Research On The Preparation Of Two Hydrogels And Their Application As Wound Dressings

The skin is the first line of defense of the immune system,protecting the body from microorganisms and maintaining fluids.Skin tissue can form wounds from cuts,surgery,burns,chronic diseases and more.Although skin tissue has a certain ability of self-healing,it is often affected by the external environment.For serious skin defects,wound dressing must be used to promote the closure and healing of the wound.Traditional wound dressings are generally non-woven dry dressings,which have limited ability to absorb wound exudate and poor ability to protect the wound from infection,and have been unable to meet the medical needs of contemporary society.At present,the theory of wet wound healing has attracted public attention,and many new wet wound dressings have been developed and put into use,such as hydrogels,polyurethane foam foam and so on.Among them,hydrogel has become an excellent choice for wound dressing due to its strong ability to absorb wound exudate,good biocompatibility,flexibility and hydrophilicity.Based on this,two new multifunctional hydrogel wound dressings were designed and prepared in this subject,and their performance in promoting wound healing was explored.Specific work contents were as follows:1.Multifunctional conductive hydrogel wound dressing was prepared based on low eutectic solvent(DES).First,take sodium hyaluronate(SH)and polydopamine(PDA)were the gel skeleton,and the use of polydopamine made the hydrogel have good adhesion and bacteriostasis.Then,Weiland gum was used as the emulsifier of tea tree oil(TTO),and TTO was added into the hydrogel,which improved the antibacterial and antioxidant properties of the hydrogel.Finally,Panax notoginseng extract(PNE)was added to the hydrogel to further improve the antioxidant activity of the hydrogel.The antibacterial and cytotoxicity tests showed that the hydrogels had excellent antibacterial performance and good biocompatibility.The existence of DES makes the hydrogels had wide temperature resistance and good electrical conductivity.We used portable button batteries instead of traditional large power sources to combine external electrical stimulation(ES)with hydrogels for wound treatment.The results showed that hydrogel combined with ES could effectively promote wound healing in mice,and the effect was better than that of commercial Duo DERM dressing.In addition,hydrogels also show strain response in sensor testing,which has the potential application of human h ealth monitoring.2.A hydrogel with reactive oxygen species(ROS)/glucose responsiveness was prepared based on flaxseed gel modified by phenylboric acid group(LP).Firstly,flaxseed gum modified with phenylboric acid group was prepared by grafting 3-aminobenzoborate onto flaxseed gum rich in carboxyl group.Then,the hydrogel precursor polyvinyl alcohol(PVA)was mixed with flaxseed gum modified with phenylboric acid group at a mass ratio of 3:2,and the hydrogel was crosslinked by borate ester bond.Finally,dopamine-modified Mxene(PMX),chlorogenic acid(CA),L-ascorbate phosphate(L)and human umbilical cord mesenchymal stem cell exosomes(E)were added into the hydrogel by one-pot method,and P-LP-PMX-CA-L/E hydrogel was prepared.The physical and chemical properties of hydrogels were characterized.The results showed that P-LP-PMX-CA-L/E hydrogels had good antioxidant,electrical conductivity,ROS/ glucose response and excellent bacteriostatic effect.In vitro antibacterial tests showed that P-LP-PMX-CA-L/E hydrogel had strong inhibitory effect on gram-negative bacteria(Escherichia coli,Pseudomonas aeruginosa)and Gram-positive bacteria(Staphylococcus aureus).After 24 h co-culture of Pseudomonas aeruginosa,Escherichia coli and Staphylococcus aureus,the inhibition rate of the three bacteria reached more than 99%.Biocompatibility tests showed that P-LP-PMX-CA-L/E hydrogel had good blood compatibility and cell compatibility,and could effectively promote cell proliferation and migration.In this study,a full-layer skin injury model was established in diabetic mice.The results showed that P-LP-PMX-CA-L/E hydrogel could effectively promote wound healing in diabetic mice by inhibiting bacterial growth,removing free radicals,and promoting information exchange between cells.