An effective metal-organic framework-based electrochemical non-enzymatic glucose sensor

Abstract

• Non-enzymatic glucose sensor based on MOF for long-term glucose monitoring. • Excellent electrocatalytic behaviour of Ni-BDC-NH 2 towards oxidation of glucose. • Ni-BDC-NH 2 displayed a lower detection limit, higher stability and sensitivity. • NH 2 functional group has facilitated the electron transfer during glucose detection. • Molecular sieve effect in the MOF enabled the selective diffusion of glucose. Herein, we report a non-enzymatic glucose sensor based on a metal-organic framework (MOF) as alternative approach for long-term glucose monitoring. Specifically, nickel-based MOFs were solvothermally synthesized using either 2-amino-1,4-benzenedicarboxylic acid (BDC-NH 2 ) or 2-hydroxy-1,4-benzenedicarboxylic acid (H 2 BDC-OH), both of which were characterized by different physicochemical techniques. The electrochemical performance of both electrodes towards glucose sensing was investigated and Ni-BDC-NH 2 exhibited a significantly better electrocatalytic behaviour towards oxidation of glucose than bare Ni-BDC or Ni-BDC-OH in an alkaline media. This was attributed to a favourable multi-layered sheet-like structure that allowed diffusion for entrapment of glucose and the incorporation of –NH 2 functional groups attached to the BDC linker which, were responsible for electrochemical adsorption of glucose molecules. Ni-BDC-NH 2 displayed a lower detection limit (3.82 μM), higher stability (>180 days), and remarkable sensitivity (308 μA mM −1 cm −2 ). Additionally, a molecular sieve effect for Ni-BDC-NH 2 led to a noteworthy anti-interference ability and the sensor displays a fast response time of 5.4 s towards glucose detection. These results indicate that the as-synthesized non-enzymatic glucose sensor operates with a longer lifetime and is viable for use as an intensive monitoring system.