Hydroxylated Quantum Dots as Luminescent Probes for in Situ Hybridization

Pathak, Srikant; Choi, Subin; Arnheim, Norman; Thompson, Mark E.

doi:10.1021/ja0058334

Cited by 595 publications

(405 citation statements)

References 29 publications

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“…12 Hydroxylated QDs were prepared with 1,1′-carbonyl diimidazole (CDI) for linkage to DNA and used in fluorescence in situ hybridization (FISH) experiments with human sperm cells. 15 The viability of QD bioconjugates for medical and biological applications is becoming well established, and their popularity is increasing in turn. Importantly, recent findings of acute toxicity in hepatocytes by CdSe without surface coatings highlights the need to properly condition the surface to be biocompatible and nontoxic.…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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

et al. 2006

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“…Antibody sensitized NCs were prepared according to the procedure of Thompson and co-workers [27]. The NC were functionalized with carboxyl groups by suspending 6.0 mg of the NC in 600 L of 11-mercaptoundecanoic acid (0.1 M in 4:1, v/v ethanol:water), and mixing for 30 min.…”

Section: Preparation Of the Nanocrystals Bioconjugatesmentioning

confidence: 99%

Electrochemical immunosensor for multiplexed detection of food-borne pathogens using nanocrystal bioconjugates and MWCNT screen-printed electrode

Subramanian

Rani²,

2012

Talanta

154

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a b s t r a c tBacterial food poisoning is an ever-present threat that can be prevented with proper care and handling of food products. A disposable electrochemical immunosensor for the simultaneous measurements of common food pathogenic bacteria namely Escherichia coli O157:H7 (E. coli), campylobacter and salmonella were developed. The immunosensor was fabricated by immobilizing the mixture of anti-E. coli, anticampylobacter and anti-salmonella antibodies with a ratio of 1:1:1 on the surface of the multiwall carbon nanotube-polyallylamine modified screen printed electrode (MWCNT-PAH/SPE). Bacteria suspension became attached to the immobilized antibodies when the immunosensor was incubated in liquid samples. The sandwich immunoassay was performed with three antibodies conjugated with specific nanocrystal (␣-E. coli-CdS, ␣-campylobacter-PbS and ␣-salmonella-CuS) which has releasable metal ions for electrochemical measurements. The square wave anodic stripping voltammetry (SWASV) was employed to measure released metal ions from bound antibody nanocrystal conjugates. The calibration curves for three selected bacteria were found in the range of 1 × 10 3 -5 × 10 5 cells mL −1 with the limit of detection (LOD) 400 cells mL −1 for salmonella, 400 cells mL −1 for campylobacter and 800 cells mL −1 for E. coli. The precision and sensitivity of this method show the feasibility of multiplexed determination of bacteria in milk samples.

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“…After annealing overnight, the excess selenium/cadmium precursor was removed by centrifugation, and the CdSe cores were kept in a mixture of toluene, butanol, and hexane. To protect the core from oxidation and improve quantum yield, the cores were then overcoated with multiple ZnS layers (3)(4)(5). During the shell synthesis, CdSe cores were added into the degassed ligand mixture (TOPO and HPA) where solvent was removed by a liquid nitrogen solvent trap,…”

Section: Cdse-zns Quantum Dot Synthesismentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8] Despite many reported methods for their preparation, biocompatible QDs have been limited in these applications largely due to the shortcomings of surface ligands that confer solubility in water. The dispersion of QDs in water can be driven by either electrostatic stabilization through capping exchange with small charged ligands [1][2][3][4][5][6] or steric stabilization through coating with polymers. [7][8][9][10] Small ligands containing mono or bidentate thiol species have been used extensively to endow QDs with watersolubility.…”

Section: Introductionmentioning

confidence: 99%

Mixed-surface, lipid-tethered quantum dots for targeting cells and tissues

Zhang

Haage

Whitley

et al. 2012

Colloids and Surfaces B: Biointerfaces

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Quantum dots (QDs), with their variable luminescent properties, are rapidly transcending traditional labeling techniques in biological imaging and hold vast potential for biosensing applications. An obstacle in any biosensor development is targeted specificity. Here we report a facile procedure for creating QDs targeted to the cell membrane with the goal of cell-surface protease biosensing. This procedure generates water-soluble QDs with variable coverage of lipid functional groups. The resulting hydrophobicity is quantitatively controlled by the molar ratio of lipids per QD. Appropriate tuning of the hydrophobicity ensures solubility in common aqueous cell culture media and while providing affinity to the lipid bilayer of cell membranes. The reaction and exchange process was directly evaluated by measuring UV-vis absorption spectra associated with dithiocarbamate formation. Cell membrane binding was assessed using flow cytometry and total internal reflection fluorescence imaging with live cells, and tissue affinity was measured using histochemical staining and fluorescence imaging of frozen tissue sections. Increases in cell and tissue binding were found to be regulated by both QD hydrophobicity and surface charge, underlying the importance of QD surface properties in the optimization of both luminescence and targeting capability. the hydrophobicity ensures solubility in common aqueous cell culture media and while providing affinity to the lipid bilayer of cell membranes. The reaction and exchange process was directly evaluated by measuring UV-vis absorption spectra associated with dithiocarbamate formation. Cell membrane binding was assessed using flow cytometry and total internal reflection fluorescence imaging with live cells, and tissue affinity was measured using histochemical staining and fluorescence imaging of frozen tissue sections. Increases in cell and tissue binding were found to be regulated by both QD hydrophobicity and surface charge, underlying the importance of QD surface properties in the optimization of both luminescence and targeting capability. Mixed-surface, Lipid-tethered Quantum Dots for Targeting Cells and Tissues

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Hydroxylated Quantum Dots as Luminescent Probes for in Situ Hybridization

Cited by 595 publications

References 29 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

Electrochemical immunosensor for multiplexed detection of food-borne pathogens using nanocrystal bioconjugates and MWCNT screen-printed electrode

Mixed-surface, lipid-tethered quantum dots for targeting cells and tissues

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