Study On Nanosliver-based Natural Polysaccharide Hydrogel For Diabetic Ulcers

ObjectiveWith the continued increasing prevalence of diabetes,more and more people pay close attention to its complications.Diabetic foot ucler,as one of serious diabetes complications,would bring huge pain and heavy financial burden to patients and familities due to its repeated course of disease,susceptibility to infection and easily lead to limb amputation.40%-80% of diabetic foot ucler has a great risk of infection.With the presence of infections,disease would aggravate and the difficulty of treatment would increase.With antibiotics abuse,the emergence of multi-drug resistant microorganisms also make the infection more difficult to control.Blood perfusion around diabetic foot ulcer were blocked,drug concentration of antimicrobial agents on the ulcer is low,so it is difficult to achieve the antibacterial effect.This study focus on synthesis of a novel antibacterial hydrogel which has low propensity to induce bacterial resistance to promotes ucler healing.MethodNatural polysaccharide hydrogel were synthesized based on thiolated chitosan and maleic acid-grafted dextran,mixed with AgNPs solution.The structure of the hydrogel was analyzed by FT-IR spectroscopy and 1H-NMR spectra.Scanning electron microscope was used to observe the morphology of hydrogel.Swelling ratio of hydrogel was analysed the hydrophilic properties.Cytotoxicity was tested to evaluate the biocompatibility of hydrogel.LIVE/DEAD assay was to evaluate the antibacterial property.In vivo study,full thickness infectious wound model of diabetic rats were used to evaluate the wound healing effect.Wounds with surrounding tissue were harvested for histological evaluation and immunohistochemical staining to detecte the expression of CD3 and CD68 which was used for analysis of T cells and macrophage,respectively.ResultAntibacterial hydrogel with three-dimensional network were synthesized by adjusting the molar ratio of thiol group and double bond,mixed with AgNPs solution.The morphology images of hydrogels exhibited a three-dimensional network and highly porous sponge like structure.The swelling ratio of the hydrogels was up to 400% after 5 min of incubation,so it can rapidly absorb tissue drainage which is helpful for wound healing.Cytotoxicity test showed that the cell viability of NIH3T3 showed more than 80% after incubation with AgNPs@CNDM hydrogel for 24 and 48 h,showing good biocompatibility.AgNPs@CNDM hydrogel would gradually release Ag+ to avoid the Ag+ sudden realease,show a substantial effect to improve wound healing in SD rats.AgNPs@CNDM hydrogel has a antibacterial activity against Gram-negative and Gram-negative bacteria,after treated with AgNPs@CNDM hydrogel,all bacterial cells were dead.In animal experiment,AgNPs@CNDM group not only can effectively inhibit infection but also accelerate wound healing.CD68 macrophages and CD3 T cells were significantly higher than other groups,indicating that AgNPs@CNDM hydrogel can stimulated an increase in T cells and trigger immune cells to congregate around wound site and thus activate the immune system and accelerate wound healing process.ConclusionIn this study,we had synthesized a natural polysaccharide hydrogel under the mild preparation conditions.AgNPs@CNDM hydrogel has a three-dimensional porous structure,good biocompatibility and swelling property,so it can keep moist wound repair environment,and can effectively inhibit microorganism proliferation and activate the immune system at animal level.AgNPs@CNDM hydrogel can promote wound healing and do not trigger bacterial drug resistance,providing a new way for the treatment of diabetic foot ulcer.