Preparation And Antibacterial Study In Vitro Of Carboxymethyl Chitosan Composite Ag Nanoparticles Natural Rubber Latex

Objective:A new antibacterial biomaterial based on Carboxymethyl chitosan-Ag nanoparticles(CMCS-Ag NPs)and Natural rubber latex(NRL)was developed and tested for its in vitro antibacterial performance against six common pathogenic bacteria in the urinary tract and evaluated for its feasibility as a raw material for urological implants.Methods:1.Preparation of CMCS-Ag NPsThe silver nitrate was reduced to Ag nanoparticles(Ag NPs)by hydrothermal reduction using Carboxymethyl chitosan(CMCS),and tested by Ultraviolet-visible(UV-vis),X-ray diffractometry(XRD)and Transmission electron microscope(TEM).The best method for the preparation of the composite antibacterial materials was obtained.A preliminary assessment of the in vitro bacterial inhibitory capacity of CMCS-Ag NPs using Escherichia coli was carried out by co-culture and plate colony counting methods.2.Preparation of antibacterial latex and in vitro antibacterial studyA co-blending method was adopted to make an antibacterial latex from CMCS-Ag NPs and NRL.The contact culture method and plate colony count method were used to test the in vitro antibacterial performance against the top six pathogenic bacteria currently ranked in China for urinary tract infections: Escherichia coli,Staphylococcus aureus,Staphylococcus epidermidis,Enterococcus faecalis,Klebsiella pneumoniae and Acinetobacter chimaera.Results:1.Characterization of CMCS-Ag NPsCMCS-Ag NPs have high solubility,good water solubility and high stability.The UV-vis results showed that the absorption peaks appeared around 410 nm and the absorption bands were narrow.The XRD results proved that the peaks contained the characteristic diffraction peaks of singlet silver and no diffraction peaks of other impurities.The TEM tests showed that the Ag NPs particles were spherical or nearly spherical,and the sizes were concentrated in the range of 10-20 nm.The in vitro antibacterial ability of CMCS-Ag NPs was evaluated and the inhibition rates of Escherichia coli in groups A and B were 89.7% and 92.4%.2.Preparation of antibacterial latex and in vitro evaluation of antibacterial abilityThe CMCS-Ag NPs were blended into the NRL by co-blending method to prepare antibacterial latex films.All the experimental groups showed obvious contact inhibition effect,and the comparison of the six types of strains showed that the inhibition effect of Enterococcus faecalis > Escherichia coli > Staphylococcus epidermidis > Klebsiella pneumoniae > Staphylococcus aureus > Proteus mirabilis.The inhibition rate of the high concentration group was better than that of the low concentration group.The inhibition effect of the antibacterial latex film showed a dose-proportional relationship.Conclusion:The CMCS-Ag NPs produced in this study were stable and antimicrobial.The antibacterial latex obtained by the co-blending method has the ability to contact inhibit the six most common bacteria that cause urinary tract infections.