scholarly journals Dependence of Graphene Oxide (GO) Toxicity on Oxidation Level, Elemental Composition, and Size

2021 ◽  
Vol 22 (19) ◽  
pp. 10578
Author(s):  
Tao Jiang ◽  
Carlo Alberto Amadei ◽  
Yishan Lin ◽  
Na Gou ◽  
Sheikh Mokhlesur Rahman ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Elemental Composition ◽  
Toxicity Testing ◽  
Yeast Cells ◽  
Public Concern ◽  
Main Mode ◽  
Oxidation Level ◽  
Physicochemical Factors ◽  
Toxicity Level ◽  
Toxicity Pathways

The mass production of graphene oxide (GO) unavoidably elevates the chance of human exposure, as well as the possibility of release into the environment with high stability, raising public concern as to its potential toxicological risks and the implications for humans and ecosystems. Therefore, a thorough assessment of GO toxicity, including its potential reliance on key physicochemical factors, which is lacking in the literature, is of high significance and importance. In this study, GO toxicity, and its dependence on oxidation level, elemental composition, and size, were comprehensively assessed. A newly established quantitative toxicogenomic-based toxicity testing approach, combined with conventional phenotypic bioassays, were employed. The toxicogenomic assay utilized a GFP-fused yeast reporter library covering key cellular toxicity pathways. The results reveal that, indeed, the elemental composition and size do exert impacts on GO toxicity, while the oxidation level exhibits no significant effects. The UV-treated GO, with significantly higher carbon-carbon groups and carboxyl groups, showed a higher toxicity level, especially in the protein and chemical stress categories. With the decrease in size, the toxicity level of the sonicated GOs tended to increase. It is proposed that the covering and subsequent internalization of GO sheets might be the main mode of action in yeast cells.

scholarly journals Temperature and volatile organic compound concentrations as controlling factors for chemical composition of <i>α</i>-pinene-derived secondary organic aerosol

2021 ◽  
Vol 21 (15) ◽  
pp. 11545-11562
Author(s):  
Louise N. Jensen ◽  
Manjula R. Canagaratna ◽  
Kasper Kristensen ◽  
Lauriane L. J. Quéléver ◽  
Bernadette Rosati ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Organic Compound ◽  
Organic Acids ◽  
Organic Acid ◽  
Elemental Composition ◽  
Volatile Organic Compound ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Oxidation Level ◽  
Volatile Organic

Abstract. This work investigates the individual and combined effects of temperature and volatile organic compound precursor concentrations on the chemical composition of particles formed in the dark ozonolysis of α-pinene. All experiments were conducted in a 5 m3 Teflon chamber at an initial ozone concentration of 100 ppb and initial α-pinene concentrations of 10 and 50 ppb, respectively; at constant temperatures of 20, 0, or −15 ∘C; and at changing temperatures (ramps) from −15 to 20 and from 20 to −15 ∘C. The chemical composition of the particles was probed using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). A four-factor solution of a positive matrix factorization (PMF) analysis of the combined HR-ToF-AMS data is presented. The PMF analysis and the elemental composition analysis of individual experiments show that secondary organic aerosol particles with the highest oxidation level are formed from the lowest initial α-pinene concentration (10 ppb) and at the highest temperature (20 ∘C). A higher initial α-pinene concentration (50 ppb) and/or lower temperature (0 or −15 ∘C) results in a lower oxidation level of the molecules contained in the particles. With respect to the carbon oxidation state, particles formed at 0 ∘C are more comparable to particles formed at −15 ∘C than to those formed at 20 ∘C. A remarkable observation is that changes in temperature during particle formation result in only minor changes in the elemental composition of the particles. Thus, the temperature at which aerosol particle formation is induced seems to be a critical parameter for the particle elemental composition. Comparison of the HR-ToF-AMS-derived estimates of the content of organic acids in the particles based on m/z 44 in the mass spectra show good agreement with results from off-line molecular analysis of particle filter samples collected from the same experiments. Higher temperatures are associated with a decrease in the absolute mass concentrations of organic acids (R-COOH) and organic acid functionalities (-COOH), while the organic acid functionalities account for an increasing fraction of the measured particle mass.

scholarly journals Temperature and VOC concentration as controlling factors for chemical composition of alpha-pinene derived secondary organic aerosol

2020 ◽  
Author(s):  
Louise N. Jensen ◽  
Manjula R. Canagaratna ◽  
Kasper Kristensen ◽  
Lauriane L. J. Quéléver ◽  
Bernadette Rosati ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Organic Acids ◽  
Organic Acid ◽  
Elemental Composition ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Particle Formation ◽  
Composition Analysis ◽  
Oxidation Level ◽  
The Individual

Abstract. This work investigates the individual and combined effects of temperature and volatile organic compound precursor concentration on the chemical composition of particles formed in the dark ozonolysis of α-pinene. All experiments were conducted in a 5 m3 Teflon chamber at an initial ozone concentration of 100 ppb and α-pinene concentrations of 10 ppb and 50 ppb, respectively, at constant temperatures of 20 °C, 0 °C, or −15 °C, and at changing temperatures (ramps) from −15 °C to 20 °C and from 20 °C to −15 °C. The chemical composition of the particles was probed using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). A four-factor solution of a Positive Matrix Factorization (PMF) analysis of combined HR-ToF-AMS data from experiments conducted under different conditions is presented. The PMF analysis as well as elemental composition analysis of individual experiments show that secondary organic aerosol particles with the highest oxidation level are formed from the lowest initial α-pinene concentration (10 ppb) and at the highest temperature (20 °C). Higher initial α-pinene concentration (50 ppb) and/or lower temperature (0 °C or −15 °C) result in lower oxidation level of the molecules contained in the particles. With respect to carbon oxidation state, particles formed at 0 °C are more comparable to particles formed at −15 °C than to those formed at 20 °C. A remarkable observation is that changes in temperature during or after particle formation result in only minor changes in the elemental composition of the particles. The temperature at which aerosol particle formation is initiated thus seems to be a critical parameter for the particle elemental composition. Comparison of the AMS derived estimates of the content of organic acids in the particles based on m/z 44 in the spectra show good agreement with results from off-line molecular analysis of particle filter samples collected from the same experiments. While higher temperatures are associated with a decrease in the absolute mass concentrations of organic acids (R-COOH) and organic acid functionalities (-COOH), the organic acid functionalities account for an increasing fraction of the measured SOA mass at higher temperatures.

scholarly journals Influence of Oxidation Level of Graphene Oxide on the Mechanical Performance and Photo-Oxidation Resistance of a Polyamide 6

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 857 ◽  
Author(s):  
Roberto Scaffaro ◽  
Andrea Maio
Keyword(s):  
Graphene Oxide ◽  
Mechanical Performance ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Polyamide 6 ◽  
Uv Exposure ◽  
Mechanical Reinforcement ◽  
Photo Oxidation ◽  
Oxidation Level ◽  
Two Samples

The aim of this work is to study the relationship between the chemical-physical properties of graphene oxide (GO) and the performance of a polyamide 6 (PA6) in terms of mechanical reinforcement and resistance to UV-exposure. For this purpose, two samples of GO possessing different oxidation degrees were added (0.75 wt.%) to PA6 by way of a two-step technique and the materials achieved were carefully analysed from a morphological, chemical-physical, mechanical point of view. Photo-oxidation tests were carried out to assess the performance of this class of nanohybrids after 240 h of UV-exposure. The results reveal that both nanocomposites exhibit enhanced mechanical performance and durability of PA6. However, the most oxidized GO led to a higher increase of mechanical properties and a stronger resistance to UV-exposure. All the analyses confirm that both GO samples are well dispersed and covalently attached to PA6. However, the higher the oxidation level of GO the stronger and the more extended the chemical interphase of the nanocomposite. As regards photochemical stability, both GO samples display UV-shielding capacity but the most oxidized GO also shows radical scavenging activity by virtue of its nanocavities and defects, imparted by prolonged oxidation, which endows PA6 with an outstanding durability even after 240 h of UV-exposure.

scholarly journals Interfacing Living Yeast Cells with Graphene Oxide Nanosheaths

2011 ◽  
Vol 12 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Sung Ho Yang ◽  
Taemin Lee ◽  
Eunyong Seo ◽  
Eun Hyea Ko ◽  
Insung S. Choi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Yeast Cells

Control of the oxidation level of graphene oxide for high efficiency polymer solar cells

RSC Advances ◽  
2015 ◽  
Vol 5 (61) ◽  
pp. 49182-49187 ◽  
Author(s):  
Rui Wu ◽  
Ying Wang ◽  
Lie Chen ◽  
Liqiang Huang ◽  
Yiwang Chen
Keyword(s):  
Graphene Oxide ◽  
Solar Cells ◽  
High Efficiency ◽  
Polymer Solar Cells ◽  
Oxidation Level

Achieving high efficiency polymer solar cells by controlling the oxidation level of graphene oxide.

scholarly journals Linear control of the oxidation level on graphene oxide sheets using the cyclic atomic layer reduction technique

Nanoscale ◽  
2019 ◽  
Vol 11 (16) ◽  
pp. 7833-7838 ◽  
Author(s):  
Bikash Chandra Mallick ◽  
Chien-Te Hsieh ◽  
Ken-Ming Yin ◽  
Jianlin Li ◽  
Yasser Ashraf Gandomi
Keyword(s):  
Graphene Oxide ◽  
Atomic Layer ◽  
Reduction Technique ◽  
Linear Control ◽  
Precise Control ◽  
Oxidation Level ◽  
Graphene Oxide Sheets

Precise control of the oxidation level on graphene oxide (GO) sheets is still a big challenge.

scholarly journals Effect of the Albumin Corona on the Toxicity of Combined Graphene Oxide and Cadmium to Daphnia magna and Integration of the Datasets into the NanoCommons Knowledge Base

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1936 ◽  
Author(s):  
Diego Stéfani T. Martinez ◽  
Gabriela H. Da Silva ◽  
Aline Maria Z. de Medeiros ◽  
Latif U. Khan ◽  
Anastasios G. Papadiamantis ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Acute Toxicity ◽  
Knowledge Base ◽  
Daphnia Magna ◽  
Colloidal Stability ◽  
Cadmium Toxicity ◽  
Toxicity Testing ◽  
Mixture Toxicity ◽  
Water Quality Monitoring ◽  
Corona Formation

In this work, we evaluated the effect of protein corona formation on graphene oxide (GO) mixture toxicity testing (i.e., co-exposure) using the Daphnia magna model and assessing acute toxicity determined as immobilisation. Cadmium (Cd2+) and bovine serum albumin (BSA) were selected as co-pollutant and protein model system, respectively. Albumin corona formation on GO dramatically increased its colloidal stability (ca. 60%) and Cd2+ adsorption capacity (ca. 4.5 times) in reconstituted water (Daphnia medium). The acute toxicity values (48 h-EC50) observed were 0.18 mg L−1 for Cd2+-only and 0.29 and 0.61 mg L−1 following co-exposure of Cd2+ with GO and BSA@GO materials, respectively, at a fixed non-toxic concentration of 1.0 mg L−1. After coronation of GO with BSA, a reduction in cadmium toxicity of 110 % and 238% was achieved when compared to bare GO and Cd2+-only, respectively. Integration of datasets associated with graphene-based materials, heavy metals and mixture toxicity is essential to enable re-use of the data and facilitate nanoinformatics approaches for design of safer nanomaterials for water quality monitoring and remediation technologies. Hence, all data from this work were annotated and integrated into the NanoCommons Knowledge Base, connecting the experimental data to nanoinformatics platforms under the FAIR data principles and making them interoperable with similar datasets.

Immobilised yeast cells biosensor for total toxicity testing

1995 ◽  
Vol 171 (1-3) ◽  
pp. 227-234 ◽  
Author(s):  
L. Campanella ◽  
G. Favero ◽  
M. Tomassetti
Keyword(s):  
Toxicity Testing ◽  
Yeast Cells ◽  
Immobilised Yeast
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