High-Performance Non-Enzymatic Electrochemical Dopamine Sensors Based on Metal-Organic Framework Derived Co-C-Matrix Nanoplatforms

A facile electrochemical sensing nanoplatform for detection of ultralow dopamine (DA) concentrations is developed through modification of cobalt-benzene tricarboxylic acid (Co-BTC) derived cobalt-carbon-matrix (Co-C-matrix). To enhance surface reactions and enzyme-like activities involved in interaction with DA, the structural integration of hybrid Co-C-matrix into Co-BTC as metal-organic framework is investigated, resulting in nanostructured transducing media with high sensitivity and selectivity as the catalyst. The Co-C-matrix nanoplatform exhibited the improved performance based on electrocatalytic oxidation of DA with high sensitivity of 7176 µA mM-1 cm-2 and low detection limit of 10 nM. Furthermore, the linearity of an amperometry peak toward DA concentration over a wide concentration range of 10-25 µM was observed under optimal conditions. Excellent selectivity in the presence of potential interferents and operational stability in ambient air for 30 days as well as under environmental conditions for the electrochemical oxidation of dopamine were achieved. The practical feasibility of these non-enzymatic biosensors is demonstrated on real samples, where DA is detected in human serum with outstanding recovery of up to 100%. The synergetic effect of Co atoms dispersed in the matrix of the carbon nanohybrid results in abundant active sites for DA oxidation and electron transfer pathways.