Polyethylene glycol modified graphene oxide-silver nanoparticles nanocomposite as a novel antibacterial material with high stability and activity

Inorganic antibacterial nanomaterials play an increasingly important role in addressing the growing threat of drug-resistant bacteria. Graphene oxide-silver nanoparticles composite (GO-AgNPs), as a kind of inorganic nanomaterials, have excellent antibacterial properties, showing promising potential in biomedical field. However, GO-AgNPs are terribly prone to sedimentation due to aggregation in physiological solutions, along with its non-environmental issues during the synthesis process, seriously limits the antibacterial application of GO-AgNPs in the biomedical field. To solve this problem, herein, polyethylene glycol-graphene oxide-silver nanoparticles composite (GO-AgNPs-PEG) were prepared by modifying GO-AgNPs with polyethylene glycol to enhance their dispersion stability in physiological solutions. In addition, GO-AgNPs-PEG were prepared with using the natural product gallic acid as a reductant and stabilizer, exhibiting the characteristic of environmentally friendly. Meanwhile, the dispersion stability and antibacterial activity of GO-AgNPs-PEG were characterized by various technical methods, it was found that GO-AgNPs-PEG can be stably dispersed in a variety of physiological solutions (e.g., physiological saline, phosphate buffer solution, Luria-Bertani medium, Murashige and Skoog medium) for more than one week. Moreover, the antibacterial properties of GO-AgNPs-PEG in physiological solutions were significantly better than those of GO-AgNPs. Furthermore, it was discovered that the antibacterial mechanism of GO-AgNPs-PEG was probably associated to destroying the integrity of bacterial cell walls and membranes. The findings in this work can provide new ideas and references for the development of new inorganic antibacterial nanomaterials with stable dispersion in physiological solutions.