A molecular chirality detection and identification method based on composite plasmon chiral nanostructures

Abstract

The present invention provides a method for detecting and identifying molecular chirality based on a composite plasmon chiral nanostructure. The present invention constructs a composite plasmon chiral nanostructure using chiral nanofibers and gold nanorods as basic components, and achieves molecular chirality recognition and detection through plasmon chiral optical amplification. The excellent plasmon circular dichroism optical properties of the composite nanostructure can convert the host-guest chiral recognition interaction occurring at the fiber interface into an asymmetric plasmon chiral optical amplification signal. This technology can detect and identify the chiral enantiomers of amino acid molecules in about 1 minute, with a sensitivity of 10 ‑6 mol / L. This structure can also be used for quantitative analysis of molecular enantiomeric excess (ee), with a detection sensitivity of ±0.05. Furthermore, given that the chiral host-guest complexes involved in this technology are primarily based on hydrogen bonding interactions, the chiral fiber host can be used as a universal substrate for the detection of chiral amino acid molecules.

Description

Technical Field

[0001] The present invention provides a molecular chirality detection and identification method based on composite plasmon chiral nanostructures, belonging to the application field of nanophotonics. Background Art

[0002] Chirality is a property of structures that cannot be aligned with their mirror images through translation or rotation. The vast majority of amino acids, proteins, monosaccharides, and polysaccharides in living organisms are chiral. The amino acids that make up proteins are all L-type, while monosaccharides and polysaccharides are all D-type. Chirality plays an important biological role in the human body, and molecules of opposite chirality can play completely different roles in life. For example, thalidomide is used as an analgesic, but its S-isomer is severely teratogenic. Therefore, developing a rapid, convenient, and accurate chiral recognition method that can be used in situ in biological systems is of great significance.

[0003] Collective oscillations of electrons on the nanoparticle surface under optical excitation give achiral gold nanorods excellent surface plasmon optical properties, which are often used to construct molecular chiral sensors. Achiral gold nanoparticles can be assembled into chiral assemblies using thiol-containing small molecules or biomolecules and polymers. In gold nanoparticle assemblies, surface plasmon resonances between adjacent particles couple to each other, giving the assembly unique collective plasmon properties. In light of this, we designed a self-assembled nanocomposite plasmon chiral structure using gold nanorods and a biocompatible chiral gel molecule (N-lauroyl-glutamic acid di-n-butylamide, hereafter referred to as GP1). Based on this, we investigated the optical detection and recognition of molecular chirality using amino acid enantiomers as an example.

[0004] Small organic molecules can self-assemble into chiral fiber structures in solution through interactions such as hydrogen bonding, π-π stacking, electrostatic interactions, dipole-dipole interactions, van der Waals interactions, and metal-ligand coordination. They are often used for molecular chirality recognition. In the design of molecular or supramolecular chiral sensors, the chromophores and fluorophores of the host-guest system are key units. For example, for chiral sensors of molecular gels, the addition of chiral enantiomer molecules makes the solution appear different colors, or emit fluorescence of different colors / intensities. Although chromophores and fluorophores are widely used in chiral recognition, the design and preparation of host-guest complexes with specific chromophores or fluorophores often requires complex and tedious processes or is relatively time-consuming. In addition, chiral spectroscopy is another important method for detecting and identifying molecular chirality. It uses the different electronic circular dichroism optical properties generated when molecular chiral sensors interact with molecular enantiomers. However, due to the extremely weak interaction between light and molecules, its detection sensitivity is very low, usually below 10 -4To this end, we designed a simple, efficient, and highly sensitive chiral recognition method based on plasmon optics that does not rely on chromophores or fluorophores.

[0005] N-lauroyl-glutamic acid di-n-butylamide (GP-1), a chiral gel molecule, can form chiral helical nanofiber structures in a cosolvent of water and propylene glycol. Gold nanorods can self-assemble into chiral assemblies on the chiral helical nanofibers, exhibiting plasmonic circular dichroism (PCD). PCD is extremely sensitive to the relative position and orientation of the gold nanorods. Amino acids interact with the chiral helical fiber micro- and nanostructures through hydrogen bonding. The resulting micro- and nanostructural changes in chiral recognition lead to subtle shifts in the geometric positions of the gold nanorods assembled on the chiral fibers. Detecting the corresponding changes in the PCD signal enables the detection and identification of amino acid enantiomers. In short, we utilize GP-1 chiral gel molecules as chiral hosts to recognize amino acid chiral guests. Amino acid enantiomers are identified through the circular dichroism of the self-assembled nanocomposite plasmonic chiral structure formed by the self-assembly of gold nanorods on the chiral fibers. Because the biocompatible gel fibers are used, this chiral sensor has the potential for in vivo application. Summary of the Invention

[0006] A molecular chirality detection and identification method based on composite plasmon chiral nanostructures aims to prepare a self-assembled nanocomposite plasmon chiral structure and apply it to the detection and identification of molecular chirality. The scale is between 500 nanometers and several micrometers. Through the electromagnetic enhancement effect on the surface of gold nanorods, the plasmon circular dichroism (CD) spectral signal can be transferred and amplified from the weak ultraviolet spectral region where it is usually located to the visible / near-infrared spectral region for detection.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A molecular chirality detection and identification method based on a composite plasmon chiral nanostructure is prepared by the following method:

[0009] Step 1: Preparation of chiral nanofibers

[0010] 0.1 wt% of N-lauroyl-L-glutamic acid di-n-butylamide / propylene glycol (L-GP-1 / PG) and 0.2 wt% of N-lauroyl-D-glutamic acid di-n-butylamide propylene glycol (D-GP-1 / PG) were formulated.

[0011] Left-handed (LH) and right-handed (RH) chiral nanofibers were obtained by adding 0.1 wt% L-GP-1 / PG and 0.2 wt% D-GP-1 / PG to deionized water and mixing them uniformly. The chiral nanofibers, which served as the chiral host, were formed in a cosolvent of propylene glycol and water. The volume ratio of propylene glycol to water ranged from 1:110 to 4:110.

[0012] Step 2: Preparation of host-guest molecular recognition system

[0013] Take the chiral nanofibers prepared in step 1 and add deionized water or an aqueous solution of L- / D-amino acids.

[0014] Among them, when deionized water is added to LH nanofibers, it is still called LH nanofibers; when L-amino acids are added to LH nanofibers, it is called LH- L Nanofibers; Add D-amino acids to LH nanofibers, called LH- D Nanofibers. LH and LH- L and LH- D In the serum, the concentration of L-GP-1 is between 20–80 μmol / L, and the concentration of LH- L and LH- D The concentration of amino acid molecules in the culture medium is between 1–100 μmol / L.

[0015] When deionized water is added to RH nanofibers, they are still called RH nanofibers; when L-amino acids are added to RH nanofibers, they are called RH- L Nanofibers; D-amino acids are added to RH nanofibers, which are called RH- D Nanofibers. RH and RH- L and RH- D The concentration of D-GP-1 was between 40–161 μmol / L, and the concentration of RH- L and RH- D The concentration of amino acid molecules in the culture medium is between 1–100 μmol / L.

[0016] The surface potential values ​​of the six nanofibers obtained above were measured and the values ​​were between -20 and -29 mV. L and LH- D For the left-handed helical structure, RH and RH- L and RH- D It is a right-handed helical structure with a diameter between 20–80 nanometers, a half-pitch of around 580 nanometers, and a length between 500 nanometers and 10 microns.

[0017] For LH and LH-L and LH- D The circular dichroism spectra of the nanofibers were measured, and the three nanofibers showed negative ECD bands in the ultraviolet region with peaks between 219–221 nm. When the concentration of the added amino acids was low, LH and LH- L and LH- D When the concentration of amino acids added was high, LH and LH- L and LH- D The ECD can be distinguished, and the size relationship is LH- D >LH>LH- L That is, the addition of D-amino acids enhanced the ECD of the nanofibers, while the addition of L-amino acids weakened the ECD of the nanofibers.

[0018] For RH and RH- L and RH- D The circular dichroism spectra of the nanofibers were measured, and the three nanofibers showed positive ECD bands in the ultraviolet region with peaks between 219–221 nm. When the concentration of the added amino acid was low, RH and RH- L and RH- D When the concentration of the added amino acids was high, the ECDs of RH, RH-L and RH-D were distinguishable, and the size relationship was RH- L >RH>RH- D That is, the addition of L-amino acids enhanced the ECD of the nanofibers, while the addition of D-amino acids weakened the ECD of the nanofibers.

[0019] Step 3: Preparation of gold nanorod colloidal solution

[0020] Gold nanorods were prepared using the seed growth method.

[0021] The prepared gold nanorod colloidal solution was subjected to optimized centrifugation screening to obtain a precipitate and a supernatant. The precipitate consisted of gold nanorods coated with cetyltrimethylammonium bromide (CTAB). After removing the supernatant, water was added to the precipitate to obtain a gold nanorod colloidal solution that was further centrifuged. The concentration of the resulting gold nanorod colloidal solution was adjusted to 150 pmol / L according to Beer's law. At this point, the CTAB concentration in the gold nanorod colloidal solution was between 4 and 10 μmol / L. The gold nanorods in the resulting gold nanorod dispersion were 43–65 nm in length and 16–22 nm in width. The zeta potential of the gold nanorod solution was measured to be between +45 and +55 mV.

[0022] Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures

[0023] The six types of nanofibers prepared in step 2 were added with the gold nanorod colloidal solution prepared in step 3 to obtain a self-assembled nanocomposite plasmon chiral structure.

[0024] Among them, the self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to LH nanofibers is defined as M; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- L ; To LH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- D ; The self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to RH nanofibers is defined as P; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- L ; To RH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- D .

[0025] The concentration of gold nanorods in the self-assembled nanocomposite plasmonic chiral structure samples prepared above is between 60–130 pmol / L.

[0026] The six self-assembled nanocomposite plasmonic chiral structures were characterized by scanning electron microscopy. The gold nanorods assembled on the nanofibers were separated from each other, with the distance between the cores of adjacent gold nanorods ranging from 60 to 260 nanometers and the average distance between the cores ranging from 140 to 150 nanometers.

[0027] The six self-assembled nanocomposite plasmonic chiral structures were subjected to circular dichroism spectroscopy measurement, and PCD signals were measured in the visible / near-infrared region.

[0028] Among them, M and M- L and M- D The PCD signal value is characterized by being positive first and then negative (from long wave to short wave), and M and M- L and M- D The PCD positive peak-to-peak relationship is M- L >M- D >M, the absolute value of the negative peak-to-peak value of PCD is |M- L |>|M- D |>|M|. And P and P- L and P- DThe PCD signal value is characterized by being negative first and then positive (from long wave to short wave), and P and P- L and P- D The positive peak-to-peak relationship of PCD is P- D >P- L >P, the absolute value of the negative peak-to-peak value of PCD is |P- D |>|P- L |>|P|. This means that, relative to M or P, M- L and M- D , or P- L and P- D , its PCD signal appears to be enhanced.

[0029] Beneficial effects

[0030] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0031] 1. In the present invention, the chiral host and guest involved do not need to have a chromophore or a fluorophore but only need to have a group capable of forming a hydrogen bond;

[0032] 2. The present invention provides a self-assembled nanocomposite plasmonic chiral structure that, through the chiral recognition effect of nanofibers and amino acids, can transfer and amplify the electron circular dichroism (ECD) signal in the ultraviolet spectral region to the plasmon circular dichroism (PCD) signal in the visible / infrared spectral region for detection;

[0033] 3. The self-assembled chiral plasmon nanocomposite fibers described in this invention can detect and distinguish the chirality of enantiomeric molecules, down to a detection level of 1 μM. This detection method is economical, rapid, highly sensitive, simple to operate, and non-toxic. DETAILED DESCRIPTION

[0034] The present invention is described in detail below through specific examples. In Examples 1-6, the gold nanorod concentration in the gold nanorod colloidal solution was measured by UV-visible absorption spectroscopy; the zeta potential of the centrifuged gold nanorod colloidal solution was measured by laser particle size analysis; the spectral characteristics of the self-assembled chiral plasmonic nanocomposite fibers were examined by circular dichroism spectroscopy; and the prepared micro-nanostructures were observed by scanning electron microscopy. CTAB, glycine, L- / D- / DL-cysteine, L- / D-alanine, L- / D-penicillamine, glycine, and L- / D-proline were all purchased from Shanghai Sigma Reagent Co., Ltd.

[0035] Example 1

[0036] Step 1: Preparation of chiral nanofibers

[0037] Weigh 5 mg of N-lauroyl-L-glutamic acid di-n-butylamide (L-GP-1) or 10 mg of N-lauroyl-D-glutamic acid di-n-butylamide (D-GP-1) using an electronic scale and pour into a clean brown glass bottle (2 cm diameter, 5 cm height). Add 4995 mg or 4990 mg of propylene glycol (PG) and seal with foil. Place in a 100°C forced air drying oven. After 0.5–1 hour, GP-1 will completely dissolve in PG, resulting in a 0.1 wt% L-GP-1 / PG or 0.2 wt% D-GP-1 / PG mixture. Remove and allow to cool naturally to room temperature.

[0038] Take 250uL of deionized water, add 15uL of 0.1wt% L-GP-1 / PG or 15uL of 0.2wt% D-GP-1 / PG, mix well, and obtain chiral nanofibers.

[0039] Among them, the chiral nanofibers obtained by adding 0.1wt% L-GP-1 / PG to deionized water are left-handed chiral nanofibers, defined as LH; the chiral nanofibers obtained by adding 0.2wt% D-GP-1 / PG to deionized water are right-handed chiral nanofibers, defined as RH.

[0040] Step 2: Preparation of host-guest molecular recognition system

[0041] The chiral nanofibers prepared above were taken and 17 uL of deionized water or 17 uL of a 1 mmol / L L- / D-cysteine ​​aqueous solution was added respectively.

[0042] Among them, 17uL deionized water was added to 250uL LH nanofibers, which was still called LH nanofibers; 17uL 1mmol / L L-cysteine ​​was added to 250uL LH nanofibers, which was called LH- L Nanofibers; add 17uL 1mmol / L D-cysteine ​​to 250uL LH nanofibers, called LH- D Nanofibers. LH and LH- L and LH- D The concentration of L-GP-1 was 60 μmol / L, and the concentration of LH- L and LH- D The concentration of cysteine ​​molecules in the culture medium is 30 μmol / L.

[0043] 17uL deionized water was added to 250uL RH nanofibers, which was still called RH nanofibers; 17uL 1mmol / L L-cysteine ​​was added to 250uL RH nanofibers, which was called RH- LNanofibers; 17uL 1mmol / L D-cysteine ​​was added to 250uL RH nanofibers, referred to as RH- D Nanofibers. RH and RH- L and RH- D The concentration of D-GP-1 was 121 μmol / L, and the concentration of RH- L and RH- D The concentration of cysteine ​​molecules in the culture medium is 30 μmol / L.

[0044] The surface potential values ​​of the six nanofibers obtained above were measured and the values ​​were between -20 and -29 mV. L and LH- D It is a left-hand helical structure, RH and RH- L and RH- D It is a right-handed helical structure with a diameter between 20–80 nanometers, a half-pitch of around 580 nanometers, and a length between 500 nanometers and 10 microns.

[0045] For LH and LH- L and LH- D The circular dichroism spectra of the nanofibers were measured, and the three nanofibers showed negative ECD bands in the ultraviolet region with peaks between 219–221 nm. L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L That is, the addition of D-cysteine ​​enhanced the ECD of the nanofibers, while the addition of L-cysteine ​​weakened the ECD of the nanofibers.

[0046] Changing the volume of cysteine ​​added, when the concentration of cysteine ​​added was less than 10 μmol / L, LH and LH- L and LH- D When the added cysteine ​​concentration is greater than or equal to 10 μmol / L, LH and LH- L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L |.

[0047] For RH and RH- L and RH- DThe circular dichroism spectra of the nanofibers were measured. The three nanofibers showed positive ECD bands in the ultraviolet region with peak values ​​between 219–221 nm. The ECDs of RH, RH-L and RH-D were distinguishable, with the magnitude relationship being RH- L >RH>RH- D That is, the addition of L-cysteine ​​increased the ECD of the nanofibers, while the addition of D-cysteine ​​decreased the ECD of the nanofibers. This shows that by measuring the ECD of the nanofibers, we can distinguish between L- and D-cysteine.

[0048] The volume of cysteine ​​added was changed. When the concentration of cysteine ​​added was less than 10 μmol / L, RH and RH- L and RH- D When the added cysteine ​​concentration is greater than or equal to 10 μmol / L, RH and RH- L and RH- D The ECD can be distinguished, and the size relationship is RH- D >RH>RH- L .

[0049] When the volume of L-GP-1 / PG solution added was changed so that the concentration of L-GP-1 / PG was between 20–80 μmol / L, or the volume of D-GP-1 / PG solution added was changed so that the concentration of D-GP-1 / PG was between 40–161 μmol / L, the above-mentioned ECD relationship still held.

[0050] Step 3: Preparation of gold nanorod colloidal solution

[0051] Preparation of gold nanorods using the seed-grown method

[0052] 1. Gold Seed Preparation

[0053] Take 7.5 mL of 0.1 mol / L CTAB solution, add 1.8 mL of water, and, while stirring, add 100.4 μL of a 24.7 mmol / L aqueous solution of chloroauric acid (HAuCl4). Then, add 600 μL of a 10 μmol / L sodium borohydride (NaBH4) solution. Stir for 3 minutes and incubate in a 30°C water bath for 2–5 hours to obtain a gold seed for use.

[0054] 2. Growth Medium Preparation

[0055] Take 100 mL of 0.1 mol / L CTAB solution, add 2 mL of 25 mmol / L chloroauric acid (HAuCl4) aqueous solution, 120 μL of 0.1 mol / L silver nitrate (AgNO3) aqueous solution, and 552 μL of 0.1 mol / L ascorbic acid aqueous solution.

[0056] 3. Preparation of Gold Nanorods

[0057] Add 120 μL of the gold seed prepared in step 1 to the growth solution prepared in step 2. Add 55.2 μL of 0.1 M ascorbic acid twice every 40 minutes. Grow at 30°C for 12 hours. Centrifuge the resulting solution at 12,000 rpm for 10 minutes to obtain a precipitate and a supernatant. The precipitate contains gold nanorods coated with CTAB. Remove the supernatant and add 20 mL of water to the precipitate to obtain a colloidal solution of gold nanorods, which has been centrifuged once.

[0058] In the gold nanorod colloidal solution, the gold nanorod concentration is 2 nmol / L and the free CTAB concentration is 5 mmol / L. Transmission electron microscopy (TEM) measurement shows that the gold nanorods are 65 nm long, 22 nm wide, contain {111} faces at both ends, and have an aspect ratio of 2.9.

[0059] The gold nanorods prepared above are subjected to optimized centrifugal screening to obtain a precipitate and an upper liquid; the precipitate is gold nanorods with CTAB coated on the surface; after removing the upper liquid, water is added to the precipitate to obtain a further centrifuged gold nanorod colloidal solution. The centrifugation process was as follows: ① Take 200 μL of the seed-grown gold nanorod solution, add 800 μL of deionized water, and centrifuge at 11,800 rpm for 5 minutes. Remove the supernatant, add 25 μL of 10 mmol / L CTAB and 975 μL of deionized water, and incubate at 30°C in a water bath for 30 minutes. ② Centrifuge at 11,800 rpm for 5 minutes, remove the supernatant, add 25 μL of 10 mmol / L CTAB and 975 μL of deionized water, and incubate at 30°C in a water bath for 30 minutes. ③ Centrifuge at 11,800 rpm for 5 minutes, remove the supernatant, add 20 μL of 10 mmol / L CTAB and 980 μL of deionized water, and incubate at 30°C in a water bath for 30 minutes. ④ Centrifuge at 11,800 rpm for 5 minutes, remove the supernatant, and add 1000 μL of deionized water. The concentration of the resulting gold nanorod solution was adjusted to 150 pmol / L according to Beer's law. At this time, the CTAB concentration in the gold nanorod colloidal solution was between 4 and 10 μmol / L, and the zeta potential of the gold nanorod colloidal solution was between +45 and +55 mV.

[0060] Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures

[0061] Take the six nanofiber samples prepared in step 2, and add 300 μL of the gold nanorod colloidal solution prepared in step 3 to obtain a self-assembled nanocomposite plasmon chiral structure.

[0062] Among them, the self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to LH nanofibers is defined as M; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- L ; To LH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- D ; The self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to RH nanofibers is defined as P; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- L ; To RH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- D .

[0063] The concentration of gold nanorods in the self-assembled nanocomposite plasmon chiral structure sample prepared above is 80 pmol / L.

[0064] The six self-assembled nanocomposite plasmonic chiral structures were characterized by scanning electron microscopy, and the gold nanorods assembled on the nanofibers were separated from each other.

[0065] The six self-assembled nanocomposite plasmonic chiral structures were subjected to circular dichroism spectroscopy measurement, and PCD signals were measured in the visible / near-infrared region.

[0066] Among them, M and M- L and M- D The PCD signal value is characterized by being positive first and then negative (from long wave to short wave), and M and M- L and M- D The PCD positive peak-to-peak relationship is M- L >M- D >M, the absolute value of the negative peak-to-peak value of PCD is |M- L |>|M- D |>|M|. And P and P- L and P- D The PCD signal value is characterized by being negative first and then positive (from long wave to short wave), and P and P- L and P- D The positive peak-to-peak relationship of PCD is P- D >P- L >P, the absolute value of the negative peak-to-peak value of PCD is |P- D |>|P-L |>|P|. This means that, relative to M or P, M- L and M- D , or P- L and P- D By preparing a self-assembled nanocomposite plasmonic chiral structure, the ECD signal change in the ultraviolet region is transferred and amplified into a PCD signal in the visible / near-infrared region, thereby distinguishing L- and D-cysteine.

[0067] The concentration of the added gold nanorod colloidal solution was changed so that when the concentration of gold nanorods in the self-assembled nanocomposite plasmonic chiral structure sample was 60–130 pmol / L, the above-mentioned PCD relationship still held.

[0068] Example 2

[0069] Step 1: Preparation of chiral nanofibers

[0070] The preparation of chiral nanofibers is the same as step 1 in Example 1.

[0071] Step 2: Preparation of host-guest molecular recognition system

[0072] The chiral nanofibers prepared above were taken and 22.66 uL of deionized water or 22.66 uL of a 1 mmol / L L- / D-alanine aqueous solution was added respectively.

[0073] Among them, 22.66uL of deionized water was added to 250uL of LH nanofibers, which was still called LH nanofibers; 22.66uL of 1mmol / L L-alanine was added to 250uL of LH nanofibers, which was called LH- L Nanofibers; 22.66uL 1mmol / L D-alanine was added to 250uL LH nanofibers, referred to as LH- D Nanofibers. LH and LH- L and LH- D The concentration of L-GP-1 was 60 μmol / L, and the concentration of LH- L and LH- D The concentration of alanine molecules in the solution is 40 μmol / L.

[0074] 22.66uL of deionized water was added to 250uL of RH nanofibers, which was still called RH nanofibers; 22.66uL of 1mmol / L L-alanine was added to 250uL of RH nanofibers, which was called RH- L Nanofibers; 22.66uL 1mmol / L D-alanine was added to 250uL RH nanofibers, referred to as RH- DNanofibers. RH and RH- L and RH- D The concentration of D-GP-1 was 121 μmol / L, and the concentration of RH- L and RH- D The concentration of alanine molecules in the solution is 40 μmol / L.

[0075] The surface potential values ​​of the six nanofibers obtained above were measured and the values ​​were between -20 and -29 mV. L and LH- D It is a left-hand helical structure, RH and RH- L and RH- D It is a right-handed helical structure with a diameter between 20–80 nanometers, a half-pitch of around 580 nanometers, and a length between 500 nanometers and 10 microns.

[0076] For LH and LH- L and LH- D The circular dichroism spectra of the nanofibers were measured, and the three nanofibers showed negative ECD bands in the ultraviolet region with peaks between 219–221 nm. L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L That is, the addition of D-alanine enhanced the ECD of the nanofibers, while the addition of L-alanine weakened the ECD of the nanofibers.

[0077] Changing the volume of alanine added, when the concentration of alanine added was less than 40 μmol / L, LH and LH- L and LH- D When the concentration of alanine added is greater than or equal to 40 μmol / L, LH and LH- L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L |.

[0078] For RH and RH- L and RH- D The circular dichroism spectra of the nanofibers were measured. The three nanofibers showed positive ECD bands in the ultraviolet region with peak values ​​between 219–221 nm. The ECDs of RH, RH-L and RH-D were distinguishable, with the magnitude relationship being RH- L >RH>RH- DThat is, the addition of L-alanine increased the ECD of the nanofibers, while the addition of D-alanine decreased the ECD of the nanofibers. This shows that by measuring the ECD of the nanofibers, we can distinguish between L- and D-alanine.

[0079] Changing the volume of alanine added, when the concentration of alanine added was less than 40 μmol / L, RH and RH- L and RH- D When the concentration of alanine added was greater than or equal to 40 μmol / L, RH and RH- L and RH- D The ECD can be distinguished, and the size relationship is RH- D >RH>RH- L .

[0080] When the volume of L-GP-1 / PG solution added was changed so that the concentration of L-GP-1 / PG was between 20–80 μmol / L, or the volume of D-GP-1 / PG solution added was changed so that the concentration of D-GP-1 / PG was between 40–161 μmol / L, the above-mentioned ECD relationship still held.

[0081] Step 3: Preparation of gold nanorod colloidal solution

[0082] The preparation of the gold nanorod colloidal solution was the same as step 3 of Example 1.

[0083] Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures

[0084] Take the six nanofiber samples prepared in step 2, and add 300 μL of the gold nanorod colloidal solution prepared in step 3 to obtain a self-assembled nanocomposite plasmon chiral structure.

[0085] Among them, the self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to LH nanofibers is defined as M; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- L ; To LH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- D ; The self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to RH nanofibers is defined as P; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- L ; To RH- DThe self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- D .

[0086] The concentration of gold nanorods in the self-assembled nanocomposite plasmon chiral structure sample prepared above is 80 pmol / L.

[0087] The six self-assembled nanocomposite plasmonic chiral structures were subjected to circular dichroism spectroscopy measurement, and PCD signals were measured in the visible / near-infrared region.

[0088] Among them, M and M- L and M- D The PCD signal value is characterized by being positive first and then negative (from long wave to short wave), and M and M- L and M- D The PCD positive peak-to-peak relationship is M- L >M- D >M, the absolute value of the negative peak-to-peak value of PCD is |M- L |>|M- D |>|M|. And P and P- L and P- D The PCD signal value is characterized by being negative first and then positive (from long wave to short wave), and P and P- L and P- D The positive peak-to-peak relationship of PCD is P- D >P- L >P, the absolute value of the negative peak-to-peak value of PCD is |P- D |>|P- L |>|P|. This means that, relative to M or P, M- L and M- D , or P- L and P- D By preparing a self-assembled nanocomposite plasmonic chiral structure, the ECD signal change in the ultraviolet region is transferred and amplified into a PCD signal in the visible / near-infrared region, thereby distinguishing L- and D-alanine.

[0089] The concentration of the added gold nanorod colloidal solution was changed so that when the concentration of gold nanorods in the self-assembled nanocomposite plasmonic chiral structure sample was 60–130 pmol / L, the above-mentioned PCD relationship still held.

[0090] Example 3

[0091] Step 1: Preparation of chiral nanofibers

[0092] The chiral nanofibers are prepared in the same manner as in step 1 of Example 1.

[0093] Step 2: Preparation of host-guest molecular recognition system

[0094] The chiral nanofibers prepared above were taken and 17 uL of deionized water or 17 uL of a 1 mmol / L L- / D-penicillamine aqueous solution was added respectively.

[0095] Among them, 17uL deionized water was added to 250uL LH nanofibers, which was still called LH nanofibers; 17uL 1mmol / L L-penicillamine was added to 250uL LH nanofibers, which was called LH- L Nanofibers; add 17uL 1mmol / L D-penicillamine to 250uL LH nanofibers, referred to as LH- D Nanofibers. LH and LH- L and LH- D The concentration of L-GP-1 was 60 μmol / L, and the concentration of LH- L and LH- D The concentration of penicillamine molecules in it is 30μmol / L.

[0096] 17uL deionized water was added to 250uL RH nanofibers, which was still called RH nanofibers; 17uL 1mmol / L L-penicillamine was added to 250uL RH nanofibers, which was called RH- L Nanofibers; 17uL 1mmol / L D-penicillamine was added to 250uL RH nanofibers, referred to as RH- D Nanofibers. RH and RH- L and RH- D The concentration of D-GP-1 was 121 μmol / L, and the concentration of RH- L and RH- D The concentration of penicillamine molecules in it is 30μmol / L.

[0097] The surface potential values ​​of the six nanofibers obtained above were measured and the values ​​were between -20 and -29 mV. L and LH- D It is a left-hand helical structure, RH and RH- L and RH- D It is a right-handed helical structure with a diameter between 20–80 nanometers, a half-pitch of around 580 nanometers, and a length between 500 nanometers and 10 microns.

[0098] For LH and LH- L and LH- DThe circular dichroism spectra of the nanofibers were measured, and the three nanofibers showed negative ECD bands in the ultraviolet region with peaks between 219–221 nm. L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L That is, the addition of D-penicillamine enhanced the ECD of the nanofibers, while the addition of L-penicillamine weakened the ECD of the nanofibers.

[0099] The volume of penicillamine added was changed. When the concentration of penicillamine added was less than 30 μmol / L, LH and LH- L and LH- D When the concentration of penicillamine added is greater than or equal to 30 μmol / L, LH and LH- L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L |.

[0100] For RH and RH- L and RH- D The circular dichroism spectra of the nanofibers were measured. The three nanofibers showed positive ECD bands in the ultraviolet region with peak values ​​between 219–221 nm. The ECDs of RH, RH-L and RH-D were distinguishable, with the magnitude relationship being RH- L >RH>RH- D That is, the addition of L-penicillamine increased the ECD of the nanofibers, while the addition of D-penicillamine decreased the ECD of the nanofibers. This shows that by measuring the ECD of the nanofibers, we can distinguish between L- and D-penicillamine.

[0101] The volume of penicillamine added was changed. When the concentration of penicillamine added was less than 30 μmol / L, RH and RH- L and RH- D When the concentration of penicillamine added was greater than or equal to 30 μmol / L, RH and RH- L and RH- D The ECD can be distinguished, and the size relationship is RH- D >RH>RH- L .

[0102] When the volume of L-GP-1 / PG solution added was changed so that the concentration of L-GP-1 / PG was between 20–80 μmol / L, or the volume of D-GP-1 / PG solution added was changed so that the concentration of D-GP-1 / PG was between 40–161 μmol / L, the above-mentioned ECD relationship still held.

[0103] Step 3: Preparation of gold nanorod colloidal solution

[0104] The preparation of the gold nanorod colloidal solution was the same as step 3 of Example 1.

[0105] Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures

[0106] Take the six nanofiber samples prepared in step 2, and add 300 μL of the gold nanorod colloidal solution prepared in step 3 to obtain a self-assembled nanocomposite plasmon chiral structure.

[0107] Among them, the self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to LH nanofibers is defined as M; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- L ; To LH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- D ; The self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to RH nanofibers is defined as P; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- L ; To RH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- D .

[0108] The concentration of gold nanorods in the self-assembled nanocomposite plasmon chiral structure sample prepared above is 80 pmol / L.

[0109] The six self-assembled nanocomposite plasmonic chiral structures were subjected to circular dichroism spectroscopy measurement, and PCD signals were measured in the visible / near-infrared region.

[0110] Among them, M and M- L and M- D The PCD signal value is characterized by being positive first and then negative (from long wave to short wave), and M and M- Land M- D The PCD positive peak-to-peak relationship is M- L >M- D >M, the absolute value of the negative peak-to-peak value of PCD is |M- L |>|M- D |>|M|. And P and P- L and P- D The PCD signal value is characterized by being negative first and then positive (from long wave to short wave), and P and P- L and P- D The positive peak-to-peak relationship of PCD is P- D >P- L >P, the absolute value of the negative peak-to-peak value of PCD is |P- D |>|P- L |>|P|. This means that, relative to M or P, M- L and M- D , or P- L and P- D By preparing a self-assembled nanocomposite plasmonic chiral structure, the ECD signal change in the ultraviolet region is transferred and amplified into a PCD signal in the visible / near-infrared region, thereby distinguishing L- and D-penicillamine.

[0111] The concentration of the added gold nanorod colloidal solution was changed so that when the concentration of gold nanorods in the self-assembled nanocomposite plasmonic chiral structure sample was 60–130 pmol / L, the above-mentioned PCD relationship still held.

[0112] Example 4

[0113] Step 1: Preparation of chiral nanofibers

[0114] The preparation of chiral nanofibers is the same as step 1 in Example 1.

[0115] Step 2: Preparation of host-guest molecular recognition system

[0116] The chiral nanofibers prepared above were taken and 22.67 uL of deionized water or 22.67 uL of a 1 mmol / L L- / D-proline aqueous solution was added respectively.

[0117] Among them, 22.67uL of deionized water was added to 250uL of LH nanofibers, which was still called LH nanofibers; 22.67uL of 1mmol / L L-proline was added to 250uL of LH nanofibers, which was called LH- L Nanofibers; 22.67uL 1mmol / L D-proline was added to 250uL LH nanofibers, referred to as LH- DNanofibers. LH and LH- L and LH- D The concentration of L-GP-1 was 60 μmol / L, and the concentration of LH- L and LH- D The concentration of proline molecules in the solution is 40 μmol / L.

[0118] 22.67uL of deionized water was added to 250uL of RH nanofibers, which was still called RH nanofibers; 22.67uL of 1mmol / L L-proline was added to 250uL of RH nanofibers, which was called RH- L Nanofibers; 22.67uL 1mmol / L D-proline was added to 250uL RH nanofibers, referred to as RH- D Nanofibers. RH and RH- L and RH- D The concentration of D-GP-1 was 121 μmol / L, and the concentration of RH- L and RH- D The concentration of proline molecules in the solution is 40 μmol / L.

[0119] The surface potential values ​​of the six nanofibers obtained above were measured and the values ​​were between -20 and -29 mV. L and LH- D It is a left-hand helical structure, RH and RH- L and RH- D It is a right-handed helical structure with a diameter between 20–80 nanometers, a half-pitch of around 580 nanometers, and a length between 500 nanometers and 10 microns.

[0120] For LH and LH- L and LH- D The circular dichroism spectra of the nanofibers were measured, and the three nanofibers showed negative ECD bands in the ultraviolet region with peaks between 219–221 nm. L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L That is, the addition of D-proline enhanced the ECD of the nanofibers, while the addition of L-proline weakened the ECD of the nanofibers.

[0121] Changing the volume of proline added, when the concentration of proline added was less than 40 μmol / L, LH and LH- L and LH- DWhen the added proline concentration is greater than or equal to 40 μmol / L, LH and LH- L and LH- D The ECD of can be distinguished, and the size relationship is |LH- D |>|LH|>|LH- L |.

[0122] For RH and RH- L and RH- D The circular dichroism spectra of the nanofibers were measured. The three nanofibers showed positive ECD bands in the ultraviolet region with peak values ​​between 219–221 nm. When the added proline concentration was less than 30 μmol / L, RH and RH- L and RH- D When the added proline concentration is greater than or equal to 30 μmol / L, the ECD of RH, RH-L and RH-D can be distinguished, and the size relationship is RH- L >RH>RH- D That is, the addition of L-proline increased the ECD of the nanofibers, while the addition of D-proline decreased the ECD of the nanofibers. This shows that by measuring the ECD of the nanofibers, we can distinguish between L- and D-proline.

[0123] Changing the volume of proline added, when the concentration of proline added was less than 40 μmol / L, RH and RH- L and RH- D When the added proline concentration is greater than or equal to 40 μmol / L, RH and RH- L and RH- D The ECD can be distinguished, and the size relationship is RH- D >RH>RH- L .

[0124] When the volume of L-GP-1 / PG solution added was changed so that the concentration of L-GP-1 / PG was between 20–80 μmol / L, or the volume of D-GP-1 / PG solution added was changed so that the concentration of D-GP-1 / PG was between 40–161 μmol / L, the above-mentioned ECD relationship still held.

[0125] Step 3: Preparation of gold nanorod colloidal solution

[0126] The gold nanorod colloidal solution is the same as step 3 of Example 1.

[0127] Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures

[0128] Take the six nanofiber samples prepared in step 2, and add 300 μL of the gold nanorod colloidal solution prepared in step 3 to obtain a self-assembled nanocomposite plasmon chiral structure.

[0129] Among them, the self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to LH nanofibers is defined as M; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- L ; To LH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- D ; The self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to RH nanofibers is defined as P; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- L ; To RH- D The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- D .

[0130] The concentration of gold nanorods in the self-assembled nanocomposite plasmon chiral structure sample prepared above is 80 pmol / L.

[0131] The six self-assembled nanocomposite plasmonic chiral structures were subjected to circular dichroism spectroscopy measurement, and PCD signals were measured in the visible / near-infrared region.

[0132] Among them, M and M- L and M- D The PCD signal value is characterized by being positive first and then negative (from long wave to short wave), and M and M- L and M- D The PCD positive peak-to-peak relationship is M- L >M- D >M, the absolute value of the negative peak-to-peak value of PCD is |M- L |>|M- D |>|M|. And P and P- L and P- D The PCD signal value is characterized by being negative first and then positive (from long wave to short wave), and P and P- L and P- D The positive peak-to-peak relationship of PCD is P- D >P- L >P, the absolute value of the negative peak-to-peak value of PCD is |P- D|>|P- L |>|P|. This means that, relative to M or P, M- L and M- D , or P- L and P- D By preparing a self-assembled nanocomposite plasmonic chiral structure, the ECD signal change in the ultraviolet region is transferred and amplified into a PCD signal in the visible / near-infrared region, thereby distinguishing L- and D-proline.

[0133] The concentration of the added gold nanorod colloidal solution was changed so that when the concentration of gold nanorods in the self-assembled nanocomposite plasmonic chiral structure sample was 60–130 pmol / L, the above-mentioned PCD relationship still held.

[0134] Example 5

[0135] Step 1: Preparation of chiral nanofibers

[0136] The preparation of chiral nanofibers is the same as step 1 in Example 1.

[0137] Step 2: Preparation of host-guest molecular recognition system

[0138] The chiral nanofibers prepared above were added with 17 μL of deionized water or 17 μL of a 1 mmol / L glycine aqueous solution, respectively. The added glycine was achiral.

[0139] Among them, 22.67uL deionized water was added to 250uL LH nanofibers, which was still called LH nanofibers; 17uL 1mmol / L L-glycine was added to 250uL LH nanofibers, which was called LH- GLY Nanofibers. LH and LH- GLY The concentration of L-GP-1 was 60 μmol / L, and the concentration of LH- GLY The concentration of glycine molecules in the solution is 30 μmol / L.

[0140] Among them, 22.67uL deionized water was added to 250uL RH nanofibers, which was still called RH nanofibers; 17uL 1mmol / L L-glycine was added to 250uL RH nanofibers, which was called RH- GLY Nanofibers. RH and RH- GLY The concentration of D-GP-1 was 60 μmol / L, and the concentration of RH- GLY The concentration of glycine molecules in the solution is 30 μmol / L.

[0141] The surface potential values ​​of the six nanofibers obtained above were measured and the values ​​were between -20 and -29 mV. L and LH- D It is a left-hand helical structure, RH and RH- L and RH- D It is a right-handed helical structure with a diameter between 20–80 nanometers, a half-pitch of around 580 nanometers, and a length between 500 nanometers and 10 microns.

[0142] For LH and LH- GLY The nanofibers were subjected to circular dichroism spectroscopy measurements, and a negative ECD band was measured in the ultraviolet region with a peak between 219–221 nm. GLY The ECD of can be distinguished, and the size relationship is |LH|>|LH- GLY That is, the ECD of glycine nanofibers was weakened.

[0143] Changing the volume of glycine added, when the concentration of glycine added was less than 30 μmol / L, LH and LH- GLY When the added glycine concentration is greater than or equal to 30 μmol / L, LH and LH- GLY The ECD of can be distinguished, and the size relationship is |LH|>|LH- GLY |.

[0144] For RH and RH- GLY The nanofibers were subjected to circular dichroism spectroscopy measurements, and positive and negative ECD bands were measured in the ultraviolet region, with peaks between 219–221 nm. GLY The ECD can be distinguished, and the size relationship is RH- GLY That is, the ECD of glycine nanofibers was enhanced.

[0145] Changing the volume of glycine added, when the concentration of glycine added was less than 30 μmol / L, RH and RH- GLY When the added glycine concentration is greater than or equal to 30 μmol / L, RH and RH- GLY The ECD can be distinguished, and the size relationship is RH- GLY >RH.

[0146] When the volume of L-GP-1 / PG solution added was changed so that the concentration of L-GP-1 / PG was between 20–80 μmol / L, or the volume of D-GP-1 / PG solution added was changed so that the concentration of D-GP-1 / PG was between 40–161 μmol / L, the above-mentioned ECD relationship still held.

[0147] Step 3: Preparation of gold nanorod colloidal solution

[0148] The preparation of the gold nanorod colloidal solution was the same as step 3 of Example 1.

[0149] Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures

[0150] Take the four nanofiber samples prepared in step 2, and add 300 μL of the gold nanorod colloidal solution prepared in step 3 to obtain a self-assembled nanocomposite plasmon chiral structure.

[0151] Among them, the self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to LH nanofibers is defined as M; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- GLY ; The self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to RH nanofibers is defined as P; L The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- GLY .

[0152] The concentration of gold nanorods in the self-assembled nanocomposite plasmon chiral structure sample prepared above is 80 pmol / L.

[0153] The four self-assembled nanocomposite plasmon chiral structures were subjected to circular dichroism spectroscopy measurement, and PCD signals were measured in the visible / near-infrared region.

[0154] Among them, M and M- GLY The PCD signal value is characterized by being positive first and then negative (from long wave to short wave), but the M and M- GLY The PCD of P and P- GLY The PCD signal value is characterized by being negative first and then positive (from long wave to short wave), but P and P- GLY The PCD of M- is also almost indistinguishable. This shows that, relative to M or P, M- GLY or P- GLY , and its PCD signal did not show any enhancement. In other words, glycine cannot be distinguished by measuring the PCD of self-assembled nanocomposite plasmonic chiral structures.

[0155] Although achiral glycine can be distinguished by measuring the ECD of nanofibers, this ECD change cannot be transferred and amplified to the visible / near-infrared PCD for measurement.

[0156] Example 6

[0157] Step 1: Preparation of chiral nanofibers

[0158] The preparation of chiral nanofibers is the same as step 1 in Example 1.

[0159] Step 2: Preparation of host-guest molecular recognition system

[0160] Take the chiral nanofibers prepared above and add 17uL deionized water or 17uL 1mmol / L respectively. The ee value is defined as ee=[(X L -X D ) / (X L +X D )]×100%. X L and X D It is the percentage of L-cysteine ​​and D-cysteine ​​in the total amount of solution.

[0161] Among them, 17uL of deionized water was added to 250uL of LH nanofibers, which was still called LH nanofibers; 17uL of 1mmol / L cysteine ​​aqueous solution with an ee value between -1 and 1 was added to 250uL of LH nanofibers, which was called LH- ee Nanofibers. LH and LH- ee The concentration of L-GP-1 was 60 μmol / L, and the concentration of LH- ee The concentration of cysteine ​​molecules in the culture medium is 30 μmol / L.

[0162] When 17uL of deionized water was added to 250uL of RH nanofibers, it was still called RH nanofibers; when 17uL of 1mmol / L cysteine ​​aqueous solution with an ee value between -1 and 1 was added to 250uL of RH nanofibers, it was called RH- ee Nanofibers. RH and RH- ee The concentration of D-GP-1 was 121 μmol / L, and the concentration of RH- ee The concentration of cysteine ​​molecules in the culture medium is 30 μmol / L.

[0163] The surface potential values ​​of the above series of nanofibers were measured and the measured values ​​were between -20 and -29 mV. The six nanofibers obtained were observed under a scanning electron microscope. ee It is a left-hand helical structure, RH and RH- ee It is a right-handed helical structure with a diameter between 20–80 nanometers, a half-pitch of around 580 nanometers, and a length between 500 nanometers and 10 microns.

[0164] For LH and LH- eeThe nanofibers were subjected to circular dichroism spectroscopy measurement, and a negative ECD band was measured in the ultraviolet region with a peak between 219–221 nm. ee The ECD between them is distinguishable. When ee>0, the size relationship is |LH|>|LH- ee |; When ee<0, the size relationship is |LH- ee |>|LH|. That is, the addition of cysteine ​​with an ee value <0 enhances the ECD of the nanofibers, while the addition of cysteine ​​with an ee value >0 weakens the ECD of the nanofibers.

[0165] The concentration of added cysteine ​​was changed. When the concentration of added cysteine ​​was less than 30 μmol / L, LH and LH- ee When the added cysteine ​​concentration is greater than or equal to 30 μmol / L, LH and LH- ee The ECD of can be distinguished, and the size relationship is |LH- ee |>|LH|(ee<0) and |LH- ee |<|LH|(ee>0).

[0166] For RH and RH- ee The nanofibers were subjected to circular dichroism spectroscopy measurements, and a positive ECD band was measured in the ultraviolet region of the nanofibers, with a peak between 219–221 nm. ee The ECD between them is distinguishable. When ee>0, the size relationship is RH<RH- ee ; When ee<0, the size relationship is RH- ee That is, the addition of cysteine ​​with an ee value greater than 0 enhances the ECD of the nanofibers, while the addition of cysteine ​​with an ee value less than 0 weakens the ECD of the nanofibers.

[0167] The concentration of cysteine ​​added was changed. When the concentration of cysteine ​​added was less than 30 μmol / L, RH and RH- ee When the added cysteine ​​concentration is greater than or equal to 30 μmol / L, RH and RH- ee The ECD can be distinguished, and the size relationship is RH- ee <RH(ee<0) and RH- ee >RH(ee>0).

[0168] When the volume of L-GP-1 / PG solution added was changed so that the concentration of L-GP-1 / PG was between 20–80 μmol / L, or the volume of D-GP-1 / PG solution added was changed so that the concentration of D-GP-1 / PG was between 40–161 μmol / L, the above-mentioned ECD relationship still held.

[0169] Step 3: Preparation of gold nanorod colloidal solution

[0170] The gold nanorod colloidal solution is the same as step 3 of Example 1.

[0171] Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures

[0172] Take the six nanofiber samples prepared in step 1, add 300 μL of the gold nanorod colloidal solution prepared in step 3 respectively, and obtain a self-assembled nanocomposite plasmon chiral structure.

[0173] Among them, the self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to LH nanofibers is defined as M; ee The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as M- ee ; The self-assembled nanocomposite plasmon chiral structure obtained by adding gold nanorod colloidal solution to RH nanofibers is defined as P; ee The self-assembled nanocomposite plasmonic chiral structure obtained by adding gold nanorod colloidal solution into nanofibers is defined as P- ee .

[0174] The concentration of gold nanorods in the self-assembled nanocomposite plasmon chiral structure sample prepared above is 80 pmol / L.

[0175] The obtained series of self-assembled nanocomposite plasmonic chiral structures are subjected to circular dichroism spectroscopy measurement, wherein PCD signals are measured in the visible / near-infrared region.

[0176] Among them, M and M- ee The PCD signal value is characterized by being positive first and then negative (from long wave to short wave), and M and M- ee The PCD positive peak-to-peak relationship is M- ee >M, the absolute value of the negative peak-to-peak value of PCD is |M- ee |>|M|, for different ee M- ee , if ee1>ee2, then M- ee1 >M- ee2 .

[0177] P and P-ee The PCD signal value is characterized by being negative first and then positive (from long wave to short wave), and P and P- ee The positive peak-to-peak relationship of PCD is P- ee >P, the absolute value of the negative peak-to-peak value of PCD is |P- ee |>|P|, for different ee P- ee , if ee1>ee2, then M- ee2 >M- ee1 This indicates that by preparing a self-assembled nanocomposite plasmonic chiral structure, the ECD signal change in the ultraviolet region is transferred and amplified into a PCD signal in the visible / near-infrared region, thereby distinguishing cysteines with different ee values.

[0178] The difference in ECD is amplified by the difference in PCD, with an amplification factor exceeding 1000. The amplification factor is defined as β = ΔPCD (%) / ΔECD (%), where ΔECD (%) is the percentage change in the ECD peak at 219–221 nm between a solution containing cysteine ​​molecules of a certain ee and a solution containing chiral nanofibers of an equal amount of water. ΔPCD (%) is the percentage change in the PCD peak in the visible / near-infrared region between a solution containing cysteine ​​molecules of a certain ee and a solution containing chiral nanofibers of an equal amount of water after the addition of a gold nanorod solution.

[0179] The concentration of the added gold nanorod colloidal solution was changed so that when the concentration of gold nanorods in the self-assembled nanocomposite plasmonic chiral structure sample was 60–130 pmol / L, the above-mentioned PCD relationship still held.

[0180] This invention was supported by the National Natural Science Foundation of China under Grant No. 12074035.

[0181] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A molecular chirality detection and identification method based on composite plasmon chiral nanostructures, characterized in that: The following steps are involved: Step 1: Preparation of chiral nanofibers Formulated with 0.1 wt% N-lauroyl-L-glutamic acid di-n-butylamide / propylene glycol, i.e., L-GP-1 / PG, and 0.2 wt% N-lauroyl-D-glutamic acid di-n-butylamide propylene glycol, i.e., D-GP-1 / PG; 0.1 wt% L-GP-1 / PG or 0.2 wt% D-GP-1 / PG was added to deionized water and mixed uniformly to obtain left-handed LH and right-handed RH chiral nanofibers. The chiral nanofibers, as the chiral host, were formed in a co-solvent of propylene glycol and water, with a volume ratio of propylene glycol to water ranging from 1:110 to 4:

110. Step 2: Preparation of host-guest molecular recognition system Deionized water or L- or D-amino acids are added to the LH chiral nanofibers to obtain LH, LH-L, and LH-D nanofibers; deionized water or L- or D-amino acids are added to the RH chiral nanofibers to obtain RH, RH-L, and RH-D nanofibers; Step 3: Preparation of gold nanorod colloidal solution Gold nanorods were prepared using the seed growth method; The prepared gold nanorods were subjected to optimized centrifugal screening to obtain a colloidal solution of gold nanorods coated with hexadecyltrimethylammonium bromide (CTAB). Step 4: Preparation of self-assembled nanocomposite plasmonic chiral structures The nanofibers prepared in step 2 are added to the gold nanorod colloidal solution prepared in step 3 to obtain a self-assembled nanocomposite plasmon chiral structure; Among them, the self-assembled nanocomposite plasmonic chiral structures obtained by adding gold nanorod colloidal solution to LH, LH-L, LH-D, RH, RH-L, and RH-D nanofibers were defined as M, ML, MD, P, PL, and PD, respectively; Circular dichroism (PCD) spectra of the six self-assembled nanocomposite plasmonic chiral structures were measured, and plasmonic circular dichroism (PCD) signals were measured in the visible / near-infrared region. Among them, the characteristics of the PCD signal values ​​of M, ML and MD are that they are first positive and then negative from long wave to short wave, and the relationship between the PCD long-wave peak values ​​of M, ML and MD is ML>MD>M, and the relationship between the absolute values ​​of the negative peak-to-peak values ​​of PCD is |ML|>|MD|>|M|; while the characteristics of the PCD signal values ​​of P, PL and PD are that they are first negative and then positive from long wave to short wave, and the relationship between the PCD long-wave peak values ​​of P, PL and PD is PD>PL>P, and the relationship between the absolute values ​​of the negative peak-to-peak values ​​of PCD is |PD|>|PL|>|P|.

2. The method for molecular chirality detection and identification based on composite plasmon chiral nanostructures according to claim 1, characterized in that: The chiral nanofibers prepared in step 2 have the following characteristics: The surface potential of the obtained nanofibers was measured, and the measured values ​​were between -20 and -29 mV; under scanning electron microscopy, the obtained nanofibers were observed to have left-handed helical structures, LH, LH-L and LH-D, and right-handed helical structures, with diameters between 20 and 80 nm, half-helical pitches of around 580 nm, and lengths between 500 nm and 10 microns.

3. The molecular chirality detection and identification method based on composite plasmon chiral nanostructures according to claim 1, characterized in that: In the preparation of the host-guest molecular recognition system in step 2: The concentration of L-GP-1 in LH chiral nanofibers ranged from 20–80 μmol / L, and the concentration of D-GP-1 in RH chiral nanofibers ranged from 40–161 μmol / L; Circular dichroism (CD) spectra of LH, LH-L, and LH-D nanofibers revealed negative electronic circular dichroism (ECD) signal bands in the ultraviolet region, with peak values ​​between 219 and 221 nm. At low amino acid concentrations, the ECDs of LH, LH-L, and LH-D were indistinguishable. However, at high amino acid concentrations, the ECDs of LH, LH-L, and LH-D became distinguishable, with the order |LH-D| > |LH| > |LH-L|. This suggests that the addition of D-amino acids enhanced the ECD of the nanofibers, while the addition of L-amino acids weakened the ECD. Circular dichroism (CD) spectra of RH, RH-L, and RH-D nanofibers revealed positive ECD bands in the ultraviolet region, with peaks between 219 and 221 nm. At low amino acid concentrations, the ECDs of RH, RH-L, and RH-D were indistinguishable. However, at high amino acid concentrations, the ECDs of RH, RH-L, and RH-D became distinguishable, with the order RH-L > RH > RH-D. This suggests that the addition of L-amino acids enhanced the ECD of the nanofibers, while the addition of D-amino acids weakened the ECD. Among them, the concentration of amino acid molecules in LH-L, LH-D, RH-L, and RH-D nanofiber solutions was between 1–100 μmol / L.

4. The method for molecular chirality detection and identification based on composite plasmon chiral nanostructures according to claim 1, characterized in that: The gold nanorod colloidal solution in step three was obtained by multiple centrifugation methods; the centrifugation method in step three was as follows: ① 200 μL of the gold nanorod solution prepared by the seed growth method was taken, 800 μL of deionized water was added, and the solution was centrifuged at 11800 rpm for 5 min, the supernatant was removed, 25 μL of 10 mmol / L hexadecyltrimethylammonium bromide CTAB and 975 μL of deionized water were added, and the solution was in a water bath at 30°C for 30 min; ② 11800 rpm was centrifuged for 5 min, the supernatant was removed, 25 μL of 10 mmol / L CTAB and 975 μL of deionized water were added, and the solution was in a water bath at 30°C for 30 min; ③ 11800 rpm was centrifuged for 5 min, the supernatant was removed, and 20 μL of 10mmol / L CTAB and 980μL deionized water, incubate in a 30℃ water bath for 30min; ④ centrifuge at 11800rpm for 5min, remove the supernatant, and add 1000μL deionized water; adjust the concentration of the gold nanorod solution obtained above to 150pmol / L according to Beer's law; the purpose of multiple centrifugation is to reduce the CTAB concentration in the gold nanorod colloid; at this time, the CTAB concentration in the gold nanorod colloidal solution is between 4-10μmol / L, and the surface potential value is between +45-+55mV; the gold nanorods in the obtained gold nanorod dispersion are 43-65nm long and 16-22nm wide; Due to the electrostatic attraction between gold nanorods and nanofibers, gold nanorods are assembled on the fibers; after adding gold nanorods, the concentration of gold nanorods in the self-assembled nanocomposite plasmon chiral structure solution is between 60–130 pmol / L.

5. The method for molecular chirality detection and identification based on composite plasmon chiral nanostructures according to claim 1, characterized in that: The diameter of the fiber prepared in step 2 is 20–80 nm, and the length of the gold nanorods prepared in step 3 is 43–65 nm and the width is 16–22 nm, and the two sizes are matched.

6. The molecular chirality detection and identification method based on composite plasmon chiral nanostructures according to claim 1, characterized in that: Composite structures have the following characteristics: In the self-assembled nanocomposite plasmonic chiral structure, adjacent gold nanorods assembled on the nanofibers are separated from each other; the distance between the gold nanorods is between 60–260 nm, and the average distance is between 140–140 nm.

7. The method for molecular chirality detection and identification based on composite plasmon chiral nanostructures according to claim 1, characterized in that: For chiral amino acid molecules: after the chiral nanofiber body interacts with the chiral amino acid molecules, when the amino acid reaches a certain concentration, the ECD can measure the difference relative to the control sample with water added; after the action of the fiber, after the addition of gold nanorod solution, its PCD shows an enhanced phenomenon compared with the control sample; and for achiral molecules: after the chiral nanofiber body interacts with the achiral amino acid molecules, when the achiral amino acid reaches a certain concentration, the ECD can measure the difference relative to the control sample with water added; after the action of the fiber, after the addition of gold nanorod solution, its PCD does not show an enhanced phenomenon compared with the control sample.

8. The method for molecular chirality detection and identification based on composite plasmon chiral nanostructures according to claim 1, characterized in that: After the chiral nanofiber host interacts with the chiral guest amino acid molecules, the ECD signal in the ultraviolet region cannot be measured or the difference is very small. By constructing a self-assembled nanocomposite plasmonic chiral structure, the host chirality transfer is amplified to appear in the form of PCD; when the enantiomeric excess value ee is not 0, the amplification factor β is between 50–400; when ee = 0, β can reach 1382; the amplification factor is defined as β = △PCD (%) / △ECD (%); where △ECD (%) is the percentage change in the ECD peak at 219–221nm of the chiral nanofiber solution with the addition of a certain ee relative to the chiral nanofiber solution with the same amount of water, and △PCD (%) is the percentage change in the PCD peak in the visible / near-infrared region between the cysteine ​​molecule solution with a certain ee and the chiral nanofiber solution with the same amount of water after the addition of the gold nanorod solution.