Dual-CARS microscopy
Paper in proceeding, 2007

We present a new Coherent Anti-Stokes Raman Scattering (CARS) microscopy technique for label-free imaging of bio-molecules in living cells; dual-CARS microscopy. The use of three synchronized laser pulses in a dual-pump/dual-detection configuration enables imaging of two species with different molecular vibrations simultaneously, as well as acquisition of images free of non-resonant background. We show the power of the method by imaging deuterated nonadecane slowly diffusing into a suspension of living yeast cells in medium, clearly distinguishing the medium and the lipid droplets in the cells by probing the CH2 vibration from the D-nonadecane by probing the CD vibration. In addition, images of lipid stores in living C. elegans nematodes free of non-resonant background are shown. This results in a significant enhancement of the image contrast, allowing the visualization of emerging, low-density lipid stores in a dauer larva, difficult to distinguish in conventional CARS microscopy. The separation of the non-resonant background is shown to be beneficial also when monitoring molecules with weak vibrational modes. The improved sensitivity obtained is illustrated by probing the C=C vibration in polyunsaturated lipids extracted from fish. This enables the monitoring of the degree of unsaturation of lipids, a high value of which is reported in foods known to have positive effects on human health.

Saccharomyces cerevisiae

unsaturated lipids

chemical imaging


vibrational imaging

image contrast enhancement

non-linear microscopy

Caenorhabditis elegans


Annika Enejder

Chalmers, Chemical and Biological Engineering, Molecular Biotechnology

Christian Brackmann

Chalmers, Chemical and Biological Engineering, Molecular Biotechnology

Ondrej Burkacky

Madeleine Åkeson

Chalmers, Chemical and Biological Engineering, Molecular Biotechnology


0277-786X (ISSN)

Vol. 6442 15
978-0-8194-6555-9 (ISBN)

Subject Categories

Atom and Molecular Physics and Optics



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