Duo-role Platelet-rich Plasma: temperature-induced fibrin gel and growth factors' reservoir for microneedles to promote hair regrowth.

[Display omitted] • A temperature-sensitive Platelet-rich Plasma (PRP) induced fibrin gel interpenetrated with the GelMA on a detachable transdermal microneedle (MN) for hair regrowth. • Duo-role PRP: temperature-induced fibrin gel as microneedle's enhanced network and GFs reservoir for microneedles to promote hair regrowth. • PRP-released GFs can be anchored into a GelMA/PRP matrix with an increased lifespan for a truly controlled release. • The application of PRP-MNs has promising effects and more cost-effective for hair regrowth due to the synergistic effect of multiple GFs. • PRP-MNs can benefit many other applications, such as oral and maxillofacial surgery, refractory wound, skin disease and rejuvenation, and reproductive medicine. Alopecia concerns more than half our adult population. Platelet-rich plasma (PRP) has been applied in skin rejuvenation and hair loss treatment. However, the pain and bleeding during injection and the troublesome for fresh preparation of each action limit PRP's in-depth applying dedication to clinics. We report a temperature-sensitive PRP induced fibrin gel included in a detachable transdermal microneedle (MN) for hair growth. PRP gel interpenetrated with the photocrosslinkable gelatin methacryloyl (GelMA) to realize sustained release of growth factors (GFs) and led to 14% growth in mechanical strength of a single microneedle whose strength reached 1.21 N which is sufficient to penetrate the stratum corneum. PRP-MNs' release of VEGF, PDGF, and TGF-β were characterized and quantitatively around the hair follicles (HFs) for 4–6 days consecutively. PRP-MNs promoted hair regrowth in mice models. From transcriptome sequencing, PRP-MNs induced hair regrowth through angiogenesis and proliferation. The mechanical and TGF-β sensitive gene Ankrd1 was significantly upregulated by PRP-MNs treatment. PRP-MNs show convenient, minimally invasive, painless, inexpensive manufacture, storable and sustained effects in boosting hair regeneration. [ABSTRACT FROM AUTHOR]