Preparation And Characterization Of S-nitrosated Sodium Alginate Antibacterial Hydrogel

The prevalence of drug-resistant bacteria is one of the most serious public health challenges in the 21 st century.Nitric oxide(NO)is an endogenously produced diatomic free radical with a short half-life and plays a key role in the immune response of mammals to pathogens.In addition,due to the non-specific effects of NO,short half-life and rapid reduction of microbial load life,the use of NO is unlikely to stimulate the production of drug-resistant strains.The research results confirmed that although the NO material has an inhibition rate of 99.8% against bacteria,it does not show any toxic effect on mammalian cells.Nitric oxide-releasing materials have been widely developed for many different biomedical applications.However,the currently studied NO donors still have many shortcomings,such as poor biocompatibility,low NO loading,and poor controlled-release and slow-release effects.Sodium alginate is an abundant natural biopolymer.Due to its biocompatibility and biodegradability,it has been widely used in biomedical applications,including tissue engineering,drug delivery and antibacterial agents.The hydrogel is composed of an infinite three-dimensional network structure and water.It has a soft texture and has properties similar to natural extracellular matrix(ECM).It can absorb wound exudate and maintain a moist repair environment to accelerate Wound healing is a wound dressing with good application prospects.In this paper,the polysaccharide sodium alginate was used to prepare the active material sulfhydryl sodium alginate and the NO donor S-nitroso sodium alginate.Three gelling methods were used to prepare the sulfhydryl sodium alginate(SA-SH)and S-Sodium nitrosoalginate(SA-SNO)composite hydrogel,and the prepared hydrogel was systematically analyzed for mechanical,microscopic morphology,swelling,rheology,adhesion and biocompatibility Evaluation,the main experimental results are as follows:Gel time and rheological measurements show that the hydrogel reacts quickly and can be gelled within 5 to 15 minutes.The compression mechanics test results show the excellent mechanical properties of the hydrogel.The swelling test results show that the hydrogel It has strong water absorption performance and high swelling ratio,which can store a large amount of S-nitrosothiol.The micro morphology of the scanning electron microscope explains the high swelling ratio and excellent mechanical properties,a large number of holes in the cross section and The dense morphology of the longitudinal section intersects each other,resulting in these characteristics.The excellent adhesion performance allows the hydrogel to adhere firmly to the wound,as a dressing,it can cover the wound to block external infections,promote wound closure and skin regeneration.The hydrogel NO release experiment demonstrated the excellent performance of the hydrogel donor in terms of NO release under physiological conditions.The reaction conditions and the amount of reactant SA-SNO can be controlled in the range of tens of nanomoles to several micromoles.Internally regulate the release of NO.The cell CCK-8 test and the live-dead staining experiment proved the good biocompatibility of the hydrogel.The test of inhibition zone and inhibition curve shows that SA-SH/ SA-SNO hydrogel has a significant bactericidal effect on E.coli and Staphylococcus aureus,and a SA-SH/ SA-SNO hydrogel sample can maintain high strength Bacteriostatic for more than three days.The results of comparative experiments between S-nitrosoalginate sodium and antibacterial products on the market show that the antibacterial effect of S-nitrosoalginate sodium is stronger than that of antibacterial products such as hand sanitizers and dressings on the market.Finally,the microscopic morphology of the bacteria co-cultured with the hydrogel reveals the entire process of SA-SH/SA-SNO hydrogel(NO)killing bacteria.