Highly efficient surface-enhanced Raman scattering substrate formulation by self-assembled gold nanoparticles physisorbed on poly(N-isopropylacrylamide) thermoresponsive hydrogels.

Employing thermoresponsive hydrogels as scaffolding material for noble metal surface loading might be useful for the fabrication of surface-enhanced Raman scattering (SERS) surfaces. Here, we report on a new, reproducible, and simple approach to engineer poly(N-isopropylacrylamide) (PNIPAAm) hydrogel surfaces optimized for physisorption of gold nanoparticles (AuNPs). The advantage of this approach consists of the simple mechanism by which AuNPs are adsorbed on hydrogel templates, without sophisticated chemical treatments for their conjugation with the hydrogel. The resulting PNIPAAm-40 nm AuNP modes demonstrate that this approach gives the capability to tune the interparticle distance and, therefore, to control and modulate SERS affinity upon temperature changing.