| Hydrogels are materials composed of hydrophilic polymer networks.Due to its good biocompatibility and hydrophilicity,it is widely used in wound dressings,drug delivery,tissue engineering,bioreactors,contact lenses and other fields.Modern antibacterial hydrogels usually need to have comprehensive functions to meet the increasing application demands,such as high antibacterial properties,strong adhesion ability,non-toxic and harmless,and good healing function.Therefore,designing a multifunctional hydrogel with high antibacterial properties,self-healing properties and strong adhesion is of great significance for achieving ideal therapeutic effects and promoting skin wound healing.In this paper,silver nitrate,sodium citrate and tannic acid were used as raw materials to prepare nano-silver by liquid phase reduction method,and then polyvinyl alcohol(PVA),gelatin(Gelatin)and carboxymethyl chitosan(CMCS)were used as construction materials.The raw material of the hydrogel is added with a certain amount of nano-silver,and the nano-silver antibacterial hydrogel is prepared by means of self-assembly.The morphology,microstructure,mechanical properties,swelling,moisturizing properties,antibacterial properties,adhesion properties,and degradation properties of antibacterial hydrogels were studied.The research results show that the special structure of"active methylene"in sodium citrate makes it reducible,which can reduce silver ions(Ag~+)to zero-valent nano-silver(Ag);adding tannic acid,due to its molecular It contains a large number of hydroxyl groups,which can bind silver ions and weaken the activity of silver ions.When a reduction reaction occurs,silver ions are reduced to silver elements in situ,and the interaction between tannic acid molecules and intramolecular hydrogen bonds can wrap silver elements,play the role of stabilization and protection,thereby preparing nano-silver with small particle size,uniform and stable,and its average particle size is 14.5nm.The hydrogels prepared with different ratios of polyvinyl alcohol,gelatin and carboxymethyl chitosan were studied(xP-yG-zC,x,y,z are the ratios of three raw materials),and the mechanical properties were good,and it has good viscoelastic behavior,and the viscoelastic behavior of hydrogel can be adjusted by changing the ratio of hydrogel raw materials,temperature and total concentration of raw materials;its viscosity increases with the increase of temperature within the range of human body temperature.The optimal conditions for the preparation of xP-yG-zC hydrogels in this paper are that the temperature is40°C,the total concentration of raw materials is 25%,and the mass ratio of PVA/Gelatin/CMCS raw materials is 1:2:2.The prepared antibacterial hydrogel has a tight internal network structure and uniform dispersion of nano-silver.Nano-silver antibacterial hydrogel has good water absorption and moisturizing properties,which can ensure a moist environment for wound healing.Nanosilver can effectively resist Escherichia coli and Staphylococcus aureus.When the content of nanosilver was 0.5%(w/w),the antibacterial effect of nanosilver antibacterial hydrogel(AgNPs-xP-yG-zC)was good.Taking glass and pig skin as the bonding objects,the bonding strengths reached 220kPa and 80kPa,respectively,indicating that the antibacterial hydrogel has good adhesion ability.With the increase of bonding time,the AgNPs-x P-y G-z C hydrogel and The bond strength produced by the above-mentioned bonded objects is also stronger.In addition,the degradation cycle of nano-silver antibacterial hydrogel is suitable. |
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