Simultaneous glucose sensing and bioenergy harnessing

We describe herein the construction of a glucose biosensor system that senses glucose without the use of potentiostat and harness usable electrical energy from glucose to power a digital electronic device simultaneously. This system is powered by a single enzymatic glucose biofuel cell comprising a highly dense mesh network of multi-walled carbon nanotubes and enzymes that results in the immobilization and direct electrical connection of the enzymes. The bioanode is functionalized with pyroloquinoline quinone glucose dehydrogenase, while the biocathode is functionalized with bilirubin oxidase. The glucose biofuel cell assembly and its performance were investigated under physiological conditions (pH 7.4 and 37 °C) at which a maximum open circuit voltage of 548.2 mV, short circuit current density of 7.19 mA/cm2 and peak power density of 1.475 mA/cm2 were obtained in 20 mM glucose. The nominal electrical power generated from the single glucose biofuel cell (∼ 548 mV) was amplified to 3.2 V using a two stage electrical power amplification circuit and a capacitive element functioning as a glucose transducer. The self-powered glucose biosensor exhibited a linear dynamic range of 1 mM–45 mM and a high sensitivity of 92.51 Hz/cm2.mM when simultaneously sensing glucose and powering a glucometer. Additionally, the system demonstrated excellent operational stability over a 53-day period.