16 July 2014 Single bacteria identification by Raman spectroscopy
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Abstract
We report on rapid identification of single bacteria using a low-cost, compact, Raman spectroscope. We demonstrate that a 60-s procedure is sufficient to acquire a comprehensive Raman spectrum in the range of 600 to 3300  cm−1. This time includes localization of small bacteria aggregates, alignment on a single individual, and spontaneous Raman scattering signal collection. Fast localization of small bacteria aggregates, typically composed of less than a dozen individuals, is achieved by lensfree imaging over a large field of view of 24  mm2. The lensfree image also allows precise alignment of a single bacteria with the probing beam without the need for a standard microscope. Raman scattered light from a 34-mW continuous laser at 532 nm was fed to a customized spectrometer (prototype Tornado Spectral Systems). Owing to the high light throughput of this spectrometer, integration times as low as 10 s were found acceptable. We have recorded a total of 1200 spectra over seven bacterial species. Using this database and an optimized preprocessing, classification rates of ∼90% were obtained. The speed and sensitivity of our Raman spectrometer pave the way for high-throughput and nondestructive real-time bacteria identification assays. This compact and low-cost technology can benefit biomedical, clinical diagnostic, and environmental applications.
© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
Samy Andrea Strola, Jean-Charles Baritaux, Emmanuelle Schultz, Anne Catherine Simon, Cédric Allier, Isabelle Espagnon, Dorothée Jary, Jean-Marc Dinten, "Single bacteria identification by Raman spectroscopy," Journal of Biomedical Optics 19(11), 111610 (16 July 2014). https://doi.org/10.1117/1.JBO.19.11.111610 . Submission:
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