Preparation And Performances Of In Situ Polyacrylamide Hydrogel Modified By Catechol

In recent years,in situ hydrogel has received widely attention due to its ability to match irregular defects.However,as hemostatic material,its application is limited by insufficient mechanical strength and long gelation time.Although some specifical in situ chemically cross-linked hydrogels could be fast formed and exhibit high mechanical strength,they unable to absorb blood.Hence their applications are further limited in emergency hemostasis usage.Therefore,it is of great research significance to prepare an in situ hemostatic hydrogel with high mechanical strength,short gelation time and the ability of absorbing blood at the same time.In this paper,an in-situ polyacrylamide(PAAM)hydrogel was prepared by hydrogen bonding reforming.Here,the original PAAM hydrogel prepared by free radical polymerization was dried and ground.The hydrogel powders absorbed blood at the wound site to swell to a microgel,and then the microgels reconnected through hydrogen bonds to form the in-situ hydrogel.The dynamic process of gelation of the PAAM hydrogel powders prepared in this article and the commercially available PAAM powders were compared through the microscope.The results showed that the PAAM powders prepared by this method could form hydrogel quickly and form a complete hydrogel.The morphology analysis also showed the successful preparation of the in-situ hydrogel.In order to improve the mechanical properties and adhesion properties of the in-situ hydrogel,ε-polylysine(PL)and catechol groups were successfully introduced into the PAAM system to prepare in situ PL-CAT/PAAM hydrogel.Firstly,catechol-modified polylysine(PL-CAT)was synthesized by conjugating PL and 3,4-dihydroxyphenylpropionic acid(DOHA),which was characterized by ~1H-NMR,FTIR and UV-Vis.Research experiments showed that the compressive strength of the in-situ PL-CAT/PAAM hydrogel was 3 times of in situ PAAM hydrogel,and the adhesive strength has also increased from 2.66 k Pa to 3.05 k Pa.In addition,compared with PAAM powders,the hemostatic effect of PL-CAT/PAAM powders could be increased by 25%.Generally,the possibility of absorbing blood and gelling at the wound site was realized in this article,and the gelling time was reduced greatly.In addition,the cytotoxicity studies indicated that the in-situ PL-CAT/PAAM hydrogel had low toxicity.To summarize,this hydrogel could be expected to play an application value in emergency hemostasis.