Development of Synthetic Platelet-Activating Hydrogel Matrices to Induce Local Hemostasis

Several hemostatic strategies rely on the use of blood components such as fibrinogen and thrombin, which suffer from high cost and short shelf-life. Here, a cost-effective synthetic biomaterial is developed for rapid local hemostasis. Instead of using thrombin, thrombin-receptor-agonist-peptide-6 (TRAP6) is covalently engineered in polyvinyl alcohol (PVA) hydrogels. Soluble PVA-TRAP6 is first prepared by covalent attachment of cysteine-containing TRAP6 onto the backbone of PVA-norbornenes (PVA-NB) through photoconjugation. Cytotoxicity studies using C2C12 myoblasts indicate that PVA-NB and PVA-TRAP6 are nontoxic. Thromboelastography reveals that hemostatic activity of TRAP6 is retained in conjugated form, which is comparable to free TRAP6 solutions with equal concentrations. A 0.1% PVA-TRAP6 solution can shorten the clotting time (CT) to ca. 45% of the physiological CT. High platelet-activating efficiency is further confirmed by platelet aggregation assay and flow cytometry (FACS). For potential clinical applications, TRAP6-presenting hydrogel particulates (PVA-TRAP6-P) are developed for local platelet activation and hemostasis. PVA-TRAP6-P is prepared by biofunctionalization of photopolymerized PVA-NB hydrogel particulates (PVA-NB-P) with TRAP6. It is demonstrated that PVA-TRAP6-P can effectively shorten the CT to ca. 50%. FACS shows that PVA-TRAP6-P can activate platelets to a comparable extent as soluble TRAP6 control. Altogether, PVA-TRAP6-P represents a promising class of biomaterials for safe hemostasis and wound healing.