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.日益加剧的多重耐药（multidrug resistant, MDR）细菌感染威胁，凸显了开发新型、持久且创新抗菌策略的迫切需求。本研究揭示了一种可持续的一锅法绿色合成策略：以芭蕉（Musa paradisiaca）叶边缘提取物（M.P. Rim）作为天然生物源试剂，合成生物源性氧化锌纳米颗粒（biosynthesized ZnO NPs, BZN），并将其与活性炭（activated carbon, AC）封装，制备得到纳米复合材料BZNAC。结构表征结果证实，该复合材料呈球形形貌，平均粒径为45 nm，对应能带隙为3.2 eV。通过DPPH实验评估，BZNAC展现出良好的自由基清除能力，其半数抑制浓度（IC50）为109.45 µg/mL。此外，针对斑马鱼胚胎的体内毒性分析表明，该材料具备优异的生物相容性，存活率与孵化率均超过95%，与对照组无统计学差异（p>0.05）。具体而言，抗菌实验结果显示，BZNAC对金黄色葡萄球菌（Staphylococcus aureus，抑菌圈直径29±0.1 mm）、枯草芽孢杆菌（Bacillus subtilis，抑菌圈直径19.5±0.3 mm）、痢疾志贺氏菌（Shigella dysenteriae，抑菌圈直径21±0.5 mm）以及大肠杆菌（Escherichia coli，抑菌圈直径26±0.4 mm）均表现出显著的抑菌活性，且差异具有统计学意义（p>0.01）。虚拟分子对接（in silico molecular docking, MD）研究表明，BZN、BZNAC与关键细菌酶——UDP-N-乙酰葡糖胺烯醇丙酮酸转移酶（MurA）和胸苷酸激酶（TMK）之间存在可靠的相互作用，结合亲和力分别为-8.91 kcal/mol和-9.05 kcal/mol，这提示细胞壁生物合成与DNA复制的抑制可能是其抗菌功效的核心机制。本研究证实BZNAC具备潜在药用价值，作为对抗多重耐药细菌感染的机制性治疗候选物，值得进一步开展临床前与临床试验分析。