Fabrication and implementation of printed sensors for taste sensing applications

This paper presents the design, fabrication, and implementation of low-cost taste sensors. A single-step procedure was performed using commercial polymer films to develop laser-induced graphene which was used as electrodes in sensor patches for taste sensing purposes. The cost of these sensor patches is less than two dollars based on the requirement for low-cost polymer films and Kapton tapes for developing the sensor patches. Five different chemicals corresponding to the five fundamental tastes of sour, sweet, salty, bitter and umami were tested with the developed sensors. The electrical parameters of the circuitry formed between the electrode-electrolyte interfaces during the experimental procedure were obtained by using the complex non-linear least square curve fitting technique by fitting a simulation curve to the Cole-Cole curve obtained from the experimental results. The sensor patches operating on a capacitive principle, exhibited significant differences in terms of their impedimetric responses for the kinetic processes taking place during the experiments, with different concentrations for each chemical. Four different concentrations were tested for each chemical to analyze the performance of the sensor for that particular chemical. A comparison between the responses of the five chemicals for each concentration was done to inspect the differences between their responses. An analysis of the differences in the conductivity response by the sensor patch for the five chemicals at a specific concentration was also done. The sensor patches did not show any hysteresis in their output responses, while obtaining significant repeatability when testing the chemicals with them. The response time of the sensor patches was around two seconds with the recovery time is 10 min for the sensor being thoroughly washed and dried in between experiments The obtained experimental results from these sensor patches and their low cost, and easy fabrication process make them promising for their utilization in taste sensing purposes.