Characterization and assessment of potential risks of titanium dioxide nanoparticles isolated from gummy candies

Abstract

Nanomaterials in food emerge in an endless stream; thus, the safety evaluation of nanomaterials in food is essential. In this study, titanium dioxide nanoparticles (TiO2-NPs) were extracted from five different gummy candies. The nanoparticles were comprehensively characterized using scanning electron microscopy, energy spectrum analysis, Fourier-transform infrared spectroscopy, and X-ray diffraction. The safety of TiO2 was evaluated using a simulated gastrointestinal system. Cell viability was determined using a Cell-Counting Kit-8 assay, and reactive oxygen species levels were measured to examine the cytotoxicity of TiO2 in GES-1 and Caco-2 cells. The effects of direct TiO2-NP exposure in animals were assessed by determining the body weight, organ coefficients, and tissue histopathology of mice. The energy-dispersive spectroscopy results demonstrated TiO2 present as separated nanoparticles. These negatively charged particles had a particle size of 180–300 nm and mostly comprised anatase crystals. TiO2 showed significantly more agglomeration during the gastric digestion phase relative to the oral and intestinal tracts with an increased particle size. The cytotoxicity of the nanoparticles increased with digestion time, leading to an insignificant increase in the intracellular ROS levels. Animal experiments revealed a significant increase in the five organ coefficients after TiO2-NP compared with those of the control group. Collectively, the results of this study suggest that organ damage caused by nanoparticles in food could be discerned from the tissue histopathology. The content and distribution of Ti in the experimental group could be detected by energy dispersive X-ray spectroscopy and inductively coupled plasma mass spectrometry, although this value was very small. These results suggest that daily intake of gummy candies has negligible harm to bodily function.