Rapid bioparticle concentration and detection by combining a discharge driven vortex with surface enhanced Raman scattering |
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Authors: | Diana Hou Siddharth Maheshwari and Hsueh-Chia Chang |
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Institution: | Department of Chemical and Biomolecular Engineering, Center for Microfluidics and Medical Diagnostics, University of Notre Dame, Notre Dame, Indiana 46556 |
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Abstract: | Rapid concentration and detection of bacteria in integrated chips and microfluidic devices is needed for the advancement of lab-on-a-chip devices because current detection methods require high concentrations of bacteria which render them impractical. We present a new chip-scale rapid bacteria concentration technique combined with surface-enhanced Raman scattering (SERS) to enhance the detection of low bacteria count samples. This concentration technique relies on convection by a long-range converging vortex to concentrate the bacteria into a packed mound of 200 μm in diameter within 15 min. Concentration of bioparticle samples as low as 104 colony forming units (CFU)∕ml are presented using batch volumes as large as 150 μl. Mixtures of silver nanoparticles with Saccharomyces cerevisiae, Escherichia coli F-amp, and Bacillus subtilis produce distinct and noticeably different Raman spectra, illustrating that this technique can be used as a detection and identification tool. |
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