A Colloidal Singularity Reveals the Crucial Role of Colloidal Stability for Nanomaterials In-Vitro Toxicity Testing: nZVI-Microalgae Colloidal System as a Case Study

For more than 40 years, intensive research has been devoted to shedding light on the mechanisms of asbestos toxicity. Given the key role of fibre length in the mechanisms of asbestos toxicity, much work has been devoted to finding suitable comminution routes to produce fibres in desired size intervals. A promising method is cryogenic milling that, unlike other mechanical size reduction techniques, preserves the crystal–chemical properties of materials. In this study, the effect of cryogenic milling on the physical–chemical properties of commercial Russian chrysotile was studied in order to produce precise size fractions with invariant properties compared to the pristine fibres. In particular, two batches with fibres > 5 µm and <5 µm were prepared, as this limit sets their potential toxicity. The results are fundamental for future in vitro toxicity testing of this commercial product, widely used in chrysotile-friendly countries but not yet adequately studied. Results show that fibre length can be controlled by milling time under cryogenic conditions without inducing structural defects or amorphization; short fibres (95% L < 5 µm) can be obtained by cryogenic milling for 40 min, while 10 min is enough to yield long chrysotile fibres (90% L > 5 µm).

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Testing Strategies of the In Vitro Micronucleus Assay for the Genotoxicity Assessment of Nanomaterials in BEAS-2B Cells

Nanomaterials ◽

10.3390/nano11081929 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1929

Author(s):

Tereza Cervena ◽

Andrea Rossnerova ◽

Tana Zavodna ◽

Jitka Sikorova ◽

Kristyna Vrbova ◽

...

Keyword(s):

Cytochalasin B ◽

Culture Media ◽

Methodological Approach ◽

Micronucleus Assay ◽

Toxicity Testing ◽

In Vitro Toxicity ◽

Testing Strategies ◽

Transmission Electron ◽

The Impact

The evaluation of the frequency of micronuclei (MN) is a broadly utilised approach in in vitro toxicity testing. Nevertheless, the specific properties of nanomaterials (NMs) give rise to concerns regarding the optimal methodological variants of the MN assay. In bronchial epithelial cells (BEAS-2B), we tested the genotoxicity of five types of NMs (TiO2: NM101, NM103; SiO2: NM200; Ag: NM300K, NM302) using four variants of MN protocols, differing in the time of exposure and the application of cytochalasin-B combined with the simultaneous and delayed co-treatment with NMs. Using transmission electron microscopy, we evaluated the impact of cytochalasin-B on the transport of NMs into the cells. To assess the behaviour of NMs in a culture media for individual testing conditions, we used dynamic light scattering measurement. The presence of NMs in the cells, their intracellular aggregation and dispersion properties were comparable when tests with or without cytochalasin-B were performed. The genotoxic potential of various TiO2 and Ag particles differed (NM101 < NM103 and NM302 < NM300K, respectively). The application of cytochalasin-B tended to increase the percentage of aberrant cells. In conclusion, the comparison of the testing strategies revealed that the level of DNA damage induced by NMs is affected by the selected methodological approach. This fact should be considered in the interpretation of the results of genotoxicity tests.

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A survey of aerosol exposure systems relative to the analysis of cytotoxicity: A Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) perspective

Toxicology Research and Application ◽

10.1177/23978473211022267 ◽

2021 ◽

Vol 5 ◽

pp. 239784732110222

Author(s):

David Thorne ◽

Roman Wieczorek ◽

Toshiro Fukushima ◽

Han-Jae Shin ◽

Robert Leverette ◽

...

Keyword(s):

Scientific Research ◽

Toxicity Testing ◽

User Preferences ◽

In Vitro Toxicity ◽

Aerosol Generation ◽

Aerosol Exposure ◽

Comprehensive Survey ◽

Survey Results ◽

System Data

During a Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) meeting, the in vitro toxicity testing Sub-Group (IVT SG) met to discuss the evolving field of aerosol exposure research. Given the diversity of exposure parameters and biological endpoints being used, it was considered a high priority to investigate and contextualise the responses obtained. This is particularly driven by the inability to compare between studies on different exposure systems due to user preferences and protocol differences. Twelve global tobacco and contract research companies met to discuss this topic and formulate an aligned approach on how this diverging field of research could be appropriately compared. Something that is becoming increasingly important, especially in the light of more focused regulatory scrutiny. A detailed and comprehensive survey was conducted on over 40 parameters ranging from aerosol generation, dilution and data analysis across eight geographically independent laboratories. The survey results emphasise the diversity of in vitro exposure parameters and methodologies employed across the IVT SG and highlighted pockets of harmonisation. For example, many of the biological protocol parameters are consistent across the Sub-Group. However, variables such as cell type and exposure time remain largely inconsistent. The next steps for this work will be to map parameters and system data against biological findings and investigate whether the observed inconsistencies translate into increased biological variability. The results from the survey provide improved awareness of parameters and nuances, that may be of substantial benefit to scientists in intersecting fields and in the development of harmonised approaches.

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In Vitro Toxicity Testing: Redefining our Objectives

Alternatives to Laboratory Animals ◽

10.1177/026119299202000411 ◽

1992 ◽

Vol 20 (4) ◽

pp. 571-574

Author(s):

Oliver Flint

Keyword(s):

Toxicity Testing ◽

In Vitro Toxicity

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Time-lapse Phase-contrast Microphotography of Cell Populations as a Basis for Improvement of In Vitro Toxicity Assessment

Alternatives to Laboratory Animals ◽

10.1177/026119299202000223 ◽

1992 ◽

Vol 20 (2) ◽

pp. 302-306

Author(s):

Miroslav Červinka

Keyword(s):

Cell Proliferation ◽

Cell Morphology ◽

Video Recording ◽

Toxicity Testing ◽

Time Lapse ◽

Time Dependent ◽

In Vitro Toxicity ◽

Simple Modification ◽

Pertinent Data

Recent trends in the field of in vitro toxicology have centred around the validation of in vitro methods. The ultimate goal is to obtain pertinent data with the minimum of effort. In our laboratory, we have used toxicological methods based on the evaluation of cell morphology and cell proliferation. A method suitable for this purpose is time-lapse microcinematographic (or video) recording of cellular changes, which we used for many years. For practical in vitro toxicity testing, however, this method is far too complicated. Therefore, we have tried to develop a simple modification for the evaluation of cell morphology and cell proliferation, which would still allow for a basic time-dependent analysis. Comparison of detailed microcinematographic analysis with analysis according to our new proliferation assay is demonstrated with cisplatin as the toxicant. We believe that a time-dependent approach could improve the in vitro assessment of toxicity.

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