A high-sensitivity continuous glucose sensor using porous 3D cellulose/ carbon nanotube network

While numerous needle-based continuous glucose monitoring (CGM) devices have been available today, the insufficient enzyme immobilization on monitoring sensor severely limited the detection sensitivity of CGM devices. This manuscript describes here a high-sensitivity continuous glucose sensor (CGS) by engineering a porous 3D cellulose/carbon nanotube (CNT) network on the working electrode, which subcutaneously increases the detection enzyme capacity and thus significantly enhances the signal intensity and sensitivity. Furthermore, a tapered needle made of soft resin is engraved into three distinct microgrooves where the glucose oxidase (GOD)-modified working electrode, Pt-modified counter electrode, and Ag/AgCl-modified reference electrode are separately constructed inside the microgrooves. Moreover, a miniature potentiostat tailored for signal acquisition, processing, and transmission is engineered. After incorporated with a wireless circuit, the proposed CGS achieves continuous glucose monitoring in interstitial fluid with a surprising sensitivity of 9.15 μA/mM/cm², as well as maintaining functionality for a period of up to 9 days in live rats. This work provides the public a high-sensitivity continuous glucose monitoring device.