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The labeling of cell surface receptors by fluorescentmarkers is an established method for the identification of cell phenotypein both research and clinical settings. Fluorescence dye labelinghas inherent constraints, most notably the upper limit of labels percell that may be probed using a single excitation source, in additionto a physical limit to the number of broad emission spectra that canbe distinctly collected within the visible wavelength region. SERSlabeling has the potential to mitigate these shortfalls. Herein, antibody-targeted,PEG-coated surface-enhanced Raman scattering (SERS) Au nanoparticlesare used simultaneously to label three cell surface markers of intereston malignant B cells from the LY10 lymphoma cell line. The SERS probeswere characterized by multiple methods to confirm their monodispersityand functionalization with both PEG and monoclonal antibodies. Thespecificity of the particles’ cell labeling was demonstratedon both primary chronic lymphocytic leukemia and LY10 cells usingSERS from cell suspensions and confocal Raman mapping, respectively.Fluorescence flow cytometry was employed to confirm the binding ofSERS probes to LY10 over large cell populations, and the particles’SERS was collected directly from labeled cells using a commercialflow cytometer. To the best of our knowledge, this is the first demonstrationof SERS flow cytometry from cells tagged with targeted SERS probes. [ABSTRACT FROM AUTHOR]

Abstract: Selective targeting and detection of a hematologic malignancy, chronic lymphocytic leukemia, using surface enhanced Raman scattering (SERS) gold nanoparticles is reported. The functional nanoparticles were composed of a gold core onto which an optical reporter dye was adsorbed, protected from aggregation by grafted polyethyleneglycol, and targeted to CD19 antigen by antibodies. The signals were detected by dark-field microscopy and Raman spectrometry. The observation that the Raman signals are not disrupted by several traditional pathology stains indicates advantages over fluorescence methods. [Copyright &y& Elsevier]