Biomedical potential of green-engineered chitosan-magnesium oxide nanoparticles: An in vitro study on antibacterial and anticancer activities

The development of low-cost, highly effective, environmentally friendly, multi-functional bio-cidal substances has become a top priority in the current scenario. This study aimed to create low-cost materials, such as green-engineered magnesium oxide (GEMgO) and chitosan-coated magnesium oxide (GECsMgO) nanoparticles (NPs), using Chara zeylanica Klein ex Willd extract as a reducing agent. The X-ray diffraction results confirmed the cubic face-centered structure of the GEMgO and GECsMgO NPs. The field emission scanning electron microscopy and transmission electron microscopy results showed that GEMgO and GECsMgO NPs exhibit a spherical structure and nanoflakes with spherical structures, respectively. The Mg–O stretching frequencies were measured at 779 and 456 cm⁻¹ for GEMgO and 543 cm⁻¹ for GECsMgO NPs in the Fourier-transform infrared spectra. The oxygen vacancies responsible for the biocidal activities of GEMgO and GEC-MgO NPs were observed in their photoluminescence spectra at 501 and 520 nm and at 506 and 524 nm, respectively. The antioxidant activity of GEMgO and GECsMgO NPs was investigated using a DPPH assay. The GECsMgO NPs exhibited higher scavenging activity than the GEMgO NPs. Antibacterial studies on gram-negative bacteria treated with GEMgO and GECsMgO NPs showed that GECsMgO NPs exhibited the highest antibacterial activity. The ultrastructural morphological results of E. coli showed that GECsMgO NPs can damage it better than GEMgO NPs. An MTT assay determined that GEC-MgO NPs had better anticancer properties than GEMgO NPs when tested against a blood cancer cell line (MOLT-7). Fibroblast L929 cell toxicity tests showed that GEC-MgO NPs were less toxic than GEMgO NPs. In the future, GECsMgO NPs can be used as biocidal agents in clinical and industrial applications.