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Real-Time Detection of Staphylococcus Aureus Using Whispering Gallery Mode Optical Microdisks
Hala Ghali1, Hicham Chibli2, Jay L Nadeau3
1Department of Engineering Physics, Polytechnique Montreal, Montreal, QC, H3T 1J4, Canada. hala.ghali@polymtl.ca.
Biosensors
|May 7, 2016
Summary
Whispering Gallery Mode (WGM) microdisk biosensors detect Staphylococcus aureus using LysK functionalization. This label-free method achieves high sensitivity and specificity, detecting as few as 20 bacterial cells.
Area of Science:
- Biophotonics
- Biosensing Technology
- Microfluidics
Background:
- Whispering Gallery Mode (WGM) microresonators offer high sensitivity for label-free biological target detection.
- Biosensor selectivity relies on surface functionalization with specific ligands.
- Staphylococcus aureus detection is crucial in clinical diagnostics.
Purpose of the Study:
- To develop and evaluate WGM microdisk resonators as biosensors for Staphylococcus aureus detection.
- To demonstrate label-free, real-time detection of bacteria.
- To assess the specificity of the functionalization strategy.
Main Methods:
- WGM microdisks with Q-factors around 10⁴ were fabricated.
- Microdisk surfaces were functionalized with LysK, a staphylococci-specific phage protein.
- Bacterial binding events were detected via shifts in resonance peaks.
Main Results:
- A limit of detection of 5 pg/mL (approximately 20 cells) for Staphylococcus aureus was achieved.
- Specific binding of Staphylococcus aureus was observed, indicated by resonance peak shifts.
- No binding of Escherichia coli was detected, confirming specificity.
Conclusions:
- WGM microdisk resonators functionalized with LysK provide a sensitive and selective platform for Staphylococcus aureus detection.
- The label-free, real-time detection capability is advantageous for rapid diagnostics.
- The functionalization scheme demonstrates high specificity at the genus level.
