Search

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.

A dual thermoresponsive and magnetic colloidal gel matrix is described for enhanced stem-cell culture. The combined properties of the material allow enzyme-free passaging and expansion of mesenchymal stem cells, as well as isolation of cells postculture by the simple process of lowering the temperature and applying an external magnetic field. The colloidal gel can be reconfigured with thermal and magnetic stimuli to allow patterning of cells in discrete zones and to control movement of cells within the porous matrix during culture.