Synthesis, characterization, and antibacterial activity of chitosan-chelated silver nanoparticles

AbstractBacterial infections pose a significant threat to human health and safety, necessitating the urgent resolution of the problem through the development and implementation of highly effective antibacterial agents. However, the emergence of multidrug-resistant bacteria has diminished the satisfactory effectiveness of antibacterial treatments. To overcome this obstacle, we developed effective antibacterial agents by chemical reduction for inhibiting bacterial proliferation and inducing membrane damage. Specifically, four different types of chitosan/Ag nanoparticle (CS-AgNPs-i) (i-1, 2, 3, 4) complexes were synthesized by varying the quantity of chitosan added during the synthesis process. We found that the amount of CS does not affect the morphology and size of CS-AgNPs-i, which remained at approximately 20 nm and all CS-AgNPs were mostly spherical. The zeta potential measurements indicated that the surface of CS-AgNPs carries a positive charge. Notably, elevating the chitosan concentration led to a more pronounced antibacterial impact, particularly evident in its interaction with the peptidoglycan layer on the bacterial surface. Our experimental results undeniably establish the potent antibacterial efficacy of CS-AgNPs against both Escherichia coli and Staphylococcus aureus. Employing live/dead bacterial staining, we reveal the marked capability of CS-AgNPs to effectively hinder bacterial proliferation. Furthermore, our experimental investigations revealed that CS-AgNPs possess broad-spectrum antimicrobial activity. The results of in vitro cytotoxicity experiments substantiated the high biocompatibility of CS-AgNPs with elevated chitosan loading. The study provides valuable insights into the development of nano-antibacterial agents that exhibit significant potential as a substitute to replace traditional antibiotics for medical applications.Keywords: Silver nanoparticleschitosanantibacterial activitymembrane damagebacteria Disclosure statementNo potential conflict of interest was reported by the authors.Author's contributionsXiaoyong deng and QingChang designed the experiments and revised the paper; Jiu Ge and Mengting Li contributed equally to this work; Jiu Ge and Mengting Li performed the experiments and analysed the data; Jiahui Fan performed materials characterization work; Christian Celia and Yijun Xie revised the draft and performed results analysis.Code availabilityNot applicable.Availability of data and materialAll data are available.Additional informationFundingThis study is supported by the National Natural Science Foundation of China (Nos. 21371118, 41573116, and 21701109). The research activity of Christian Celia was supported by Overseas Visiting Fellow Program 2022, Shanghai University, China.