In situ transplantation of adipose tissue-derived stem cells organized on porous polymer nanosheets for murine skin defects.

Stem cell transplantation is expected to be an effective early-phase treatment for deep burn injuries and intractable ulcers. Localizing and proliferating stem cells on the lesion utilizing engineered scaffolds is important for this treatment. In this study, we demonstrated in situ transplantation of adipose-tissue derived stem cells (ASCs) organized on free-standing porous polymer ultrathin films (referred to as "porous nanosheets") to a skin defect model in diabetic mice. Porous nanosheets were prepared by a combination of micro-gravure coating with macrophase separation of poly(d,l-lactic acid) and polystyrene under a roll-to-roll process and solvent etching process with cyclohexane. The permeable structure of porous nanosheets (thickness of 150 nm, average pore diameter of 4 μm) allowed for proliferation of ASCs and also provided sufficient nutrient inflow into multilayered ASC constructs. Then, transplantation of a trilayered ASC-laden porous nanosheet achieved homogeneous transference of ASCs onto the skin lesion. Transplanted ASCs contributed to wound healing in a dorsal skin defect model in diabetic mice. Thus, cell transplantation using porous nanosheets will be a new method for promoting wound healing in diabetic and other kinds of refractory ulcers. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B, 2018.