Highly stable and biocompatible gold nanorod–DNA conjugates as NIR probes for ultrafast sequence-selective DNA melting

Baumann, Verena; Röttgermann, Peter J. F.; Haase, Frederik; Szendrei, Katalin; Dey, Priyanka; Lyons, Katja; Wyrwich, Regina; Gräßel, Matthias; Stehr, Joachim; Ullerich, Lars; Bürsgens, Federico; Rodrı́guez-Fernández, Jessica

doi:10.1039/c6ra17156g

Cited by 6 publications

(6 citation statements)

References 79 publications

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“…Functionalization with 6-mercaptohexanoic acid (MHA) allowed for back-transfer into TBE 1× buffer and subsequent functionalization with ssDNA, namely HS-T 18 -6-FAM (T 18 -DNA hereafter, as in the main text), at a dose of~1 ssDNA strand/nm 2 , which yielded AuNRs@DNA with a grafting density of~727 DNA strands/NR. As demonstrated in our earlier work [28], the AuNRs@DNA prepared this way are very stable in buffer and biological media. They are also highly biocompatible due to their robust colloidal stability and efficient CTAB removal during the functionalization process.…”

Section: Chemicalssupporting

confidence: 59%

“…As starting building blocks, we synthesized single-crystal CTAB-capped AuNRs measuring 74 ± 7 nm in length and 21 ± 3 nm in width, and with an average aspect ratio of~3.5 [26,27]. The AuNRs were functionalized with ssDNA, namely with a 5 -thiol-C6-T 18 -3 -6-FAM sequence (T 18 -DNA), as recently reported by us [28], leading to the dispersion of highly stable, biocompatible, CTAB-free AuNRs@DNA in Tris-acetate-EDTA (TAE) 1× buffer containing 0.001% Tween 80. We pursued the selective inactivation of the ssDNA grafted on the lateral facets of AuNRs@DNA by overgrowing Ag on their surfaces.…”

Section: Resultsmentioning

confidence: 99%

“…CTAB-capped AuNRs measuring 74 ± 7 nm in length and 21 ± 3 nm in width with an aspect ratio~3.5 were synthesized as reported earlier [26,27]. The single-crystal NRs were functionalized with single-stranded DNA, as described recently by us [28]. For this, the AuNRs@CTAB were functionalized with poly(ethylene glycol) (MeO-PEG-SH, added dose~20 PEG chains/nm 2 ) and ultimately redispersed in THF, as described therein.…”

Section: Chemicalsmentioning

confidence: 99%

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Gold Nanorod Assemblies: The Roles of Hot-Spot Positioning and Anisotropy in Plasmon Coupling and SERS

2020

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Plasmon-coupled colloidal nanoassemblies with carefully sculpted “hot-spots” and intense surface-enhanced Raman scattering (SERS) are in high demand as photostable and sensitive plasmonic nano-, bio-, and chemosensors. When maximizing SERS signals, it is particularly challenging to control the hot-spot density, precisely position the hot-spots to intensify the plasmon coupling, and introduce the SERS molecule in those intense hot-spots. Here, we investigated the importance of these factors in nanoassemblies made of a gold nanorod (AuNR) core and spherical nanoparticle (AuNP) satellites with ssDNA oligomer linkers. Hot-spot positioning at the NR tips was made possible by selectively burying the ssDNA in the lateral facets via controlled Ag overgrowth while retaining their hybridization and assembly potential at the tips. This strategy, with slight alterations, allowed us to form nanoassemblies that only contained satellites at the NR tips, i.e., directional anisotropic nanoassemblies; or satellites randomly positioned around the NR, i.e., nondirectional nanoassemblies. Directional nanoassemblies featured strong plasmon coupling as compared to nondirectional ones, as a result of strategically placing the hot-spots at the most intense electric field position of the AuNR, i.e., retaining the inherent plasmon anisotropy. Furthermore, as the dsDNA was located in these anisotropic hot-spots, this allowed for the tag-free detection down to ~10 dsDNA and a dramatic SERS enhancement of ~1.6 × 108 for the SERS tag SYBR gold, which specifically intercalates into the dsDNA. This dramatic SERS performance was made possible by manipulating the anisotropy of the nanoassemblies, which allowed us to emphasize the critical role of hot-spot positioning and SERS molecule positioning in nanoassemblies.

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Section: Chemicalssupporting

confidence: 59%

Section: Resultsmentioning

confidence: 99%

Section: Chemicalsmentioning

confidence: 99%

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Gold Nanorod Assemblies: The Roles of Hot-Spot Positioning and Anisotropy in Plasmon Coupling and SERS

2020

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“…Achieving CTA+ free prepares the essential foundation for visualizing dynamic interlinking networks. Traditionally, AuNRs [ 14–25 ] are synthesized with a strong cationic charge from hexadecyltrimethylammonium bromide (CTAB) capping, [ 26–34 ] which can impact subsequent ligand exchange. [ 35 ] In this study, the alternative bromide surfactant, CTAC, was used as the primary surfactant for seed‐mediated growth of AuNRs to achieve CTA+ free.…”

Section: Figurementioning

confidence: 99%

Optically and Structurally Stabilized Plasmo‐Bio Interlinking Networks

Lin

Cui

Burns

et al. 2020

Adv Materials Inter

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Visualization of dynamic interlinking networks which respond and adapt to the constantly changing environment would be highly beneficial in developing new composite materials and active/responsive materials. Here, optically and structurally stabilized plasmo‐bio interlinking networks (PBINs) free from photobleaching for high resolution, long term visualization are reported. Necessary for structural and optical stability, a new stability algorithm to comprehensively quantify stability and detect minute instability undetectable by traditional methods is introduced. Biocompatible plasmonic gold nanorods (Bio‐AuNRs) are synthesized for high resolution, long term imaging by utilizing bromide‐free alternatives to achieve CTA+ free. Systematic physical, chemical, and biological characterizations reveal the structural and optical stability of Bio‐AuNRs required for constructing PBIN. Lastly, with actin as a model of interlinking networks of the cytoskeleton, optically and structurally stable PBIN (100% CTA+ free, 97% crosslinking rate) in applications as active/responsive materials, are demonstrated.

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“…The direct attachment of thiol-modified DNA onto NRs has been reported, [8][9][10][11] however complete displacement of the oppositely charged CTAB is unlikely and improved approaches include the presence of surfactants and thiolated polyethylene glycol. [11][12][13][14] Other alternatives involve first displacing CTAB with either an alkanethiol either directly 15 or via a multi-step two phase extraction 16,17 followed by DNA conjugation. The combination of encapsulation in a silica shell and silanization chemistry has also been reported.…”

Section: Introductionmentioning

confidence: 99%

Optimized polydopamine coating and DNA conjugation onto gold nanorods for single nanoparticle bioaffinity measurements

Azab

Cherif

Finnie

et al. 2018

Analyst

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Gold nanorods (NRs) have attracted a great deal of interest for a variety of biomedical and sensing applications. However, developing robust methods for biofunctionalizing NRs has continued to be challenging, especially for NR-DNA conjugates. This is due to the presence of cetyltrimethylammonium bromide (CTAB), which plays an essential role in controlling the anisotropic particle growth. In this article, we systematically explore the growth of a polydopamine (PDA) layer on a range of NR surfaces, comparing different polyelectrolyte and alkanethiol coatings as well as direct CTAB displacement. This revealed that the PDA layer thickness and growth rate is strongly dependent on the underlying nanorod functionalization chemistry and allowed us to establish a preferred route for the creation of stable, non-aggregated suspensions of PDA-coated NRs. The utility of this platform was then demonstrated by self-assembling packed monolayers of single-stranded DNA on the outer surface. Both the surface attachment and bioactivity of the resulting NR-DNA conjugates was then demonstrated by performing bulk solution and single nanoparticle imaging fluorescence measurements.

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Highly stable and biocompatible gold nanorod–DNA conjugates as NIR probes for ultrafast sequence-selective DNA melting

Abstract: Colloidally stable and biocompatible DNA-functionalized Au nanorods are proved as NIR-addressable probes and mediators for ultrafast and sequence-selective DNA melting.

Cited by 6 publications

References 79 publications

Gold Nanorod Assemblies: The Roles of Hot-Spot Positioning and Anisotropy in Plasmon Coupling and SERS

Gold Nanorod Assemblies: The Roles of Hot-Spot Positioning and Anisotropy in Plasmon Coupling and SERS

Optically and Structurally Stabilized Plasmo‐Bio Interlinking Networks

Optimized polydopamine coating and DNA conjugation onto gold nanorods for single nanoparticle bioaffinity measurements

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