Rapid bioparticle concentration and detection by combining a discharge driven vortex with surface enhanced Raman...

Area of Science:

• Microfluidics
• Biotechnology
• Analytical Chemistry

Background:

• Current lab-on-a-chip devices require high bacterial concentrations for detection, limiting their practicality.
• Advancements in microfluidic devices necessitate rapid and sensitive methods for bacteria concentration and detection.

Purpose of the Study:

• To develop a chip-scale technique for rapid concentration of bacteria.
• To combine this concentration method with Surface-Enhanced Raman Scattering (SERS) for enhanced detection of low bacterial counts.
• To demonstrate the utility of the technique for bacteria identification.

Main Methods:

• A chip-scale vortex-based fluid dynamics method was employed for rapid bacteria concentration.
• Concentration was achieved within 15 minutes, creating a packed mound of bacteria (200 µm diameter).
• Surface-Enhanced Raman Scattering (SERS) was used in conjunction with the concentrated bacteria for detection.

Main Results:

• The technique successfully concentrated bacteria from sample volumes as large as 150 µL.
• Detection of bacterial samples as low as 10^4 colony forming units (CFU)/mL was achieved.
• Distinct Raman spectra were obtained for mixtures of silver nanoparticles with Saccharomyces cerevisiae, Escherichia coli, and Bacillus subtilis.

Conclusions:

• The developed vortex-based concentration technique significantly enhances the detection sensitivity for low bacterial counts in microfluidic devices.
• The combined concentration and SERS method serves as a viable tool for bacteria detection and identification.
• This approach advances the capabilities of lab-on-a-chip devices for microbial analysis.