Detection of Bacterial Metabolic Volatile Indole Using a Graphene-Based Field-Effect Transistor Biosensor.

Area of Science:

• Food Safety
• Biosensors
• Nanotechnology

Background:

• Bacterial contamination poses a significant threat to food safety.
• Volatile organic compounds (VOCs) produced during bacterial metabolism can indicate contamination.
• Indole is a specific VOC released by Escherichia coli (E. coli).

Purpose of the Study:

• To develop a sensitive method for detecting E. coli presence in food.
• To utilize indole as a biomarker for E. coli detection.
• To explore the use of graphene field-effect transistors (G-FETs) for VOC sensing.

Main Methods:

• A G-FET biosensor was designed to detect the volatile molecule indole.
• The detection mechanism relies on π-π stacking interactions between indole molecules and the graphene surface.
• Changes in the electrical signal of the G-FET were measured upon indole exposure.

Main Results:

• The G-FET biosensor demonstrated detection of indole within a concentration range of 10 ppb to 250 ppb.
• A limit of detection (LOD) of 10 ppb for indole was achieved.
• Indole adsorption on graphene induced charge rearrangement, altering the G-FET's electrical signal.

Conclusions:

• The developed G-FET biosensor effectively detects indole, indicating E. coli presence.
• This strategy offers a promising platform for real-time bacterial detection in food safety.
• The π-π stacking interaction provides a robust mechanism for sensitive VOC sensing.