Bioactivity Assessment of Functionalized TiO₂ Powder with Dihydroquercetin

Biological activities, including cell viability, oxidative stress, genotoxicity/antigenotoxicity, and antimicrobial activity, were evaluated for a visible-light-responsive TiO₂-based ICT complex with dihydroquercetin (DHQ) and compared with pristine TiO₂, its inorganic component. Pristine TiO₂ did not induce cytotoxicity in MRC-5 or HeLa cells within the tested concentration range (1-20 mg/mL), while TiO₂/DHQ displayed a significant reduction in cell viability in both cell lines at higher concentrations (≥10 mg/mL). The analysis of reactive oxygen species (ROS) production revealed that TiO₂/DHQ significantly reduced ROS levels in both cell types (MRC-5 and HeLa), with HeLa cells showing a more substantial reduction at lower concentrations. Genotoxicity assessment using the comet assay demonstrated that TiO₂ induced DNA damage in MRC-5 cells, while TiO₂/DHQ did not, indicating that DHQ mitigates the genotoxic potential of TiO₂. Furthermore, TiO₂/DHQ exhibited antigenotoxic effects by reducing H₂O₂-induced DNA damage in MRC-5 cells, supporting its protective role against oxidative stress. Preliminary antimicrobial tests revealed that TiO₂/DHQ exhibits antimicrobial activity against E. coli under visible-light excitation, while TiO₂ does not. These findings suggest that the TiO₂-based ICT complex with DHQ with enhanced antioxidant properties can potentially serve as a safe, non-toxic biocide agent.