Palladium Nanoparticles Stabilized by Lentinan with Enhanced Peroxidase-like Activity for Sensitive Detection of H2O2

Natural enzymes are special proteins with excellent catalytic activity and selectivity. It is difficult to purify, store without losing the catalytic ability. Therefore, it is of great significance to study mimetic enzymes to realize the functions of natural enzymes and overcome their shortcoming. Herein, lentinan was used as a biological template to prepare palladium nanoparticles stabilized by lentinan (Pd-LNT NPs), whose structure, activity and function were characterized. In addition, the 3,3 ',5,5 '-tetramethylbenzidine (TMB) was oxidized by Pd-LNT NPs in the presence of H2O2, which proved that they had good peroxidase-like activity. The optimum reaction conditions were 30 degrees C and pH 4, the catalytic kinetic parameters were consistent with Michaelis-Menten equation, and the good catalytic performance was verified. Furthermore, the colorimetric reaction based on the good peroxidase-like activity of Pd-LNT NPs was used for the convenient detection of H2O2. The linear range of colorimetric detection of H2O2 was 3.571-107.143 mu M, and it is worth noting that the detection limit was low to 4.714 mu M. At last, Pd-LNT NPs as biomimetic enzymes were used to detect the H2O2 released from HeLa cells, indicating they have great potential in the field of biological application.