Mitigation Effects and Associated Mechanisms of Environmentally Relevant Thiols on the Phytotoxicity of Molybdenum Disulfide Nanosheets

Abstract

Thorough investigations of the environmental fate and risks are necessary for the safe application of engineered nanomaterials. Nevertheless, the current understanding of potential transformations of MoS2 (an intensively studied two-dimensional nanosheet) upon interactions with ubiquitous environmentally relevant thiols (ERTs) in water is limited. This study revealed that two ERTs, l-cysteine and mercaptoacetic acid, could modify MoS2 by covalently grafting thiol groups on S atoms of 1T phases, improving the colloidal persistence and chemical stability of MoS2. Compared with the pristine form, MoS2–thiols with higher dispersity exhibited significantly mitigated envelopment and ultrastructural damage to microalgae. MoS2-triggered growth inhibition, upregulation of reactive oxygen species, photosynthetic injury, and metabolic perturbation in algae were remarkably attenuated by ERTs. The diminished capability for MoS2 to generate reactive intermediates and glutathione oxidation driven by ERTs caused the weakness of oxidative stress and negative effects. Additionally, molecular dynamics simulations demonstrated that ERTs altered the extent of the influence of MoS2 on the secondary structures and functions of adsorbed intracellular proteins, which also contributed to the lower phytotoxicity of MoS2. Our findings provide evidence for the crucial role of specific organic ligands in the risk of MoS2 in aquatic environments.

Earthworm Coelomocyte Internalization of MoS2 Nanosheets: Multiplexed Imaging, Molecular Profiling, and Computational Modeling

“…Protein structural changes are an important factor affecting overall function . Given this, we attempted to further mechanistically characterize the interaction processes of different Mo forms with key proteins involved in cellular uptake.…”

“…Protein structural changes are an important factor affecting overall function. 55 Given this, we attempted to further mechanistically character-ize the interaction processes of different Mo forms with key proteins involved in cellular uptake. Through high-throughput proteomics, we identified DNM1_3, SORL1, and VPS4 as key functional proteins impacted by exposure to P-NSMoS 2 , V-NSMoS 2 , and molybdate, respectively (abundances are shown in Figure S14, sequence match >80%) responsible for cytoskeleton organization, transport, and ion binding, respectively.…”

Mechanistic Insights into the Biodegradation of Carbon Dots by Fungal Laccase

“…Despite the ubiquitous secretion of laccase by plants and soil microorganisms, much remains unknown about their potential catalytic roles in the transformation of CNMs including CDs. These processes may alter the physicochemical properties of CDs, thereby affecting their subsequent uptake, translocation, and phytotoxicity in plants. , Nevertheless, quantification of CDs in vivo remains a challenge because plant tissues have high background carbon levels that obstruct the high-precision quantification of CDs in biological samples.…”

“…These processes may alter the physicochemical properties of CDs, thereby affecting their subsequent uptake, translocation, and phytotoxicity in plants. 25,26 Nevertheless, quantification of CDs in vivo remains a challenge because plant tissues have high background carbon levels that obstruct the high-precision quantification of CDs in biological samples.…”