SERS Gold Nanoparticles for Cancer Surface Marker Detection
C.T. Nguyen, J. Nguyen, S. Rutledge, C. Wang, G.C. Walker
University of Toronto, CA
Keywords: Immunopathology, Nanoparticle conjugate, Surface Enhanced Raman Scattering, Chronic Lymphocytic Leukemia, hematology
Abstract:Surface Enhanced Raman Scattering (SERS) gold nanoparticles may provide novel optical tags for cellular analysis. Currently, cell markers are mostly assessed by fluorescence labeling using flow cytometry. However, fluorescence dyes are usually limited to 4-5 colors per single staining. This limits the accuracy and efficiency of detecting multiple cell markers. SERS nanoparticles can be brighter than fluorescence. Also, their Raman spectral bands are 20-30 times narrower than fluorescence. Here we describe the engineering, synthesis and testing of SERS gold nanoparticles for selective targeting and imaging of Chronic Lymphocytic Leukemia (CLL) cells. The SERS nanoparticles were conjugated to monoclonal antibodies that selectively target the CD19 antigen, a diagnostic marker of B-cell CLL. The nanoparticles were protected with polyethyleneglycol to impart stability and prevent aggregation. The specific SERS signals of CLL cells were detected by using dark-field microscopy and Raman spectrometry. The SERS nanoparticle specificity was measured using controls of unconjugated nanoparticles or conjugated to anti-CD4 antibody. A strong Raman enhancement effect was observed, providing the optical tag. The results indicate that SERS gold nanoparticles can be used to selectively target cell markers and Raman analysis of CLL cells.