Pluronic F-127, a biodegradable, biocompatible copolymer of polyethylene oxide and polyprolylene oxide can be used successfully as a vehicle for cell delivery in tissue engineering. Pluronic F-127 evokes minimal inflammatory response and allows a more organized arrangement of the cells when compared to other polymers. We investigated the potential of Pluronic F-127 to deliver skin cells and the ability of these cells to engineer autologous skin in vivo in the porcine model.

Keratinocytes and fibroblasts were isolated by enzymatic digestion from porcine skin. Cells were cultured for 4 weeks and then suspended in 25% Pluronic F-127. A total of 10 full thickness wounds (3x3 cm) were created. Five of these full thickness defects were covered by a bilayer of Pluronic, the bottom layer containing a mixture of autologous fibroblasts-Pluronic and the top layer containing autologous keratinocytes-Pluronic suspension. The remaining full thickness wounds were covered with Pluronic alone. Skin biopsies were taken at 2-4-16 weeks. Histology and DNA, GAG and hydroxyproline content analyzed specimens.

Histology analysis demonstrated variable degrees of epithelium after 2 weeks. After 16 weeks in vivo the experimental group showed looser collagen and woven loose keratosis. Closer inspection revealed areas of the dermis reminiscent of early adnexal structures. Cell density was 50% that of native skin at 16 w. Collagen and proteoglycans were also present in the experimental and control groups, always in lesser concentration than in native tissue.

This study demonstrates the feasibility of bilayer skin regeneration using Pluronic F-127 as a delivery vehicle. The unique gelation properties of this polymer present the possibility of delivery of skin cells by painting or spraying techniques.
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