Cellular Internalization and Toxicity of Chitosan Nanoparticles Loaded with Nobiletin in Eukaryotic Cell Models (Saccharomyces cerevisiae and Candida albicans).

This study involved the synthesis and characterization of chitosan nanoparticles loaded with nobiletin (CNpN) and assessed their toxicity and cellular internalization in eukaryotic cell models (Saccharomyces cerevisiae and Candida albicans). Nanoparticles were prepared via the nanoprecipitation method and physicochemically characterized to determine their hydrodynamic diameter using dynamic light scattering (DLS), their surface charge through ζ-potential measurements, and their chemical structure via Fourier-transform infrared spectroscopy (FTIR). The hydrodynamic diameter and ζ-potential of chitosan nanoparticles (CNp) and CNpN were found to be 288.74 ± 2.37 nm and 596.60 ± 35.49 nm, and 34.51 ± 0.66 mV and 37.73 ± 0.19 mV, respectively. The scanning electron microscopy (SEM) images displayed a particle size of approximately 346 ± 69 nm, with notable sphericity for CNpN. FTIR analysis provided evidence of potential imine bonding between chitosan and nobiletin. Membrane integrity damage could be observed in both S. cerevisiae and C. albicans yeast stained with propidium iodide, demonstrating membrane integrity damage caused by CNp and CNpN, where higher concentration treatments inhibited the development of yeast cells. These findings suggest a selective therapeutic potential of CNpN, which could be promising for the development of antifungal and anticancer therapies. This study contributes to understanding the interaction between nanoparticles and eukaryotic cells, offering insights for future biomedical applications.

Synthesis and toxicological study of chitosan-pirul (Schinus molle L.) essential oil nanoparticles on Aspergillus flavus.

In recent years, the study of essential oils as antifungal alternatives and their encapsulation to increase their properties for greater effects has been tested. In this work, nanoparticles of chitosan-Schinus molle L. essential oil (CS-PEO-Np) with a size of 260 ± 31.1 nm were obtained by ionic gelation and evaluated in some growth phases of Aspergillus flavus, a toxigenic fungus. At a concentration of 250 µg/mL of CS-PEO-Np, the A. flavus mycelial growth was inhibited at 97.1% with respect to control, at 96 h of incubation; the germination and viability of spores were inhibited at 74.8 and 40%, respectively, after exposure to 500 µg/mL of these nanomaterials, at 12 h of incubation. The fluorescence images of stained spores with DAPI showed the affectations caused by nanoparticles in the cell membrane, vacuoles and vacuolar content, cell wall, and nucleic acids. For both nanoparticles, CS-Np and CS-PEO-Np, no mutagenic effect was observed in Salmonella Typhimurium; also, the phytotoxic assay showed low-to-moderate toxicity toward seeds, which was dependent on the nanoparticle's concentration. The acute toxicity of CS-PEO-Np to A. salina nauplii was considered low in comparison to CS-Np (control), which indicates that the incorporation of Schinus molle essential oil into nanoparticles of chitosan is a strategy to reduce the toxicity commonly associated with nanostructured materials. The nanoparticulated systems of CS-PEO-Np represent an effective and non-toxic alternative for the control of toxigenic fungi such as A. flavus by delaying the initial growth stage.