Sea Urchin-Like Platinum-Coated Gold Nanozymes-Based Ultra-Sensitive Colorimetric Detection and Mechanism...

The evaluation of compound genotoxicity is of great significance for drug safety assurance, and the existing evaluation methods have the problems of false-positive/negative, low throughput, or complicated operation. Although enzyme-linked immunosorbent assays (ELISA) kits targeting some genotoxic targets have high throughput, there are limitations in sensitivity and stability due to the use of horseradish peroxidase (HRP). In this study, an integrated evaluation platform based on novel sea urchin-like platinum-coated gold nanoparticles (Pt/Au NPs) was developed to address the above problems. Pt/Au NPs nanozymes were synthesized by deposition of a platinum layer on the surface of gold seeds. The nanozymes exhibited excellent peroxidase activity as well as superior stability compared to natural enzymes. Pt/Au NPs nano-enzymes were replaced for the construction of nano-enzyme-linked immunosorbent assay (NLISA), which has better sensitivity and stability, decreasing the acquired amount of test compounds. Through quantification of genotoxicity damage markers, phosphorylated histone H2AX (γH2AX) and phosphorylated histone H3 (p-H3) in metabolic human hepatocytes, this study has proposed a "see-saw" model to differentiate the genotoxic compounds of DNA breakage or aneuploidy: the breakage agent can significantly increase γH2AX levels, whereas the aneuploidy agent can increase p-H3 levels. Therefore, this microplate-based high-throughput colorimetric detection method can provide an efficient assessment tool for drug safety.