Nanocapsule Formation of Ciprofloxacin-Loaded Zirconia Nanoparticles Coated with Chitosan for Antibacterial, Antibiofilm, Anti-Inflammatory, and Catalytic Applications

Bacterial infections and inflammation pose significant challenges, particularly with the rise of multidrug-resistant (MDR) pathogens. The development of innovative therapeutic strategies is essential to enhance antimicrobial efficacy while reducing resistance. In this study, we report the green synthesis of zirconia nanoparticles (ZrO₂ NPs) using propolis extract, an eco-friendly reducing agent with known bioactive properties. To enhance their biomedical applications, ciprofloxacin (CIP) was loaded onto these NPs, followed by a chitosan coating to form novel nanocapsules. The synthesized nanocomposites were systematically characterized using UV-vis spectroscopy, XRD, SEM, TEM, FTIR, and zeta potential analysis, while their thermal stability was evaluated via DSC and TGA. Biological assessments revealed that the CIP/ZrO₂ nanocapsules exhibited potent anti-inflammatory activity (94%) and significant catalytic potential in nitrophenol reduction. The in vitro drug release study demonstrated a biphasic release pattern of CIP from ZrO₂ nanocapsules, with an initial rapid release followed by sustained diffusion-controlled release. Antibacterial studies demonstrated inhibition zones ranging from 28 to 46 mm against MDR bacteria, with MIC and MBC values between 3.12 and 6.25 µg/mL. Notably, the combination of CIP with ZrO₂ NPs and chitosan coating enhanced antibiofilm activity compared to the individual components. These findings highlight the potential of chitosan-coated ciprofloxacin-loaded ZrO₂ NPs as a promising multifunctional platform for antibacterial, anti-inflammatory, and environmental applications.