title: Surface-enhanced Raman spectroscopy of the endothelial cell membrane.
abstract: We applied surface-enhanced Raman spectroscopy (SERS) to cationic gold-labeled endothelial cells to derive SERS-enhanced spectra of the bimolecular makeup of the plasma membrane. A two-step protocol with cationic charged gold nanoparticles followed by silver-intensification to generate silver nanoparticles on the cell surface was employed. This protocol of post-labelling silver-intensification facilitates the collection of SERS-enhanced spectra from the cell membrane without contribution from conjugated antibodies or other molecules. This approach generated a 100-fold SERS-enhancement of the spectral signal. The SERS spectra exhibited many vibrational peaks that can be assigned to components of the cell membrane. We were able to carry out spectral mapping using some of the enhanced wavenumbers. Significantly, the spectral maps suggest the distribution of some membrane components are was not evenly distributed over the cells plasma membrane. These results provide some possible evidence for the existence of lipid rafts in the plasma membrane and show that SERS has great potential for the study and characterization of cell surfaces.
authors.affiliation: Division of Biomedical and Life Sciences, Lancaster University, Lancaster, Lancashire, United Kingdom; Centre for Biophotonics, Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, United Kingdom.
authors.forename: Simon W
authors.initials: SW
authors.lastname: Fogarty
authors.affiliation: Centre for Biophotonics, Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, United Kingdom; Cavendish Laboratory, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom.
authors.forename: Imran I
authors.initials: II
authors.lastname: Patel
authors.affiliation: Centre for Biophotonics, Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, United Kingdom.
authors.forename: Francis L
authors.initials: FL
authors.lastname: Martin
authors.affiliation: Division of Biomedical and Life Sciences, Lancaster University, Lancaster, Lancashire, United Kingdom.
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Fullwood
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D015999:Multivariate Analysis; D013059:Spectrum Analysis, Raman / Q000379:methods*