Laser-scribed flexible interdigitated electrodes using DIY laser engraver and electrodeposition of polyaniline and silver for pH monitoring

Abstract

It is crucial to have an impartial indicator to assess the progress of healing, considering the complexity of the wound healing process. Here, sensitivity, repeatability and accuracy are the optimal criteria for such a measurement along with the elimination of patient discomfort. In this work, a flexible pH sensor has been developed with polyaniline and silver electrodeposited on laser-scribed interdigitated electrodes. Importantly, the fabrication of laser-induced graphene (LIG) based interdigitated electrodes using a low-cost DIY (do-it-yourself) diode laser engraver has been demonstrated with a critical strategy to improve conductivity. Subsequently, polyaniline (PANI) was electropolymerized on LIG through voltammetric cycles over a potential range from −0.1–1.2 V at 100.0 mV/s scan rate. The Ag/AgCl pseudo-reference electrode was also electrodeposited on the interdigitated LIG pattern under galvanostatic conditions with subsequent electrochemical chlorination. The obtained sensors showed an average responsivity of 47.9 mV/pH, which is comparable to the Nernstian value (59.0 mV/pH) in the 4.0–8.0 pH range. The response time, cyclical, and temporal stability of the sensor were tested, which showed a rapid and stable response. Overall, the developed sensor accurately monitors pH values in the physiologically significant range for wound healing with the added advantage of low capital expenditure, making it a cost-effective option.