Rapid, Selective, and Ultra-Sensitive Field Effect Transistor-Based Detection of Escherichia coli

Area of Science:

• Microbiology
• Biosensor Technology
• Materials Science

Background:

• Escherichia coli (E. coli) is a model organism in microbiology research.
• E. coli infections pose significant health risks, especially to vulnerable populations.
• Bacterial contamination leads to costly product recalls and public health concerns.

Purpose of the Study:

• To develop a rapid and sensitive biosensor for detecting live E. coli in liquid samples.
• To utilize a field-effect transistor (FET) biosensor functionalized with B/N co-doped reduced graphene oxide (BN-rGO).
• To assess the biosensor's limit of detection, range, and selectivity for E. coli K12.

Main Methods:

• Fabrication of a field-effect transistor (FET) biosensor using B/N co-doped reduced graphene oxide (BN-rGO) gel.
• Functionalization of the FET with antibodies specific to E. coli K12 O-antigens.
• Testing the biosensor's performance in phosphate-buffered saline (PBS) with varying concentrations of E. coli and Bacillus thuringiensis.

Main Results:

• The BN-rGO FET biosensor detected live E. coli K12 within 2 minutes.
• Achieved a limit of detection (LOD) of 10 cells per sample, extrapolatable to single-cell detection.
• Demonstrated a wide detection range (10-10^8 CFU/mL) and high selectivity against Bacillus thuringiensis.

Conclusions:

• The developed BN-rGO FET biosensor offers a rapid, sensitive, and selective method for detecting E. coli.
• This technology has potential applications in food safety, clinical diagnostics, and environmental monitoring.
• The biosensor performance surpasses or matches existing E. coli detection methods.