Plasmonic nanostructures encapsulated with hydrogel skin for in-site raman detection of small molecules in complex fluids

Abstract

Surface-enhanced Raman spectroscopy (SERS) techniques amplify the Raman signal of molecules via the localized surface plasmon resonance (LSPR) effect at metallic nanostructures. SERS technique is the rapid, sensitive and nondestructive tool that widely used for molecular analysis in the various fields of biosensing, chemical analysis and environmental security testing. However, when analyzing SERS in a mixed fluid, the irreversible adsorption of macromolecules such as proteins prevents the access of small molecules to the metal surface. Accordingly, pretreatment processes such as centrifugation to exclude proteins and extraction using solvents are unavoidable, and in this process, not only loss of target small molecules but also field applicability is reduced. Within this work, Plasmonic metal nanostructures were fabricated through multilayer silver nanowire stacking method, vacuum deposition method, and synthesized nanoparticle fixation method. In addition, a hydrogel thin film having size selectivity was encapsulated over the surface of the plasmonic nanostructure and used in the field of in-situ detection biosensor with ultra-sensitivity without pretreatment in biological fluids through selective permeation of small molecules in complex fluids.