Microspheres powder as potential clinical auxiliary materials for combining with platelet-rich plasma to prepare cream gel towards wound treatment

Platelet-rich plasma (PRP), which contains several growth factors (GFs), is used clinically in various wound treatments. To promote treatment efficacy of PRP in wound healing, the present study is inspired by the spreadable feature of commonly used creams in dermatology, developing a microspheres powder, which can be used easily to combine with PRP to form a cream gel. The microspheres powder is composed of hydroxy propyl chitosan (CSPO) microspheres and oxidized alginic acid (OALG) microspheres. Due the advanced permeability among microspheres that caused by larger specific surface area and abundant gaps, by simply adding PRP into microspheres powder, even without stirring, a granular gel is immediately formed based on electrostatic action and Schiff base interaction between OALG microspheres and CSPO microspheres, as well as fibrin network formed by PRP and thrombin. The PRP-granular gel exhibited bulk hydrogel feature, while it's shear-thinning and self-healing performance makes it behave like creams, thus can be applied to the whole wound area via spread. Besides, due to the charge action and Schiff base interaction, the PRP-granular gel can attach on the wound, ensuring PRP functions on the wound. Subsequently, in vivo evaluation confirms that the PRP-granular gel can promote the healing of skin wounds. Further transcriptome sequencing suggests that the PRP-granular gel can change the expression of multiple genes in wound tissue by which it can alter the process of wound healing. In a word, the present study demonstrates the great potential of transforming this gel into the next generation of PRP-based bioactive wound dressing.