Curcumin delivery and release by using a dual cooperative encapsulation system constructed with ZIF-8 MOFs and silk fibroin/polycaprolactone nanofibers for accelerated wound healing.

The development and design of novel nanofibrous dressings (NFDs) with biomimetic structure and multifunctional properties through electrospinning technique have aroused significant interest in the disciplines of wound treatment. In this study, curcumin (Cur) was firstly incorporated into zeolitic imidazolate framework-8 (ZIF-8), to generate Cur@ZIF-8 nanoparticles, which displayed a homogeneous, consistent, and nearly similar rhombic dodecahedral structure with the mean diameter of ~190 nm. Then the Cur@ZIF-8 was loaded into the silk fibroin (SF)/polycaprolactone (PCL) hybrid nanofibers to obtain a NFD through an electrospinning strategy. The other three different NFDs, i.e., SF/PCL, SF/PCL/ZIF-8, and SF/PCL/Cur, were fabricated as control groups. All the four different NFDs were found to exhibit uniform and bead-free morphology. Among them, the SF/PCL/Cur@ZIF-8 NFD exhibited superior mechanical properties, high porosity (83.8 ± 3.7 %), and water uptake (292.4 ± 9.5 %). Importantly, the SF/PCL/Cur@ZIF-8 NFD showed a controlled Cur release profile, fitting the Krosmeyer-Peppas model. The in vitro cell experiments indicated that the SF/PCL/Cur@ZIF-8 NFD obviously improved the proliferation and adhesion of human dermal fibroblasts (HDFs). Moreover, the SF/PCL/Cur@ZIF-8 NDF also exhibited great antibacterial activity, with the inhibition rate of 83.2 ± 1.7 % and 80.2 ± 4.7 % against E. coli and S. aureus, correspondingly. In vivo, the SF/PCL/Cur@ZIF-8 NFD not only significantly reduced the bleeding amount in a mouse liver hemorrhage model, but also obviously accelerated the wound healing (~99 %) by augmenting the collagen growth and re-epithelialization. The present study revealed that the SF/PCL/Cur@ZIF-8 NFD generated by a combination of metal-organic framework (MOF) synthesis and electrospinning showed significant promise for applications in wound treatment and skin tissue engineering.