Comparative toxicological analysis of two pristine carbon nanomaterials (graphene oxide and aminated graphene oxide) and their corresponding degraded forms using human in vitro models.

Despite the wide application of graphene-based materials, the information of the toxicity associated to some specific derivatives such as aminated graphene oxide is scarce. Likewise, most of these studies analyse the pristine materials, while the available data regarding the harmful effects of degraded forms is very limited. In this work, the toxicity of graphene oxide (GO), aminated graphene oxide (GO-NH2), and their respective degraded forms (dGO and dGO-NH2) obtained after being submitted to high-intensity sonication was evaluated applying in vitro assays in different models of human exposure. Viability and ROS assays were performed on A549 and HT29 cells, while their skin irritation potential was tested on a reconstructed human epidermis model. The obtained results showed that GO-NH2 and dGO-NH2 substantially decrease cell viability in the lung and gastrointestinal models, being this reduction slightly higher in the cells exposed to the degraded forms. In contrast, this parameter was not affected by GO and dGO which, conversely, showed the ability to induce higher levels of ROS than the pristine and degraded aminated forms. Furthermore, none of the materials is skin irritant. Altogether, these results provide new insights about the potential harmful effects of the selected graphene-based nanomaterials in comparison with their degraded counterparts.

Toxicological assessment of pristine and degraded forms of graphene functionalized with MnOx nanoparticles using human in vitro models representing different exposure routes.

The development of novel advanced nanomaterials (NMs) with outstanding characteristics for their use in distinct applications needs to be accompanied by the generation of knowledge on their potential toxicological impact, in particular, that derived from different occupational risk exposure routes, such as inhalation, ingestion, and skin contact. The harmful effects of novel graphene-metal oxide composites on human health are not well understood, many toxicological properties have not been investigated yet. The present study has evaluated several toxicological effects associated with graphene decorated with manganese oxide nanoparticles (GNA15), in a comparative assessment with those induced by simple graphene (G2), on human models representing inhalation (A549 cell line), ingestion (HT29 cell line) and dermal routes (3D reconstructed skin). Pristine and degraded forms of these NMs were included in the study, showing to have different physicochemical and toxicological properties. The degraded version of GNA15 (GNA15d) and G2 (G2d) exhibited clear structural differences with their pristine counterparts, as well as a higher release of metal ions. The viability of respiratory and gastrointestinal models was reduced in a dose-dependent manner in the presence of both GNA15 and G2 pristine and degraded forms. Besides this, all NMs induced the production of reactive oxygen species (ROS) in both models. However, the degraded forms showed to induce a higher cytotoxicity effect. In addition, we found that none of the materials produced irritant effects on 3D reconstructed skin when present in aqueous suspensions. These results provide novel insights into the potentially harmful effects of novel multicomponent NMs in a comprehensive manner. Furthermore, the integrity of the NMs can play a role in their toxicity, which can vary depending on their composition and the exposure route.

On the Tunability of Toxicity for Viologen-Derivatives as Anolyte for Neutral Aqueous Organic Redox Flow Batteries.

Viologen-derivatives are the most widely used redox organic molecules for neutral pH negative electrolyte of redox flow batteries. However, the long-established toxicity of the herbicide methyl-viologen raises concern for deployment of viologen-derivatives at large scale in flow batteries. Herein, we demonstrate the radically different cytotoxicity and toxicology of a series of viologen-derivatives in in vitro assays using model organisms representative of human and environmental exposure, namely human lung carcinoma epithelial cell line (A549) and the yeast Saccharomyces cerevisiae. The results show that safe viologen derivatives can be molecularly engineered, representing a promising family of negolyte materials for neutral redox flow batteries.

Identification of Aspergillus niger Aquaporins Involved in Hydrogen Peroxide Signaling.

Aspergillus niger is a robust microbial cell factory for organic acid production. However, the regulation of many industrially important pathways is still poorly understood. The regulation of the glucose oxidase (Gox) expression system, involved in the biosynthesis of gluconic acid, has recently been uncovered. The results of that study show hydrogen peroxide, a by-product of the extracellular conversion of glucose to gluconate, has a pivotal role as a signaling molecule in the induction of this system. In this study, the facilitated diffusion of hydrogen peroxide via aquaporin water channels (AQPs) was studied. AQPs are transmembrane proteins of the major intrinsic proteins (MIPs) superfamily. In addition to water and glycerol, they may also transport small solutes such as hydrogen peroxide. The genome sequence of A. niger N402 was screened for putative AQPs. Seven AQPs were found and could be classified into three main groups. One protein (AQPA) belonged to orthodox AQP, three (AQPB, AQPD, and AQPE) were grouped in aquaglyceroporins (AQGP), two (AQPC and AQPF) were in X-intrinsic proteins (XIPs), and the other (AQPG) could not be classified. Their ability to facilitate diffusion of hydrogen peroxide was identified using yeast phenotypic growth assays and by studying AQP gene knock-outs in A. niger. The X-intrinsic protein AQPF appears to play roles in facilitating hydrogen peroxide transport across the cellular membrane in both Saccharomyces cerevisiae and A. niger experiments.

Lab-on-a-chip for the easy and visual detection of SARS-CoV-2 in saliva based on sensory polymers.

The initial stages of the pandemic caused by SARS-CoV-2 showed that early detection of the virus in a simple way is the best tool until the development of vaccines. Many different tests are invasive or need the patient to cough up or even drag a sample of mucus from the throat area. Besides, the manufacturing time has proven insufficient in pandemic conditions since they were out of stock in many countries. Here we show a new method of manufacturing virus sensors and a proof of concept with SARS-CoV-2. We found that a fluorogenic peptide substrate of the main protease of the virus (Mpro) can be covalently immobilized in a polymer, with which a cellulose-based material can be coated. These sensory labels fluoresce with a single saliva sample of a positive COVID-19 patient. The results matched with that of the antigen tests in 22 of 26 studied cases (85% success rate).

Advances in experimental and computational methodologies for the study of microbial-surface interactions at different omics levels.

The study of the biological response of microbial cells interacting with natural and synthetic interfaces has acquired a new dimension with the development and constant progress of advanced omics technologies. New methods allow the isolation and analysis of nucleic acids, proteins and metabolites from complex samples, of interest in diverse research areas, such as materials sciences, biomedical sciences, forensic sciences, biotechnology and archeology, among others. The study of the bacterial recognition and response to surface contact or the diagnosis and evolution of ancient pathogens contained in archeological tissues require, in many cases, the availability of specialized methods and tools. The current review describes advances in in vitro and in silico approaches to tackle existing challenges (e.g., low-quality sample, low amount, presence of inhibitors, chelators, etc.) in the isolation of high-quality samples and in the analysis of microbial cells at genomic, transcriptomic, proteomic and metabolomic levels, when present in complex interfaces. From the experimental point of view, tailored manual and automatized methodologies, commercial and in-house developed protocols, are described. The computational level focuses on the discussion of novel tools and approaches designed to solve associated issues, such as sample contamination, low quality reads, low coverage, etc. Finally, approaches to obtain a systems level understanding of these complex interactions by integrating multi omics datasets are presented.

Toxicology assessment of manganese oxide nanomaterials with enhanced electrochemical properties using human in vitro models representing different exposure routes.

In the present study, a comparative human toxicity assessment between newly developed Mn3O4 nanoparticles with enhanced electrochemical properties (GNA35) and their precursor material (Mn3O4) was performed, employing different in vitro cellular models representing main exposure routes (inhalation, intestinal and dermal contact), namely the human alveolar carcinoma epithelial cell line (A549), the human colorectal adenocarcinoma cell line (HT29), and the reconstructed 3D human epidermal model EpiDerm. The obtained results showed that Mn3O4 and GNA35 harbour similar morphological characteristics, whereas differences were observed in relation to their surface area and electrochemical properties. In regard to their toxicological properties, both nanomaterials induced ROS in the A549 and HT29 cell lines, while cell viability reduction was only observed in the A549 cells. Concerning their skin irritation potential, the studied nanomaterials did not cause a reduction of the skin tissue viability in the test conditions nor interleukin 1 alpha (IL- 1 α) release. Therefore, they can be considered as not irritant nanomaterials according to EU and Globally Harmonized System of Classification and Labelling Chemicals. Our findings provide new insights about the potential harmful effects of Mn3O4 nanomaterials with different properties, demonstrating that the hazard assessment using different human in vitro models is a critical aspect to increase the knowledge on their potential impact upon different exposure routes.

Comparative toxicological assessment of three soils polluted with different levels of hydrocarbons and heavy metals using in vitro and in vivo approaches.

The biological effects induced by the pollutants present in soils, together with the chemical and physical characterizations, are good indicators to provide a general overview of their quality. However, the existence of studies where the toxicity associated to soils contaminated with mixtures of pollutants applying both in vitro and in vivo models are scarce. In this work, three soils (namely, Soil 001, Soil 002 and Soil 013) polluted with different concentrations of hydrocarbons and heavy metals were evaluated using different organisms representative of human (HepG2 human cell line) and environmental exposure (the yeast Saccharomyces cerevisiae, the Gram-negative bacterium Pseudomonas putida and, for the in vivo evaluation, the annelid Enchytraeus crypticus). In vitro assays showed that the soluble fraction of the Soil 001, which presented the highest levels of heavy metals, represented a great impact in the viability of the HepG2 cells and S. cerevisiae, while organic extracts from Soils 002 and 013 caused a slight decrease in the viability of HepG2 cells. In addition, in vivo experiments showed that Soils 001 and 013 affected the survival and the reproduction of E. crypticus. Altogether, these results provide a general overview of the potential hazards associated to three specific contaminated sites in a variety of organisms, showing how different concentrations of similar pollutants affect them, and highlights the relevance of testing both organic and soluble extracts when in vitro safety assays of soils are performed.

Evaluation of biostimulation, bioaugmentation, and organic amendments application on the bioremediation of recalcitrant hydrocarbons of soil.

In the present work, the operational conditions for improving the degradation rates of Total Petroleum Hydrocarbons (TPHs) in contaminated soil from a machinery park were optimized at a microcosms scale along a 90-days incubation period. In this study, bioremediation strategies and an organic amendment have been tested to verify the remediation of soil contaminated with different hydrocarbons, mineral oils, and heavy metals. Specifically, designed biostimulation and bioaugmentation strategies were compared with and without adding vermicompost. The polluted soil harboring multiple contaminants, partially attenuated for years, was used. The initial profile showed enrichment in heavy linear alkanes, suggesting a previous moderate weathering. The application of vermicompost increased five and two times the amounts of available phosphorus (P) and exchangeable potassium (K), respectively, as a direct consequence of the organic amendment addition. The microbial activity increased due to soil acidification, which influenced the solubility of P and other micronutrients. It also impacted the predominance and variability of the different microbial groups and the incubation, as reflected by phospholipid fatty acid (PLFA) results. An increase in the alkaline phosphatases and proteases linked to bacterial growth was displayed. This stimulation of microbial metabolism correlated with the degradation rates since TPHs degradation' efficiency after vermicompost addition reached 32.5% and 34.4% of the initial hydrocarbon levels for biostimulation and bioaugmentation, respectively. Although Polycyclic Aromatic Hydrocarbons (PAHs) were less abundant in this soil, results also decreased, especially for the most abundant, the phenanthrene. Despite improving the degradation rates, results revealed that recalcitrant and hydrophobic petroleum compounds remained unchanged, indicating that mobility, linked to bioavailability, probably represents the limiting step for further soil recovery.

A theoretical study on CO2 at Li4SiO4 and Li3NaSiO4 surfaces.

Lithium silicates have attracted great attention in recent years due to their potential use as high-temperature (450-700 °C) sorbents for CO2 capture. Lithium orthosilicate (Li4SiO4) can theoretically adsorb CO2 in amounts up to 0.36 g CO2 per g Li4SiO4. The development of new Li4SiO4-based sorbents is hindered by a lack of knowledge of the mechanisms ruling CO2 adsorption on Li4SiO4, especially for eutectic mixtures. In this work, the structural, electronic, thermodynamic and CO2 capture properties of monoclinic phases of Li4SiO4 and a binary (Li3NaSiO4) eutectic mixture are investigated using density functional theory. The properties of the bulk crystal phases as well as of the relevant surfaces are analysed. Likewise, the results for CO2-lithium silicates indicate that CO2 is strongly adsorbed on the oxygen sites of both sorbents through chemisorption, causing an alteration not only in the chemical structure and atomic charges of the gas, as reflected by both the angles and bond distances as well as atomic charges, but also in the cell parameters of the Li4SiO4 and Li3NaSiO4 systems, especially in Li4SiO4(001) and Li3NaSiO4(010) surfaces. The results confirm strong adsorption of CO2 molecules on all the considered surfaces and materials followed by CO2 activation as inferred from CO2 bending, bond elongation and surface to CO2 charge transfer, indicating CO2 chemisorption for all cases. The Li4SiO4 and Li3NaSiO4 surfaces may be proposed as suitable sorbents for CO2 capture in wide temperature ranges.

Toxicological assessment of nanocrystalline metal alloys with potential applications in the aeronautical field.

The development of new candidate alloys with outstanding characteristics for their use in the aeronautical field is one of the main priorities for the sector. In this context, nanocrystaline (nc) alloys are considered relevant materials due to their special features, such as their exceptional physical and mechanical properties. However, another important point that needs to be considered with newly developed alloys is the potential toxicological impact that these materials may have in humans and other living organisms. The aim of this work was to perform a preliminary toxicological evaluation of three nc metal alloys (WCu, WAl and TiAl) in powder form produced by mechanical alloying, applying different in vitro assays, including a mix of W-Cu powders with standard grain size in the experiments to stablish comparisons. The effects of the direct exposure to powder suspensions and/or to their derived leachates were analysed in three model organisms representative of human and environmental exposures (the adenocarcinomic human alveolar basal epithelial cell line A549, the yeast Saccharomyces cerevisiae and the Gram negative bacterium Vibrio fischeri). Altogether, the results obtained provide new insights about the potential harmful effects of the selected nc alloys, showing that, from a toxicological perspective, nc TiAl is the safest candidate in the model organisms and conditions tested.

Interactive effect of biochar and compost with Poaceae and Fabaceae plants on remediation of total petroleum hydrocarbons in crude oil contaminated soil.

The current study was dedicated to finding the effect of soil amendments (biochar and compost) on plants belonging to Poaceae and Fabaceae families. Plants selected for the phytoremediation experiment included wheat (Triticum aestivum), maize (Zea mays), white clover (Trifolium repens), alfalfa (Medicago sativa), and ryegrass (Lolium multiflorum). The physiological and microbial parameters of plants and soil were affected negatively by the 4 % TPHs soil contamination. The studied physiological parameters were fresh and dried biomass, root and shoot length, and chlorophyll content. Microbial parameters included root and shoot endophytic count. Soil parameters included rhizospheric CFUs and residual TPHs. Biochar with wheat, maize, and ryegrass (Fabaceae family) and compost with white clover and alfalfa (Poaceae family) improved plant growth parameters and showed better phytoremediation of TPHs. Among different plants, the highest TPH removal (68.5 %) was demonstrated by ryegrass with compost, followed by white clover with biochar (68 %). Without any soil amendment, ryegrass and alfalfa showed 59.55 and 35.21 % degradation of TPHs, respectively. Biochar and compost alone removed 27.24 % and 6.01 % TPHs, respectively. The interactive effect of soil amendment and plant type was also noted for studied parameters and TPHs degradation.

Low Toxicological Impact of Commercial Pristine Multi-Walled Carbon Nanotubes on the Yeast Saccharomyces cerevisiae.

Carbon nanotubes (CNTs) have attracted the attention of academy and industry due to their potential applications, being currently produced and commercialized at a mass scale, but their possible impact on different biological systems remains unclear. In the present work, an assessment to understand the toxicity of commercial pristine multi-walled carbon nanotubes (MWCNTs) on the unicellular fungal model Saccharomyces cerevisiae is presented. Firstly, the nanomaterial was physico-chemically characterized, to obtain insights concerning its morphological features and elemental composition. Afterwards, a toxicology assessment was carried out, where it could be observed that cell proliferation was negatively affected only in the presence of 800 mg L-1 for 24 h, while oxidative stress was induced at a lower concentration (160 mg L-1) after a short exposure period (2 h). Finally, to identify possible toxicity pathways induced by the selected MWCNTs, the transcriptome of S. cerevisiae exposed to 160 and 800 mg L-1, for two hours, was studied. In contrast to a previous study, reporting massive transcriptional changes when yeast cells were exposed to graphene nanoplatelets in the same exposure conditions, only a small number of genes (130) showed significant transcriptional changes in the presence of MWCNTs, in the higher concentration tested (800 mg L-1), and most of them were found to be downregulated, indicating a limited biological response of the yeast cells exposed to the selected pristine commercial CNTs.

Processing Optimization and Toxicological Evaluation of "Lead-Free" Piezoceramics: A KNN-Based Case Study.

Due to the ever-increasing limitations of the use of lead-based materials, the manufacturing of lead-free piezoceramics with competitive piezoelectric properties and established nontoxicity is considered a priority for the scientific and industrial community. In this work, a lead-free system based on sodium potassium niobate (KNN), opportunely modified with MgNb2O6 (MN), was prepared through a combination of a mechanochemical activation method and air sintering, and its toxicity was evaluated. The effect of the mechanical processing on the microstructure refinement of the processed powders was established by X-ray diffraction and the average crystallite size content of the Nb2O5 species was evaluated. The experimental evidence was rationalized using a phenomenological model which permitted us to obtain the amount of powder processed at each collision and to optimize the activation step of the pre-calcined reagents. This influenced the final density and piezoresponse of the as-sintered pellets, which showed optimal properties compared with other KNN systems. Their toxicological potential was evaluated through exposure experiments to the pulverized KNN-based pellets, employing two widely used human and environmental cellular models. The in vitro assays proved, under the selected conditions, the absence of cytotoxicity of KNN-bases systems here studied.

Global Transcriptional Response of Aspergillus niger to Blocked Active Citrate Export through Deletion of the Exporter Gene.

Aspergillus niger is the major industrial citrate producer worldwide. Export as well as uptake of citric acid are believed to occur by active, proton-dependent, symport systems. Both are major bottlenecks for industrial citrate production. Therefore, we assessed the consequences of deleting the citT gene encoding the A. niger citrate exporter, effectively blocking active citrate export. We followed the consumption of glucose and citrate as carbon sources, monitored the secretion of organic acids and carried out a thorough transcriptome pathway enrichment analysis. Under controlled cultivation conditions that normally promote citrate secretion, the knock-out strain secreted negligible amounts of citrate. Blocking active citrate export in this way led to a reduced glucose uptake and a reduced expression of high-affinity glucose transporter genes, mstG and mstH. The glyoxylate shunt was strongly activated and an increased expression of the OAH gene was observed, resulting in a more than two-fold higher concentration of oxalate in the medium. Deletion of citT did not affect citrate uptake suggesting that citrate export and citrate uptake are uncoupled from the system.

In vitro safety evaluation of rare earth-lean alloys for permanent magnets manufacturing.

Due to their exceptional physico-chemical and magnetic characteristics, rare earth (RE) permanent magnets are applied in multiple critical technologies. However, several environmental and economic difficulties arising from obtaining RE elements have prompted the search of alternatives with acceptable magnetic properties but containing a lower percentage of these elements in their composition. The aim of this work was to perform a preliminary toxicological evaluation of three forms of newly developed RE-lean alloys (one NdFeTi and two NdFeSi alloys) applying different in vitro assays, using as a benchmark a commercial NdFeB alloy. Thus, the effects of the direct exposure to powder suspensions and to their derived leachates were analysed in two model organisms (the A549 human cell line and the yeast Saccharomyces cerevisiae) applying both viability and oxidative stress assays. Moreover, the impact of the alloy leachates on the bioluminescence of Vibrio fischeri was also investigated. The obtained data showed that only the direct interaction of the alloys particulates with the applied organisms resulted in harmful effects, having all the alloys a comparable toxicological potential to that presented by the reference material in the conditions tested. Altogether, this study provides new insights about the safety of NdFeTi and NdFeSi alloys.

Toxicological assessment of commercial monolayer tungsten disulfide nanomaterials aqueous suspensions using human A549 cells and the model fungus Saccharomyces cerevisiae.

The utilization of tungsten disulfide (WS2) nanomaterials in distinct applications is raising due to their unique physico-chemical properties, such as low friction coefficient and high strength, which highlights the necessity to study their potential toxicological effects, due to the potential increase of environmental and human exposure. The aim of this work was to analyze commercially available aqueous dispersions of monolayer tungsten disulfide (2D WS2) nanomaterials with distinct lateral size employing a portfolio of physico-chemical and toxicological evaluations. The structure and stoichiometry of monolayer tungsten disulfide (WS2-ACS-M) and nano size monolayer tungsten disulfide (WS2-ACS-N) was analyzed by Raman spectroscopy, whereas a more quantitative approach to study the nature of formed oxidized species was undertaken employing X-ray photoelectron spectroscopy. Adenocarcinomic human alveolar basal epithelial cells (A549 cells) and the ecotoxicology model Saccharomyces cerevisiae were selected as unicellular eukaryotic systems to assess the cytotoxicity of the nanomaterials. Cell viability and reactive oxygen species (ROS) determinations demonstrated different toxicity levels depending on the cellular model used. While both 2D WS2 suspensions showed very low toxicity towards the A549 cells, a comparable concentration (160 mg L-1) reduced the viability of yeast cells. The toxicity of a nano size 2D WS2 commercialized in dry form from the same provider was also assessed, showing ability to reduce yeast cells viability as well. Overall, the presented data reveal the physico-chemical properties and the potential toxicity of commercial 2D WS2 aqueous suspensions when interacting with distinct eukaryotic organisms, showing differences in function of the biological system exposed.

Assessment of Physico-Chemical and Toxicological Properties of Commercial 2D Boron Nitride Nanopowder and Nanoplatelets.

Boron nitride (BN) nanomaterials have been increasingly explored for potential applications in chemistry and biology fields (e.g., biomedical, pharmaceutical, and energy industries) due to their unique physico-chemical properties. However, their safe utilization requires a profound knowledge on their potential toxicological and environmental impact. To date, BN nanoparticles have been considered to have a high biocompatibility degree, but in some cases, contradictory results on their potential toxicity have been reported. Therefore, in the present study, we assessed two commercial 2D BN samples, namely BN-nanopowder (BN-PW) and BN-nanoplatelet (BN-PL), with the objective to identify whether distinct physico-chemical features may have an influence on the biological responses of exposed cellular models. Morphological, structural, and composition analyses showed that the most remarkable difference between both commercial samples was the diameter of their disk-like shape, which was of 200-300 nm for BN-PL and 100-150 nm for BN-PW. Their potential toxicity was investigated using adenocarcinomic human alveolar basal epithelial cells (A549 cells) and the unicellular fungus Saccharomycescerevisiae, as human and environmental eukaryotic models respectively, employing in vitro assays. In both cases, cellular viability assays and reactive oxygen species (ROS) determinations where performed. The impact of the selected nanomaterials in the viability of both unicellular models was very low, with only a slight reduction of S. cerevisiae colony forming units being observed after a long exposure period (24 h) to high concentrations (800 mg/L) of both nanomaterials. Similarly, BN-PW and BN-PL showed a low capacity to induce the formation of reactive oxygen species in the studied conditions. Even at the highest concentration and exposure times, no major cytotoxicity indicators were observed in human cells and yeast. The results obtained in the present study provide novel insights into the safety of 2D BN nanomaterials, indicating no significant differences in the toxicological potential of similar commercial products with a distinct lateral size, which showed to be safe products in the concentrations and exposure conditions tested.

Toxicological evaluation of MnAl based permanent magnets using different in vitro models.

Due to economic, environmental and geopolitical issues, the development of permanent magnets with a composition free of rare earth elements and with acceptable magnetic properties has been considered a priority by the international community, being MnAl based alloys amongst the most promising candidates. The aim of this work was to evaluate the toxicity of powders of two forms of newly developed MnAl(C) permanent magnets through exposure experiments applying three model organisms, using as a benchmark powders of a commercial rare-earth-containing magnet (Nd2Fe14B). For this purpose, the direct exposure to the different particles suspensions as well as to magnets leachates was evaluated. Both viability and oxidative stress assays were applied in an adenocarcinomic human alveolar basal epithelial cell line (A549) and in the yeast Saccharomyces cerevisiae, together with the bioluminescent inhibition assay in the Gram negative bacterium Vibrio fischeri. The obtained results indicate that MnAl(C) permanent magnets, in general terms, presented similar toxicity than the Nd magnet for the selected biological models under the studied conditions. Overall, the presented data provide, for the first time, an in vitro toxicity analysis of MnAl based magnets.

Commonalities and Differences in the Transcriptional Response of the Model Fungus Saccharomyces cerevisiae to Different Commercial Graphene Oxide Materials.

Graphene oxide has become a very appealing nanomaterial during the last years for many different applications, but its possible impact in different biological systems remains unclear. Here, an assessment to understand the toxicity of different commercial graphene oxide nanomaterials on the unicellular fungal model organism Saccharomyces cerevisiae was performed. For this task, an RNA purification protocol was optimized to avoid the high nucleic acid absorption capacity of graphene oxide. The developed protocol is based on a sorbitol gradient separation process for the isolation of adequate ribonucleic acid levels (in concentration and purity) from yeast cultures exposed to the carbon derived nanomaterial. To pinpoint potential toxicity mechanisms and pathways, the transcriptome of S. cerevisiae exposed to 160 mg L-1 of monolayer graphene oxide (GO) and graphene oxide nanocolloids (GOC) was studied and compared. Both graphene oxide products induced expression changes in a common group of genes (104), many of them related to iron homeostasis, starvation and stress response, amino acid metabolism and formate catabolism. Also, a high number of genes were only differentially expressed in either GO (236) or GOC (1077) exposures, indicating that different commercial products can induce specific changes in the physiological state of the fungus.