Synthesis And Antibacterial Application Of Quaterniated Nano-Zinc Oxide With Dual Antibacterial Activity

In daily life,various surfaces are vulnerable to the invasion of microorganisms in the air and solution,which in turn endangers human health.Homogeneous or heterogeneous bacterial communities can attach to biological and non-biological surfaces,and produce scaffolds composed of extracellular polymeric substances(EPS)to form biofilms,which become a potential source of refractory infections.At present,various types of release-type antibacterial agents,such as antibiotics,silver ions,or zinc ions,can be immersed on the surface.Studies have shown that these strategies can effectively remove microorganisms in liquid,but in the absence of liquid,they will not have an effective antibacterial effect on microorganisms in the air.In addition,due to the limited release of antibacterial agents,the antibacterial surface will lose its antibacterial activity over time due to the depletion of antibacterial agents,and form potential environmental risks.Therefore,this paper aims to develop a long-term antibacterial surface with dual antibacterial activity mechanisms.The main research contents and achievements of this paper are as follows:Polyethyleneimine(PEI)was doped into zinc oxide(ZnO)by one-step method,and positively charged polyethyleneimine zinc oxide nanoparticles(ZnO-PEI)were successfully prepared.Subsequently,quaternized zinc oxide nanoparticles(ZnO-QPEI)with a large number of positive charges were prepared by alkylation modification.As an inorganic antibacterial agent,ZnO has received extensive attention,which destroys the negatively charged cell wall by releasing free positively charged zinc ions to kill aquatic bacteria.Compared with other antibacterial agents,ZnO has the advantages of good biocompatibility,wide antibacterial spectrum,and less resistance to bacterial resistance.However,the poor dispersibility and weak antibacterial effect of traditional ZnO limit its application.Therefore,PEI with a large number of coordination functional groups(amino)was added to form a complex with zinc ions.Under the interaction of intramolecular and intermolecular hydrogen bonds,the growth was delayed and the particle size was reduced,which was helpful to improve the dispersibility and antibacterial strength of ZnO.Due to the alkylation modification,part of the amino group of PEI can be transformed into quaternary ammonium salt to form quaternary ammonium polyethylenimide(QPEI),which adsorbs the bacteria through the contact of positively charged quaternary ammonium molecules and kills the aerial bacteria,thus forming a dual antibacterial activity mechanism with ZnO.ZnO-QPEI was successfully prepared by scanning electron microscopy,Zeta potential,Fourier transform infrared spectroscopy,X-ray diffraction analysis,and thermogravimetric analysis.Through in vitro antibacterial and anti-biofilm performance experiments,it is proved that ZnO-QPEI has antibacterial and anti-biofilm performance and dual antibacterial mechanism.At the same time,the dispersion test proves that the material can be uniformly dispersed in polar/non-polar solvents and can be used to construct a bactericidal surface.An antibacterial catheter surface(TPU/ZnO-QPEI)was designed by using ZnO-QPEI particles compatible with polar matrix polyurethane(TPU).It is proved that the catheter has good mechanical properties by contact angle measurement and mechanical properties test.In vitro antibacterial and antibiofilm performance experiments showed that the catheter had long-term antibacterial anti-biofilm ability and good anti-adhesion performance.In addition,through in vivo animal experiments,it was proved that the catheter had efficient in vivo antibacterial ability and good biocompatibility.An antibacterial gel(ZnO-QPEI antibacterial gel)was prepared by adding ZnO-QPEI particles into hydroxypropyl methyl cellulose(HPMC),polyvinylpyrrolidone(PVP)and moisturizing agent glycerol(Gl).The prescription of the gel was comprehensively investigated through process screening,single factor experiment,orthogonal experiment,and antibacterial experiment.The prescription was optimized and the antibacterial gel with uniform appearance,suitable pH value,good stability,and filmforming property was successfully prepared.The safety of skin administration and in vivo animal experiments proved that the gel had good biocompatibility.In summary,based on the prepared ZnO-QPEI antibacterial nanomaterials,an antibacterial coated catheter,and an antibacterial film-forming gel were successfully designed.The results showed that these two antibacterial applications could effectively use contact,release or synergistic mechanisms to kill bacteria from air and solution,prevent bacterial adhesion on the surface,and prevent the occurrence of susceptible events and biofilm formation.The material with dual bactericidal activity mechanism designed in this paper provides an effective platform for preventing and controlling bacterial infections and has broad application prospects.