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Zn2+ leakage and photo-induced reactive oxidative species do not explain the full toxicity of ZnO core Quantum Dots
摘要： Metal oxide nanoparticles (NPs), and among them metal oxides Quantum Dots (QDs), exhibit a multifactorial toxicity combining metal leaching, oxidative stress and possibly direct deleterious interactions, the relative contribution of each varying according to the NP composition and surface chemistry. Their wide use in public and industrial domains requires a good understanding and even a good control of their toxicity. To address this question, we engineered ZnO QDs with di?erent surface chemistries, expecting that they would exhibit di?erent photo-induced reactivities and possibly di?erent levels of interaction with biological materials. No photo-induced toxicity could be detected on whole bacterial cell toxicity assays, indicating that ROS-dependent damages, albeit real, are hidden behind a stronger source of toxicity, which was comforted by the fact that the di?erent ZnO QDs displayed the same level of cell toxicity. However, using in vitro DNA damage assays based on quantitative PCR, signi?cant photo-induced reactivity could be measured precisely, showing that di?erent NPs exhibiting similar inhibitory e?ects on whole bacteria could di?er dramatically in terms of ROS-generated damages on biomolecules. We propose that direct interactions between NPs and bacterial cell surfaces prime over any kind of intracellular damages to explain the ZnO QDs toxicity on whole bacterial cells.
关键词： Cell surface damages,Nanotoxicity,ZnO Quantum Dots,Photo-induced reactive oxygen species,Metal oxide nanoparticles
更新于2025-09-23 15:21:01
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Shell-free Copper Indium Sulfide Quantum Dots Induce Toxicity <i>In Vitro</i> and <i>In Vivo</i>
摘要： Semiconductor quantum dots (QDs) are attractive fluorescent contrast agents for in vivo imaging due to their superior photophysical properties, but traditional QDs comprise toxic materials such as cadmium or lead. Copper indium sulfide (CuInS2, CIS) QDs have been posited as a non-toxic and potentially clinically translatable alternative; however, previous in vivo studies utilized particles with a passivating zinc sulfide (ZnS) shell, limiting direct evidence of the biocompatibility of the underlying CIS. For the first time, we assess the biodistribution and toxicity of unshelled CIS and partially zinc-alloyed CISZ QDs in a murine model. We show that bare CIS QDs breakdown quickly, inducing significant toxicity as seen in organ weight, blood chemistry, and histology. CISZ demonstrate significant, but lower, toxicity compared to bare CIS, while our measurements of core/shell CIS/ZnS are consistent with literature reports of general biocompatibility. In vitro cytotoxicity is dose-dependent on the amount of metal released due to particle degradation, linking degradation to toxicity. These results challenge the assumption that removing heavy metals necessarily reduces toxicity: indeed, we find comparable in vitro cytotoxicity between CIS and CdSe QDs, while CIS caused severe toxicity in vivo compared to CdSe. In addition to highlighting the complexity of nanotoxicity and the differences between the in vitro and in vivo outcomes, these unexpected results serve as a reminder of the importance of assessing the biocompatibility of core QDs absent the protective ZnS shell when making specific claims of compositional biocompatibility.
关键词： in vivo imaging,biodegradable,CIS,nanotoxicity,nanomedicine,CuInS2,fluorescent contrast agent,QDs
更新于2025-09-19 17:13:59
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Non-destructive and rapid interrogation of biochemical response of the leaves of wheat seedlings towards Al2O3 nanoparticles stress using attenuated total reflectance Fourier transform infrared spectroscopy
摘要： There has been tremendous development in the field of nanotechnology and consequently the release of nanoparticles in the environment and its interaction with the biotic components is inevitable. However, knowledge concerning nanomaterial biosafety, adverse effects, fate, and acquired biological reactivity is still at infancy and requires further scientific efforts to assess their possible nano-agricultural risks. Therefore, the present study aims to reveal the molecular alterations in the leaves of the wheat seedlings caused by direct exposure of Al2O3 NPs in non-destructive and rapid manner using attenuated total reflectance Fourier transform infrared spectroscopy. For this, the seedlings of wheat have been grown in sand matrix under controlled growth conditions and the toxicity of Al2O3 NPs has been introduced to the seedlings at different concentrations (0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 and 1.6 mM). For determining the biochemical alterations, the infrared spectra of the leaves of control and Al2O3 NPs treated seedlings have been recorded in the wavenumber range 4000-400 cm-1. The principle component analyses of the preprocessed spectra indicate significant discrimination between the spectral signatures of control and Al2O3 NPs treated seedlings. The treatment of Al2O3 NPs enhances the spectral features of cellulose, hemicelluloses, lignin and pectin in the leaves of wheat seedlings. The treatment also increases the area of mehtylene bands of lipids, carboxyl and amine groups of amino acids and protein. Enhancement is also observed in carbonyl fingerprint region. The increase in the area of these molecules indicates the physiological significance of these molecules in the modulation of Al2O3 NPs stress in the wheat seedlings. The study adds substantive spectral data base to the existing elusive knowledge of nanotoxicity especially Al2O3 NPs to the plants and provides a molecular mechanism that defines the occurrence of biochemical changes and defense strategy of plants towards Al2O3 NPs toxicity.
关键词： biochemical analysis,ATR-FTIR,Al2O3 nanoparticles,wheat seedlings,nanotoxicity
更新于2025-09-11 14:15:04
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Effect of Polyethylene Glycol Surface Charge Functionalization of SWCNT on the in vitro and in vivo Nanotoxicity and Biodistribution Monitored Noninvasively using MRI
摘要： The current study evaluated in vitro and in vivo toxicity of carboxyl or amine PEG surface functionalization of single walled carbon nanotubes (SWCNTs). Assessments of cytotoxicity, genotoxicity, immunotoxicity and oxidative stress were performed in vitro and in vivo (in a one-month follow-up study). The SWCNT biodistribution was investigated using noninvasive MRI. Results confirmed the enhanced biocompatibility of PEG-functionalized SWCNTs compared to non-functionalized materials with significant decreases (p<0.05) in the percentage of cell viability and increases in ROS generation, mitochondrial membrane potential, cell apoptosis, oxidative stress generation and oxidative DNA damage in vitro. PEG-functionalized SWCNTs with amine terminals were found to induce prominent increases in ROS generation, mitochondrial membrane potential, and oxidative stress compared to carboxy functionalized SWCNTs. No significant difference in the biodistribution of either PEG-COOH or PEG-NH2 functionalized SWCNTs was observed in MRI. In vivo assessments revealed a statistically significant increase (p<0.05) in oxidative stress as early as 24 h in serum and liver; however, all values normalized at 2 weeks’ investigation time point. DNA damage was minimal with either PEG-COOH or PEG-NH2 functionalized SWCNTs after two weeks’ exposure. The negatively charged SWCNTs caused lesser DNA damage compared to positively charged samples. Carboxy-functionalized SWCNTs did not caused substantial changes in inflammatory mediators and were found to be significantly safer than non-functionalized SWCNTs and may pave the way for novel biomedical applications in cancer diagnosis and therapy.
关键词： Nanotoxicity,Cytotoxicity,Carbon nanotubes,In vivo biodistribution,Magnetic Resonance Imaging
更新于2025-09-04 15:30:14