In vivo Drug Screening in Human Skin Using Femtosecond Laser Multiphoton TomographyKönig K. · Ehlers A. · Stracke F. · Riemann I.
aFraunhofer Institute of Biomedical Technology (IBMT), St. Ingbert, bFaculty of Mechatronics and Physics, Saarland University, Saarbrücken, Germany
The novel femtosecond laser multiphoton imaging system DermaInspect forin vivotomography of human skin was used to study the diffusion and intradermal accumulation of topically applied cosmetic and pharmaceutical components. Near-infrared 80 MHz picojoule femtosecond laser pulses were employed to excite endogenous fluorophores and fluorescent components of a variety of ointments via a two-photon excitation process. In addition, collagen was imaged by second harmonic generation. A high submicron spatial resolution and 50 ps temporal resolution was achieved using galvoscan mirrors and piezodriven focusing optics together with a time-correlated single-photon counting module with a fast microchannel plate detector. Individual intratissue cells, intracellular mitochondria, melanosomes, and the morphology of the nuclei as well as extracellular matrix elements were clearly visualized due to NAD(P)H, melanin, elastin, and collagen imaging and the calculation of fluorescence lifetime images. Nanoparticles and intratissue drugs were detected by two-photon-excited fluorescence. In addition, hydration effects and UV effects were studied by monitoring modifications of cellular morphology and autofluorescence. The system was used to observe the diffusion through the stratum corneum and the accumulation and release of functionalized nanoparticles along hair shafts and epidermal ridges. The novel noninvasive 4-D multiphoton tomography tool provides high-resolution optical biopsies with subcellular resolution, and offers for the first time the possibility to study in situthe diffusion through the skin barrier, long-term pharmacokinetics, and cellular response to cosmetic and pharmaceutical products.
Fraunhofer IBMT, Ensheimer Strasse 48
DE–66386 St. Ingbert (Germany)
Tel. +49 6894 980 150, Fax +49 6894 980 152
Received: September 2, 2005
Accepted: November 17, 2005
Published online: May 9, 2006
Number of Print Pages : 11
Number of Figures : 9, Number of Tables : 0, Number of References : 24
Skin Pharmacology and Physiology (Journal of Pharmacological and Biophysical Research)
Vol. 19, No. 2, Year 2006 (Cover Date: May 2006)
Journal Editor: Lademann, J. (Berlin)
ISSN: 1660–5527 (print), 1660–5535 (Online)
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