| The presence of harmful bacteria in the environment poses a threat to human health.For example,bacteria entering the body through the respiratory tract may cause diseases such as influenza and pneumonia,while bacteria attached to the surface of a wound may cause serious wound infections and delayed healing.Therefore,how to kill harmful bacteria to prevent their invasion of the human body has become a concerning problem.As effective antibacterial agents,antibiotics are widely used in the antibacterial field.However,the overuse of antibiotics can easily lead to bacterial resistance problems.Electrical stimulation can disrupt the protective effect of bacterial biofilms and effectively kill multi-drug resistant bacteria.Electroactive materials have emerged as a promising alternative to materials used to fight bacterial infections,effectively avoiding the potential threat to public health and the environment caused by antibiotic abuse.In recent years,researchers have developed various types of electroactive antibacterial materials,including electrochemical antibacterial materials,conductive antibacterial materials,piezoelectric antibacterial materials,triboelectric antibacterial materials,micro battery antibacterial materials,especially the micro battery antibacterial material,it has no external power supply,but since the power supply and easy to use,and other advantages favored by researchers.Because cotton nonwoven has the advantages of soft texture,good moisture absorption,not easy to absorb dust or bacteria,and low price,it is very suitable for medical applications.However,cotton nonwoven itself has no antibacterial properties,which limits its widespread use to a certain extent.In this study,two different kinds of silver-zinc electrode arrays were coated on the cotton nonwoven’s surface by high vacuum DC magnetron sputtering technology.Moreover,its application in air filtration and wound dressing was investigated as follows:(1)Silver oxide(Ag)and zinc(Zn)electrode coatings are coated on both sides of cotton nonwoven(cotton)by magnetron sputtering technology.Ag/Zn micro-battery is activated by water vapor from human respiration to prepare antibacterial cotton nonwoven(Ag/cotton/Zn)with wet electrosensitive activity.X-ray diffraction(XRD),Xray photoelectron spectroscopy(XPS),Energy spectroscopy(EDS),and other measuring and testing techniques have confirmed that the micro-battery on the surface of cotton nonwoven mainly exists in the form of silver oxide and pure zinc.Ag/cotton/Zn produces an open circuit voltage of about 1.1V under humidification.Ag/cotton/Zn has excellent antibacterial properties due to the synergistic effect of metal ions released by redox reaction and electrical stimulation.In addition,the antibacterial efficiency of Ag/cotton/Zn against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)in simulated bacterial aerosols reached 99.74% and 99.79%,respectively.CCK-8cytotoxicity results indicated that Ag/cotton/Zn had good biosafety.When Ag/cotton/Zn as an additional antibacterial layer is compounded with polypropylene melt-blown nonwoven(PP)or polylactic acid nanofiber(PLA)to prepare personal protective masks,the filtering efficiency is up to 96.8%,without significantly increasing the pressure resistance of the filter material.Ag/cotton/Zn wet inductive electroactive antibacterial cotton nonwoven is expected to design and manufacture personal protective air filter materials.(2)An electroactive antibacterial dressing against bacterial adhesion(Ag/Zn@Cotton/Paraffin)was developed by magnetron sputtering technique to construct strip Ag/Zn electrode array on one side of cotton nonwoven,and paraffin solution was sprayed on the other side to construct hydrophobic surface.Scanning electron microscopy(SEM),XRD,and FTIR analysis showed that paraffin and Ag/Zn electrodes were successfully coated on the surface of cotton fiber.The air permeability,moisture permeability,water absorption,moisture retention,and softness showed that Ag/Zn@Cotton/Paraffin was suitable for wound dressings.The contact angles of E.coli and S.aureus suspensions on the hydrophobic side surface of Ag/Zn@Cotton/Paraffin are 141±1.6° and 150±0.6°,respectively.Meanwhile,the anti-adhesion rates of Ag/Zn@Cotton/Paraffin to E.coli and S.aureus were up to 97.92% and 99.82%,respectively,showing excellent anti-bacterial adhesion,which is related to the high hydrophobicity of Paraffin side surface.In addition,The Ag/Zn micro-batteries on the Ag/Zn@Cotton/Paraffin surface can produce electrical stimulation after contact with wound blood or exudate,and their antibacterial efficiency against E.coli and S.aureus is up to 100%.Meanwhile,cell scratches and Transwell experiments showed that electrical stimulation produced by Ag/Zn@Cotton/Paraffin could promote cell migration.Cytotoxicity results showed that Ag/Zn@Cotton/Paraffin had good biocompatibility and no adverse effects on cells.Ag/Zn@Cotton/Paraffin has a good application prospect in preparing anti-adhesion,antibacterial,and healing promoting dressings.In conclusion,the electroactive cotton nonwoven based on Ag/Zn electrode array has an excellent wet-sensitive electroactive antibacterial function,which is expected to provide theoretical and experimental reference for the development and design of new antibacterial air filtration materials and medical antibacterial dressings. |
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