Pt-DNA complexes as peroxidase mimetics and their applications in colorimetric detection of H2O2 and glucose

A recent study reported by Higuchi's group has shown that Pt-DNA complexes possess peroxidase enzymatic activity similar to natural peroxidases. In this study, we prepared Pt-DNA complexes and demonstrated their use in catalyzing the oxidation of a peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to the oxidized product which provided a colorimetric detection of H2O2. As low as 3.92 x 10(-4) mol L-1 H2O2 could be detected with a linear range from 9.79 x 10(-4) to 1.76 x 10(-2) mol L-1 via our method. Furthermore, PVDF membranes were employed to increase sensitivity and decrease the detection limit of H2O2, enabling a two-fold improvement in the detection sensitivity as compared with the above counterparts. More importantly, a sensitive and selective method for glucose detection was developed using glucose oxidase (GOx) and the as-prepared Pt-DNA complexes. We realized the test of glucose as low as 10(-7) mol L-1 by the color change, which was comparable to or even better than the existing methods, and identified the concentration of glucose in Sprite with the naked eye without referring to any sophisticated apparatus. The detection platforms for H2O2 and glucose developed in the present work showed great potential for applications in the future.