Synthesis and Characterization of Rutile TiO₂ Nanoparticles for the Toxicological Effect on the H9c2 Cell Line from Rats

The widespread use of titanium dioxide (TiO2) has raisedconcerns about potential health risks associated with its cytotoxicityin the cardiovascular system. To evaluate the cytotoxicity of TiO2 particles, the H9c2 rat cardiomyoblasts were used as a biologicalmodel, and their toxicological susceptibility to TiO2-anataseand TiO2-rutile particles was studied in vitro. The studyexamined dose and time exposure responses. The cell viability wasevaluated based on metabolic inhibition and membrane integrity loss.The results revealed that both TiO2-anatase and TiO2-rutile particles induced similar levels of cytotoxicity atthe inhibition concentrations IC25 (1.4-4.4 mu g/cm(2)) and IC50 (7.2-9.3 mu g/cm(2)). However, at more significant concentrations, TiO2-rutileappeared to be more cytotoxic than TiO2-anatase at 24 h.The study found that the TiO2 particles induced apoptosisevents, but necrosis was not observed at any of the concentrationsof particles used. The study considered the effects of microstructuralproperties, crystalline phase, and particle size in determining thecapability of TiO2 particles to induce cytotoxicity inH9c2 cardiomyoblasts. The microstress in TiO2 particleswas assessed using powder X-ray diffraction through Williamson-Halland Warren-Averbach analysis. The analysis estimated the apparentcrystallite domain and microstrain of TiO2-anatase to be29 nm (epsilon = 1.03%) and TiO2-rutile to be 21 nm (epsilon= 0.53%), respectively. Raman spectroscopy, N-2 adsorptionisotherms, and dynamic light scattering were used to identify thepresence of pure crystalline phases (>99.9%), comparative surfaceareas (10 m(2)/g), and zeta-potential values (-24mV). The difference in the properties of TiO2 particlesmade it difficult to attribute the cytotoxicity solely to one variable.