A Biocompatible, Highly Sensitive, and Non-Enzymatic Glucose Electrochemical Sensor Based on a Copper-Cysteamine (Cu-Cy)/Chitosan-Modified Electrode

A biocompatible, highly sensitive, and enzyme-free glucose electrochemical sensor was developed based on a copper-cysteamine (Cu-Cy)-modified electrode. The catalytically active biocompatible material Cu-Cy was immobilized on the electrode surface by the natural polymer chitosan (CTS). The electrochemical characterization and glucose response of the Cu-Cy/CTS/glassy carbon electrode (GCE) were investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and constant potential amperometry. The significant electrocatalytic activity of Cu-Cy to the oxidation of glucose in an alkaline environment was revealed. Several crucial parameters, including the number of scanning cycles for electrode activation, applied potential, and the contents of Cu-Cy and chitosan, were investigated to understand their impact on the sensor's response. The proposed sensing platform exhibited linear ranges of 2.7 mu M to 1.3 mM and 1.3 mM to 7.7 mM for glucose detection, coupled with high sensitivity (588.28 and 124.42 mu A<middle dot>mM-1<middle dot>cm-2), and commendable selectivity and stability. Moreover, a Cu-Cy/CTS-modified screen-printed electrode (SPE) was further developed for portable direct detection of glucose in real samples.