Biocidal Activity of Barium and Iron-Co-Doped Titanium Dioxide Nanocomposites, Synthesized by Psidium guajava-Mediated Precipitation Method.

The emergence of drug-resistant microorganisms and the need for effective anticancer agents necessitate the development of novel nanomaterials with enhanced biomedical performance. This study aims to synthesize barium and iron dual-doped titanium dioxide (TiBaFeO NC) using a green precipitation method with Psidium guajava leaf extract, targeting improved antimicrobial and anticancer efficacy. The synthesized nanocomposite was characterized by various analytical techniques. XRD confirmed the crystalline anatase phase of TiO and TiBaFeO NC, with average crystallite sizes of 40 and 37 nm, respectively, suitable for biomedical applications. UV-Vis analysis showed a decrease in bandgap from 3.79 eV for TiO to 3.67 eV for TiBaFeO NC, indicating enhanced reactive oxygen species (ROS) generation potential. PL spectra exhibited green emissions at 520 nm for TiO and 523 nm for TiBaFeO NC, reflecting a higher oxygen vacancy defect density in the doped nanocomposite. Biological evaluations demonstrated that TiBaFeO NC exhibited superior antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus megaterium), Gram-negative bacteria (Shigella dysenteriae, Escherichia coli, Proteus vulgaris), and fungi (Candida albicans). Furthermore, TiBaFeO NC showed enhanced anticancer activity against human breast cancer cells (MDA-MB-231) with an IC of 9.8 µg/mL, outperforming TiO. These results suggest that TiBaFeO NC is a promising nanocomposite for advanced biomedical applications, combining enhanced antimicrobial and anticancer properties through defect-mediated ROS generation.