Preparation And Properties Of Kerateine/Sodium Alginate/Polyacrylamide Hydrogel Skin Dressing

Skin dressing is an important medical product for skin wound care.It is used to prevent further damage to skin wounds and accelerate healing of skin wound defects.This topic prepared KTN/SA/PAM hydrogel skin dressing with sodium alginate（SA）,acrylamide（AM）and keratin（KTN）as raw materials.The specific research contents are described as follows:（1）The SA/PAM doublenetwork hydrogels were prepared by ionic crosslinking reaction and covalent crosslinking reaction.The elastic modulus was measured by tensile tests,and the elastic modulus was used as the index tooptimize the raw material ratio of the SA/PAM and the amount of ionic crosslinking agents by the single factor optimal methods.The results showed that:raw material ratio SA:PAM=1:5 and ionic crosslinking agent CaSO₄/SA（wt%）was 10.22%.The elastic modulus of the SA/PAMdouble network hydrogelswas 11.81 kPa,which was close to the average elastic modulus of the normal human forearm skin of 14.80 kPa,so it had good bionic performance.Fourier transform infrared spectroscopy（FT-IR）confirmed the successful preparation of the the SA/PAM double network hydrogelswhich had the formation of new bonds.Scanning electron microscopy（SEM）showed that the SA/PAM double network hydrogels had a hollow grid structure.（2）The KTN solution was modified on the surface of the SA/PAM double network hydrogels to obtain the KTN/SA/PAM skin dressings,which was optimized by using the adhesion strength as the index.The results showed that:the adhesion strength between the KTN/SA/PAM skin dressings and porcine skin was 5.11 kPa,when the400μL of 50%KTN solution was compounded on the surface ofthe SA/PAM double network hydrogels.The adhesion strength of the KTN/SA/PAM skin dressingswith clean and bloody porcine skinwas higher than that of the SA/PAM double network hydrogels.Dynamic torsion experiments showed that the KTN/SA/PAM skin dressings can maintain a stable bonding relationship with porcine skin and fit the curved surface of porcine skin,when the adhesive position between the skin dressings and porcine skin changed dynamically.The tensile modulus of the KTN/SA/PAM skin dressings was11.19 kPa,which was not significantly different from that of SA/PAM doublenetwork hydrogels.FT-IR results showed that KTN and SA/PAM hydrogels occurred physical cross-linking.SEM results showed that the KTN protein network structures is evenly distributed on the surface of the SA/PAM double network hydrogels.（3）The in vitro coagulation tests of the KTN/SA/PAM skin dressings,the SA/PAM double network hydrogels and band-aids showed that the KTN/SA/PAM skin dressings had a minimum BCI of 43.06%,indicating that the skin dressings had a better coagulation effect.The tail-breaking hemostasis experiments in rats showed that the order of hemostasis performance was as follows:KTN/SA/PAM skin dressings>SA/PAM double network hydrogels>band-aids,which was consistent with the results of in vitro coagulationtests.Full-layer skin defect repair experiments in rats showed that the KTN/SA/PAM skin dressings had the greatest repair effect on skin tissues,and have the largest area of skin healing after the surgeriesafter 14 days,and the rate of skin wound healing reached 93.11%,indicating that the KTN/SA/PAM skin dressings had good skin defect repair ability.The analysis of H&E stained images of skin tissues showed that the KTN/SA/PAM skin dressings had no toxic side effects on skin wounds,its immature tissue area is smallest,and collagen fibers are arranged most neatly,and the degree of healing of the skin defects is almost close to that of normal skin.In summary,the KTN/SA/PAM hydrogel skin dressings has mechanical strength close to that of normal human forearm skin,and at the same time they has multiple properties of good tissue adhesionstrength,hemostasis and tissue repair.This paper provides new ideas for the development of protein skin dressings.