Preparation and optical property analysis of gold–polymer hybrids for surface-enhanced Raman scattering-assisted bioimaging

Subject of study. This study focuses on hybrid structures composed of gold nanoparticles, a polymer shell, and a molecular dye. Aim of study. The objective was to determine the influence of preparative factors on the optical properties and stability of organo-inorganic hybrids, as well as to evaluate the performance of the resulting three-component systems for surface-enhanced Raman scattering (SERS)-assisted bioimaging. Method. Rod-shaped gold nanoparticles were synthesized using a seed-mediated growth method and subsequently coated with a multilayer polymer shell incorporating the cyanine 5.5 dye through covalent conjugation. The morphology of the nanoparticles was confirmed by transmission electron microscopy, and the stability of the dispersions was assessed using electrophoretic light scattering. The optical properties of the hybrid nanostructures were investigated using SERS. Main results. Core–shell structures with covalently conjugated dye exhibited a more intense spectral response compared with hybrids in which the dye was immobilized via nonspecific adsorption. The prepared plasmonic tags enabled bioimaging of cellular samples, resulting in high-contrast images. Practical significance. The gold–polymer hybrid tags developed in this study can be utilized as optical contrast agents in medical diagnostics and photothermal therapy.