The biomimic oxidase activity of layered V2O5 nanozyme for rapid and sensitive nanomolar detection of glutathione

Abstract

The development of efficient sensing element for rapid and sensitive measurement of glutathione is important on early detection of human diseases. Herein, we introduce the V2O5 nanosheets (NS) as a novel nanozyme to biomimic the oxidase activity toward the rapid detection of glutathione. The 5-6 layered V2O5 NS with 300-600 nm in size is successfully fabricated by ultra-sonication assisted exfoliation of bulk V2O5 using N, N-dimethyl formamide as the intercalation reagent. The sensing mechanism involves the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by V2O5 NS with the concomitant increase in absorption intensity. Upon introduction of glutathione, the oxidized TMB is converted back to its original form and results in the simultaneous decrease in peak intensity at 650 nm. The sensor exhibits a good linear response to glutathione in the range of 10-500 nM with a limit of detection of 2.4 nM. Moreover, the V2O5-TMB sensor exhibits a good selectivity and high specificity, which makes the detection of glutathione applicable in diluted human serum samples. Since no functionalization of the V2O5 NS is required, this sensing system can open a new avenue to serve as an efficiently biomimic oxidase for glutathione detection in biological fluid samples.