A Direct Immunoassay Based on Surface-Enhanced Spectroscopy Using AuNP/PS-b-P2VP Nanocomposites

A biosensor was developed for directly detecting human immunoglobulin G (IgG) and adenosine triphosphate (ATP) based on stable reproducible gold nanoparticles/polystyrene-b-poly(2-vinylpyridine) (AuNP/PS-b-P2VP) nanocomposites. The substrates were functionalized with carboxylic acid groups the covalent binding of anti-IgG anti-ATP detection IgG ATP (1 to 150 ?g/mL). SEM images nanocomposite show 17 ± 2 nm AuNP clusters adsorbed over a continuous porous PS-b-P2VP thin film. UV–VIS SERS used characterize each step substrate functionalization specific interaction between targeted analyte. results redshift LSPR band as surface measurements showed consistent changes in spectral features. Principal component analysis (PCA) discriminate samples before after affinity tests. Moreover, designed proved be sensitive different concentrations limit-of-detection (LOD) down 1 ?g/mL. selectivity confirmed using standard solutions IgM control. Finally, direct immunoassay (LOD = ?g/mL) has demonstrated that this platform can detect types biomolecules proper functionalization.