Sustainable Honey-Mediated Synthesis of Oligochitosan-Functionalized Ca(OH)₂ Nanoparticles with Enhanced Antibacterial and Biocompatible Properties

• Honey-assisted green synthesis enables controlled formation of Ca(OH)₂ nanoparticles • Oligochitosan functionalization improves stability and surface bioactivity • Nanocomposites show enhanced antibacterial activity against Gram+ and Gram− bacteria • Molecular docking reveals multi-target interactions with bacterial proteins • Oligochitosan coating reduces toxicity and improves biocompatibility 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.