CN-121994776-A - SERS detection method based on spherical hydrogel metal nanoparticle composite gel beads

Abstract

The invention discloses a SERS detection method based on spherical hydrogel metal nanoparticle composite beads, which comprises the following steps of S1, obtaining silver nanoparticles, S2, mixing the silver nanoparticles with an alginate aqueous solution, dripping the mixed solution into a CaCl 2 aqueous solution to obtain the hydrogel metal nanoparticle composite beads, S3, adding the hydrogel metal nanoparticle composite beads into a sample solution to be detected, carrying out sample adsorption, then taking out, evaporating and concentrating the sample, and S4, carrying out SERS detection on the hydrogel metal nanoparticle composite beads after evaporating and concentrating. The invention constructs the spherical hydrogel metal nanoparticle composite gel bead with regular geometry and uniform structure as the SERS substrate material, has structural stability, interface controllability and excellent salt resistance, protein resistance and multicomponent interference resistance, and is suitable for high-reliability surface-enhanced Raman detection under the condition of complex and real samples.

Inventors

• ZHANG ZHIYANG
• LIU KE
• SU XIAOTONG
• CHEN LINGXIN
• ZHOU NA
• LIU SHUAIQI
• CHEN YAN
• SUI YIFAN

Assignees

• 中国科学院烟台海岸带研究所

Dates

Publication Date

20260508

Application Date

20260313

Claims (10)

1. 1. The SERS detection method based on the spherical hydrogel metal nanoparticle composite beads is characterized by comprising the following steps of: S1, obtaining silver nano particles; s2, mixing the silver nano-particles with an alginate aqueous solution to obtain a hydrogel mixed solution, dripping the hydrogel mixed solution into a CaCl 2 aqueous solution for crosslinking reaction to obtain hydrogel metal nano-particle composite gel beads; s3, adding the hydrogel metal nanoparticle composite gel beads into a sample solution to be detected, carrying out sample adsorption, and then taking out the hydrogel metal nanoparticle composite gel beads, and standing for 10-50 min to evaporate and concentrate the hydrogel metal nanoparticle composite gel beads; S4, performing SERS detection on the hydrogel metal nanoparticle composite gel beads after evaporation and concentration.
2. 2. The SERS detection method according to claim 1, wherein in the step S2, the alginate is sodium alginate.
3. 3. The SERS detection method according to claim 1, wherein in the step S2, the concentration of alginate in the hydrogel mixed solution is 0.5-2 wt%.
4. 4. The SERS detection method according to claim 1, wherein in the step S2, the concentration of the CaCl 2 aqueous solution is 1wt% to 30wt%.
5. 5. The SERS detection method according to claim 1, wherein in the step S2, the crosslinking reaction time is 1-15 min.
6. 6. The SERS detection method according to claim 1, wherein in the step S3, the sample adsorption time is 10-40 min.
7. 7. The SERS according to claim 1, wherein the silver nanoparticles are synthesized by reducing silver nitrate with sodium citrate in step S1.
8. 8. The SERS detection method according to claim 7, wherein in the step S1, sodium citrate is added into a silver nitrate aqueous solution, and the mixture is reacted for 20-50 min at 120-150 ℃ to obtain silver nanoparticle suspension.
9. 9. The SERS detection method of claim 8, wherein, In the step S1, the concentration of the silver nitrate solution is 200-400 mg/L; In the step S2, the silver nanoparticle suspension obtained in the step S1 is concentrated to 5% -15% of the original volume to obtain a concentrated suspension, and the concentrated suspension and an alginate aqueous solution are mixed according to the volume ratio of (0.05-1): 1 to obtain a hydrogel mixed solution.
10. 10. The use of the SERS detection method based on spherical hydrogel metal nanoparticle composite beads according to any one of claims 1 to 9 in detection of nile blue, malachite green or lutein.

Description

SERS detection method based on spherical hydrogel metal nanoparticle composite gel beads Technical Field The invention belongs to the technical field of surface-enhanced Raman detection, and particularly relates to a SERS detection method based on spherical hydrogel metal nanoparticle composite beads. Background Surface enhanced Raman scattering (Surface ENHANCED RAMAN SCATTERING, SERS) is a high-sensitivity detection technology which relies on a local electromagnetic field enhancement effect generated by a metal nano structure to realize trace or single-molecule horizontal analysis. By virtue of the advantages of strong molecular fingerprint identification capability, good photobleaching resistance, non-destructiveness and the like, SERS has important application potential in analysis of complex systems such as biological fluids, environmental water samples, food safety and the like. SERS detection performance depends largely on the structural stability and interfacial controllability of the SERS substrate material. However, in real biological fluids such as urine and blood and lutein adulterated samples, interference components such as high ionic strength, complex matrix composition and a large amount of proteins are easy to cause aggregation runaway of metal nano particles or shielding of surface active sites by nonspecific adsorption, so that signal attenuation, uneven spatial distribution and reduced repeatability are caused. In recent years, hydrogel materials have shown unique advantages in the field of complex sample pretreatment due to their three-dimensional hydrophilic network, high porosity and molecular sieving capability. The natural polysaccharide gel such as alginate can efficiently remove macromolecular interferents such as proteins through electrostatic repulsion and steric hindrance double mechanisms, and simultaneously selectively enrich micromolecular substances to be detected through electrostatic adsorption, hydrogen bonds and hydrophobic interactions. On the basis, the metal nano particles are uniformly loaded in the hydrogel matrix, so that a composite system with enrichment and sensing functions can be formed. Some anisotropic two-dimensional films and bulk hydrogel Surface Enhanced Raman Scattering (SERS) substrates have been used in the prior art to achieve sensitivity enhancement using evaporation induced shrinkage, but the influence of asymmetric structures and hydrogel types on signal uniformity and reproducibility has not been fully studied. These parameters can lead to signal non-uniformity through mechanisms such as non-uniform evaporation, redistribution of the analyte, and substrate curling. Therefore, there is a need to develop a SERS detection method using a spherical hydrogel composite bead with regular geometry as a core, which uses isotropic uniform shrinkage characteristics to fundamentally inhibit the coffee ring effect, and simultaneously endows a system with excellent salt resistance, protein resistance and multi-component interference resistance, so as to realize high-sensitivity and high-reliability detection of a target in a complex real sample. The hydrogel SERS platform with higher sensitivity and reproducibility has important significance for promoting trace analysis in complex actual samples. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a SERS detection method based on spherical hydrogel metal nanoparticle composite beads, which is used as a SERS substrate material and has the advantages of structural stability, interface controllability, excellent salt resistance, protein resistance and multicomponent interference resistance, and is suitable for high-reliability surface-enhanced Raman detection under complex real sample conditions. The specific technical scheme is as follows: The invention aims to provide a SERS detection method based on spherical hydrogel metal nanoparticle composite beads, which comprises the following steps of: S1, obtaining silver nano particles (AgNPs); s2, mixing the silver nano-particles with an alginate aqueous solution to obtain a hydrogel mixed solution, dripping the hydrogel mixed solution into a CaCl 2 aqueous solution for crosslinking reaction to obtain hydrogel metal nano-particle composite gel beads; s3, adding the hydrogel metal nanoparticle composite gel beads into a sample solution to be detected, carrying out sample adsorption, and then taking out the hydrogel metal nanoparticle composite gel beads, and standing for 10-50 min to evaporate and concentrate the hydrogel metal nanoparticle composite gel beads; S4, performing SERS detection on the hydrogel metal nanoparticle composite gel beads after evaporation and concentration. The detection method has the following mechanism that the core of the invention is to construct a spherical hydrogel metal nanoparticle composite gel bead with regular geometry and uniform structure as an SERS substrate material. The gel beads take alginate