Saidun Fiddaroini, Berlian Zetta Batari, Budi Mulyati, Ahmad Luthfi Fahmi, Yosep Yuswanto Tri Ananda, Andini, Moh. Farid Rahman, Akhmad Sabarudin
The alarming rise of antimicrobial resistance (AMR) has prompted the search for alternative strategies beyond conventional antibiotics. Nickel hydroxide nanoparticles (Ni(OH)₂ NPs) are promising antimicrobial agents, yet their practical application is hindered by colloidal instability and potential cytotoxicity. Herein, we report a green and optimized synthesis of Ni(OH)₂ nanoparticles using cottonwood ( Ceiba pentandra ) honey as a natural bioreductor, followed by surface modification with oligochitosan to enhance stability and biocompatibility. The synthesis parameters were systematically optimized by varying pH, honey concentration, precursor concentration, and reaction time. The optimal conditions (pH 10, 5 % honey, 0.05 M precursor, and 30 min) were selected based on yielded Ni(OH)₂ nanoparticles with the highest UV–Vis absorbance intensity, the strongest Ni–OH fingerprint bands in FTIR, and the most uniform particle morphology. Morphological analyses confirmed the formation of quasi-spherical nanoparticles with the particle size is ∼56 nm. Surface modification with oligochitosan markedly increased the zeta potential (+60.99 mV) and hydrodynamic size, indicating strong electrosteric stabilization. Antibacterial evaluation revealed a substantial enhancement in activity after oligochitosan coating, with minimum inhibitory concentrations (MICs) reduced by 3.62-fold against Staphylococcus aureus and 4.25-fold against Pseudomonas aeruginosa compared to uncoated Ni(OH)₂ nanoparticles. Toxicity evaluation via brine shrimp lethality test indicated improved biocompatibility of the coated nanocomposites. Collectively, this study establishes a sustainable and effective strategy for producing stable, bioactive Ni(OH)₂–oligochitosan nanocomposites with strong potential as next-generation antibacterial materials. © 2025 Elsevier B.V.
Department of Chemistry, Faculty of Science, Brawijaya University, Malang, Indonesia; Research Center for Advanced System and Material Technology, Brawijaya University, Malang, Indonesia
