Study On Polylysine And Its Derivatives Modified Porous Starch To Construct High-performance Hemostatic Powder

Complications caused by uncontrollable blood loss are the main cause of a large number of casualties.Therefore,rapid and effective hemostasis is practical significance for disease prevention and control,clinical surgery,and rescue work.Traditional hemostatic materials(such as tourniquets,gauze,hemostatic bandages)are limited by the application.Hence,It is desirable to develop a new type of hemostatic materials with superior hemostasis,biosafety and easy-to-use This thesis has carried out the following two parts of work by studying about the negatively charged porous starch(PSt)and the natural cationic polymer polylysine(EPL)and its derivatives:The first part of the work is to prepare high-performance hemostatic powder by grafting or loading EPL on PSt through chemical grafting and electrostatic adsorption separately.The in vitro coagulation tests indicated that PSt-EPL-A0.5(EPL was chemically grafted on PSt,the degree of the substitution(DS)of EPL was 7.21%)exhibited excellent hemostatic properties due to the ability of accumulating blood cells.The enzymatic hydrolysis performance of PSt-EPL-A0.5 was tested by in vitro enzymolysis,and it was found that PSt-EPL-A0.5 can be fully degraded in the presence of amyloglucosidase and ?-amylase,demonstrating the good degradability.In a femoral artery hemostasis model of SD rats,PSt-EPL-A0.5 exhibits the favorable hemostatic effect,further demonstrating the outstanding hemostasis.The second part of the work is divided into two stages.The first stage is to prepare modified polylysine(EPL)by grafting succinic anhydride and butyric anhydride to introducing carboxyl and n-butyl,respectively.In a comparison with the unmodified EPL,this modified EPL showed good blood compatibility,and the optimal DS of H2(the DS of carboxyl was 8%)could reduce the negative effect on PT and APTT index.The PT index of C3(n-butyl branch rate is 16%)has been well improved;the APTT index has improved.At the same time,both H2 and C3 can accumulate blood cells well,so the prepared H2 and C3 can be used as new polymers for blood coagulation.The second stage is to chemically graft the selected modified EPL:H2 and C3 onto PSt to prepare hemostatic powder PSt-H2 and PSt-C3.By comparing with PSt and PSt-EPL,it is proved that PSt-H2 and PSt-C3 have better in vitro coagulation performance and can better aggregate blood cells.