Electrochemical detection of E. coli using ISFET setup

In this study, the method of laser-induced graphene (LIG) growth on a polyimide film was explored, along with its application in Escherichia coli (E. coli) detection using an ion-sensitive field effect transistor (ISFET), and the electrical characterization of LIG under various conditions. The LIG growth involved irradiation with pulsed CO₂ laser, with parameter optimization to enhance conductivity. The ISFET construction utilized a thin film architecture on flexible substrates, incorporating semiconductor polymer P3HT/PC₇₁BM and polydimethylsiloxane dielectric. Finally, the electrical characterization involved was used to evaluate the resistance of the LIG sheet under different laser powers, water pH, exposure to UVO3, and E. coli concentrations. The distribution of E. coli was visualized due to the confocal microscopy, confirming its transport through the material. The ISFET's electrical response was assessed, showing a linear relationship between CFU/µl concentration and a percentual decrease in the saturation current. These findings indicated the potential of LIG as a versatile material for biodetection applications, particularly in E. coli detection.