Antimicrobial, anticancer activities and molecular docking of eco-friendly chitosan nanocapsule loaded with biosynthesized titanium nanoparticles by <i>Aspergillus flavus</i>.

Abstract

<h4>Introduction</h4>Chitosan have been leveraged to create chitosan nanocapsules within a bio-based nanocarrier system, enhancing efficacy and overcoming widespread microbial resistance. To generate chitosan nanocapsules (CNCs) that act as inhibitory agents against pathogenic microbes, this study combined titanium nanoparticles (TiO₂ NPs) with chitosan nanoparticles (Cs NPs).<h4>Methods</h4><i>A.flavus</i> was used for the biosynthesis of TiO₂NPs. Dynamic light scattering (DLS), zeta potential, atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), were utilized to assess the physicochemical properties of TiO₂NPs and their CNCs. These techniques clarified particle diameter, charge stability, specific surface area, surface morphology, shape, dimensional forms, and structural parameters, respectively.<h4>Results</h4>The findings showed that TiO₂NPs and their nanocapsules achieved an encapsulation efficacy of over 86.7 ± 1.8% at 1.5% w/v chitosan concentration, with particle sizes of 40.7, 40.6, and 87.3 nm for TiO₂NPs, CsNPs, and CNCs, respectively. Nanoparticle stability was confirmed by a zeta potential greater than -30.1 ± 4.5mV for TiO₂NPs. Furthermore, TiO₂NPs and their nanocapsules suppressed both Gram-positive and Gram-negative bacteria, with CNCs exhibiting more potent inhibitory effects than either TiO₂NPs or CsNPs. The minimum inhibitory concentrations (MICs) of CNCs against <i>Salmonella typhimurium</i> and <i>Aspergillus fumigatus</i> were remarkably low, at 20 and 10 μg mL^-1, respectively. TEM images of <i>S. typhimurium</i> and <i>A. fumigatus</i> treated with CNCs exhibited asymmetric cell deformations, wrinkled external surfaces, cell depressions, and declined cell counts. Cytotoxicity studies showed that CNCs exhibited non-cytotoxic behavior on normal human melanocytes (HFB4). In contrast, CNCs reduced the viability of human colon carcinoma (HCT-116) and hepatocellular carcinoma (HepG-2).<h4>Conclusion</h4>Nanomaterials, both alone or in nanocapsules, offer a promising alternative for inhibiting harmful microorganisms and represent a potential pathway for the development of anticancer medications. The findings indicate that CNCs are safe and effective against multidrug-resistant bacteria and fungi, making them a viable alternative to current antibiotic therapies.