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Zinc oxide (ZnO) nanostructures were synthesized in the form of nanoparticles, nanoflowers and nanourchins. Structural. electronic and optical characterization of the samples were done via standard techniques such as X-ray...

The present study was designed to investigate genotoxic and cytotoxic effects and oxidative damage of increasing concentrations of nano-hydroxyapatite (5, 10, 20, 50, 75, 100, 150, 300, 500 and 1000 ppm) in primary human blood cell cultures. Cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] assay and lactate dehydrogenase release, while total antioxidant capacity and total oxidative stress levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by sister chromatid exchange, micronuclei, chromosome aberration assays and 8-oxo-2-deoxyguanosine level as indicators of genotoxicity. The results of [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] and lactate dehydrogenase assays showed that the higher concentrations (150, 300, 500 and 1000 ppm) of hydroxyapatite nanoparticles (HAP NPs) decreased cell viability. HAP NPs led to increases of total oxidative stress (300, 500 and 1000 ppm) levels and decreased total antioxidant capacity (150, 300, 500 and 1000 ppm) levels in cultured human blood cells. On the basis of increasing concentrations, HAP NPs caused significant increases of sister chromatid exchange, micronuclei, chromosome aberration rates and 8-oxo-2-deoxyguanosine levels as compared to untreated culture. In conclusion, the obtained in vitro results showed that HAP NPs had dose-dependent effects on inducing oxidative damage, genotoxicity and cytotoxicity in human blood cells.

Supercapacitor devices are interesting owing to their broad range of applicability from wearable electronics to energy storage in electric vehicles. One of the key parameters that affect the efficiency of supercapacitor devices is selecting the ideal electrode material for a specific application. Regarding this, recently developed metal oxides, specifically nanostructured ZnO, and MXenes with their defect structures, size effects, as well as optical and electronic properties have been presented as electrode material in supercapacitor devices. The discussion of MXenes along with ZnO, although different in chemistry, also highlights the differences in dimensionality when it comes to defect-driven effects, especially in carrier transport. The volume under the influence of the defect centers is expected to be different in bulk and 2D structures, regardless of composition. Hence, analysis and discussion of both materials provide a fundamental understanding regarding the manner in which 2D structures are impacted by defects compared to bulk. Such an approach would therefore serve the scientific community with the material design tools needed to fabricate the next generation of supercapacitor devices.