Thiol-Capping of CdTe Nanocrystals:  An Alternative to Organometallic Synthetic Routes

Gaponik, Nikolai; Talapin, Dmitri V.; Rogach, Andrey L.; Hoppe, Kathrin; Shevchenko, Elena V.; Kornowski, Andreas; Eychmüller, Alexander; Weller, Horst

doi:10.1021/jp025541k

Cited by 1,499 publications

(1,547 citation statements)

References 61 publications

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“…7 It is also possible to narrow the size distributions using size-selective precipitation for as-synthesized aqueous QDs. 36 The use of basified dialysis during the ligand exchange process has dual benefits in that excess reactive precursors (TGA, Cd 2+ ) are removed, and it advances the priming of MPS onto the QD surface.…”

Section: Discussionmentioning

confidence: 99%

“…Thioglycolic-acidcapped CdTe nanoparticles were synthesized in the standard fashion from the literature. 7 Briefly, 0.985 g Cd(ClO 4 ) 2 ‚6H 2 O was dissolved in 125 mL of Milli-Q water, and 388.9 µL (5.7 mmol) of pure TGA was added. Dropwise addition of 1 N NaOH was then used to adjust the pH to 11.2-11.8 under vigorous stirring.…”

Section: Methodsmentioning

confidence: 99%

“…27 Water-soluble CdTe nanoparticles can be synthesized with many stabilizing agents such as TGA, mercaptoethylamine (MA), thioglycerol, and Lcysteine. 7 The quasi-shell of Cd-S on the surface is dynamic and is very sensitive to changes in pH and buffer solutions; both are prime disadvantages in performing conjugation of biomolecules. We found that as-prepared CdTe nanoparticles lose their highly fluorescent properties in the presence of common buffers such as phosphate-buffered saline (PBS) and Tris-borate-ethylenediaminetetraacetate (TBE).…”

Section: Introductionmentioning

confidence: 99%

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Silica-Coated CdTe Quantum Dots Functionalized with Thiols for Bioconjugation to IgG Proteins

et al. 2006

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Quantum dots (QDs) have been increasingly used in biolabeling recently as their advantages over molecular fluorophores have become clear. For bioapplications QDs must be water-soluble and buffer stable, making their synthesis challenging and time-consuming. A simple aqueous synthesis of silica-capped, highly fluorescent CdTe quantum dots has been developed. CdTe QDs are advantageous as the emission can be tuned to the near-infrared where tissue absorption is at a minimum, while the silica shell can prevent the leakage of toxic Cd 2+ and provide a surface for easy conjugation to biomolecules such as proteins. The presence of a silica shell of 2-5 nm in thickness has been confirmed by transmission electron microscopy and atomic force microscopy measurements. Photoluminescence studies show that the silica shell results in greatly increased photostability in Tris-borate-ethylenediaminetetraacetate and phosphate-buffered saline buffers. To further improve their biocompatibility, the silica-capped QDs have been functionalized with poly(ethylene glycol) and thiol-terminated biolinkers. Through the use of these linkers, antibody proteins were successfully conjugated as confirmed by agarose gel electrophoresis. Streptavidin-maleimide and biotinylated polystyrene microbeads confirmed the bioactivity and conjugation specificity of the thiolated QDs. These functionalized, silica-capped QDs are ideal labels, easily synthesized, robust, safe, and readily conjugated to biomolecules while maintaining bioactivity. They are potentially useful for a number of applications in biolabeling and imaging.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Silica-Coated CdTe Quantum Dots Functionalized with Thiols for Bioconjugation to IgG Proteins

et al. 2006

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“…For example, CdTe QDs were synthesized by a chemical aerosol flow approach [34]. Organic phase synthesis routes with hydrophobic capping agents were also used to synthesize CdTe QDs [35][36].…”

Section: Biophotonicsmentioning

confidence: 99%

Aqueous phase synthesis of CdTe quantum dots for biophotonics

Yong

Law

Roy

et al. 2010

Journal of Biophotonics

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Over the past few years, CdTe quantum dots have been demonstrated as powerful probes for biophotonics applications. The aqueous phase synthesis technique remains the best approach to make high quality CdTe QDs in a single‐pot process. CdTe QDs prepared directly in the aqueous phase can have quantum yield as high as 80%. In addition, the surface of CdTe QDs prepared using the aqueous phase technique is functionalized with reactive groups that enable them to be directly conjugated with specific ligands for targeted delivery and sensing. In this contribution, we review recent progress in fabricating aqueous CdTe QDs and exploiting their optical properties in novel approaches to biomedical imaging and sensing applications. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Surface functionalized nanoparticles can be attached to larger particles 22 or modified to suit a particular environment or application. Three different approaches have been used to obtain water-soluble semiconductor QDs: ligand-exchange 23,24 , encapsulation into a water-soluble shell (e.g., silica 25 or phospholipids 26 ) and arrested precipitation in water 27,28 .…”

Section: Introductionmentioning

confidence: 99%

Determination of Silver Ion with Cadmium Sulfide Quantum Dots Modified by Bismuthiol II as Fluorescence Probe

et al. 2006

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Summary -CdS quantum dots (QDs) modified with bismuthiol II potassium salt is prepared in one step. Based on the characteristic fluorescence enhancement of CdS QDs at 480 nm by silver ions, simultaneously, a red shift of fluorescence emission bands of CdS QDs from 460 to 480 nm is observed. A simple, rapid, sensitive and specific detection method for silver ion is proposed. Under optimum conditions, the fluorescence intensity of CdS QDs was linearly proportional to silver ion concentration from 0.01 to 5.0 µmol L -1 with a detection limit of 1.6 nmol L -1 . In comparison with single organic fluorophores, functionalized CdS quantum dots are brighter, more stable against photobleaching and do not suffer from blinking. Furthermore, the proposed method shows higher sensitivity and selectivity. A possible fluorescence enhancement mechanism is also studied.

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Thiol-Capping of CdTe Nanocrystals: An Alternative to Organometallic Synthetic Routes

Cited by 1,499 publications

References 61 publications

Silica-Coated CdTe Quantum Dots Functionalized with Thiols for Bioconjugation to IgG Proteins

Silica-Coated CdTe Quantum Dots Functionalized with Thiols for Bioconjugation to IgG Proteins

Aqueous phase synthesis of CdTe quantum dots for biophotonics

Determination of Silver Ion with Cadmium Sulfide Quantum Dots Modified by Bismuthiol II as Fluorescence Probe

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