Facile Hydrothermal Synthesis of BiVO 4 /MWCNTs Nanocomposites and Their Influences on the Biofilm Formation of Multidrug Resistance Streptococcus mutans and Proteus mirabilis .

This study utilized a simple hydrothermal technique to prepare pure BiVO 4 and tightly bound BiVO 4 /multiwalled carbon nanotubes (MWCNTs) nanocomposite materials. The surfactant was employed to control the growth, size, and assembly of BiVO 4 and the nanocomposite. Various techniques including X-ray diffraction (XRD), Ultraviolet-visible (UV-vis), photoluminescence (PL), Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were utilized to analyze and characterize BiVO 4 and the BiVO 4 /MWCNTs nanocomposite. Through XRD analysis, it was found that the carbon nanotubes were effectively embedded within the lattice of BiVO 4 without generating any separate impurity phase and had no influence on the BiVO 4 monoclinic structure. TEM images confirmed the presence of MWCNTs within BiVO 4 . Furthermore, adding MWCNTs in the BiVO 4 /MWCNTs nanocomposite resulted in an effective charge transfer transition and improved carrier separation, as evidenced by PL analysis. The introduction of MWCNTs also led to a significant reduction in the optical band gap due to quantum effects. Finally, the antibacterial activity of pure BiVO 4 and the BiVO 4 /MWCNTs nanocomposite was assessed by exposing Proteus mirabilis and Streptococcus mutans to these materials. Biofilm inhibition and antibiofilm activity were measured using a crystal violet assay and a FilmTracer LIVE/DEAD Biofilm Viability Kit. The results demonstrated that pure BiVO 4 and BiVO 4 /MWCNTs effectively inhibited biofilm formation. In conclusion, both pure BiVO 4 and BiVO 4 /MWCNTs are promising materials for inhibiting the bacterial biofilm during bacterial infections.