Nanozyme Rich in Oxygen Vacancies Derived from Mn-Based Metal-Organic Gel for the Determination of Alkaline Phosphatase

A robust nanozyme rich in oxygenvacancies derived fromMn-based metal-organic gel has been strategically designed as a colorimetricsensor for the highly sensitive detection of alkaline phosphatase. Vacancy engineering as an effective strategy has beenwidely employedto regulate the enzyme-mimic activity of nanomaterials by adjustingthe surface, electronic structure, and creating more active sites.Herein, we purposed a facile and simple method to acquire transitionmetal manganese oxide rich in oxygen vacancies (OVs-Mn2O3-400) by pyrolyzing the precursor of the Mn(II)-basedmetal-organic gel directly. The as-prepared OVs-Mn2O3-400 exhibited superior oxidase-like activity as oxygenvacancies participated in the generation of O-2 (& BULL;-). Besides, steady state kinetic constant (K (m)) and catalytic kinetic constant (E (a)) suggested that OVs-Mn2O3-400 had a strongeraffinity toward 3,3 & PRIME;,5,5 & PRIME;-tetramethylbenzidine and possessedprominent catalytic performance. By taking 2-phospho-l-ascorbicacid as the substrate, which can be converted into reducing substanceascorbic acid in the presence of alkaline phosphatase (ALP), OVs-Mn2O3-400 can be applied as an efficient nanozymefor ALP colorimetric analysis without the help of destructive H2O2. The colorimetric sensor established by OVs-Mn2O3-400 for ALP detection showed a good linearityfrom 0.1 to 12 U/L and a lower limit of detection of 0.054 U/L. Ourwork paves the way for designing enhanced enzyme-like activity nanozymes,which is of significance in biosensing.