Saidun Fiddaroini, Ardini Nurul Janah, Budi Mulyati, Ahmad Luthfi Fahmi, Yosep Yuswanto Tri Ananda, Andini, Nike Fitayatul Khusnah, Moh. Farid Rahman, Akhmad Sabarudin
Antimicrobial resistance (AMR) remains a critical global challenge, particularly against Staphylococcus aureus and Pseudomonas aeruginosa. This study presents a green synthesis of Ca(OH)₂ nanoparticles using cottonwood honey (Ceiba pentandra) as a direct reducing–stabilizing agent. The novelty lies in eliminating extraction steps and combining honey-mediated synthesis with oligochitosan coating to enhance stability and antibacterial performance. Ca(OH)₂ nanoparticles were synthesized via a honey-mediated approach and subsequently functionalized with oligochitosan. Structural, morphological, and colloidal properties were characterized using UV–Vis, FTIR, FESEM–EDX, TEM–SAED, XRD, DLS, and TGA, while antibacterial activity was evaluated using the broth microdilution method. FTIR confirmed successful surface functionalization, and TEM revealed relatively uniform nanoparticles (20–30 nm) with improved dispersion after coating. DLS analysis showed increased hydrodynamic diameter and a shift in zeta potential, indicating the formation of a stable polymeric shell. The antibacterial activity significantly increased after coating, with enhancement efficiencies of 443 % against S. aureus and 545 % against P. aeruginosa, demonstrating a strong synergistic effect. In silico molecular docking supported a multi-target antibacterial mechanism through strong interactions with membrane- and cell-wall–associated proteins. Biocompatibility assessment using the brine shrimp lethality test showed higher LC₅₀ values for coated nanoparticles, indicating reduced toxicity. This work demonstrates that cottonwood honey–derived Ca(OH)₂–oligochitosan nanocomposites present a promising, eco-friendly, and biocompatible antibacterial platform for combating drug-resistant pathogens. © 2026 The Author(s)
Department of Chemistry, Faculty of Science, Brawijaya University, Malang, Indonesia; Integrated Research Laboratory, Brawijaya University, Malang, Indonesia; Research Center for Advanced System and Material Technology, Brawijaya University, Malang, Indonesia
