Redesign of hydrophobic quantum dots mitigates ligand-dependent toxicity in the nematode C. elegans

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https://www.sciencedirect.com/science/article/pii/S2452074821000276?via%3Dihub

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https://doi.org/10.1016/j.impact.2021.100318
 http://hdl.handle.net/11603/24756

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UMBC Chemistry & Biochemistry Department
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https://orcid.org/0000-0002-6314-2052
 https://orcid.org/0000-0001-6098-3932

Date

2021-04

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journal articles
postprints
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Citation of Original Publication

Niemuth, NicholasJ et al. Redesign of hydrophobic quantum dots mitigates ligand-dependent toxicity in the nematode C. elegans. NanoImpact 22, (April 2021) no. 100318. https://doi.org/10.1016/j.impact.2021.100318

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Access to this item begins on 04/01/2023

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Abstract

Surface properties of engineered nanomaterials (ENMs) have been shown to influence their interaction with biological systems. However, studies to date have largely focused on hydrophilic materials, likely due to biocompatibility concerns and aqueous exposure conditions necessary for many model systems. Therefore, a knowledge gap exists in nanotoxicity literature for impacts of hydrophobic ENMs, with studies of hydrophobic materials largely limited to carbon ENMs. Here we demonstrate testing of hydrophobic quantum dots (QDs) using the nematode C. elegans, a model soil organism cultured on solid media and amenable to hydrophobic exposures. To evaluate the influence of hydrophobicity, we compared CdSe/ZnS QDs functionalized with hydrophobic trioctylphosphine oxide (TOPO) to identical QDs functionalized with hydrophilic dihydrolipoic acid-polyethylene glycol (DHLA-PEG) and alternative hydrophobic CdSe/ZnS QDs functionalized with oleic acid (OA). Results show that hydrophobic TOPO QDs are significantly more toxic than hydrophilic DHLA-PEG QDs, and substitution of TOPO with OA yields relatively non-toxic hydrophobic QDs. Fluorescence microscopy shows TOPO QDs loosely associated with the organism's cuticle, but atomic force microscopy shows no difference in cuticle structure from exposure. Importantly, TOPO ligand alone is as toxic as TOPO QDs, and our data suggests that TOPO may impact neuromuscular function, perhaps upon displacement from the QD surface. This study demonstrates the importance of examining ligand-specific impacts of hydrophobic ENMs and indicates OA-functionalized QDs as a potential alternative to TOPO QDs for reduced toxicity.