Rapid vertical flow immunoassay on AuNP plasmonic paper for SERS-based point of need diagnostics

SERS based immunoassays for point-of-care diagnostics are a promising tool to facilitate biomarker detection early disease diagnosis and control. The technique is on sandwiched system in which antigen first captured by selective plasmonic paper substrate then labeled an extrinsic Raman label (ERL), consisting of 60 nm gold nanoparticle (AuNP) functionalized with mixed monolayer antibody 4-nitrobenezenethiol (NBT) as reporter molecule. Here, we report the use AuNP modified filter novel capture membrane vertical flow format. This configuration affords reproducible sample through overcome diffusion limited kinetics significantly reduced assay time. was selected due its affordability availability, while embedded AuNPs maximized coupling ERLs enhancement. Additionally, served scaffold immobilize specifically bind antigen. In this work, SERS-based rapid (SERS-RVF) immunoassay mouse IgG developed establish proof-of-principle. Optimization conditions led limit 3 ng/mL, comparable more traditional formats carried out multi-well plates, time less than 2 min. accurately quantified normal serum validate SERS-RVF application analysis biological samples. These results highlight potential advantages platform point-of-need testing.