Journal article
Uptake, translocation, and transformation of quantum dots with cationic versus anionic coatings by Populus deltoides × nigra cuttings
Environmental science & technology, Vol.48(12), pp.6754-6762
06/17/2014
DOI: 10.1021/es501425r
PMID: 24870363
Abstract
Manipulation of the organic coatings of nanoparticles such as quantum dots (QDs) to enhance specific applications may also affect their interaction and uptake by different organisms. In this study, poplar trees (Populus deltoides × nigra) were exposed hydroponically to 50-nM CdSe/CdZnS QDs coated with cationic polyethylenimine (PEI) (35.3 ± 6.6 nm) or poly(ethylene glycol) of anionic poly(acrylic acid) (PAA-EG) (19.5 ± 7.2 nm) to discern how coating charge affects nanoparticle uptake, translocation, and transformation within woody plants. Uptake of cationic PEI-QDs was 10 times faster despite their larger hydrodynamic size and higher extent of aggregation (17 times larger than PAA-EG-QDs after 11-day incubation in the hydroponic medium), possibly due to electrostatic attraction to the negatively charged root cell wall. QDs cores aggregated upon root uptake, and their translocation to poplar shoots (negligible for PAA-EG-QDs and 0.7 ng Cd/mg stem for PEI-QDs) was likely limited by the endodermis. After 2-day exposure, PEI and PAA-EG coatings were likely degraded from the internalized QDs inside the plant, leading to the aggregation of the metallic cores and a "red-shift" of fluorescence. The fluorescence of PEI-QD aggregates was stable inside the roots through the 11-day exposure period. In contrast, the PAA-EG-QD aggregates lost fluorescence inside the plant after 11 days probably due to destabilization of the coating, even though these QDs were stable in the hydroponic solution. Overall, these results highlight the importance of coating properties in the rate and extent to which nanoparticles are assimilated by plants and potentially introduced into food webs.
Details
- Title: Subtitle
- Uptake, translocation, and transformation of quantum dots with cationic versus anionic coatings by Populus deltoides × nigra cuttings
- Creators
- Jing Wang - Department of Civil & Environmental Engineering, ‡Department of Chemistry, and §Department of Biochemistry & Cell Biology, Rice University , Houston, Texas 77005, United StatesYu YangHuiguang ZhuJanet BraamJerald L SchnoorPedro J J Alvarez
- Resource Type
- Journal article
- Publication Details
- Environmental science & technology, Vol.48(12), pp.6754-6762
- Publisher
- United States
- DOI
- 10.1021/es501425r
- PMID
- 24870363
- ISSN
- 0013-936X
- eISSN
- 1520-5851
- Language
- English
- Date published
- 06/17/2014
- Academic Unit
- Civil and Environmental Engineering; Occupational and Environmental Health
- Record Identifier
- 9983992089202771
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