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CN-121994775-A - SERS substrate based on supermolecule plasma gold nanoparticle-mirror surface and preparation method and application thereof

CN121994775ACN 121994775 ACN121994775 ACN 121994775ACN-121994775-A

Abstract

The invention relates to the technical field of chiral molecule detection and analysis, in particular to a SERS substrate based on a supermolecule plasma gold nanoparticle-mirror surface, and a preparation method and application thereof. The SERS substrate based on the supermolecule plasma gold nanoparticle-mirror surface sequentially comprises a substrate, an AuF film layer, an MPBA-beta-CD complex layer and a nanoparticle Au NPs layer from bottom to top, wherein the MPBA-beta-CD complex layer is formed by adsorbing MPBA-beta-CD complex on the surface of the AuF film layer, and a nano gap is formed between the AuF film layer and the Au NPs layer. The invention provides a SERS substrate based on a supermolecule plasma gold nanoparticle-mirror surface, wherein beta-CD captures enantiomer molecules to form a supermolecule assembly, nano-level gap hot spots are precisely manufactured between gold nanoparticles and a gold film, and synchronous identification and authentication of aromatic amino acid enantiomers can be realized.

Inventors

  • CHEN XIAOQING
  • Zuo Jiasi
  • LIU QI

Assignees

  • 中南大学

Dates

Publication Date
20260508
Application Date
20260228

Claims (9)

  1. 1. The SERS substrate based on the supermolecule plasma gold nanoparticle-mirror surface is characterized by comprising a substrate, an AuF film layer, an MPBA-beta-CD complex layer and a nanoparticle Au NPs layer from bottom to top, wherein the MPBA-beta-CD complex layer is formed by adsorbing an MPBA-beta-CD complex on the surface of the AuF film layer, and a nano gap is formed between the AuF film layer and the Au NPs layer.
  2. 2. The substrate of claim 1, wherein the AuF thin film layer has a thickness of 50-200 nm and au NPs has a particle size of 60-100 nm, and the substrate is monocrystalline silicon.
  3. 3. The substrate of claim 1, wherein the nanogap width is 1 to 2 nm.
  4. 4. The substrate of claim 1, wherein the MPBA- β -CD complex is formed by complexing MPBA with β -CD via a borate bond, the MPBA being adsorbed to the surface of the AuF film layer via an Au-S bond.
  5. 5. The preparation method of the SERS substrate based on the supermolecule plasma gold nanoparticle-mirror surface is characterized by comprising the following steps of: S1, performing plasma sputtering on an AuF film layer on the surface of a substrate; S2, incubating and combining MPBA on the surface of the AuF film layer in S1 to obtain AuF-MPBA, and continuously complexing beta-CD to obtain AuF-MPBA-beta-CD; S3, preparing Au NPs by a gold seed growth method, dripping the Au NPs on the surface of the AuF-MPBA-beta-CD, and drying to obtain the SERS substrate based on the supermolecule plasma gold nanoparticle-mirror surface.
  6. 6. The method of claim 5, wherein the step S1 of plasma sputtering the AuF thin film layer on the surface of the substrate comprises preparing a monocrystalline silicon wafer, sequentially ultrasonic cleaning with acetone, absolute ethyl alcohol and ultrapure water, drying, placing the monocrystalline silicon wafer in a vacuum chamber of an ion sputtering system, pumping the vacuum degree of the chamber to 1X 10 –3 Pa or below, applying a sputtering voltage of 90-110V and a sputtering current of 10-40 mA for deposition, and controlling the deposition time to be 100-500 seconds, thereby forming an AuF thin film with a thickness of 50-200 nm on the surface of the monocrystalline silicon wafer.
  7. 7. The preparation method according to claim 5, wherein the surface incubation of the AuF film layer in S2 and the combination of MPBA specifically comprises immersing the substrate sputtered with the AuF film layer in an MPBA ethanol solution with the concentration of 0.1-2 mmol/L in S1, and reacting at the temperature of 25-50 ℃ for 4-12 hours; The method for preparing the AuF-MPBA-beta-CD by continuously complexing beta-CD comprises the steps of transferring the substrate into a beta-CD solution with the concentration of 1-10 mmol/L, preparing the solution by using phosphate buffer solution with the pH value of 6.5-10.5, incubating for 12-24 hours at the temperature of 15-30 ℃, flushing the functionalized surface by using ultrapure water after the reaction is finished, and drying under nitrogen flow to obtain the AuF-MPBA-beta-CD substrate.
  8. 8. The method of claim 5, wherein the preparing Au NPs by the gold seed growth method in S3 specifically comprises: S3.1, preparing gold seed solution, namely heating 100-150 ml of ultrapure water to 85-110 ℃ and stirring for 15-30 minutes, then sequentially adding 1-4 ml of sodium citrate solution with the concentration of 20-60 mmol/L and chloroauric acid solution with the concentration of 0.5-2.0 mL and the concentration of 10-30 mmol/L, and keeping the temperature for reacting for 25-35 minutes to obtain gold seed solution; S3.2, the first step of growth, namely regulating the temperature of the gold seed solution to 80-110 ℃, adding 0.2-0.6 mL of chloroauric acid solution, and reacting for 10-30 minutes, wherein the growth step is repeated once; S3.3, a second step of growth, wherein the solution obtained in the step S3.2 is mixed with 30-60 mL and 30-60 mL ultrapure water, heated for 15-30 minutes at 85-110 ℃, then 0.5-2.0 ml of sodium citrate solution and 0.2-0.6-mL chloroauric acid solution are sequentially added for reaction for 10-30 minutes, and the second step of growth process is repeated twice to obtain Au NPs with the particle size of 60-100 nanometers; S3.4, washing and purifying, namely centrifuging the obtained Au NPs suspension for 5-20 minutes at the rotating speed of 3000-8000 rpm, discarding the supernatant, re-suspending with ultrapure water, repeatedly centrifuging and cleaning for 1-3 times, finally re-dispersing the purified Au NPs in the ultrapure water to prepare the Au NPs suspension, and storing at the temperature of 2-8 ℃ for later use; The Au NPs are dropwise added on the surface of the AuF-MPBA-beta-CD, which comprises the steps of vertically dropwise adding 2-15 mu L of Au NPs suspension prepared in the step S3.4 on the surface of the AuF-MPBA-beta-CD substrate prepared in the step S2, standing for 5-15 minutes at 15-30 ℃, and then drying in an oven at 25-35 ℃ to obtain the SERS substrate based on the supermolecule plasma gold nanoparticle-mirror surface.
  9. 9. The supramolecular plasmonic gold nanoparticle-mirror based SERS substrate according to any one of claims 1 to 4 or the supramolecular plasmonic gold nanoparticle-mirror based SERS substrate prepared by the method according to any one of claims 5 to 8, wherein the supramolecular plasmonic gold nanoparticle-mirror based SERS substrate is used for synchronous identification and species identification of aromatic amino acid enantiomers.

Description

SERS substrate based on supermolecule plasma gold nanoparticle-mirror surface and preparation method and application thereof Technical Field The invention relates to the technical field of chiral molecule detection and analysis, in particular to a SERS substrate based on a supermolecule plasma gold nanoparticle-mirror surface, and a preparation method and application thereof. Background Chirality is a fundamental property in nature and has a decisive influence on the structure and function of biomolecules. Chiral molecules exist in mirror image forms that cannot overlap each other, known as enantiomers. Although the physicochemical properties of enantiomers are similar, there are often significant differences in their biological activity, pharmacological and toxicological effects, even in the opposite sense. A typical example is the drug thalidomide, RThe enantiomer has sedative effect, and SEnantiomers exhibit strong teratogenicity. This variability makes the precise identification and differentiation of chiral molecules critical in drug development, food safety, disease diagnosis, and life science research. The chiral aromatic amino acid is used as an important bioactive molecule and a drug synthesis intermediate, and the identification and detection of different enantiomers of the chiral aromatic amino acid have important scientific value and application prospect. The existing analysis method is difficult to realize high-sensitivity identification and three-dimensional configuration characterization in one-time detection, and a plurality of technologies are often needed to be combined. Therefore, development of a novel chiral analysis platform that is rapid, highly sensitive, and provides rich structural information is becoming an urgent need. Surface Enhanced Raman Scattering (SERS) technology has great potential in chiral recognition due to its single molecular level sensitivity and fingerprint spectral characteristics. Its signal enhancement stems from localized surface plasmon resonance of noble metal nanostructures, while nanostructure gap ("hot spot") size is critical. The smaller the gap (nano/sub-nano scale), the stronger the electromagnetic field confinement and the more pronounced the signal enhancement. However, conventional SERS substrates (e.g., colloidal agglomerates or rough films) have difficulty in precisely controlling gap size and morphology, limiting resolution and reproducibility of chiral analysis. In recent years, nanoparticle-mirror (NPoM) structures have received attention as a new type of plasma nanochamber. The structure can form a sub-nanometer gap with controllable size and high localization of electromagnetic field by precisely assembling uniform metal nano particles on a smooth metal film, thereby providing an ideal platform for ultrasensitive detection and structural analysis. The NPoM structure is combined with the specific chiral recognition function, and a reliable SERS sensing interface with high sensitivity and high chiral resolution capability is constructed, so that the method is a key research direction for pushing the practical application of the technology. However, the existing NPoM structure construction method still has many challenges, namely, how to realize accurate, controllable and large-scale assembly of metal nanoparticles on a mirror surface in terms of nanoparticle assembly, and the difficulties of the current technology still remain. The existing NPoM platform generally adopts an inorganic medium layer such as SiO 2、Al2O3 or a molecular self-assembled monolayer as a gap interval, the thickness of the inorganic medium layer is controllable, but the inorganic medium layer lacks a molecular recognition function, and the molecular self-assembled monolayer can introduce a specific functional group, but has the problem of poor structural stability. Therefore, a NPoM construction strategy which has the advantages of accurate gap control, good structural stability and integrated chiral recognition function is developed, and the method has important significance for promoting the practical application of the method in the chiral sensing field. Disclosure of Invention Aiming at the problems, the invention provides a SERS substrate (NPoM/MPBA-beta-CD/SERS) based on a supermolecule plasma gold nanoparticle-mirror surface, wherein beta-CD captures enantiomer molecules to form a supermolecule assembly, nano-level gap hot spots are precisely manufactured between gold nanoparticles and a gold film, and synchronous identification and authentication of aromatic amino acid enantiomers can be realized. In order to achieve the aim, the SERS substrate based on the supermolecule plasma gold nano particle-mirror surface comprises a substrate, an AuF film layer, an MPBA-beta-CD complex layer and a nano particle Au NPs layer from bottom to top, wherein the MPBA-beta-CD complex layer is formed by adsorbing MPBA-beta-CD complex on the surface of the AuF film layer, and a nano ga