Preparation And Properties Of Multifunctional Hemostatic Compound Hydrogel Dressing

In the face of many unexpected disasters,such as earthquakes,landslides,mudslides,car accidents,surgery,etc.,the key factor leading to death is uncontrollable bleeding.Many reasons are due to untimely ambulance,that is,blood loss is serious before the arrival of ambulance.Human beings have been tirelessly seeking solutions to stop bleeding since time immemorial.Some achievements have been made in the research of hemostatic materials,but there are still many shortcomings in the practical application process,such as rejection and infection,long hemostasis time,poor mechanical properties and toxic side effects.This project aims to develop a class of hemostatic materials with strong anti-infectivity,strong adhesion,low cytotoxicity and good stability,which can achieve rapid healing of wounds by accelerating the activation of platelet adhesion and aggregation time.In this paper,gel hemostatic materials were prepared,and the superior properties of this material was tested on multiple levels such as rheological properties,MP,tissue adhesion,BP,swelling properties,in vitro antibacterial properties,TGP,DGR,wetting performance,thermal properties,hemolysis properties,WBC and PAS,the specific research contents are as follows:（1）In order to avoid the traditional cross-linking method and excessive use of toxic glutaraldehyde and other cross-linking agents,two kinds of biomimetic injectable hydrogels were designed by using milder enzyme-catalyzed cross-linking method,andγ-PGA was grafted onto DA successfully by acylation method,and its structures were characterized by ¹H-MNR,FTIR and UV-vis.In the gelation,an enzyme-catalyzed cross-linking method is employed,in water-borne polymers,phenol hydroxyl groups or coupling aniline groups were oxidized to realize the polymerization.In this system,H₂O₂ plays a key role as a crosslinking agent and decomposes water and O₂ molecules by HRP.Then,the residual H₂O₂ in the hydrogel acts as a bactericidal effect.In this study,the small scorpion extract（CSE）was introduced into the gelling system to improve the antibacterial properties and hemostatic effect.In conclusion,PD hydrogels have good antibacterial and adhesion properties,and the synergistic interaction between H₂O₂ and CSE makes the bactericidal rate reach 98%and the bio-adhesive performance reaches 30 kPa.In addition,this type of injectable hydrogel can be gelatinzed within 30 s,and can be closely adhere to the wound site due to the size of the wound,which can quickly seal the wound site.The SEM also shows that the platelets were activated by PD hydrogels.,allowing red blood cells to adhere quickly.（2）Double network（DN） gels were prepared by Schiff base reaction and freeze thawing cross-linking method.The structure and properties of DN were characterized by SEM,FTIR,TG and MTT.The swelling of DN hydrogel slowly reached the swelling equilibrium after 32h,the swelling degree remained at 20,indicating that the DN gel structure was relatively stable.It had swelling properties to achieve sustained release drugs,and it would not cause rapid degradation due to low mechanical strength.And it has good mechanical properties,the maximum strain can reach 80%,and the maximum stress is 0.23 MPa.Loading 2.5 mg?mL^-1SD-Ag,the cumulative release rate was only 55.47%with 72 h,indicating that the stability of DN hydrogel due to its internal structures can make SD-Ag release the smallest,but the effect is the best,achieving a very obvious slow release effect.MTT experiments also showed that the relative survival rate of cells was over 85%,and DN gel met the standard of use.（3）The NIR-CB bandage containing caffeic acid was prepared by sol-gel method,so that it had good flexibility and mechanical properties.The hydrophobic polydimethylsiloxane（PDMS）approved by FDA in the United States is used to construct hydrophobic layer on one side.The contact angle could reach 146.7℃,which could achieve antifouling and reduce excessive blood loss.Then,the silver nanowires were deposited on the other side by dropping coating method,forming an infrared reflector and an antimicrobial layer.The infrared transmittance of NIR-CB bandage is almost 0,which shows that NIR-CB bandage has good reflection effect.By contrast with thermal image,the maximum temperature difference is 1.5℃ and the minimum temperature difference is 0.6℃.It shows that the actual temperature of NIR-CB bandage is lower than that of ordinary CB bandage,and the heat dissipation of ordinary bandage is faster.It also proves that NIR-CB bandage can reflect near infrared effect,which can achieve the purpose of heat preservation.