Biosynthesis of novel MnO<SUB>2</SUB> nanocapsules via <I>C. spinosa</I> extract and honeybee-derived chitosan: exploring antibacterial and anticancer properties

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This investigation delves into the integration of Capparis spinosa extract (CSLe) onto manganese dioxide nanoparticles (MnO2NPs) and chitosan derived from honeybees (CSH) in a nanostructured configuration. The resultant nanocomposites, namely CSLe@MnO2NPs and CSH/CSLe@MnO2NPs, underwent thorough characterization through various analytical techniques. UV-Vis spectroscopy unveiled distinctive features, such as ligand-to-metal charge transfer and photoluminescence, affirming the successful chitosan-functionalization of the MnO2NPs, thereby differentiating them from their pristine counterparts. FTIR spectra corroborated the binding of chitosan and identified crucial molecular functional groups. SEM-EDX analysis revealed the morphological properties, addressing non-uniform sizes in the as-calcined MnO2NPs by the uniform coating of CSH on CSLe@MnO2NPs, while EDX confirmed the presence of essential elements. TEM and SAED provided insights into the spherical morphology, crystalline structure, and lattice planes of these nanoparticles. Size distribution measurements highlighted distinctions between CSLe@MnO2NPs and CSH/CSLe@MnO2NPs. The nanomaterials underwent evaluation for their antimicrobial properties against a spectrum of Gram-negative and Gram-positive bacterial strains, with CSH/CSLe@MnO2NPs exhibiting the highest bactericidal activity. Additionally, they demonstrated low minimum inhibitory concentration (MIC) values, especially against S. aureus (MIC as low as 12.5 µg/ml). Their efficacy extended to anti-biofilm formation, significantly diminishing biofilm development in a dose-dependent manner, a pivotal factor in addressing biofilm-related infections. The study also scrutinized their cytotoxicity against normal Vero and PC3 prostate cancer cells, revealing potential anticancer properties. Dose-dependent reductions in cell viability were observed for both normal and cancer cells. In conclusion, these findings underscore the versatility and promise of CSH/CSLe@MnO2NPs in diverse biomedical applications, including antibacterial, anti-biofilm, and anticancer therapies.