Direct, ultrafast, and sensitive detection of environmental pathogenic microorganisms based on a graphene biosensor.

ABSTRACT

Pathogenic microorganisms in the environment pose a serious threat to global human health. This study developed a reduced graphene oxide (rGO)-field effect transistor (FET) biosensor to realize the rapid and sensitive detection of pathogenic microorganisms. The rGO-FET sensors were prepared by in-situ thermal reduction method, and biorecognition elements were immobilized using a crosslinking agent to realize the surface functionalization of rGO. The rGO-FET biosensors can detect Escherichia coli O157H7 as low as 1.4 CFU mL-1 within 46 s. The normalized current response was linearly correlated with E. coli concentration in the range of 1.4-1.4 × 107 CFU mL-1. The normalized current response of E. coli O157H7 was about an order of magnitude higher than those of other microorganisms, indicating that the biosensor has good specificity. The current loss rates of the unmodified rGO-FET sensors and the biosensors modified with anti-E. coli O157H7 after 30 days of storage at 4 °C were approximately 8% and 15%, respectively. Most importantly, the rGO-FET biosensors can directly detect real samples without pretreatment. Compared with other technologies, the rGO-FET biosensors can detect pathogenic microorganisms with a wider linear range in a shorter time, which is of great importance for the rapid warning and control of pathogenic microorganisms in the environment.