Highly Sensitive Non-Enzymatic Glucose Sensor Based on Metal-Organic Framework

Abstract

The reliable and fast determination of glucose is very important in the diagnosis of diabetes, waste water treatment and food industry. Although conventional glucose sensors based on enzymes such as glucose oxidase (GOx) display high sensitivity and selectivity to glucose, their activity is easily affected by the variation in temperature and pH and the presence of other chemicals. To improve this drawback, non-enzymatic glucose sensors that exhibit better device lifetime and stability have been recently proposed. Metal-organic frameworks (MOFs), a new class of porous materials consisting of metal ions and organic linkers, have attracted interest because of their physicochemical properties such as crystalline ordered structure, tunable pore sizes, large surface areas and thermal stability. Although most MOFs have poor electron-conductivity, they have been investigated actively because of redox properties of metal ions and tunable linker in their structure. In this study, we synthesized solvothermally MOFs consisting of various transition metal ions and organic linkers as electrocatalysts for glucose sensing. The synthesized MOFs were transformed to stable form for glucose detection by electrochemical treatment and the process was characterized by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM) and N 2 adsorption isotherm. By measuring their electrochemical properties from cyclic voltammetry and chronoamperometry analyses, we studied the effect of metal ions and organic linkers on electrocatalytic performance including sensitivity, limit of detection (LOD), linear range and selectivity. As a result of improvement of glucose sensing performance by controlling physicochemical properties of MOFs, a Ni-based MOF showed good electrocatalytic activity with high sensitivity. This study suggests that MOFs can be considered potential electrode materials for non-enzymatic glucose sensors.