Synthesis, Characterization, and Cytotoxicity of Photochromic Molybdenum Oxide‐Doped Tungsten Oxide Polymeric Nanohybrid Films for Biomedical Applications

Despite the known nontoxicity, stability, and efficiency of WO₃ and MoO₃ against microbes as a result of their catalytic activities, these oxides are not effective photocatalysts because the O₂ absorbed cannot be reduced by the photogenerated electrons in their conduction band, which leads to the rebinding of electrons and holes on the surface. The doping of these two n-type semiconductor metal oxides and incorporation of a biocompatible, biodegradable, and bioavailable polymer (such as chitosan) to form a film, to a large extent, affects the surface area interaction and multipurpose applicability of the film as a therapeutic, controlled delivery, and dual sensitive material. The WO₃-NP and WO₃MoO₃ nanocomposites are synthesized via a deep eutectic solvent-assisted hydrothermal-based method, which afford fine-sized nanoparticles and nanocomposites, which are further incorporated into a chitosan matrix to form nanohybrid films via the solvent casting method. The structural, optical, and morphological characterization of the materials is carried out via X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and dynamic light scattering. XRD and FT-IR analyses reveal that WO₃MoO₃ nanocomposites are successfully formed and incorporated into the chitosan matrix. The nanohybrid film shows antimicrobial activity with a minimum inhibitory concentration of 100 μg mL^-1. Furthermore, the nanohybrid film shows no significant toxicity.