Organ culture of human scalp skin is usually performed with serum-containing medium, which limits its analytical usefulness. Here we report that intact human scalp skin can be grown at the air/liquid interface in supplemented, serum-free William's E medium for more than 2 weeks. Active hair shaft growth was visible until day 16 and was significantly enhanced compared with minimum essential medium (MEM) + 10% fetal bovine serum (FBS). Moreover, William's E medium protected better against cell death than MEM + 10% FBS before day 12. Using quantitative immunochemistry, proliferating (Ki-67+) cells could still be observed in the epithelium of hair follicles even on day 17 of serum-free skin organ culture. The number of apoptotic (TUNEL+) cells in the skin epithelium rose steadily after day 5. Giemsa stains revealed mature skin mast cells even after 13 days in culture. The percentage of surviving hair follicles (mostly with catagen-or telogen-like morphology) gradually increased over time displaying mostly catagen hair follicles after 17 days of culture. Although epidermis and hair follicle epithelium showed increasing atrophy and degeneration, and their pigmentation decreased gradually over time, some long-term-surviving epithelial islands were found in association with remnants of follicular structures as late as on day 88. These preliminary data suggest that a very simple serum-free organ culture method allows prolonged human skin and hair follicle survival as well as some limited hair follicle cycling in intact skin for more than 2 weeks under well-defined experimental conditions. This pragmatic assay invites multiple uses, and may become a valuable tool for both skin and hair research.Key words: hair follicle -hair growth -human scalp skinlong-term organ culture -pigmentation Please cite this paper as: Towards the development of a simplified long-term organ culture method for human scalp skin and its appendages under serumfree conditions. Experimental Dermatology 2007; 16: 37-44.
A new kind of triboelectric nanogenerator (TENG) is developed based on electrospun PVDF and nylon nanowires. This nanogenerator exhibits the remarkable characteristics of easy fabrication, low cost and high output. Its open-circuit voltage and short-circuit current density respectively reach up to 1163 V and 11.5 μA cm(-2) driven by the vibration with a triggering frequency of 5 Hz and an amplitude of 20 mm. The peak power density is 26.6 W m(-2). It directly powered a DC motor without an energy storage system for the first time. By harvesting energy from the environment using this TENG, a fully self-powered UVR detection device is developed to show the level of UVR directly without additional components.
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