title: Chemically-specific dual/differential CARS micro-spectroscopy of saturated and unsaturated lipid droplets.
abstract: We have investigated the ability of dual-frequency Coherent Antistokes Raman Scattering (D-CARS) micro-spectroscopy, based on femtosecond pulses (100 fs or 5 fs) spectrally focussed by glass dispersion, to distinguish the chemical composition of micron-sized lipid droplets consisting of different triglycerides types (poly-unsaturated glyceryl trilinolenate, mono-unsaturated glyceryl trioleate and saturated glyceryl tricaprylate and glyceryl tristearate) in a rapid and label-free way. A systematic comparison of Raman spectra with CARS and D-CARS spectra was used to identify D-CARS spectral signatures which distinguish the disordered poly-unsaturated lipids from the more ordered saturated ones both in the CH-stretch vibration region and in the fingerprint region, without the need for lengthy CARS multiplex acquisition and analysis. D-CARS images of the lipid droplets at few selected wavenumbers clearly resolved the lipid composition differences, and exemplify the potential of this technique for label-free chemically selective rapid imaging of cytosolic lipid droplets in living cells.
authors.affiliation: Cardiff University School of Biosciences, Museum Avenue, Cardiff CF10 3AX, United Kingdom.
authors.forename: Claudia
authors.initials: C
authors.lastname: Di Napoli
authors.forename: Francesco
authors.initials: F
authors.lastname: Masia
authors.forename: Iestyn
authors.initials: I
authors.lastname: Pope
authors.forename: Cees
authors.initials: C
authors.lastname: Otto
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Langbein
authors.forename: Paola
authors.initials: P
authors.lastname: Borri
mesh_terms: D000818:Animals; D002470:Cell Survival; D003600:Cytosol / Q000737:chemistry; D051379:Mice; D008853:Microscopy / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013997:Time Factors; D014280:Triglycerides / Q000737:chemistry*
chemical_list: D014280:Triglycerides