Fighting Multidrug-Resistant Bacteria with a Biogenic ZnO/Activated Carbon Nanocomposite: Zebrafish and Molecular Docking-Based Insights into Biocompatibility and Antibacterial Potential

The escalating threat of multidrug resistant (MDR) bacterial infections emphasizes the urgent need of novel, durable and innovative antibacterial strategies. This inquiry unveils a sustainable one-pot green synthesis approach of zinc oxide nanoparticles (ZnO NPs) using Musa paradisiaca leaf rim extract (M.P. Rim) as a natural biogenic agent, yielding biosynthesized ZnO NPs (BZN), encapsulated with activated carbon (AC), forming a nanocomposite (BZNAC). The structural characterization confirms spherical morphology with an average particle size of 45 nm and a corresponding energy band gap of 3.2 eV. From DPPH evaluation, BZNAC offered radical scavenging potential with an IC50 value of 109.45 µg/mL. In addition, in vivo toxicity analysis in zebrafish embryos implied remarkable biocompatibility, with the survival and hatching rates exceeding 95% and statistically comparable to the control group (p>0.05). Specifically, antibacterial studies revealed that BZNAC showed substantial zone of inhibition against Staphylococcus aureus (29±0.1 mm), Bacillus subtilis (19.5±0.3 mm), Shigella dysenteriae (21±0.5 mm) and Escherichia coli (26±0.4 mm) were statistically significant (p>0.01). In silico molecular docking (MD) studies which indicated reliable interactions between BZN, BZNAC and critical bacterial enzymes like UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) and thymidylate kinase (TMK) with binding affinities of -8.91 kcal/mol and -9.05 kcal/mol respectively, signifying the disruption of cell wall biosynthesis and replication of DNA might be crucial in antibacterial efficacy. The present work highlights the BZNAC’s drug potential validated as a mechanistically therapeutic candidate against MDR bacterial infections, warranting further preclinical and clinical testing analysis.