Comparison of Oligo(ethylene glycol)alkanethiols versus <i>n</i>-Alkanethiols: Self-Assembly, Insertion, and Functionalization

Shuster, Mitchell J.; Vaish, Amit; Gilbert, Megan L.; Martinez-Rivera, Michelle; Nezarati, Roya M.; Weiss, Paul S.; Andrews, Anne M.

doi:10.1021/jp207396m

Cited by 15 publications

(27 citation statements)

References 88 publications

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“…Ideally, conjugation methods should be efficient, minimally perturb QD optical properties, yield stable products, and retain the activity or binding affinity of the conjugated targeting agent. Conjugations are usually performed by covalent coupling between the ligand terminal groups on the QD and the biological molecule, and are usually more efficient when the linking group is tethered to a flexible chain [266]. As shown in Table 2, carboxylic acid, amine, and thiol groups can be used to generate stable amide or thioether bonds with biological molecules by using activating agents such as carbodiimides, succinimides, and maleimides [164, 267-271].…”

Section: Attachment To Molecular Targetsmentioning

confidence: 99%

Quantum dot surface engineering: Toward inert fluorophores with compact size and bright, stable emission

Lim

Schleife

et al. 2016

Coordination Chemistry Reviews

109

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The surfaces of colloidal nanocrystals are complex interfaces between solid crystals, coordinating ligands, and liquid solutions. For fluorescent quantum dots, the properties of the surface vastly influence the efficiency of light emission, stability, and physical interactions, and thus determine their sensitivity and specificity when they are used to detect and image biological molecules. But after more than 30 years of study, the surfaces of quantum dots remain poorly understood and continue to be an important subject of both experimental and theoretical research. In this article, we review the physics and chemistry of quantum dot surfaces and describe approaches to engineer optimal fluorescent probes for applications in biomolecular imaging and sensing. We describe the structure and electronic properties of crystalline facets, the chemistry of ligand coordination, and the impact of ligands on optical properties. We further describe recent advances in compact coatings that have significantly improved their properties by providing small hydrodynamic size, high stability and fluorescence efficiency, and minimal nonspecific interactions with cells and biological molecules. While major progress has been made in both basic and applied research, many questions remain in the chemistry and physics of quantum dot surfaces that have hindered key breakthroughs to fully optimize their properties.

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Section: Attachment To Molecular Targetsmentioning

confidence: 99%

Quantum dot surface engineering: Toward inert fluorophores with compact size and bright, stable emission

Lim

Schleife

et al. 2016

Coordination Chemistry Reviews

109

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“…Self‐assembled monolayers of thiols on Au are well‐characterized systems that have the advantages of being air stable, simply fabricated, and precisely modified 59–71. We exploit defects in SAMs to insert functional molecules and to control the placement and orientation of molecules 26, 40–42, 53–56, 62 .…”

Section: Self‐assemblymentioning

confidence: 99%

Photoresponsive Molecules in Well‐Defined Nanoscale Environments

et al. 2012

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Stimuli-responsive molecules are key building blocks of functional molecular materials and devices. These molecules can operate in a range of environments. A molecule's local environment will dictate its conformation, reactivity, and function; by controlling the local environment we can ultimately develop interfaces of individual molecules with the macroscopic environment. By isolating molecules in well-defined environments, we are able to obtain both accurate measurements and precise control. We exploit defect sites in self-assembled monolayers (SAMs) to direct the functional molecules into precise locations, providing a basis for the measurements and engineering of functional molecular systems. The structure and functional moieties of the SAM can be tuned to control not only the intermolecular interactions but also molecule-substrate interactions, resulting in extraction or control of desired molecular functions. Herein, we report our progress toward the assembly and measurements of photoresponsive molecules and their precise assemblies in SAM matrices.

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“…While the exact time is dependent upon ligand identity, ligand exchange of citrate with a thiol-functionalized ligand is on the time scale of minutes to hours, which is consistent with selfassembled monolayer (SAM) formation observed on 2D gold surfaces. 52,53 In general, for all three thiol-functionalized ligands, 4 h is sufficient for the ligand footprints to reach a consistent value with standard errors of <10%. With a time frame for functionalization defined, we then determined the ligand loading values as a function of ligand concentration.…”

mentioning

confidence: 93%

Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by ¹H NMR Spectroscopy

et al. 2015

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We use nuclear magnetic resonance spectroscopy methods to quantify the extent of ligand exchange between different types of thiolated molecules on the surface of gold nanoparticles. Specifically, we determine ligand density values for single-moiety ligand shells and then use these data to describe ligand exchange behavior with a second, thiolated molecule. Using these techniques, we identify trends in gold nanoparticle functionalization efficiency with respect to ligand type, concentration, and reaction time as well as distinguish between functionalization pathways where the new ligand may either replace the existing ligand shell (exchange) or add to it ("backfilling"). Specifically, we find that gold nanoparticles functionalized with thiolated macromolecules, such as poly(ethylene glycol) (1 kDa), exhibit ligand exchange efficiencies ranging from 70% to 95% depending on the structure of the incoming ligand. Conversely, gold nanoparticles functionalized with small-molecule thiolated ligands exhibit exchange efficiencies as low as 2% when exposed to thiolated molecules under identical exchange conditions. Taken together, the reported results provide advances in the fundamental understanding of mixed ligand shell formation and will be important for the preparation of gold nanoparticles in a variety of biomedical, optoelectronic, and catalytic applications.

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Comparison of Oligo(ethylene glycol)alkanethiols versus n-Alkanethiols: Self-Assembly, Insertion, and Functionalization

Cited by 15 publications

References 88 publications

Quantum dot surface engineering: Toward inert fluorophores with compact size and bright, stable emission

Quantum dot surface engineering: Toward inert fluorophores with compact size and bright, stable emission

Photoresponsive Molecules in Well‐Defined Nanoscale Environments

Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by ¹H NMR Spectroscopy

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Comparison of Oligo(ethylene glycol)alkanethiols versus n-Alkanethiols: Self-Assembly, Insertion, and Functionalization

Cited by 15 publications

References 88 publications

Quantum dot surface engineering: Toward inert fluorophores with compact size and bright, stable emission

Quantum dot surface engineering: Toward inert fluorophores with compact size and bright, stable emission

Photoresponsive Molecules in Well‐Defined Nanoscale Environments

Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by 1H NMR Spectroscopy

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Product

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Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by ¹H NMR Spectroscopy