Triple-layered core-shell fiber dressings with enduring platelet conservation and sustained growth factor release abilities for chronic wound healing.

Platelet-rich plasma (PRP) is one of the most popular biomaterials in regenerative medicine. However, the difficulties encountered in its preservation, and the requirement for on-demand preparation severely limit its application. In addition, its rapid degradation in the wound microenvironment makes the sustained release of growth factors impossible and finally reduces the therapeutic effect on chronic wounds. Here, a multifunctional dressing based on triple-layered core-shell fibers for loading and enduring preservation of PRP was developed using a one-step coaxial bioprinting technique combined with freeze-drying. The platelets were effectively dispersed and immobilized in the core layer of the fiber, leading to a sustained release of growth factors from the PRP. The rate of release can be controlled by adjusting the triple-layered core-shell structure. Simultaneously, the triple-layered core-shell structure can reduce the deactivation of PRP during freezing and storage. The experimental findings suggest that PRP exhibits sustained activity, facilitating the process of wound healing even after a storage period of 180 days. Furthermore, the protective mechanism of PRP by the triple-layered core-shell fiber was investigated, and the conditions for freeze-drying and storage were optimized, further enhancing the long-term storability of PRP. As a result, the multifunctional core-shell fiber dressings developed in this study offer a novel approach for sustained growth factor release and the enduring preservation of active PRP.