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- Shambetova, Nestan, et al.
(författare)
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Acid Dissociation of 3-Mercaptopropionic Acid Coated CdSe-CdS/Cd0.5Zn0.5S/ZnS Core-Multishell Quantum Dot and Strong Ionic Interaction with Ca2+ Ion
- 2016
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:6, s. 3519-3529
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Tidskriftsartikel (refereegranskat)abstract
- By devising careful electrophoresis, it was shown that at pH below 7.0, the electrophoretic mobility of 3-mercaptopropionic acid (3MPA) coated CdSe-ZnS core-shell quantum dots (denoted as QD-3MPA) was very small. At pH above 7.0, QD-3MPA migrated toward the anode, implying acid dissociation, and the degree of which was proportional to the pH value. QD-3MPA's electrophoretic mobility was impaired after adding sufficient Ca2+ ions to the QD solution and revived when a similar amount of Ca2+ chelators (ethylene glycol tetraacetic acid, EGTA) was added. This demonstrated that acid dissociation and its pH dependence of 3MPA on the QD surface are critical factors in understanding the electric and optical properties of QDs. The acid dissociated QD-3MPA interacted strongly with Ca2+, forming a charge neutral QD-3MPA Ca2+ complex in the absence of EGTA. First-principles study confirmed the observed experimental evidence. The strong ionic interaction between acid dissociated QD-3MPA and Ca2+ is critical for developing reliable QD-based biosensing assays. Moreover, the strategy and techniques reported in this work are easily applicable to other fluorescent biomarkers and therefore can be important for advancing in vivo and in vitro imaging, sensing, and labeling.
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| 3. |
- Turdalieva, Aizat, et al.
(författare)
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Bioelectric and Morphological Response of Liquid-Covered Human Airway Epithelial Calu-3 Cell Monolayer to Periodic Deposition of Colloidal 3-Mercaptopropionic-Acid Coated CdSe-CdS/ZnS Core-Multishell Quantum Dots
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Lung epithelial cells are extensively exposed to nanoparticles present in the modern urban environment. Nanoparticles, including colloidal quantum dots (QDs), are also considered to be potentially useful carriers for the delivery of drugs into the body. It is therefore important to understand the ways of distribution and the effects of the various types of nanoparticles in the lung epithelium. We use a model system of liquid-covered human airway epithelial Calu-3 cell cultures to study the immediate and long-term effects of repeated deposition of colloidal 3-mercaptopropionic-acid coated CdSe-CdS/ZnS core-multishell QDs on the lung epithelial cell surface. By live confocal microscope imaging and by QD fluorescence measurements we show that the QD permeation through the mature epithelial monolayers is very limited. At the time of QD deposition, the transepithelial electrical resistance (TEER) of the epithelial monolayers transiently decreased, with the decrement being proportional to the QD dose. Repeated QD deposition, once every six days for two months, lead to accumulation of only small amounts of the QDs in the cell monolayer. However, it did not induce any noticeable changes in the long-term TEER and the molecular morphology of the cells. The colloidal 3-mercaptopropionic-acid coated CdSe-CdS/ZnS core-multishell QDs could therefore be potentially used for the delivery of drugs intended for the surface of the lung epithelia during limited treatment periods.
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