Selective imaging of saturated and unsaturated lipids by wide-field CARS-microscopy.
Wide-field Coherent Anti-Stokes Raman Scattering (CARS) microscopy is employed to identify saturated and unsaturated fatty acids in micro-emulsions and cells, using the ratio between the strong -C-H CARS signal at 2850 cm(-1) and the weak signal of the =C-H vibration around 3015 cm(-1) for distinction. Quantitative CARS imaging at the =C-H resonance is challenging, since it yields only a low CARS signal, and small differences on the order of 5% in the concentration of polyunsaturated fatty lipids have to be detected. For this purpose we draw advantage of the high signal-to-noise ratio of wide-field CARS microscopy that is achieved by an excitation geometry involving a "sheet-of-light"-type illumination.
Division for Biomedical Physics, Innsbruck Medical University, Müllerstr. 44, A-6020 Innsbruck, Austria.
Christoph
C
Heinrich
Alexander
A
Hofer
Andreas
A
Ritsch
Christian
C
Ciardi
Stefan
S
Bernet
Monika
M
Ritsch-Marte
D005224:Fats, Unsaturated / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry; D008055:Lipids / Q000737:chemistry*; D008853:Microscopy / Q000379:methods; D010938:Plant Oils / Q000737:chemistry; D013059:Spectrum Analysis, Raman
D005224:Fats, Unsaturated; D005227:Fatty Acids; D008055:Lipids; D010938:Plant Oils