Green synthesis and antibacterial assessment of chitosan/silver nanocomposite conjugated with tobramycin against antibiotic resistant Pseudomonas aeruginosa

Abstract

In this study, we employed aqueous ginger extract as an eco-friendly approach for the synthesis of chitosan nanoparticles (CsNPs), silver nanoparticles (AgNPs), and chitosan/silver nanocomposites (Cs/AgNCs). Using spectroscopic and microscopic techniques, we thoroughly characterized the physicochemical properties of these nanomaterials, confirming their desirable attributes. The AgNPs displayed a spherical morphology with an average diameter of 19 nm, while the Cs/AgNCs exhibited a size of approximately 28 nm. To assess their antibacterial efficacy, we investigated the activity of both AgNPs and Cs/AgNCs against Gram-negative pathogenic bacteria. Remarkably, these nanomaterials demonstrated significant antibacterial properties. To further enhance their antibacterial capabilities, we conjugated the nanocomposite with tobramycin using Sulfo NHS and EDC, resulting in a four-fold increase in antibacterial activity compared to tobramycin alone. Moreover, we explored the ability of AgNPs, CsNPs, Cs/AgNCs, and Cs/AgNCs/tobramycin (Cs/AgNCs/tbn) to degrade DNA and generate reactive oxygen species (ROS) in the presence of Pseudomonas aeruginosa. Encouraging results were obtained, highlighting their potential applications in antimicrobial strategies. Furthermore, we conducted a comprehensive toxicity assessment of AgNPs, CsNPs, Cs/AgNCs, and Cs/AgNCs/tob using zebrafish embryos. The findings revealed low to moderate levels of toxicity for these nanomaterials, with Cs/AgNCs/tbn demonstrating no observable toxic effects. Our study demonstrates the immense potential of utilizing aqueous ginger extract as a green synthesis method to produce AgNPs and Cs/AgNCs with robust antibacterial properties and minimal toxicity. These findings pave the way for the development of innovative nanomaterials for various biomedical applications.

Keywords

• Silver nanoparticles
• Chitosan nanoparticles
• Silver/chitosan nanocomposite
• Silver/chitosan/tobramycin conjugation
• Antibiotic resistance