Hydrogen peroxide sensor using the biomimetic structure of peroxidase including a metal organic framework

Abstract

Abstract In this study, hemin that has excellent catalytic activity is adopted as a catalyst component and other materials, such as metal organic framework (MOF) and carbon nanotube (CNT), are further used to alleviate drawbacks of hemin, such as location issue and molecular aggregation. Based on that, a new catalyst consisting of hemin-encapsulated MOF and CNT is developed (Hemin⊂MIL-88-NH2/CNT). To evaluate its catalytic activity, colorimetric and electrochemical evaluations are conducted. When colorimetric method is used, Hemin⊂MIL-88-NH2/CNT shows good catalytic activity due to proper interaction between water media and amine bond of MOF. In electrochemical evaluations, Hemin⊂MIL-88-NH2/CNT has high sensitivity (0.538 μAμM−1cm−2) and low detection limit (0.06\xa0μM) at 0.5–203\xa0μM (R2\xa0=\xa00.999). Even in amperometric response tests, when 10\xa0μM H2O2 is injected, Hemin⊂MIL-88-NH2/CNT shows a better response than other heme protein- based catalysts ((Hb, Mb and HRP)/CNT) by 2.06–3.26 times. In terms of stability, its catalytic activity is well preserved even under harsh pH and temperature conditions for a long time (89.5% of the initial value after 15\xa0days). With that, it is confirmed that the Hemin⊂MIL-88-NH2/CNT as the catalyst for use in H2O2 sensors is attractive and better than other heme proteins.