title: Continuous cell sorting in a flow based on single cell resonance Raman spectra.
abstract: Single cell Raman spectroscopy measures a spectral fingerprint of the biochemistry of cells, and provides a powerful method for label-free detection of living cells without the involvement of a chemical labelling strategy. However, as the intrinsic Raman signals of cells are inherently weak, there is a significant challenge in discriminating and isolating cells in a flowing stream. Here we report an integrated Raman-microfluidic system for continuous sorting of a stream of cyanobacteria, Synechocystis sp. PCC6803. These carotenoid-containing microorganisms provide an elegant model system enabling us to determine the sorting accuracy using the subtly different resonance Raman spectra of microorganism cultured in a (12)C or (13)C carbon source. Central to the implementation of continuous flow sorting is the use of "pressure dividers" that eliminate fluctuations in flow in the detection region. This has enabled us to stabilise the flow profile sufficiently to allow automated operation with synchronisation of Raman acquisition, real-time classification and sorting at flow rates of ca. <100 μm s(-1), without the need to "trap" the cells. We demonstrate the flexibility of this approach in sorting mixed cell populations with the ability to achieve 96.3% purity of the selected cells at a speed of 0.5 Hz.
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK. Huabing.yin@glasgow.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: McIlvenna
authors.affiliation: Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
authors.forename: Wei E
authors.initials: WE
authors.lastname: Huang
authors.affiliation: Kroto Research Institute, Department of Civil and Structural Engineering, North Campus, The University of Sheffield, Broad Lane, Sheffield S3 7HQ, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Davison
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK. Huabing.yin@glasgow.ac.uk.
authors.forename: Andrew
authors.initials: A
authors.lastname: Glidle
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK. Huabing.yin@glasgow.ac.uk.
authors.forename: Jon
authors.initials: J
authors.lastname: Cooper
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK. Huabing.yin@glasgow.ac.uk.
authors.forename: Huabing
authors.initials: H
authors.lastname: Yin
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D002469:Cell Separation / Q000295:instrumentation / Q000379:methods*; D056656:Lab-On-A-Chip Devices; D011312:Pressure; D059010:Single-Cell Analysis / Q000295:instrumentation / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000295:instrumentation / Q000379:methods*; D046939:Synechocystis / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide