Although nanozymes with oxidase mimic activity have shown promise for biomarker sensing, their lower activity compared to natural enzymes has constrained their wider application.

In this research, the team identified that MnOx NBs with an ultrathin layered structure improve catalytic active site exposure and the negative charge layer of birnessite-type MnOx NBs enhances affinity for positive substrates such as 3,3',5,5'-tetramethylbenzidine (TMB).

Significantly, oxygen vacancies created via laser irradiation reduced the adsorption energy of the MnOx NBs for oxygen, resulting in excellent substrate affinity (Km = 0.0087 mM) and high catalytic rate (Vmax = 6.04 × 10-7 M/s).

Furthermore, glutathione (GSH) inhibition of Nanozymes with oxidase (OXD) mimics was exploited in the establishment of a fast and highly sensitive method for GSH determination.

These findings may provide new strategies for synthesizing highly active nanozymes for biomarker applications.

Growth mechanism of the ultrathin MnOx NBs (Image by JI Shihan)