Displacement reactions between environmentally and biologically relevant ligands on TiO2 nanoparticles: insights into the aging of nanoparticles in the environment

Wu, Haixin; Gonzalez‐Pech, Natalia I.; Grassian, Vicki H.

doi:10.1039/c8en00780b

Cited by 21 publications

(28 citation statements)

References 83 publications

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“…However, rinsing with pure water left the majority of the adsorbed molecules at the surface (Figure 2). Similar observations are reported in the literature, e.g., humic acid remains adsorbed on TiO 2 NPs upon interaction with proteins (bovine serum albumin) [34].…”

Section: Trophic Level 3: Crucian Carpsupporting

confidence: 90%

Transfer of Cobalt Nanoparticles in a Simplified Food Web: From Algae to Zooplankton to Fish

et al. 2021

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Cobalt (Co) nanoparticles (NPs) may be diffusely dispersed into natural ecosystems from various anthropogenic sources such as traffic settings and eventually end up in aquatic systems. As environmentally dispersed Co NPs may be transferred through an aquatic food web, this study investigated this transfer from algae (Scendesmus sp.) to zooplankton (Daphnia magna) to fish (Crucian carp, Carassius carassius). Effects of interactions between naturally excreted biomolecules from D. magna and Co NPs were investigated from an environmental fate perspective. ATR-FTIR measurements showed the adsorption of both algae constituents and excreted biomolecules onto the Co NPs. Less than 5% of the Co NPs formed heteroagglomerates with algae, partly an effect of both agglomeration and settling of the Co NPs. The presence of excreted biomolecules in the solution did not affect the extent of heteroagglomeration. Despite the low extent of heteroagglomeration between Co NPs and algae, the Co NPs were transferred to the next trophic level (D. magna). The Co uptake in D. magna was 300 times larger than the control samples (without Co NP), which were not influenced by the addition of excreted biomolecules to the solution. Significant uptake of Co was observed in the intestine of the fish feeding on D. magna containing Co NPs. No bioaccumulation of Co was observed in the fish. Moreover, 10–20% of the transferred Co NP mass was dissolved after 24 h in the simulated gut solution of the zooplankton (pH 7), and 50–60% was dissolved in the simulated gut solution of the fish (pH 4). The results elucidate that Co NPs gain different properties upon trophic transfer in the food web. Risk assessments should hence be conducted on transformed and weathered NPs rather than on pristine particles.

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Section: Trophic Level 3: Crucian Carpsupporting

confidence: 90%

Transfer of Cobalt Nanoparticles in a Simplified Food Web: From Algae to Zooplankton to Fish

et al. 2021

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“…This phenomenon can be explained by the Vroman effect . Similarly, it has been shown that different environmental species are able to adsorb and displace others on the surface of 20 nm TiO 2 NMs, where humic acid adsorbs tightly to NM surfaces to form part of the eco‐corona while smaller acidic molecules such as ascorbic and citric acid bind weakly and can easily be displaced by humic acid . Interestingly humic acid does not displace the protein bovine serum albumin (BSA) but both are able to co‐adsorb onto TiO 2 NM surfaces so that binding affinity to NM surfaces is dependent on the different functional groups interacting .…”

Section: The Eco‐coronamentioning

confidence: 99%

“…Similarly, it has been shown that different environmental species are able to adsorb and displace others on the surface of 20 nm TiO 2 NMs, where humic acid adsorbs tightly to NM surfaces to form part of the eco‐corona while smaller acidic molecules such as ascorbic and citric acid bind weakly and can easily be displaced by humic acid . Interestingly humic acid does not displace the protein bovine serum albumin (BSA) but both are able to co‐adsorb onto TiO 2 NM surfaces so that binding affinity to NM surfaces is dependent on the different functional groups interacting . The most abundant biomolecules in aquatic environments are NOM (with > 10 mg of C per L); polysaccharides which are usually deposited into fresh waters from fallen tree leaves and vegetation; and proteins which comprise 24–49% of TOC (from 158 mg L −1 ), each of which has a high propensity to bind to NMs and influence their toxicity.…”

Section: The Eco‐coronamentioning

confidence: 99%

“…Recently, it has been shown that NMs with a stabilizing shell of polyethylene glycol (PEG), which usually remains monodisperse in the short term, agglomerate when incubated in vivo as measured by the aggregation index (the ratio of the absorbance at 620 nm to the absorbance at 520 nm) and by DLS in their corresponding media, indicating the exchange of biological mater with polymer molecules originally present at the surface of the NMs. It has also been shown that humic acid strongly adsorbs to 20 nm TiO 2 surfaces and easily displaces smaller acidic molecules such as citrate, which were originally used as a capping for the NMs but are much more weakly bound …”

Section: Effect Of "Eco‐corona" On Nm Toxicity To D Magnamentioning

confidence: 99%

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Nanomaterials in the Environment Acquire an “Eco‐Corona” Impacting their Toxicity to Daphnia Magna—a Call for Updating Toxicity Testing Policies

2019

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Nanomaterials (NMs) are particles with at least one dimension between 1 and 100 nm and a large surface area to volume ratio, providing them with exceptional qualities that are exploited in a variety of industrial fields. Deposition of NMs into environmental waters during or after use leads to the adsorption of an ecological (eco-) corona, whereby a layer of natural biomolecules coats the NM changing its stability, identity and ultimately toxicity. The eco-corona is not currently incorporated into ecotoxicity tests, although it has been shown to alter the interactions of NMs with organisms such as Daphnia magna (D. magna). Here, the literature on environmental biomolecule interactions with NMs is synthesized and a framework for understanding the eco-corona composition and its role in modulating NMs ecotoxicity is presented, utilizing D. magna as a model. The importance of including biomolecules as part of the current international efforts to update the standard testing protocols for NMs, is highlighted. Facilitating the formation of an eco-corona prior to NMs ecotoxicity testing will ensure that signaling pathways perturbed by the NMs are real rather than being associated with the damage arising from reactive NM surfaces "acquiring" a corona by pulling biomolecules from the organism's surface.novel and unique qualities that are not traditionally exhibited by bulk material of the same composition. NMs have been at the core of novel research for two decades and are incorporated into products spanning a range of industrial fields. For example, NMs properties are exploited in cancer research, such as the utilization of surface plasmon resonance properties of gold (Au) NMs; here the NMs are conjugated to antibodies complementary to antigens on cancer cells and are thereby internalized, following which oscillation of the Au electron cloud at a specific wavelength of light converts the absorbed light into localized heat to specifically destroy cancer cells. [1] Another example is exploitation of the antimicrobial properties of silver (Ag) NMs which undergo high dissolution to release Ag + ions [2] and where the dissolution site, rate (and thus toxicity) can be adjusted depending on the surface coating. [3] Considering that NMs are becoming so widely used, their release into the environment is inevitable. Despite this, considerably less research has focused on the implications of NMs on environmental organisms, especially under realistic conditions, than on development of their applications. NMs may enter freshwater systems from industrial effluent, where, for example, the concentrations of zinc oxide (ZnO) NMs, widely used in sunscreens and paints, in river waters has been found to be as high as 150 ng L −1 , [4] while gold (Au) NMs excreted following use in medical applications into surface waters have been predicted to be 470 pg L −1 [5] With deposition of NMs into environmental waters increasing, concerns regarding the potential for toxicity posed by NMs have demanded action, although the standard testing approaches h...

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“…The application of advanced characterization methods (SEC and QTOF MS) enabled fundamental insights into the role of the adsorbed NOM (as opposed to bulk NOM) and mechanisms for the substrate to influence NOM adsorption to the TiO2, as well as the influence of the NOM on the DEET byproduct formation pathways. As a number of biomolecules, such as proteins and amino acids, can also adsorb to TiO2, [48][49][50][51][52][53] the generalizability of the results for NOM to other coatings or the influence of the substrate on competitive adsorption processes 27,52 can also be interesting to investigate in future studies.…”

Section: Discussionmentioning

confidence: 99%

DEET Degradation by Titanium Dioxide–Zeolite Nanocomposites: Effects of Aggregation State, Water Chemistry, and Natural Organic Matter

Berté¹,

Chen²,

Mathew³

et al. 2020

Preprint

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Immobilization of titanium dioxide nanoparticles (TiO2 NPs) facilitates their removal and reuse in water treatment applications. Composite materials of electrostatically-bound TiO2 NPs and zeolite particles have been proposed, but limited mechanistic studies are available on their performance in complex media. This study delineates the relative importance of homo- and heteroaggregation, water chemistry, and surface fouling by natural organic matter (NOM) on the photocatalytic degradation of diethyltoluamide (DEET) by TiO2-zeolite composites. Zeolite adsorbs a portion of the DEET, rendering it unavailable for degradation; corrections for this adsorption depletion allowed appropriate comparison of the reactivity of the composites to the NPs alone. The TiO2-zeolite composites showed enhanced DEET degradation in moderately hard water (MHW) compared to deionized water (DIW), likely attributable to the influence of HCO3−, whereas a net decline in reactivity was observed for the TiO2 NPs alone upon homoaggregation in MHW. The composites also better maintained reactivity in the presence of NOM in MHW, as removal of Ca2+ onto the zeolite mitigated fouling of the TiO2 surface by NOM. However, NOM induced partial dissociation of the composites. DEET byproduct formation, identified by quadrupole–time of flight (QTOF) mass spectrometry, was generally unaffected by the zeolite, while NOM fouling favored de-ethylation over hydroxylation products. Overall, the most significant factor influencing TiO2 reactivity toward DEET was NOM adsorption, followed by homoaggregation, electrolytes (here, MHW versus DIW), and heteroaggregation. These findings can inform a better understanding of NP reactivity in engineered water treatment applications.

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Displacement reactions between environmentally and biologically relevant ligands on TiO₂ nanoparticles: insights into the aging of nanoparticles in the environment

Abstract: Coatings on nanoparticle (NP) surfaces play a key role in dictating their behavior in the environment.

Cited by 21 publications

References 83 publications

Transfer of Cobalt Nanoparticles in a Simplified Food Web: From Algae to Zooplankton to Fish

Transfer of Cobalt Nanoparticles in a Simplified Food Web: From Algae to Zooplankton to Fish

Nanomaterials in the Environment Acquire an “Eco‐Corona” Impacting their Toxicity to Daphnia Magna—a Call for Updating Toxicity Testing Policies

DEET Degradation by Titanium Dioxide–Zeolite Nanocomposites: Effects of Aggregation State, Water Chemistry, and Natural Organic Matter

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