We investigated bioadhesion (bacterial and cell adhesion) and biocompatibility of poly(tetrafluoroethylene-co-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid) (Nafion) and compared the results with those obtained with poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP). When incubated with bacteria for 4 h to 7 days, Nafion film exhibited scarce bacterial adhesion at 6 h, after which the adhesion gradually increasing to relatively low levels. In contrast, significant bacterial adhesion to PVFHFP film was observed at 4 h, and much higher adhesion levels were shown thereafter. Although HEp-2 human cells adhered normally to both films, reaching confluence in 7-8 days, the cells adhered to Nafion appeared more lively and stable than those to PVFHFP. Subcutaneous implantation in mice revealed that Nafion elicited a mild acute inflammatory reaction without chronic inflammation or tissue necrosis, indicating excellent biocompatibility in mice. PVFHFP, however, provoked a moderate and prolonged acute inflammatory response. These differences in the biological characteristics of Nafion and PVFHFP films may be attributable to the differences in the chemical and physical natures of these polymer films. Nafion film provided a sufficiently solid support, expressing a high surface charge density and good water-wettability. In summary, Nafion is suitable for use in biomedical applications that require biocompatibility with a reduced possibility of post-operative infections.

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Background Skin ageing is caused by numerous factors that result in structural and functional changes in cutaneous components. Research has shown that senescent cells are known to accumulate in skin ageing, however, the role of senescent cells in skin ageing has not been defined. Objectives To elucidate the role of the senescent cell in skin ageing, we evaluated the effect of known senolytic drugs on senescent dermal fibroblasts. Methods Primary human dermal fibroblasts (HDFs) were induced to senescence by long‐term passaging, UV irradiation, and H2O2 treatment. Cell viability was measured after treatment of ABT‐263 and ABT‐737 on HDFs. Young and aged hairless mice were intradermally injected with drugs or vehicle on the dorsal skin for 10 days. Skin specimens were obtained and reverse‐transcription quantitative PCR, western blotting, and histological analysis were performed. Results We found that ABT‐263 and ABT‐737 induced selective clearance of senescent dermal fibroblasts, regardless of the method of senescence induction. Aged mouse skin treated with ABT‐263 or ABT‐737 showed increased collagen density, epidermal thickness, and proliferation of keratinocytes, as well as decreased senescence‐associated secretory phenotypes, such as MMP‐1 and IL‐6. Conclusions Taken together, our results indicate that selective clearance of senescent skin cells can attenuate and improve skin ageing phenotypes and that senolytic drugs may be of potential use as new therapeutic agents for treating ageing of the skin.