Background
Scar formation, which may be caused by myofibroblast aggregations, is the greatest challenge during skin wound healing in the clinical setting. Studies have indicated that epidermal stem cells (EPSC) improve wound healing and reduce scar formation.
Methods
We investigated the therapeutic effects of EPSC-derived exosomes (EPSC-Exos) on skin wound healing in a skin-defect rat model. We also examined the roles of EPSC-Exos-specific microRNAs in inhibiting the differentiation of human dermal fibroblasts (HDF) into myofibroblasts.
Results
We found that EPSC-Exos increased the wound healing rate and reduced scar formation in rats. Also, EPSC-Exos improved the regeneration levels of skin appendages, nerves and vessels, as well as the natural distribution of collagen. Furthermore, we found these functions may be achieved by inhibiting the activity of transforming growth factor-β1 (TGF-β1) and its downstream genes. The results showed that some specific microRNAs, including miR-16, let-7a, miR-425-5p and miR-142-3p, were enriched in EPSC-Exos. EPSC-Exos-specific microRNAs, especially miR-425-5p and miR-142-3p, played vital roles in inhibiting myofibroblast differentiation via reducing the TGF-β1 expression in dermal fibroblasts.
Conclusion
We found a novel function of EPSC-Exos-specific microRNAs, suggesting that EPSC-Exos might represent a strategy to prevent scar formation during wound healing in the clinical setting.
Summary
While higher high specific surface area allows micro‐supercapacitor (MSC) electrode materials to have improved performance, it also tends to make them less stable thermodynamically and microstructurally, which can easily deteriorate and seriously affects their service life. So here, we have chosen a cross‐linked copolymer film structure as MSC electrodes. The pyrrole‐thieno [3,4‐b] thiophene (TbT) copolymer film (namely PPy‐co‐TbT) exhibits high specific capacity, which can reach 47.8 mF cm−2 (a specific volumetric capacitance of 23.9 F cm−3 and a specific gravimetric capacitance of 28.1 F g−1) at a current density of 0.1 mA cm−2 using LiCl/PVA gel electrolyte with ultra‐long cycling stability (capacitance retention after 50 000 charge/discharge cycles is still higher than 93%, which is the leading level in MSCs). The electrochemical performance of this cross‐linked copolymer is superior to that of the single‐component polymer, achieving a 1 + 1 > 2 effect. Both features of cross‐linking and copolymerization have positive effects on microelectrodes requiring stable microstructures and high performance. The structurally stable cross‐linked copolymer obtained by copolymerization design may become a durable material for next generation ultra‐long‐life, high‐performance micro‐supercapacitor electrodes and will be widely developed.
Highlights
The electrochemical performance of the cross‐linked copolymer electrode reaches 1 + 1 > 2.
A pioneering cross‐linked copolymer was designed to prolong the stability of microsupercapacitor.
Capacitance retention rate is still higher than 93% after 50 000 cycles, which is in the leading position.
Provides an important thought for the manufacture of ultra‐long‐life microsupercapacitor.
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