Design And Preparation Of Selenium-containing Special Medical Materials And Preliminary Antibacterial Activity Testing

Antibiotics are often used clinically to treat wounds caused by external injuries with a'big wrap around' systemic anti-infection treatment,which is inappropriate from the point of view of drug abuse and pharmacoeconomic.At the same time,some heavy metal ions may be present in the wounds of workers injured in particular situations(e.g.,steel,coal,chemical,etc.).In addition to being toxic to the organism,these heavy metal ions can also bind to antibiotic drugs and thus reduce the biological activity of the antibiotic.Therefore,there is an urgent clinical need for non-antibiotic products with both antibacterial and metal ion removal functions.Selenium compounds have attracted the interest of researchers in the fields of organic synthesis,materials science,and biology due to their unique chemical and biological properties.This thesis exploits the principle that selenium compounds have some antimicrobial activity.At the same time,as a homolog of sulfur,organ selenium can bind to heavy metal ions and reduce heavy metal toxicity and explores the process of preparing surface selenization and organ selenium gels for two sterile dressings and their preliminary antimicrobial activity studies.An attempt was made to solidify the selenium compounds in a polymer network to improve the stability and safety of the selenium compounds while maintaining the antibacterial and metal ion removal effects and to provide a trauma dressing with unique antibacterial effects for clinical use.The thesis consists of three main sections as follows.(1)The selenization of sterile gauze was modified by the NaHSe method,and a three-factor.a three-level orthogonal test was designed to investigate the limits and stability of the selenization,resulting in optimal selenization conditions:reaction temperature of 80?,the reaction time of 12 h,and maximum selenium content of 0.6%at the gram scale of preparation.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)images showed that the selenisation process did not damage the surface and internal structure of the material.However,the selenium was not uniformly distributed within the material.Mechanical tensile tests showed that the selenisation process did not affect the mechanical structure of the material.A control test on the antibacterial activity of the selenised material was carried out against a blank sample,which showed that it had a certain inhibition effect on the Gram-positive bacterium S.aureus and the Gram-negative bacterium E.coli,with inhibition rates of 53.33%and 40.00%respectively.However,the removal of metal ions by the selenized cotton product material was not satisfactory and did not differ significantly from the blank material.(2)Based on the research basis of the first part,in order to improve its selenisation non-uniformity and non-elution resistance,polyacrylonitrile(PAN)material,which can be used as a raw material for sterile non-woven fabrics,was selected for selenisation modification in this chapter.A three-factor,a three-level orthogonal test was also designed to test the selenisation limits and stability.The optimum selenisation conditions were:a reaction temperature of 80?,a reaction time of 12 h,and maximum selenium content of 3.71%at the gram scale of preparation.The selenated polyacrylonitrile materials were characterized by SEM and TEM images,which showed that the surface of the polyacrylonitrile microspheres changed and developed a filamentary structure with a uniform selenium distribution after selenisation.Mechanical tensile tests showed that the selenisation process did not affect the mechanical structure of the material.The metal removal performance tests also showed that the selenised polyacrylonitrile had good removal of zinc,silver,and mercury ions,with removal rates of 94.38%,95.15%,and 98.86%,respectively.In addition,the antibacterial activity of S.aureus and E.coli was tested.The results showed that the selenated polyacrylonitrile material had good antibacterial activity,with 97.99%and 94.14%inhibition respectively.(3)Open wounds produce large amounts of tissue exudate,and hydrogels can absorb tissue exudate and protect the wound compared to conventional dressings.Therefore,this chapter explores the metal ion removal pattern of small molecule diselenide and designs and prepares 6,6'-dimethacrylate-based hexadiselenide monomer,which is cross-linked and polymerized with acrylamide,ethyl methacrylate to obtain selenium-containing polymer hydrogels,and prepares three kinds of hydrogels with different selenium contents of Se-2.5%,Se-5.0%,and Se-10.0%.The selenium-containing hydrogels were prepared by SEM,TEM,and X-Ray.The internal morphology and chemical structure of the selenium-containing hydrogels in the lyophilized state were characterized and analyzed by SEM,TEM,and XPS,and the successful construction of the selenium-containing hydrogels was confirmed.The results of the swelling rate test showed that the hydrogel has good water absorption properties with a maximum swelling rate of 2400%.According to the mechanical compression results,the selenium-containing hydrogel in the wetted state has good resilience properties.Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)were selected to test the Se-10.0%hydrogel for bacterial inhibition activity,and the results showed that the inhibition rates reached 81.49%and 99.52%respectively.In addition,the addition of selenium significantly improved the removal of metal ions and the specific removal of mercury ions with a removal rate of 84.74%.