Human platelets play important roles in several physiologic and pathologic processes.Platelet concentrates are activated with thrombin or calcium, resulting in a viscous coagulum (platelet gel [PG]), composed of 95% platelets at least. PG is increasingly used for the treatment of a variety of soft and hard tissue defects, most notably in the management of chronic non-healing wounds. During wound healing, platelets not only play a critical role in primary hemostasis and thrombosis, but also release growth factors and cytokines to promote tissue regeneration, enhance collagen synthesis, and trigger an immune response. This review addresses a variety of aspects relevant to the functions of well-known platelet growth factors, animal and clinical studies of PG in the last decade, and different sources of platelets for PG. PG is used for nonhealing chronic wounds, such as oral ulcerations related to epidermolysis bullosa and chronic graft-versus-host disease, for those, the traditional treatment effect is poor.PG maybe provide a new therapeutic direction for these diseases. Nevertheless, some uncertainty is present, the number of clinical studies is not enough. Hence, randomized controlled trials are still required to study the potential of the use of PG in the near future. K E Y W O R D Splatelet gel, platelet growth factor, platelet-rich plasma, wound healing | INTRODUCTIONOver the past three decades, extensive cellular and molecular details were elucidated regarding the regulation of cutaneous wound healing. 1,2 Although platelets are fundamental components of the hemostatic response to vessel damage. It is worth noting that platelet rich plasma (PRP) gel/platelet gel (PG) is increasingly used for the treatment of a variety of soft and hard tissue defects, most notably in the management of chronic non-healing wounds and in accelerating bone formation. [3][4][5][6][7][8] Wound healing is a very intricate process involving the complex interplay of numerous humoral factors and cells. PG as a new application was proposed during the last 30 years, to favour wound healing through the growth factors (GFs) released by platelets during clotting. Platelet concentrates are activated with thrombin or calcium, which induces the release of GFs and also fibrin generation, resulting in a viscous coagulum (PG), composed of 95% platelets at least. 9 A wound is defined as damage or disruption to the normal anatomical structure and function, and it may cause damage in other structures such as tendons, muscles, vessels, nerves, parenchymal

Human platelets play important roles in several physiologic and pathologic processes. Any defects in platelet number and function can lead to a variety of bleeding complications; platelet transfusions are commonly used to improve platelet count and hemostatic function in these cases. However, transfusions are complicated by the short storage life of donated platelets and contamination risks. Synthetic platelet substitutes can render efficient hemostasis while allowing advantages of large-scale preparation, minimum contamination risk via effective sterilization, longer shelf-life, no need for blood type matching, and reduced risks of biologic or pathologic side effects. Recent efforts in synthetic platelet design have additionally focused on applications including hemostasis, drug delivery, and targeted delivery of cancer therapeutics. In the present review, we summarize the advancement of platelet-inspired nanomedicine for artificial blood component, tumor research, and treatment of thrombi.