Detection of Glucose in Interstitial Fluid by Fca-Agarose Gel-Gox-Ag-Cof@Cnt Patch Non-Invasive Electrochemical Sensor

Abstract

Current continuous glucose monitoring is favored by diabetic patients owing to its convenience, real-time monitoring, and painlessness as compared with painful and inconvenient finger-stick monitoring. However, it still suffers from discomfort and poor accuracy and accordingly it is still not widely used. Herein, a non-invasive accurate yet comfortable biosensor based on ferrocenecarboxylic acid(FCA)-agarose gel-glucose oxidase(GOx)-Ag-covalent organic frameworks(COFs)@carbon nanotube(CNT) was developed to achieve continuous monitoring of blood glucose levels in tissue fluids in a non-invasive and painless manner. The COFTAPB-DHTP grew vertically on NH2-CNT with a thickness of about 5 nm can effectively immobilize the GOx as well as maintain its long-term bioactivity and enrich glucose to improve the sensitivity of biosensors. Ag with good antimicrobial effect, combined with agarose gel can improve comfort. The CNT and Ag enhanced the electron transfer of the FCA electron mediator. The agarose gel also alleviates the swelling and pain caused by the continuous current of Reverse Iontophoresis (RI) and provides better wearing comfort. The FCA-agarose gel-GOx-Ag-COF@CNT patch sensor can realize the monitoring of glucose with a detection limit of 0.018 mM and a sensitivity of 1.16 μA mM-1. This non-invasive glucose sensor provides excellent flexibility and wearability and is expected to be integrated with other electronic units for human health monitoring.

Keywords: Non-invasive blood glucose monitoring, Biosensors, Wearable sensing, ISF, covalent organic framework