Zwitterionic Sulfhydryl Sulfobetaine Stabilized Platinum Nanoparticles for Enhanced Dopamine Detection and Antitumor Ability.

Herein, three kinds of molecules were used to modify the surface of platinum nanoparticles (Pt NPs) to tune their surface charge. Zwitterionic thiol-functionalized sulfobetaine (SH-SB) stabilized Pt NPs (SH-SB/Pt NPs) had the highest oxidase activity and peroxidase activity in the prepared platinum nanozymes due to the generation of reactive oxygen species. In addition, a colorimetric dopamine detection method was established based on the peroxidase activity of SH-SB/Pt NPs. This method had a wide range (0-120 µM), a low detection limit (0.244 µM), and high specificity. More importantly, SH-SB/Pt NPs displayed little hemolysis and good stability in the presence of proteins. SH-SB/Pt NPs demonstrated high cytotoxicity in vitro and good antitumor ability in vivo, which was attributed to the photothermal conversion ability of SH-SB/Pt NPs and the generation of reactive oxygen species in the acidic environment. The surface modification of nanozymes using zwitterionic molecules opens a new method to improve the catalytic activity and antitumor ability of nanozymes.