In Situ Pt Staining Method for Simple, Stable, and Sensitive Pressure-Based Bioassays

Pressure-based bioassays (PASS) integrate a molecular recognition process with a catalyzed gas generation reaction, enabling sensitive and portable quantitation of biomarkers in clinical samples. Using platinum nanoparticles (PtNPs) as a catalyst has significantly improved the sensitivity of PASS compared with protein enzyme-based detection. However, PtNPs are easily deactivated during storage or after being decorated with antibodies. Moreover, nonspecific adsorption of PtNPs on substrates has been a problem, resulting in significant backgrounds. To solve these problems of PtNP-based detection, we report a robust, simple, stable, and sensitive Pt staining method for PASS. Detection antibody-decorated gold nanoparticles (AuNPs) are used to perform enzyme-linked immunosorbent assay, followed by Pt staining to stain AuNPs with Ag and Pt bimetallic shells (Au@AgPtNPs), which endow AuNPs with catalytic activity. The concentration of targets can be quantitatively determined by measuring the pressure due to O2 g...