Portable geosmin detection system based on sensor cells expressing insect odorant receptors

Area of Science:

• Biotechnology
• Biosensor Technology
• Molecular Biology

Background:

• Sensitive and selective on-site odorant detection is crucial for applications like water quality testing and disease diagnosis.
• Existing methods often require sophisticated equipment or sample concentration steps.
• Insect odorant receptors offer a promising avenue for developing novel biosensors.

Purpose of the Study:

• To develop and validate a portable biosensor technology for sensitive, on-site detection of odorants.
• To utilize engineered Sf21 insect cells expressing Drosophila melanogaster odorant receptors for geosmin detection.
• To demonstrate the feasibility of this biosensor in real-world field samples.

Main Methods:

• Sf21 cells were engineered to express specific odorant receptors, co-receptors, and calcium-sensitive fluorescent proteins.
• Sensor cartridges were fabricated by immobilizing engineered cells onto a glass surface within tubes.
• The system was coupled with a portable fluorometer for geosmin detection and field deployment.

Main Results:

• The biosensor successfully detected geosmin at concentrations as low as 100 pM (18.2 ppt) without sample pre-concentration.
• Geosmin was detected in real field samples collected from a lakeside dam.
• This represents the first successful detection of odorants using biosensors with transfected sensor cells expressing specific odorant receptor genes.

Conclusions:

• The developed portable technology using insect odorant receptor-expressing sensor cells is practical for on-site odorant detection.
• This biosensor technology holds significant potential for applications in food, beverage, and water quality testing.
• Further development could expand its utility to other odorant detection needs, including disease diagnosis.