Highly selective and sensitive glucose sensors based on organic electrochemical transistors with graphene-modified gate electrodes

The sensitivity of glucose sensors based on organic electrochemical transistors (OECT) is increased by co-modifying graphene or reduced graphene oxide (rGO) and enzyme (glucose oxidase) on the gate electrodes for the first time. The optimized device shows linear responses to glucose in a broad concentration region from 10 nM to 1 mu M and with a detection limit down to 10 nM, which is two orders of magnitude better than that for the device without the graphene modification. The selectivity of the device is systematically studied for the first time. The device selectivity is dramatically improved when the gate electrode is modified with biocompatible polymers (chitosan or Nafion). The interfering effect caused by uric acid and L-ascorbic acid is almost negligible for practical applications. Therefore, highly sensitive and selective OECT-based glucose sensors can be realized by functionalizing the gate electrodes. In addition, the devices are solution processable and low-cost, and are thus suitable for disposable sensing applications.