Electrochemical Sensors for the Detection of TiO2 Nanoparticles Genotoxicity at Different pH Values Simulating the Gastrointestinal Tract

Titanium dioxide (TiO2) is one of the most widely produced nanomaterials. Many products contain nanoparticles because they have various technological, medical, and economic benefits. However, the presence of nanoparticles in the environment has a negative impact on public health. Due to the presence of TiO2 NPs in food, food packaging, and drinking water, they can easily enter the human gastrointestinal tract (GIT), which includes environments with different pH values. These pH changes can affect the stability, dispersion, and toxicity of nanomaterials. Our experiments aimed to monitor the effect of TiO2 NPs incubated at a pH similar to the GIT values on DNA structure. DNA damage was monitored using a DNA biosensor and a biosensing approach with electrochemical voltammetric detection. Cyclic voltammetry (CV) detected damage to DNA/GCE biosensors of up to 10%. The best way to monitor the genotoxicity of TiO2 NPs on DNA structure was the biosensing approach, which changes in the redox indicator current response detected by differential pulse voltammetry (DPV) up to 47.6%. The highest effect of TiO2 was observed for guanine residues at pH 8.0. The results were confirmed by UV–vis spectrophotometry and hyperchromic and bathochromic spectral shifts.