Yeast dual-affinity biobricks: Progress towards renewable whole-cell biosensors

Area of Science:

• Biotechnology
• Biosensor Development
• Diagnostic Assays

Background:

• Point-of-care (POC) diagnostics are crucial for global healthcare access.
• Traditional immunoassays face cost and storage limitations in resource-limited settings.
• Synthetic biology offers solutions for developing affordable and user-friendly diagnostic tools.

Purpose of the Study:

• To design and develop an ultra-low cost, whole-cell "renewable" capture reagent for POC diagnostics.
• To engineer yeast cells to display antibodies and gold-binding peptides for simplified assay procedures.
• To create a functional electrochemical biosensor for detecting specific biomarkers.

Main Methods:

• Genetic engineering of yeast cells to display single chain variable fragment (scFv) antibodies and gold-binding peptides (GBP).
• Surface functionalization of gold electrodes with engineered yeast cells.
• Electrochemical impedance spectroscopy (EIS) and fluorescent imaging for characterization.
• Development and optimization of an electrochemical detection assay using screen-printed electrodes.

Main Results:

• Successful display of scFv antibodies and GBP on yeast cell surfaces.
• Verified binding of engineered yeast cells to gold electrodes.
• Demonstrated a complete electrochemical detection assay for Salmonella outer membrane protein D (OmpD).
• Achieved nanomolar detection limits using both electrochemical and fluorescence methods.

Conclusions:

• Engineered yeast cells provide a cost-effective and renewable capture reagent for POC diagnostics.
• The developed biosensor simplifies assay procedures, enhancing usability in remote settings.
• The technology shows promise for improving diagnostic capabilities in resource-limited areas.