethoxysilane and other types of aminosilylation Reagents.

Claims

A method for preparing a chiral metal nano-spiral fiber array, characterized in that it includes the following steps:

In step S1, the substrate is placed in an aminosilylation reagent and allowed to stand for a period of time, then taken out and washed;

Step S2, soaking the substrate washed in step S1 in a solution containing metal species to load the metal species;

Step S3: Put the substrate loaded with the metal species into a mixed solution containing a metal source and an inducer, add a reducing agent to perform a growth reaction for a predetermined time, so as to grow a metal spiral fiber array on the substrate;

Step S4, removing the residual inducer in the metal spiral fiber array,

Wherein, the inducer is a chiral inducer.
The method for preparing a chiral metal nano-spiral fiber array according to claim 1, wherein:

Wherein, the mixed solution in step S3 further contains a stabilizer, the stabilizer is 4-mercaptobenzoic acid, and the content is 2 mM to 8 mM.
The method for preparing a chiral metal nano-spiral fiber array according to claim 1, wherein:

Wherein, the metal species in step S2 is one of gold species, silver species, or a mixture of both,

The metal source in step S3 is one or a mixture of gold source and silver source.
The method for preparing a chiral metal nano-spiral fiber array according to claim 1, wherein:

Wherein, the chiral inducer is a thiol-containing chiral compound or a thiol-containing protein.
The method for preparing a chiral metal nano-spiral fiber array according to claim 4, wherein:

Wherein, the thiol-containing chiral compound is N-acetyl-L-cysteine or N-acetyl-D-cysteine,

The thiol-containing protein is trypsin or chymotrypsin.
The method for preparing a chiral metal nano-spiral fiber array according to claim 1, wherein:

Wherein, in step S4, the inducer remaining in the metal spiral fiber array substrate is removed by an electrochemical method,

The electrochemical method is cyclic voltammetry.
The method for preparing the chiral metal nano-spiral fiber array according to claim 6, characterized in that:

Wherein, the reducing agent in step S3 is ascorbic acid.
The method for preparing a chiral metal nano-spiral fiber array according to claim 1, wherein:

Wherein, in step S3, the predetermined time is 5-30 minutes.
The method for preparing a chiral metal nano-spiral fiber array according to claim 1, wherein:

Wherein, the substrate is a silicon substrate or a quartz substrate.
The method for preparing a chiral metal nano-spiral fiber array according to claim 1, wherein:

Wherein, the substrate is pre-cleaned, and the pre-cleaning method is:

The substrate is placed in a mixed solution containing concentrated sulfuric acid and hydrogen peroxide, heated and sonicated, and then taken out and washed with deionized water.