title: Label-free imaging of biomolecules in food products using stimulated Raman microscopy.
abstract: The development of methods that allow microscale studies of complex biomaterials based on their molecular composition is of great interest to a wide range of research fields. We show that stimulated Raman scattering (SRS) microscopy is an excellent analytical tool to study distributions of different biomolecules in multiphasic systems. SRS combines the label-free molecular specificity of vibrational spectroscopy with an enhanced sensitivity due to coherent excitation of molecular vibrations. Compared to previous imaging studies using coherent anti-Stokes Raman scattering microscopy, the main advantage of SRS microscopy is the absence of the unwanted nonresonant background, which translates into a superior sensitivity and undistorted vibrational spectra. We compare spectra of complex materials obtained with stimulated Raman scattering and spontaneous Raman scattering in the crowded fingerprint region.We find that, as expected, there is excellent correspondence and that the SRS spectra are free from interference from background fluorescence. In addition, we show high-resolution imaging of the distributions of selected biomolecules, such as lipids and proteins, in food products with SRS microscopy.
authors.affiliation: Harvard University, Department of Chemistry and Chemical Biology, Cambridge, Massachusetts 02138, USA.
authors.forename: Maarten B J
authors.initials: MB
authors.lastname: Roeffaers
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.forename: Christian W
authors.initials: CW
authors.lastname: Freudiger
authors.forename: Brian G
authors.initials: BG
authors.lastname: Saar
authors.forename: Marjolein
authors.initials: M
authors.lastname: van Ruijven
authors.forename: Gerard
authors.initials: G
authors.lastname: van Dalen
authors.forename: Chunhong
authors.initials: C
authors.lastname: Xiao
authors.forename: X Sunney
authors.initials: XS
authors.lastname: Xie
mesh_terms: D001704:Biopolymers / Q000032:analysis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D008853:Microscopy / Q000295:instrumentation*; D013059:Spectrum Analysis, Raman / Q000295:instrumentation*; D013194:Staining and Labeling
chemical_list: D001704:Biopolymers