Gold nanoparticles as a probe for prion determination via resonance light scattering method.

Dihydrolipoic acid (DHLA) modified gold nanoparticles (AuNPs) were used as a highly selective probe for the detection of prion proteins. We discovered that AuNPs undergo aggregation selectively in the presence of recombinant prion protein (rPrP), and such selective aggregation enhanced the resonance light scattering (RLS) intensity from AuNPs tremendously. Based on this phenomenon, we established a new assay for rPrP detection. This new assay is label-free, highly selective, and sensitive. The linear range for rPrP detection is from 2.0 × 10(-10) to 2.0 × 10(-8) mol L(-1) with excellent discrimination against other interfering compounds, and the detection limit is 7 × 10(-11) mol L(-1). This assay has been successfully applied for rPrP detection in E. coli lysate, bovine serum samples and human plasma samples. Compared with other methods, the detection approach described here can achieve high selectivity and sensitivity without any complicated labeling or expensive instruments.