Immunoassays based on Pt nanoparticles with peroxidase activity

In this work, Pt nanoparticles were synthesised according to the citrate reduction process. The physical properties of these Pt nanoparticles were characterised using dynamic laser scattering (DLS), zeta-potential analysis, thermal gravimetric analysis (TGA), and TEM. The peroxidase activity of the Pt nanoparticles was also analysed using a chromogenic substrate (TMB) and a luminescent probe (luminol). For application to immunoassays, Pt nanoparticles were coupled with antibodies via electrostatic interaction, and the coupling conditions were optimised at different pH conditions. Finally, the applicability of Pt nanoparticles coupled with anti-hCG (human chorionic gonadotropin) antibodies was demonstrated for the immunoassay of hCG for the medical diagnosis of pregnancy.