AuNPs network structures as a plasmonic matrix for ultrasensitive immunoassay based on surface plasmon resonance spectroscopy

Abstract Nanoparticle gap, degree of order, and the structure of the nanocomposite functionalized interface have a significant impact on sensing properties. Orderly arranged gold nanoparticles enhance the local surface plasmon resonance and the surface plasmon wave coupling on the surface of the gold film, thereby effectively improving the SPR sensitivity. The orderly adjustment of AuNPs spacing can be achieved by changing the concentration of guest, and a precise self-assembled three-dimensional network structure (3D NS) can be successfully constructed. A simple and feasible sensor based on the 3D NS formed by the self-assembly of pSC4-AuNPs was proposed. SPR refractive index change experiment was performed to value the sensitivity performance of the sensor, and the three main parameters were improved. Multiple optimization experiments proved that 3D NS mediated by 1 mM paraquat showed the highest SPR sensitization effect. Bovine serum albumin antibody immune experiment was performed as a model to verify the SPR performance of 3D NS, which was identical to the performance analysis experiment.