Printing sensors on biocompatible substrates for selective detection of glucose

This article presents development of organic electrochemical transistor (OECT) on a cellulose based biocompatible substrate for selective detection of glucose. The cost-effective manufacturing through drop on demand inkjet printing and blade casting techniques are adopted for the development of OECTs at ambient environment. The OECT is designed by printing carbon-based nanocomposite as the source, drain and gate electrodes, whereas for the channel layer, Poly (3, 4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) is printed. Optical and physical characterizations were performed to investigate the printability, patterns' uniformity, repeatability, and adhesion of the printed structures onto the target substrate. The sensors are tested against specific enzyme i.e. glucose oxidase mixed in a PBS (phosphate buffer saline) solution. Transistor characteristics of the OECTs are determined to find the best coupling parameters for the device test. The optimal coupling parameters i.e. Vds at 0.8V and Vgs at 0.7V produced the transconductance i.e. 0.15 mS, in suitable ranges of the device test. Five different concentrations of glucose were tested in the electrolyte solution starting from the 1μM and at maximum 100mM, producing a prominent change in the current response i.e. 20% of its initial value. The distinctive current responses for each glucose concentration at an average response time of 15 sec show very promising results for rapid glucose detection. The low-cost fabrication of these printed sensors on biocompatible substrates show favorable results towards deploying these sensors on human bodies for real-time glucose monitoring.