A Versatile Procoagulant Coating Based On The Assembly Of Tannic Acid And Ferric Ion

Hemostasis is one of the key steps in medical treatment.Although medical materials such as gelatin sponge and chitosan dressings have been used extensively in various hemostasis scenarios,their coagulation performance still needs to be improved.The development of higher-performance hemostatic materials will effectively increase the success rate of blood loss emergency and surgical operations,and reduce postoperative bleeding and other complications.The functional modification of the existing hemostatic materials for promoting coagulation on the surface can improve the hemostatic effect on the basis of not changing the original application scenarios,and has broad clinical application prospects.Tannic acid(TA)is a natural polyphenol with low price,wide sources and good biocompatibility.Tannic acid has a polyphenolic hydroxyl structure and can chelate with metal ions to form a complex.This complex can form a coating on a variety of substrates,and the preparation process is simple,fast,and under mild conditions.The first part of the thesis studied the effect of tannic acid-ferric ion composite coating(TF-F)coating on the coagulation performance of gelatin sponge.Modified sponges(GS-TF-F)with different coating structures were prepared by covering the commercially available gelatin sponge with a tannic acid-ferric ion coating through a two-step method.Compared with the tannic acid-ferric ion coated sponge GS-(TF)5 prepared by the one-step method,the optimal tannic acid/ferric ion loading(molar ratio 1:43.6)of GS-(TF)5-F 10 has a better performance in vitro coagulation test(lower coagulation index),the mechanism is that it has a higher platelet adhesion.The rat femoral artery injury hemostasis model was also used to further prove that GS-(TF)5-F10 has excellent hemostatic properties in vivo,which can effectively reduce blood clotting time and blood loss.The second part of the thesis studied the versatility of TF-F procoagulant coating on different substrates and the procoagulant effect in vascular embolization.The TF-F coating was covered with commercially available medical PVA sponge and gauze.Through the test of the blood coagulation index,it was found that after optimizing the tannin/ferric ion loading,the hemostatic effect of both of them would be enhanced,which proved the versatility of the TF-F coating.After the gelatin sponge was crushed and sieved,micron-sized gelatin sponge particles(GSP)were prepared,which were further coated with a TF-F coating to prepare modified sponge particles GSP-(TF)5-F10.In the rabbit renal artery embolization experiment,the amount of GSP-(TF)5-F10 required to successfully embolize the renal aorta is lower than the control GSP,which further proves that TF-F can also be used in vivo vascular embolization(unactivated coagulated blood)and has a good blood coagulation effect.