Plasmon-Enhanced Single-Molecule Enzymology

Wang, Yuyang; Zijlstra, Peter

doi:10.1021/acsphotonics.8b00327

Cited by 5 publications

(8 citation statements)

References 54 publications

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“…As an example, the 1/ e decay length of field intensity is about 5 nm for a gold nanorod with a diameter of 30 nm. 46…”

Section: Resultsmentioning

confidence: 99%

“…25,45 However, maintaining colloidal stability requires long PEG linkers to prevent aggregation during centrifugation or at physiological salt conditions, pushing the conjugated biomolecules away from the particle’s surface where the refractive index sensitivity and fluorescence enhancements are highest. 15,46 Although it has been observed that histidine-tagged biomolecules can effectively conjugate to inorganic quantum dots with zero-length spacing, 47 no general protocols exist that allow for the conjugation of a range of proteins to different types of plasmonic nanoparticles using short linkers while simultaneously preserving protein activity and colloidal stability.…”

Section: Introductionmentioning

confidence: 99%

“…Bio-orthogonal approaches using click chemistry have shown to allow accurate quantitation of the average number of biomolecules per particle. − However, click reactions rely on hydrophobic azide or alkyne groups on either the particle or on the biomolecule, which often leads to reduced solubility and colloidal stability in aqueous environments . Conjugation via biotin-streptavidin linkers has been used in the study of nanoparticle-based biosensors on ensemble and single-molecule levels and the study of nanoparticle assemblies. ,− Being a water-soluble small molecule, biotin is typically conjugated to the surface of nanoparticles via poly(ethylene)-glycol(PEG) cross-linkers, without significant aggregation of the nanoparticles. , However, maintaining colloidal stability requires long PEG linkers to prevent aggregation during centrifugation or at physiological salt conditions, pushing the conjugated biomolecules away from the particle’s surface where the refractive index sensitivity and fluorescence enhancements are highest. , Although it has been observed that histidine-tagged biomolecules can effectively conjugate to inorganic quantum dots with zero-length spacing, no general protocols exist that allow for the conjugation of a range of proteins to different types of plasmonic nanoparticles using short linkers while simultaneously preserving protein activity and colloidal stability.…”

Section: Introductionmentioning

confidence: 99%

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A Robust and General Approach to Quantitatively Conjugate Enzymes to Plasmonic Nanoparticles

2019

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Bioconjugates of plasmonic nanoparticles have received considerable attention due to their potential biomedical applications. Successful bioconjugation requires control over the number and activity of the conjugated proteins and the colloidal stability of the particles. In practice, this requires reoptimization of the conjugation protocol for each combination of protein and nanoparticle. Here, we report a robust and general protocol that allows for the conjugation of a range of proteins to different types of nanoparticles using very short polyethylene-glycol(PEG) linkers, while simultaneously preserving protein activity and colloidal stability. The use of short linkers ensures that the protein is located close to the particle surface, where the refractive index sensitivity and near-field enhancement are maximal. We demonstrate that the use of a Tween20 containing stabilizing buffer is critical in maintaining colloidal stability and protein function throughout the protocol. We obtain quantitative control over the average number of enzymes per particle by either varying the number of functional groups on the particle or the enzyme concentration during incubation. This new route of preparing quantitative protein-nanoparticle bioconjugates paves the way to develop rational and quantitative strategies to functionalize nanoparticles for applications in sensing, medical diagnostics, and drug delivery.

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“…As an example, the 1/ e decay length of field intensity is about 5 nm for a gold nanorod with a diameter of 30 nm. 46…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Robust and General Approach to Quantitatively Conjugate Enzymes to Plasmonic Nanoparticles

2019

Self Cite

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show abstract

“…25,45 However, maintaining colloidal stability requires long PEG linkers to prevent aggregation during centrifugation or at physiological salt conditions, pushing the conjugated biomolecules away from the particle's surface where the refractive index sensitivity and fluorescence enhancements are highest. 15,46 Although it has been observed that histidine-tagged biomolecules can effectively conjugate to inorganic quantum dots with zerolength spacing, 47 no general protocols exist that allow for the conjugation of a range of proteins to different types of plasmonic nanoparticles using short linkers while simultaneously preserving protein activity and colloidal stability.…”

Section: ■ Introductionmentioning

confidence: 99%

A Robust and General Approach to Quantitatively Conjugate Enzymes to Plasmonic Nanoparticles

Wang¹,

Asdonk²,

Zijlstra³

2019

Preprint

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<div>Bioconjugates of plasmonic nanoparticles have received considerable attention due to their potential biomedical applications. Succesfull bioconjugation requires control over the number and activity of the conjugated proteins, and the colloidal stability of the particles. In practice, this requires re-optimization of the conjugation protocol for each combination of protein and nanoparticle. Here we report a robust and general protocol that allows for the conjugation of a range of proteins to different types of nanoparticles using very short polyethylene-glycol(PEG) linkers, while simultaneously preserving protein activity and colloidal stability. The use of short linkers ensures that the protein is located close to the particle surface, where their refractive index sensitivity and near-field enhancement is maximal. We demonstrate that the use a Tween20 containing stabilizing buffer is critical in maintaining colloidal stability and protein function throughout the protocol. We obtain quantitative control over the average number of enzymes per particle by either varying the number of functional groups on the particle, or the enzyme concentration during incubation. This new route of preparing quantitative protein-nanoparticle bioconjugates paves the way to develop rational and quantitative strategies to functionalize nanoparticles for applications in sensing, medical diagnostics and drug delivery.</div>

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“…Plasmonic nanoapertures have shown great potential in optical sensing, − spectroscopy, − imaging, , nanofabrication, , trapping, − and nonlinear photonics . With their capacities of localizing electromagnetic field to subdiffraction regions, reducing detection volume to attoliters, and enabling background-free optical detection, nanoapertures are particularly attractive for scientific studies at the single-molecule level. − For example, their use in performing fluorescence correlation spectroscopy has enabled single-analyte characterization at high micromolar concentrations. , As optical nanotweezing elements, the nanoapertures have been used for sensing or analyzing various nanoparticles such as quantum dots, , proteins, , and DNA , with single-molecule resolution.…”

mentioning

confidence: 99%

Enhancing Single-Molecule Fluorescence Spectroscopy with Simple and Robust Hybrid Nanoapertures

2021

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Plasmonic nanoapertures have found exciting applications in optical sensing, spectroscopy, imaging, and nanomanipulation. The subdiffraction optical field localization, reduced detection volume (∼attoliters), and background-free operation make them particularly attractive for single-particle and single-molecule studies. However, in contrast to the high field enhancements by traditional "nanoantenna"-based structures, small field enhancement in conventional nanoapertures results in weak light−matter interactions and thus small enhancement of spectroscopic signals (such as fluorescence and Raman signals) of the analytes interacting with the nanoapertures. In this work, we propose a hybrid nanoaperture design termed "gold-nanoislandsembedded nanoaperture" (AuNIs-e-NA), which provides multiple electromagnetic "hotspots" within the nanoaperture to achieve field enhancements of up to 4000. The AuNIs-e-NA was able to improve the fluorescence signals by more than 2 orders of magnitude with respect to a conventional nanoaperture. With simple design and easy fabrication, along with strong signal enhancements and operability over variable light wavelengths and polarizations, the AuNIs-e-NA will serve as a robust platform for surface-enhanced optical sensing, imaging, and spectroscopy.

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Plasmon-Enhanced Single-Molecule Enzymology

Cited by 5 publications

References 54 publications

A Robust and General Approach to Quantitatively Conjugate Enzymes to Plasmonic Nanoparticles

A Robust and General Approach to Quantitatively Conjugate Enzymes to Plasmonic Nanoparticles

A Robust and General Approach to Quantitatively Conjugate Enzymes to Plasmonic Nanoparticles

Enhancing Single-Molecule Fluorescence Spectroscopy with Simple and Robust Hybrid Nanoapertures

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