PNNL

Abstract

Nanozymes (nanomaterials with intrinsic enzyme-like characteristics) have gained much attention for diagnostics and therapy due to their excellent enzyme-mimicking capability, great stability in environments, and facile and low-cost production. However, developing nanozymes with a high catalytic efficiency Kcat has been challenging. Herein, we report a class of nanozymes mimicking peroxidases, which are formed by depositing ultra-small 1 ~ 2 platinum nanoparticles (Pt NPs) on the surface of hydrophilic nitrogen-doped carbon nanoparticles (CN NPs). These nanozymes defined as CN-Pt NPs, show a high peroxidase-like activity with Kcat values of 1.27 M·mL/s·g for 3,3,5,5'-tetramethylbenzidine (TMB) and 1.97 M·mL/s·g for hydrogen peroxide (H2O2), respectively, which are at least one or two orders higher than many other reported carbon-noble metal-based nanozymes. Our developed CN-Pt NPs were further utilized in a colorimetric immunoassay as signal amplifiers for the biomarker detection of Burkholderia pseudomallei, a gram-negative bacterial pathogen classified as Tier 1 select agent by the US CDC. The assay achieved lower limits of detection of 0.11 ng/mL in phosphate-buffered saline (PBS) and 0.16 ng/mL in human serum, when compared to many other assays in detecting the same biomarker