Synthesis Of DNA-guided Silver Nanoparticles On A Graphene Oxide Surface And Its Antibacterial Effect

Over recent decades,bacterial infections which cause millions of infection-related morbidities,have seriously threatened human health and become global public health issues.The occurrence of antibiotic resistance against pathogens is rapidly increasing and endangering the efficacy of antibiotics.Furthermore,the increasing occurrence of antibiotic resistance against pathogens,espe cially“superbugs”with multidrug resistance such as Staphylococcus aureus(SA),has become the most common clinical drug-resistant infection in burn wounds,with the SA wound infection rate accounting for more than 60%.Moreover,the number of different SA strains isolated sharply increased.Thus,finding a way to address this problem has become a major challenge due to the inability of conventional antibiotics to kill these multidrug-resistant bacteria.(1)Preparation,characterization and antibacterial properties of ssDNA-AgNP@GO nanocompositeIn order to further enhance the antibacterial ability and reduce the possibility of antibiotic resistance,we developed a simple two-step approach and synthesized a new nanocomposite by directly loading single-stranded DNA(ssDNA)-guided silver nanoparticles(AgNPs)on graphene oxide(ssDNA-AgNP@GO).The samples were characterized by atomic force microscopy(AFM),Zeta potential meter,UV-vis spectroscopy,These stable ssDNA-AgNP@GO nanocomposites with uniform size.Through systematically evaluating the bactericidal activity,we found that ssDNA-AgNP@GO exhibited synergistic antibacterial activity against Escherichia coli,Pseudomonas aeruginosa,Staphylococcus aureus and Bacillus subtilis with low minimum inhibitory concentrations(6.8?g/mL,6.8?g/mL,11.9?g/mL and 10.2?g/mL,respectively).Through understanding the mechanism of the antibiotic effects of ssDNA-AgNP@GO,We know the antibacterial process of ssDNA-AgNP@GO nanocomposites entails the following steps:First,the excellent dispersibility together with electrostatic attraction promotes the positively charged ssDNA-AgNP@GO nanocomposites nanocomposite to rapidly capture and wrap negatively charged bacteria.Then,the AgNP and the released Ag~+exert physical damage to bacterial cell,which cause the loss of cellular integrity and cytoplasm leakage,leading to apoptosis of the bacteria.It was found that the AgNP could effectively damage the bacterial membrane,leading to their improvement on killing efficienc y.(2)The anti-bacterial wound healing activity of ssDNA-AgNP@GO nanocomposite.Furthermore,Through evaluating wound healing capability,The data indicates the high biocompatibility of these ssDNA-AgNP@GO.the wound healing experiment indicated that it has a striking ability to remedy wound infection caused by Staphylococcus aureus bacteria,due to the excellent reepithelialization and dense collagen deposition properties.By detecting the liver function of mice,the deposition of metallic silver and the histological morphology of animals,the material does not cause any side effects to organisms.In conclusion,the properties of ssDNA-AgNP@GO with enhanced antibacterial and wound healing capability will give it broad applications in the future.