Interaction Analysis of Commercial Graphene Oxide Nanoparticles with Unicellular Systems and Biomolecules

Abstract

The ability of commercial monolayer graphene oxide (GO) and graphene oxide nanocolloids (GOC) to interact with different unicellular systems and biomolecules was studied by analyzing the response of human alveolar carcinoma epithelial cells, the yeast Saccharomyces cerevisiae and the bacteria Vibrio fischeri to the presence of different nanoparticle concentrations, and by studying the binding affinity of different microbial enzymes, like the α-l-rhamnosidase enzyme RhaB1 from the bacteria Lactobacillus plantarum and the AbG β-d-glucosidase from Agrobacterium sp. (strain ATCC 21400). An analysis of cytotoxicity on human epithelial cell line A549, S. cerevisiae (colony forming units, ROS induction, genotoxicity) and V. fischeri (luminescence inhibition) cells determined the potential of both nanoparticle types to damage the selected unicellular systems. Also, the protein binding affinity of the graphene derivatives at different oxidation levels was analyzed. The reported results highlight the variability that can exist in terms of toxicological potential and binding affinity depending on the target organism or protein and the selected nanomaterial.

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

“…The transcriptional changes in genes associated to low nutrient availability in the presence of GO and GOC could be related to the capacity of these nanomaterials to adsorb biomolecules and ions, lowering their availability for biological systems. On one hand, the high protein adsorption capacity of GO and GOC has been recently described, which could have an impact on nitrogen availability in yeast cells (Antón-Millán et al, 2018;Domi et al, 2019). Also, iron sequestration by graphene oxide in yeast growth medium was previously described in a similar study were S. cerevisiae cells were exposed to a non-commercial sample of the nanomaterial (Yu et al, 2017).…”

“…Overall, any of the differences observed between both nanomaterial types, as well as other non-identified factors, could be responsible for the distinct toxicological response displayed by the cellular systems used as toxicity models at viability, vitality and oxidative stress levels. In case of S. cerevisiae, GO showed a higher capacity than GOC to induce oxidative stress, while differences observed in viability after the exposure to both nanomaterials were not significant (Domi et al, 2019). The study of the global transcriptional response of S. cerevisiae cells to the presence of each nanoproduct could provide additional insights into the common and/or product-specific molecular mechanisms behind their toxicity inducing factors.…”

“…To assess the impact of commercial graphene oxide products, GO and GOC, on S. cerevisiae cells, a comparative transcriptomics analysis was done. In a previous study, we characterized both nanomaterials and observed differences in their composition and their oxidative stress inducing capacity in yeast, although it was challenging to associate their toxicological potential to their physico-chemical characteristics due to the many different variables that could be involved, such as lateral dimension, surface structure, functional groups, purity and protein corona (Domi et al, 2019). GO and GOC showed a wide lateral size distribution (from the nanometric to the micrometric scale), with a flake thickness of 1-2 nm.…”

“…With this purpose, we decided to expose yeast cells to GO and GOC for 24 h and to study their global transcriptional signature. Concentrations of GO and GOC (160 mg L −1 ) were selected based on ranges used in similar studies assessing the toxicological impact of graphene derivatives in different organisms including fungi (Domi et al, 2019;Suarez-Diez et al, 2020), and specifically the works of Yu et al (2017) and Zhu et al (2017), that analyze the impact of graphene oxides, similar to the ones here studied. Yeast cells total RNA was isolated as described in the previous section and it was analyzed using the Illumina sequencing system (further details can be found in the "Materials and Methods" section).…”

“…This feature allows its use in the efficient removal of potentially toxic elements from contaminated aqueous media, but it could also impact nutrient bioavailability for the organisms present in a certain environment. Additionally, previous studies have reported that distinct graphene oxide products can have different reactivity against biological systems and biomolecules, possibly due to differences in their elemental composition or in morphological features (Antón-Millán et al, 2018;Li et al, 2018;Domi et al, 2019). Therefore, to assess whether different commercial graphene oxide products could induce different toxicity responses in S. cerevisiae, two graphene derivatives: monolayer graphene oxide (GO) and graphene oxide nanocolloids (GOC) were selected and the global transcriptional response of the yeast was compared.…”