The aim of this study was to provide experimental evidence on the formation of Co2+, Fe2+ and Fe3+ ions from CoFe2O4 nanoparticles in the digestive juices of a model organism. Standard toxicological parameters were assessed. Cell membrane stability was tested with a modified method for measurement of cell membrane stability. Proton induced x-ray emission and low energy synchrotron radiation X-ray fluorescence were used to study internalisation and distribution of Co and Fe. Co2+ ions were found to be more toxic than nanoparticles. The authores confirmed that Co2+ ions accumulate in the hepatopancreas but Fe+ ions or CoFe2O4 nanoparticles are not retained in vivo. A model biological system with a terrestrial isopod is suited to studies of the potential dissolution of ions and other products from metal-containing nanoparticles in biologically complex media.
COBISS.SI-ID: 2768975
We have studied the genotoxicity of TiO2 particles with a Comet assay on a unicellular organism, Tetrahymena thermophila. Exposure to bulk or nano-TiO2 of free cells, cells embedded in gel or nuclei embedded in gel, all resulted in a positive Comet assay result but this outcome could not be confirmed by cytotoxicity measures such as lipid peroxidation, elevated reactive oxygen species or cell membrane composition. Published reports state that in the absence of cytotoxicity, nano- and bulk TiO2 genotoxicity do not occur directly and a possible explanation of our Comet assay results is that they are false positives resulting from post-festum exposure interactions between particles and DNA. We suggest that before Comet assay is used for nanoparticle genotoxicity testing, evidence for the possibility of post-festum exposure interactions should be considered. The acellular Comet test described in this report can be used for this purpose.
COBISS.SI-ID: 2573903
Carbon-based nanomaterials (NM) are promising candidates for a myriad of applications ranging from drug delivery to biosensing platforms. In the physiological environment, proteins can be adsorbed onto the surface of NM that can alter their structure and function. Little is knownof the effect of NM on larger proteins and enzymes and an attempt has beenmadein this study to investigate the effect of carbon-based NM such as carbon black (CB), graphene oxide (GO) and fullerene (C60) on the adsorption and activity of acetylcholinesterase (AChE), a key enzyme present in brain, blood and nervous system and a suitable neurotoxicity biomarker. Experimental and computational results showed that all the carbon-based NM tested adsorb AChE but they have different effects on the catalytic activity of the enzyme. The most efficient AChE inhibitor is CB. In contrast, AChE adsorbed on the GO surface retains its native conformation and most of its activity.
COBISS.SI-ID: 2848591