Platinum Nanoparticle-Based Assay for Proteins by Resonance Light Scattering

A simple, sensitive, platinum nanoparticle-based assay for trace amounts of protein by resonance light scattering (RLS) was studied. The RLS intensities for bovine serum albumin (BSA) and human serum albumin (HSA) were remarkably enhanced due to the interaction with Pt nanoparticles at pH 3.5 or 4.0, respectively, and the maximum RLS peak appeared at 390nm. The RLS intensity increased proportionally with Pt concentration below 3.010-5molL-1 but declined gradually above 4.010-5molL-1. BSA within the range 0.1-3.0gmL-1 and HSA of 0.1-2.7gmL-1 can be detected with this method, and the detection limits were 4.2 and 10.7ngmL-1, respectively. The method was satisfactorily applied to the quantitative determination of total proteins in human serum samples with a maximum relative standard deviation (RSD) lower than 2.8% and recoveries in the range 100.4-102%.