Bacteria contaminants detected by organic inverter-based biosensors

This study presents a novel rapid bacterial detection method employing an organic complementary metal–oxide–semiconductor (O-CMOS) inverter fabricated with pentacene and PTCDI-C13. Various bacteria, including Escherichia coli (E. coli) O157, Staphylococcus aureus (S. aureus) ATCC25922, and Enterococcus faecalis (E. faecalis) SH-1051210, were tested on the inverters operating at an ultra-low voltage of 2 V. Analysis of the electrical signals revealed a discernible shift in the inverter's switching voltage attributed to the negative charge density on the surfaces of bacteria. This voltage shift exhibited a direct correlation with bacterial concentration, thereby enabling the direct measurement of concentration without the need for external devices. The inverter-based sensor demonstrated a linear response across bacterial concentrations ranging from 102 to 108 CFU/mL, with a sensitivity exceeding 60%. Its primary advantage over existing detectors lies in its ability to directly read the switching voltage, facilitating rapid and accurate measurements, and offering significant potential for mass production.