Aggregation Control of Quantum Dots through Ion-Mediated Hydrogen Bonding Shielding

Li, Jianbo; Yang, Xiaohai; Wang, Kemin; He, Xiaoxiao; Wang, Qing; Huang, Jin; Liu, Yan

doi:10.1021/nn300517k

Cited by 42 publications

(31 citation statements)

References 59 publications

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“…In agreement with TEM results, the hydrodynamic diameters of as-obtained colloidal nanoparticles are 6.5 nm, which indicates that the dispersed QDs turned out to be individual monomeric state. The larger diameter in the DLS data is due to the outmost hydration layer which increases the diameter of colloidal nanoparticles34.…”

Section: Resultsmentioning

confidence: 99%

Ultrasensitive Quantum Dot Fluorescence quenching Assay for Selective Detection of Mercury Ions in Drinking Water

Zhao

et al. 2014

Sci Rep

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Mercury is one of the most acutely toxic substances at trace level to human health and living thing. Developing a rapid, cheap and water soluble metal sensor for detecting mercury ions at ppb level remains a challenge. Herein, a metal sensor consisting of MPA coated Mn doped ZnSe/ZnS colloidal nanoparticles was utilized to ultrasensitively and selectively detect Hg2+ ions with a low detection limit (0.1 nM) over a dynamic range from 0 to 20 nM. According to strong interaction between thiol(s) and mercury ions, mercaptopropionic acid (MPA) was used as a highly unique acceptor for mercury ions in the as-obtained ultrasensitive sensor. In the presence of mercury ions, colloidal nanoparticles rapidly agglomerated due to changes of surface chemical properties, which results in severe quenching of fluorescent intensity. Meanwhile, we find that the original ligands are separated from the surface of colloidal nanoparticles involving strongly chelation between mercury ion and thiol(s) proved by controlled IR analysis. The result shows that the QD-based metal ions sensor possesses satisfactory precision, high sensitivity and selectivity, and could be applied for the quantification analysis of real samples.

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Section: Resultsmentioning

confidence: 99%

Ultrasensitive Quantum Dot Fluorescence quenching Assay for Selective Detection of Mercury Ions in Drinking Water

Zhao

et al. 2014

Sci Rep

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“…Their sizes were greater than separate QD particles (about 6 nm), and they lose the ability to produce fluorescence signals (Liu et al 2012). One reason for the formation of large particles could be that a part of the original aqueous QD suspension had started to form aggregates, which has been observed and reported previously (Noh et al 2010).…”

Section: Sem Characterizationmentioning

confidence: 69%

Surface Modification of Cellulose Paper for Quantum Dot-based Sensing Applications

Guan¹,

Tian²,

Cao³

et al. 2015

BioResources

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Cellulose paper specimens with and without surface modification were compared in order to study their physicochemical compatibility with quantum dots (QDs) for biochemical sensing applications. Silane and chitosan modification methods were applied. The distribution of QDs deposited on untreated paper and papers modified with silane and chitosan were investigated in order to understand the interaction between QDs and fibre. Modified papers were shown to significantly reduce the undesirable redistribution of QDs during paper drying. The retention ability and thermal resistance of QDs to the loss of fluorescence on modified papers were also studied for the purpose of determining the most suitable paper surface modification for developing QD-Paper-based analytical devices (QD-PADs). Furthermore, chitosan-modified paper was used to design QD-PADs to quantify glucose concentration in aqueous samples; the quenching effect of the enzymatic product on the fluorescent emission of QDs was used as the indicator system. The change of fluorescence of QDs was measured by a simple in-house constructed fluorescence imaging system. The detection limit of glucose was 5 mg/dL, which is comparable with other reported paper sensors for detection of glucose.

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“…36 As shown in Figure 4B, there were plenty of fluorescent spot on the cell dish. 36 As shown in Figure 4B, there were plenty of fluorescent spot on the cell dish.…”

Section: µMmentioning

confidence: 93%

A recognition-before-labeling strategy for sensitive detection of lung cancer cells with a quantum dot–aptamer complex

Liu

Zhang

et al. 2015

Analyst

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A highly specific recognition-before-labeling strategy has been developed for sensitive detection of non-small cell lung cancer A549 cells, by using fluorescent QDs as signal units and DNA aptamers as recognition elements. A QD-aptamer system used for cell imaging and bioanalysis mostly relies on the recognition-after-labeling strategy in which aptamers were firstly labeled with QDs and then the QD-aptamer conjugates as a whole were utilized for specific recognition. Here in our strategy, aptamers were used firstly to recognize target cells, and then fluorescent QDs were sequentially added to bind the aptamers and light the target cells. The proposed recognition-before-labeling strategy didn't require the complex process of QD functionalization, and avoided the possible impact on the aptamer configuration from steric hindrance. Meanwhile, QDs, with strong fluorescence and good photostability, also give this method a high signal-to-background ratio (S/B). The recognition-before-labeling strategy is simple and sensitive, suggesting a new method for in vitro diagnostic assays of cancer cells.

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Aggregation Control of Quantum Dots through Ion-Mediated Hydrogen Bonding Shielding

Cited by 42 publications

References 59 publications

Ultrasensitive Quantum Dot Fluorescence quenching Assay for Selective Detection of Mercury Ions in Drinking Water

Ultrasensitive Quantum Dot Fluorescence quenching Assay for Selective Detection of Mercury Ions in Drinking Water

Surface Modification of Cellulose Paper for Quantum Dot-based Sensing Applications

A recognition-before-labeling strategy for sensitive detection of lung cancer cells with a quantum dot–aptamer complex

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