Comparison of enzymatic and enzyme-free glucose sensors using organic electrochemical transistors

Organic electrochemical transistor (OECT) is an ideal platform for biosensors due to its advantages of effective signal amplification and low working voltage. Enzymatic and enzyme-free glucose sensors using OECT were fabricated, with the gate electrode being laser-induced graphene modified by gold nanoparticles (LIG/AuNPs), and a comprehensive comparison of their performances was conducted. The enzyme-free glucose sensor using OECT directly employs LIG/AuNPs as the gate electrode, which can oxidize glucose into gluconic acid directly. For the enzymatic glucose sensor, Prussian blue (PB) was first deposited on the LIG/AuNPs gate electrode, and glucose oxidase (GOx) was subsequently immobilized onto it to fabricate the gate electrode. The current signal was obtained via the reduction of hydrogen peroxide. Electrochemical experiments show that the OECT-based enzymatic glucose sensor has a lower detection limit, higher sensitivity, and specificity than enzyme-free glucose sensors. The detection ranges of the OECT-based enzymatic and enzyme-free glucose sensors are 100 nM to 10 mM and 10 μM to 10 mM, respectively.