Hydrophilic CdSe-ZnS Core-Shell Quantum Dots with Reactive Functional Groups on Their Surface

Ibrahim Yildiz, Erhan Deniz, Bridgeen Callan, Stuart F. Cruickshank, John Callan, Francisco M. Raymo

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

We synthesized macromolecular ligands for CdSe-ZnS core-shell quantum dots incorporating multiple thiol groups, poly(ethylene glycol) chains, and either carboxylic acids or primary amines along a common poly(methacrylate) backbone. The thiol groups encourage the adsorption of these macromolecular constructs on the ZnS shell of the nanoparticles, and the poly(ethylene glycol) chains impose hydrophilic character on the resulting assemblies. Indeed, the coated quantum dots are readily soluble in water and are stable under these conditions for months over a broad pH range (4.0-12.0) and even in the presence of large salt concentrations. In addition, these nanoparticles have relatively small hydrodynamic diameters (17-30 nm) and good quantum yields (0.3-0.4). Furthermore, the pendant carboxylic acids or primary amines of the macromolecular ligands can be exploited to modify the quantum dots after the adsorption of the polymers on their surface. For example, boron dipyrromethene dyes can be connected to the hydrophilic quantum dots on the basis of amide bond formation to encourage the transfer of energy from the luminescent CdSe core to the organic dyes. Our hydrophilic nanoparticles can also cross the membrane of Chinese hamster ovarian cells and accumulate in the cytosol with limited nuclear localization. Moreover, the internalized quantum dots are not cytotoxic and have essentially no influence on cell viability. Thus, our strategy for the preparation of biocompatible quantum dots can evolve into the development of valuable luminescent probes with nanoscaled dimensions and optimal photophysical properties for a diversity of biomedical applications.
LanguageEnglish
Pages11503-11511
JournalLangmuir
Volume26
Issue number13
DOIs
Publication statusPublished - Jul 2010

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Functional groups
Semiconductor quantum dots
Carboxylic Acids
Nanoparticles
Sulfhydryl Compounds
Polyethylene glycols
Amines
Coloring Agents
Ligands
Adsorption
Boron
Methacrylates
Quantum yield
Amides
Polymers
Hydrodynamics
Salts
Cells
Membranes
Water

Cite this

Yildiz, Ibrahim ; Deniz, Erhan ; Callan, Bridgeen ; Cruickshank, Stuart F. ; Callan, John ; Raymo, Francisco M. / Hydrophilic CdSe-ZnS Core-Shell Quantum Dots with Reactive Functional Groups on Their Surface. In: Langmuir. 2010 ; Vol. 26, No. 13. pp. 11503-11511.
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Hydrophilic CdSe-ZnS Core-Shell Quantum Dots with Reactive Functional Groups on Their Surface. / Yildiz, Ibrahim; Deniz, Erhan; Callan, Bridgeen; Cruickshank, Stuart F.; Callan, John; Raymo, Francisco M.

In: Langmuir, Vol. 26, No. 13, 07.2010, p. 11503-11511.

Research output: Contribution to journalArticle

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