Aggregation of titanium dioxide nanoparticles: role of calcium and phosphate

Domingos, Rute F.; Peyrot, Caroline; Wilkinson, Kevin J.

doi:10.1071/en09110

Cited by 74 publications

(47 citation statements)

References 35 publications

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“…In order to ensure that the exposure conditions elicited a response while minimizing secondary effects and lethality, conditions were selected by considering prior reports of their toxicological effects for nAg (31), nTiO 2 (1), nZnO (32), and QDs (33). The physicochemical properties and effects of the NPs change following their aggregation (17,34), dissolution (12,20,70), or coating with biological substances (e.g., proteins [35]), since these parameters affect the interfacial properties, including the rates of surface-mediated reactions, dissolution, redox reactions, and generation of ROS (36). Therefore, the sizes of the NPs were quantified in the exposure medium (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Transcriptome Sequencing (RNA-seq) Analysis of the Effects of Metal Nanoparticle Exposure on the Transcriptome of Chlamydomonas reinhardtii

Simon

Domingos

Hauser

et al. 2013

Appl Environ Microbiol

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117

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The widespread use of nanoparticles (NPs) raises concern over their potential toxicological effects in humans and ecosystems. Here we used transcriptome sequencing (RNA-seq) to evaluate the effects of exposure to four different metal-based NPs, nano-Ag (nAg), nano-TiO 2 (nTiO 2 ), nano-ZnO (nZnO), and CdTe/CdS quantum dots (QDs), in the eukaryotic green alga Chlamydomonas reinhardtii. The transcriptome was characterized before and after exposure to each NP type. Specific toxicological effects were inferred from the functions of genes whose transcripts either increased or decreased. Data analysis resulted in important differences and also similarities among the NPs. Elevated levels of transcripts of several marker genes for stress were observed, suggesting that only nZnO caused nonspecific global stress to the cells under environmentally relevant conditions. Genes with photosynthesis-related functions were decreased drastically during exposure to nTiO 2 and slightly during exposures to the other NP types. This pattern suggests either toxicological effects in the chloroplast or effects that mimic a transition from low to high light. nAg exposure dramatically elevated the levels of transcripts encoding known or predicted components of the cell wall and the flagella, suggesting that it damages structures exposed to the external milieu. Exposures to nTiO 2 , nZnO, and QDs elevated the levels of transcripts encoding subunits of the proteasome, suggesting proteasome inhibition, a phenomenon believed to underlie the development and progression of several major diseases, including Alzheimer's disease, and used in chemotherapy against multiple myeloma. N anoparticles (NPs) are materials with at least one dimension in the nanoscale (ca. 1 to 100 nm), with resulting size-related physicochemical properties that differ from those of their bulk counterparts. Specifically, their high surface-to-volume ratio generally results in highly reactive and physicochemically dynamic materials. With the increasing use of engineered NPs, there is an enormous uncertainty with respect to their potential environmental impacts, including their toxicological effects. Of special concern is the emerging evidence that numerous NPs can produce reactive oxygen species (ROS), release toxic metals, or react directly with the biological membrane (1, 2). A major key question is whether toxicological effects are due to general properties shared by diverse NP types or whether they are specific to each NP. For example, if toxicological effects are related to the size, shape, or agglomeration of the NP, then different NP compositions would likely exert similar effects (3), whereas distinct toxicological effects would be expected if particle composition controls the interaction with the biological surface (4, 5). An understanding of the toxicological effects of each NP type is critical for any prediction of their immediate and long-term risks for humans and ecosystems.A powerful approach to determine how an organism responds to a particular abiotic condition...

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Section: Resultsmentioning

confidence: 99%

Transcriptome Sequencing (RNA-seq) Analysis of the Effects of Metal Nanoparticle Exposure on the Transcriptome of Chlamydomonas reinhardtii

Simon

Domingos

Hauser

et al. 2013

Appl Environ Microbiol

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117

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“…Although NOM generally stabilizes against aggregation, it a can also enhance it by bridging flocculation, which occurs when there are free sites for interaction on the particle surface. This generally occurs at low NOM concentrations (Domingos et al, 2010). This indicates that depending on adsorption of any stabilizing agent to TiO 2 or CeO 2 (NOM or manmade) prior to release to the aquatic environment, the NOM present there can also stabilize against heteroaggregation.…”

Section: Sedimentationmentioning

confidence: 99%

A Review of the Properties and Processes Determining the Fate of Engineered Nanomaterials in the Aquatic Environment

Peijnenburg

Baalousha

Chen

et al. 2015

Critical Reviews in Environmental Science and Technology

177

103

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“…In FCS, more polydisperse systems can also be examined using a minor component analysis, which focuses on the tail of the particle size distributions. [37] Although these data are necessarily less accurate owing the smaller numbers of analysed particles, analysis indicated that a small proportion of the nanoparticles (,5 %) was significantly larger in the presence of both the SiO 2 (blue squares, Fig. 3b) and the colloidal clay (red diamonds, Fig.…”

Section: Heteroagglomeration Of the Nag-citmentioning

confidence: 99%

Heteroagglomeration of nanosilver with colloidal SiO2 and clay

et al. 2017

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Environmental context. The fate of nanomaterials in the environment is related to their colloidal stability. Although numerous studies have examined their homoagglomeration, their low concentration and the presence of high concentrations of natural particles implies that heteroagglomeration rather than homoagglomeration is likely to occur under natural conditions. In this paper, two state-of-the art analytical techniques were used to identify the conditions under which nanosilver was most likely to form heteroagglomerates in natural waters.Abstract. The environmental risk of nanomaterials will depend on their persistence, mobility, toxicity and bioaccumulation. Each of these parameters is related to their fate (especially dissolution, agglomeration). The goal of this paper was to understand the heteroagglomeration of silver nanoparticles in natural waters. Two small silver nanoparticles (nAg, ,3 nm; polyacrylic acid-and citrate-stabilised) were covalently labelled with a fluorescent dye and then mixed with colloidal silicon oxides (SiO 2 , ,18.5 nm) or clays (,550 nm SWy-2 montmorillonite). Homo-and heteroagglomeration of the nAg were first studied in controlled synthetic waters that were representative of natural fresh waters (50 mg Ag L À1 ; pH 7.0; ionic strength 10 À7 to 10 À1 M Ca) by following the sizes of the nAg by fluorescence correlation spectroscopy. The polyacrylic acid-coated nanosilver was extremely stable under all conditions, including in the presence of other colloids and at high ionic strengths. However, the citrate-coated nanosilver formed heteroaggregates in presence of both colloidal SiO 2 and clay particles. Nanoparticle surface properties appeared to play a key role in controlling the physicochemical stability of the nAg. For example, the polyacrylic acid stabilized nAg-remained extremely stable in the water column, even under conditions for which surrounding colloidal particles were agglomerating. Finally, enhanced dark-field microscopy was then used to further characterise the heteroagglomeration of a citrate-coated nAg with suspensions of colloidal clay, colloidal SiO 2 or natural (river) water.

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Aggregation of titanium dioxide nanoparticles: role of calcium and phosphate

Cited by 74 publications

References 35 publications

Transcriptome Sequencing (RNA-seq) Analysis of the Effects of Metal Nanoparticle Exposure on the Transcriptome of Chlamydomonas reinhardtii

Transcriptome Sequencing (RNA-seq) Analysis of the Effects of Metal Nanoparticle Exposure on the Transcriptome of Chlamydomonas reinhardtii

A Review of the Properties and Processes Determining the Fate of Engineered Nanomaterials in the Aquatic Environment

Heteroagglomeration of nanosilver with colloidal SiO2 and clay

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