Zinc Oxide Nanoparticles Induce Toxicity in H9c2 Rat Cardiomyoblasts.

Zinc oxide nanoparticles (ZnO NPs) are widely used in the cosmetic industry. They are nano-optical and nano-electrical devices, and their antimicrobial properties are applied in food packaging and medicine. ZnO NPs penetrate the body through inhalation, oral, and dermal exposure and spread through circulation to various systems and organs. Since the cardiovascular system is one of the most vulnerable systems, in this work, we studied ZnO NPs toxicity in H9c2 rat cardiomyoblasts. Cardiac cells were exposed to different concentrations of ZnO NPs, and then the morphology, proliferation, viability, mitochondrial membrane potential (ΔΨm), redox state, and protein expression were measured. Transmission electron microscopy (TEM) and hematoxylin-eosin (HE) staining showed strong morphological damage. ZnO NPs were not observed inside cells, suggesting that Zn2+ ions were internalized, causing the damage. ZnO NPs strongly inhibited cell proliferation and MTT reduction at 10 and 20 µg/cm2 after 72 h of treatment. ZnO NPs at 20 µg/cm2 elevated DCF fluorescence, indicating alterations in the cellular redox state associated with changes in ΔΨm and cell death. ZnO NPs also reduced the intracellular expression of troponin I and atrial natriuretic peptide. ZnO NPs are toxic for cardiac cells; therefore, consumption of products containing them could cause heart damage and the development of cardiovascular diseases.

Food grade titanium dioxide accumulation leads to cellular alterations in colon cells after removal of a 24-hour exposure.

Titanium dioxide food grade (E171) is one of the most used food additives containing nanoparticles. Recently, the European Food Safety Authority indicated that E171 could no longer be considered safe as a food additive due to the possibility of it being genotoxic and there is evidence that E171 administration exacerbates colon tumor formation in murine models. However, less is known about the effects of E171 accumulation once the exposure stopped, then we hypothesized that toxic effects could be detected even after E171 removal. Therefore, we investigated the effects of E171 exposure after being removed from colon cell cultures. Human colon cancer cell line (HCT116) was exposed to 0, 1, 10 and 50 µg/cm2 of E171. Our results showed that in the absence of cytotoxicity, E171 was accumulated in the cells after 24 of exposure, increasing granularity and reactive oxygen species, inducing alterations in the molecular pattern of nucleic acids and lipids, and causing nuclei enlargement, DNA damage and tubulin depolymerization. After the removal of E171, colon cells were cultured for 48 h more hours to analyze the ability to restore the previously detected alterations. As we hypothesized, the removal of E171 was unable to revert the alterations found after 24 h of exposure in colon cells. In conclusion, exposure to E171 causes alterations that cannot be reverted after 48 h if E171 is removed from colon cells.

Evaluation of SiO2 sonogels, prepared by a new catalyst-free method, as drug delivery system.

Recently, we reported on the synthesis of catalyst-free SiO(2) sonogels prepared by the sonication of a neutral distilled water/ tetraethyl ortosilicate mixture. The purpose of the present study was to evaluate the feasibility of using these sonogels as pharmaceutical delivery systems. A certified color additive (sunset yellow, SY) was used as a model compound for the release experiments. Different amounts of dye were incorporated into the gels before drying. Sonogels were characterized by scanning electron microscopy and differential scanning calorimetry. The effect of three drying temperatures (25 degrees C, 40 degrees C and 80 degrees C) and two mean grain sizes (1125 and 630 microm) on release behavior was analyzed. The analysis of variance showed no significant differences between the Higuchi's constants (K(H)) obtained for SY-loaded sonogels dried at 80 degrees C with different SY loads, irrespective of the mean grain size. In contrast, for SY-loaded sonogels dried at 40 degrees C, differences were found between sonogels loaded with 2.7, 7.7, 12.2, and 18.2% of SY, and no significant differences were detected between the mean grain sizes analyzed. Considering that the preparation of sonogels by the catalyst-free method allows an easy encapsulation, sonogels may offer an interesting alternative for drug release in the pharmaceutical field.