Easily fabricated SERS tags based on spherical polymer matrices decorated by gold nanoparticles

Abstract Surface-enhanced Raman scattering (SERS) is an effective technique for analyzing various analyte molecules, with applications in sensing, medicine, and studying biological processes. This paper presents a straightforward method for creating a SERS-active composite using polymer matrices and gold nanoparticles. Traditional layer-by-layer deposition with charged polyelectrolytes, often leads to formation of polyelectrolyte-gold aggregates outside the polymer sphere or in the wrapping of gold nanoparticles in the polyelectrolyte layer, reducing the effective area for SERS enhancement. In contrast, gold nanoparticles (AuNPs) produced via ascorbic acid reduction can aggregate on a charged polymer surface without polyelectrolytes. Nanoparticles obtained by citrate reduction are capable of easy ligand exchange on the surface and were tested for the obtaining of PMS decorated with gold nanoparticles. The microspheres surface filling with gold nanoparticles was calculated from SEM images. The percentage of filled with AuNPs area for samples PMS/ascorbic AuNPs and PMS/citrate AuNPs is 32% and 22%, respectively. The dye rhodamine 6G was used to evaluate SERS signal enhancement. The structures enabled detection of dye concentrations as low as 1×10 -6 mol/L, achieving an analytical enhancement factor is equal to 1.4 × 10 4 .