Electrochemically Amplified Nanozymatic Activity of Biolinker-based Synthesized Co-MOF for H 2 O 2 and Dopamine Detection

Abstract

Rapid, sensitive and selective H 2 O 2 & dopamine sensors provide enormous opportunities to health, food and environmental monitoring which could prevent major social and economic devastations. To overcome the sluggish and low sensitivity of the conventional colorimetric assay, an integration of electrochemical settings with conventional assay has been proposed in this work. At first, microwave assisted cobalt MOF (Co-MOF) was synthesized using bio-linker and characterized with FESEM and TEM. The electrochemical performance of Co-MOF was examined through cyclic voltammetry (CV) where eight-fold higher currents were achieved from the Co-MOF compared to the unmodified electrode. However, Co-MOF exhibit very weak nanozymatic activity in a mixture of 3,3′,5,5′-tetramethylbenzidine (TMB) and H 2 O 2 . Integration of the superior electrochemical nature of Co-MOF with the nanozymatic activity resulted in a six-fold enhanced nanozymatic activity that enabled H 2 O 2 quantification with a limit of detection (LOD) of 32 nM under optimized conditions. The modified electrode was further extended to quantify dopamine with a LOD of 0.81 M where a remarkably shorter detection time (60 times shorter) has been achieved compared to the conventional nanozyme. Mechanistic study showed that the Co-MOF provides a large surface area and abundant redox-active sites, facilitating fast electron transfer and significantly enhancing the electrochemical signal.