Carbon nanotube-based field-effect transistor for highly sensitive detection of foodborne pathogens

Foodborne pathogens impose a major harm on human well - being, public safety, and economic well-being worldwide. Urgently, ultraly sensitive and quick detection technologies are required to safeguard against diseases and guarantee food safety. Herein, we developed a floating-gate (FG) carbon nanotube-based field-effect transistor (CNTFET) biosensor for the rapid detection of Escherichia coli O157:H7 (E. coli) 16S rRNA without nucleic acid amplification. The dielectric layer of the CNTFET sensors was covalently functionalized with a high-density single-strand DNA probe targeting a specific gene fragment of 16S rRNA, thereby enabling the effective recognition of E. coli O157:H7. The sensor achieved a rapid detection time of 100 seconds and a detection limit as low as 54 aM for the E. coli O157:H7 gene fragment in 0.01x PBS buffer, while showing minimal cross-reactivity to other foodborne pathogen genes. Moreover, the biosensor achieved ultra-low detection limits of 60 aM for 16S rRNA and 1 CFU of E. coli per microliter, even in complex matrices like bacterial lysates and milk specimens. Therefore, the developed FG-CNT FET biosensor exhibits characteristics such as being low in cost, possessing ultra-high sensitivity, being label-free, and enabling the rapid detection of minute quantities of E. coli. This providing a promising solution for efficient and reliable foodborne pathogen detection.