Effect of TiO₂ and Fe doped TiO₂ nanoparticles on mitochondrial membrane potential in HBL-100 cells

Titanium dioxide (TiO2) nanoparticles (NPs) have made unbelievable progress in the field of nanotechnology and biomedical research. The proper toxicological assessment of TiO2 NPs and the reduction of its cytotoxicity need to be addressed. Fe doping in TiO2 has been investigated to reduce the toxic effects of TiO2 NPs. Fe doped TiO2 powder samples were synthesized by sol-gel methods. The prepared samples were characterized by x-ray diffractometer (XRD), transmission electron microscope (TEM), and Raman spectroscopy to study their structure, morphology, and molecular conformation. XRD results revealed the coexistence of anatase (A) and rutile (R) phases of TiO2. The A-R transformation was observed with an increase in Fe doping along with the formation of α-Fe2O3 phase. TEM showed changes in morphology from spherical nanoparticles to elongated rod-shaped nanostructures with increasing Fe content. Shape variation of TiO2 nanoparticles after incorporation of Fe is a key reason behind the toxicity reduction. The authors observed that the toxicity of TiO2 nanoparticles was rescued upon Fe incorporation. The effect of NPs on the mitochondrial membrane potential (MMP) was assessed using flow cytometry. The MMP (%) decreased in TiO2 treated cells and increased by 1% Fe doped TiO2 NPs treated cells. Confocal imaging revealed the presence of functional mitochondria upon the exposure of Fe doped TiO2 NPs. The goal of the present study was to decrease the toxic effects induced by TiO2 NPs on mitochondrial potential and its prevention by Fe doping.