Colloidal stability and aggregation kinetics of nanocrystal CdSe/ZnS quantum dots in aqueous systems: effects of pH and organic ligands

The aggregation kinetics of C60 nanoparticles have been investigated over a wide range of monovalent and divalent electrolyte concentrations by employing time-resolved dynamic light scattering (DLS). The results showed that the presence of electrolyte made a dramatic decrease in the surface zeta potential and increase in the particle size. The aggregation kinetics of C60 nanoparticles exhibited reaction-limited and diffusion-limited regimes, which was found to be consistent with the classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. The critical coagulation concentration (CCC) values of C60 nanoparticles were estimated as 321mM Na+, 295mM K+, 9.6mM Ca2+and 6.7mM Mg2+, which were far higher than the electrolyte concentrations in natural water. The enhanced C60 stability in the presence of humic acid was attributable to steric repulsion. Therefore C60 nanoparticles can be relatively stable in typical aquatic environments.

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Aggregation Kinetics and Self-Assembly Mechanisms of Graphene Quantum Dots in Aqueous Solutions: Cooperative Effects of pH and Electrolytes

Environmental Science & Technology ◽

10.1021/acs.est.6b04178 ◽

2017 ◽

Vol 51 (3) ◽

pp. 1364-1376 ◽

Cited By ~ 45

Author(s):

Qingqing Li ◽

Baoliang Chen ◽

Baoshan Xing

Keyword(s):

Quantum Dots ◽

Aqueous Solutions ◽

Self Assembly ◽

Graphene Quantum Dots ◽

Aggregation Kinetics ◽

Cooperative Effects ◽

Effects Of Ph

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Effect of pH and inhibitors on beta-amyloid fibril assembly

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166221 ◽

1996 ◽

Vol 54 ◽

pp. 752-753

Author(s):

Beverly E. Maleeff ◽

Timothy K. Hart ◽

Stephen J. Wood ◽

Ronald Wetzel

Keyword(s):

Amyloid Fibril ◽

Peptide Fragment ◽

Hydrophobic Peptides ◽

Amyloid Fibril Formation ◽

Effects Of Ph ◽

Severity Of The Disease ◽

Kinetics Of ◽

The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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Functional Fractionation of Platelets: Aggregation Kinetics and Glycoprotein Labeling of Differing Platelet Populations

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657259 ◽

1982 ◽

Vol 48 (02) ◽

pp. 211-216 ◽

Cited By ~ 12

Author(s):

V M Haver ◽

A R L Gear

Keyword(s):

Galactose Oxidase ◽

Aggregation Kinetics ◽

Maximal Rate ◽

Membrane Glycoproteins ◽

Whole Cells ◽

Reversible Aggregation ◽

Significant Difference ◽

Small Doses ◽

Major Loss ◽

Kinetics Of

SummaryPlatelet heterogeneity has been studied with a technique called functional fractionation which employs gentle centrifugation to yield subpopulations (“reactive” and “less-reactive” platelets) after exposure to small doses of aggregating agent. Aggregation kinetics of the different platelet populations were investigated by quenched-flow aggregometry. The large, “reactive” platelets were more sensitive to ADP (Ka = 1.74 μM) than the smaller “less-reactive” platelets (Ka = 4.08 μM). However, their maximal rate of aggregation (Vmax, % of platelets aggregating per sec) of 23.3 was significantly lower than the “less-reactive” platelets (Vmax = 34.7). The “reactive” platelets had a 2.2 fold higher level of cyclic AMP.Platelet glycoproteins were labeled using the neuraminidase-galactose oxidase – [H3]-NaBH4 technique. When platelets were labeled after reversible aggregation, the “reactive” platelets showed a two-fold decrease in labeling efficiency (versus control platelets). However, examination of whole cells or membrane preparations from reversibly aggregated platelets revealed no significant difference in Coomassie or PAS (Schiff) staining.These results suggest that the large, “reactive” platelets are more sensitive to ADP but are not hyperaggregable in a kinetic sense. Reversible aggregation may cause a re-orientation of membrane glycoproteins that is apparently not characterized by a major loss of glycoprotein material.

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Surface Organic Ligands-Passivated Quantum Dots: Toward High-Performance Light-Emitting Diodes with Long Lifetime

Journal of Materials Chemistry C ◽

10.1039/d0tc05391k ◽

2021 ◽

Author(s):

Lishuang Wang ◽

Ying Lv ◽

Jie Lin ◽

Jialong Zhao ◽

Xingyuan Liu ◽

...

Keyword(s):

Quantum Dots ◽

High Performance ◽

Light Emitting Diodes ◽

Organic Ligands ◽

Colloidal Quantum Dots ◽

Core Shell ◽

Light Emitting ◽

Long Lifetime

For quantum dots light-emitting diodes (QLEDs), typical colloidal quantum dots (QDs) are usually composed of a core/shell heterostructure which is covered with organic ligands as surface passivated materials to confine...

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Shear-induced reaction-limited aggregation kinetics of Brownian particles at arbitrary concentrations

The Journal of Chemical Physics ◽

10.1063/1.3361665 ◽

2010 ◽

Vol 132 (13) ◽

pp. 134903 ◽

Cited By ~ 33

Author(s):

Alessio Zaccone ◽

Daniele Gentili ◽

Massimo Morbidelli

Keyword(s):

Aggregation Kinetics ◽

Brownian Particles ◽

Kinetics Of ◽

Induced Reaction

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