Berlin 2005 – scientific programme

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AKB: Biologische Physik

AKB 200: Poster Session II

AKB 200.11: Poster

Tuesday, March 8, 2005, 17:00–19:00, Poster TU C

Vibrational imaging of cholesterol enriched micro-domains in the Stratum corneum model system by CARS microscopy — •A. Kovalev¹, N. Patincharath¹, M. Köhler ², and A. Volkmer¹ — ¹3rd Institute of Physics, University of Stuttgart, 70550 Stuttgart — ²Roswell Park Cancer Institute, Buffalo, NY 14263, USA

For cellular components that either do not fluoresce or cannot tolerate the toxicity associated with staining and the photo bleaching of fluorophores, their intrinsic chemical properties can be used as contrast mechanisms through coherent anti-Stokes Raman scattering (CARS) microscopy. The CARS signal is resonantly enhanced when the difference in photon energies of the pump and the Stokes pulses coincides with the frequency of a Raman resonance. CARS microscopy has been demonstrated to exhibit high sensitivity, spatial and temporal resolution, noninvasiveness, and three-dimensional sectioning capability with sub-micron resolution. In this work, the application of CARS microspectroscopy to the study of a model system of Stratum corneum, the topmost barrier on the epidermis that prevents the penetration of external reagents through the skin is reported. Electroporation combined with application of vesicles formed by positively charged lipids makes the stratum corneum transparent for chemicals. This effect, which is important in transdermal drug delivery research, is not yet well understood. Investigations are carried out on model lipid mixtures consisting of ceramides, stearic acid and cholesterol, the three main lipid species of stratum corneum. A multiplex CARS scheme was employed for imaging and fast acquisition of CARS spectra revealing cholesterol-rich regions.