INTRODUCTION A great popularity has been obtained by Microporous polysaccharide hemispheres (MPH), due to the superiority in its hemostatic performance, biodegradability, biocompatibility, origin and so on. However, the complexity in its production process and its expensive market price seriously limited its widely use around the world. In this study, we expected to prepare a new porous starch, of which the surface possessed carboxyl group and calcium ions, for rapidly hemorrhage control. MATERIALS & METHODS Oxidized porous starch (OPS), equipped with certain content of carboxyl, was obtained from normal corn starch, treated with enzyme-hydrolysis reaction and subsequent oxidation process. Calcium complexed oxidized porous starch (CaOPS) was prepared by adding calcium chloride into the OPS slurry. Then a series of physicochemical properties were characterized by SEM, BET, ICP, and adsorption test in vitro. The hemostatic performance was then evaluated by femoral artery cut experiment of rabbits and the time to control entire bleeding was recorded. RESULTS&DISCUSSION The images of SEM show its special pore structure, which was like a honeycomb, embedded from the surface to the core of microspheres(Fig. 1). A strong surface was demonstrated by BET. ICP result indicated that the content of calcium per gram starch was about 3mg, which was enough compared to that in human blood. An obvious increase in the adsorption ratio occurred from normal starch to porous starch, nearly 40% and 100% respectively. The time to complete hemostasis in rabbit femoral artery injury (Fig.3) for PS was 100±12s, which was apparently longer than that of CaOPS, 50±10s(Fig.l).The strong surface area of porous starch supplies itself an obvious advantage in water absorption, contributing to the concentration of platelets, plasma proteins and coagulation factors. The existence of positively charged Ca~(2+), the fourth coagulation factor, promotes the activation and aggregation of platelets, further leading to the activation of coagulation system. Moreover, hydrophilic and negatively charged carboxyl group activates coagulation cascade that eventually leads to the formation of thrombin. Therefore, different influencing factors discussed above existed in CaOPS for promoting hemostasis accounted for its excellent hemostatic effciency. The present results indicated that, as a hemostatic agent with the characteristic of a strong surface equipped with calcium ions and less time taken for hemostasis, CaOPS had a greater advantage in controlling the bleeding than PS.
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