Purification of Quantum Dots by Gel Permeation Chromatography and the Effect of Excess Ligands on Shell Growth and Ligand Exchange

2013 ◽  
Vol 25 (14) ◽  
pp. 2838-2848 ◽  
Author(s):  
Yi Shen ◽  
Megan Y. Gee ◽  
Rui Tan ◽  
Perry J. Pellechia ◽  
Andrew B. Greytak
Keyword(s):  
Quantum Dots ◽  
Ligand Exchange ◽  
Shell Growth ◽  
Gel Permeation Chromatography ◽  
Gel Permeation

SiO2 Beads with Quantum Dots: Synthesis and Bioapplication

2011 ◽  
Vol 306-307 ◽  
pp. 16-19
Author(s):  
Ping Yang ◽  
Norio Murase ◽  
Ai Yu Zhang ◽  
Yong Qiang Cao ◽  
Yuan Na Zhu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Ligand Exchange ◽  
Colloidal Solution ◽  
Phase Transfer ◽  
Shell Growth ◽  
Sol Gel ◽  
High Brightness ◽  
Potential Use ◽  
Poor Solvent

Aqueous CdTe and organic CdSe/ZnS quantum dots (QDs) were encapsulated into SiO2beads using various controlled sol-gel processes. Ligand exchange is a key to adjust the QD number in each bead and get a high photoluminescence (PL). Namely, partial ligand exchange from thioglycolic acid to 3-mercaptopropyotrimethoxysilane (MPS) on the CdTe QDs enables retention of the initial PL efficiency of the QDs in water, while the simultaneous addition of a poor solvent (ethanol) resulted in regulated assembly of the QDs through condensation of hydrolyzed MPS. SiO2beads thus prepared had, for example, a diameter of 17 nm and contained 3 QDs each. The PL efficiency of these beads was 30%, while the initial PL efficiency was 38% in a colloidal solution. In addition, a method including surface silanization, phase transfer and self-assembly, and SiO2shell growth has been developed to incorporate multiple hydrophobic CdSe/ZnS QDs into SiO2beads where they are well suited for bio-application due to their high brightness, less-cytotoxic, and non-blinking nature. To investigate the potential use for labeling in bio-applications, SiO2beads with multiple QDs were conjugated with IgG using streptavidin-maleimide as linkers. This preparation method is an important step towards fabricating intensely emitting biocompatible SiO2beads impregnated with semiconductor QDs.

scholarly journals Gel permeation chromatography as a multifunctional processor for nanocrystal purification and on-column ligand exchange chemistry

2016 ◽  
Vol 7 (9) ◽  
pp. 5671-5679 ◽  
Author(s):  
Yi Shen ◽  
Adam Roberge ◽  
Rui Tan ◽  
Megan Y. Gee ◽  
Dylan C. Gary ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
Continuous Flow ◽  
Flow System ◽  
Gel Permeation Chromatography ◽  
Continuous Flow System ◽  
System P ◽  
Gel Permeation

GPC provides a general approach to purification of a variety of nanocrystal types, and additionally achieves ligand exchange in a continuous flow system.

scholarly journals Simple Cubic Self-Assembly of PbS Quantum Dots by Finely Controlled Ligand Removal through Gel Permeation Chromatography

2021 ◽  
Author(s):  
Jianjun Liu ◽  
Kazushi Enomoto ◽  
Kotaro Takeda ◽  
Daishi Inoue ◽  
Yong-Jin Pu
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Optoelectronic Devices ◽  
Gel Permeation Chromatography ◽  
Optoelectronic Properties ◽  
Colloidal Quantum Dots ◽  
Critical Importance ◽  
Simple Cubic ◽  
Gel Permeation ◽  
Pbs Quantum Dots

The geometry in self-assembled superlattices of colloidal quantum dots (QDs) strongly affects their optoelectronic properties and is thus of critical importance for applications in optoelectronic devices. Here, we achieve the...

Aggregated, Conformationally Changed Fibrinogen Exposes the Stimulating Sites for t-PA-Catalysed Plasminogen Activation

1996 ◽  
Vol 75 (02) ◽  
pp. 326-331 ◽  
Author(s):  
Unni Haddeland ◽  
Knut Sletten ◽  
Anne Bennick ◽  
Willem Nieuwenhuizen ◽  
Frank Brosstad
Keyword(s):  
Conformational Changes ◽  
Gel Permeation Chromatography ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Chromogenic Substrate ◽  
Type Plasminogen Activator ◽  
Gel Permeation ◽  
Self Association ◽  
Fibrin Monomers ◽  
Stimulation Of

SummaryThe present paper shows that conformationally changed fibrinogen can expose the sites Aα-(148-160) and γ-(312-324) involved in stimulation of the tissue-type plasminogen activator (t-PA)-catalysed plasminogen activation. The exposure of the stimulating sites was determined by ELISA using mABs directed to these sites, and was shown to coincide with stimulation of t-PA-catalysed plasminogen activation as assessed in an assay using a chromogenic substrate for plasmin. Gel permeation chromatography of fibrinogen conformationally changed by heat (46.5° C for 25 min) demonstrated the presence of both aggregated and monomeric fibrinogen. The aggregated fibrinogen, but not the monomeric fibrinogen, had exposed the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation. Fibrinogen subjected to heat in the presence of 3 mM of the tetrapeptide GPRP neither aggregates nor exposes the rate-enhancing sites. Thus, aggregation and exposure of t-PA-stimulating sites in fibrinogen seem to be related phenomena, and it is tempting to believe that the exposure of stimulating sites is a consequence of the conformational changes that occur during aggregation, or self-association. Fibrin monomers kept in a monomeric state by a final GPRP concentration of 3 mM do not expose the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation, whereas dilution of GPRP to a concentration that is no longer anti-polymerizing, results in exposure of these sites. Consequently, the exposure of t-PA-stimulating sites in fibrin as well is due to the conformational changes that occur during selfassociation.

Gel Permeation Chromatography of Polyelectrolytes

1981 ◽  
Vol 4 (8) ◽  
pp. 1297-1309 ◽  
Author(s):  
M. Rinaudo ◽  
J. Desbrières ◽  
C. Rochas
Keyword(s):  
Gel Permeation Chromatography ◽  
Gel Permeation
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