Investigation of Toxicity Parameters of La-TiO₂ Nanoparticles in Allium cepa L. Root Tip Cells

In this study, the dose-dependent physiological, anatomical, and cytogenetic effects of lanthanum-doped titanium dioxide (La-TiO₂) nanoparticles, which are widely used today and have applications in electronics, optics, energy storage, and photocatalysis, were investigated in Allium cepa L. root tip cells. La-TiO₂ NPs were synthesized using the microwave method, and characterization analyses such as SEM and XRD were performed to ensure the desired nanoparticle properties before proceeding to in vivo parameters. In the study, physiological parameters including germination percentage, root length, and weight increase; cytogenetic indicators including chromosomal abnormality (CA), micronucleus (MN) frequency, and mitotic index (MI); and anatomical effects on meristematic cell damage were examined through sectioning, and the obtained data were statistically evaluated. The onion bulbs used as test materials were divided into five groups: Control (Group I) and groups Group II (10 ppm), Group III (25 ppm), Group IV (50 ppm) and Group V (100 ppm) exposed to different doses of La-TiO₂ nanoparticles. After a 72-hour application, it was determined that physiological parameters decreased in groups exposed to La-TiO₂ nanoparticles as the applied dose increased. Additionally, an increase in chromosomal abnormality (CA) and micronucleus (MN) frequency was observed. In terms of anatomical damage, epidermal cell damage, thickened cortical cell walls, flattened cell nuclei, and indistinct vascular tissues were detected in groups treated with La-TiO₂. As a result, it was demonstrated that the La-TiO₂ nanoparticles, synthesized in the desired sizes and used in this study, could cause cytotoxic, genotoxic, and anatomical damage in A. cepa L. root tip cells.