Instantaneous and Quantitative Functionalization of Gold Nanoparticles with Thiolated DNA Using a pH-Assisted and Surfactant-Free Route

Zhang, Xu; Servos, Mark R.; Liu, Juewen

doi:10.1021/ja3014055

Cited by 520 publications

(534 citation statements)

References 49 publications

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“…After incubation in 10 mM Tris(2-carboxyethyl)phosphine (TCEP, Sigma Aldritch) for 30 min, they are added in a 4,800-fold excess to the NP solution. Following a protocol given in Zhang et al 47 , citrate-HCl buffer (pH ¼ 3) is added to a final concentration of 10 mM for 10 min, before HEPES buffer (pH ¼ 7) is added at a final concentration of 100 mM. This protocol ensures quick attachment of thiolated ssDNA oligos to the gold NPs.…”

Section: Methodsmentioning

confidence: 99%

DNA origami based assembly of gold nanoparticle dimers for surface-enhanced Raman scattering

et al. 2014

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Plasmonic sensors are extremely promising candidates for label-free single-molecule analysis but require exquisite control over the physical arrangement of metallic nanostructures. Here we employ self-assembly based on the DNA origami technique for accurate positioning of individual gold nanoparticles. Our innovative design leads to strong plasmonic coupling between two 40 nm gold nanoparticles reproducibly held with gaps of 3.3±1 nm. This is confirmed through far field scattering measurements on individual dimers which reveal a significant red shift in the plasmonic resonance peaks, consistent with the high dielectric environment due to the surrounding DNA. We use surface-enhanced Raman scattering (SERS) to demonstrate local field enhancements of several orders of magnitude through detection of a small number of dye molecules as well as short single-stranded DNA oligonucleotides. This demonstrates that DNA origami is a powerful tool for the high-yield creation of SERS-active nanoparticle assemblies with reliable sub-5 nm gap sizes.

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Section: Methodsmentioning

confidence: 99%

DNA origami based assembly of gold nanoparticle dimers for surface-enhanced Raman scattering

et al. 2014

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“…To construct the SERS chip for active ricin detection, the following sequences was used: 5′-SH-AAAAAAAAAAAAAAAAAAAAA [referred to herein as 5′-SH-poly(21dA)], which was conjugated to different sized citrate− AuNPs (∼60, ∼75, ∼90, and ∼100 nm) based on the literaturereported method. 25 Detailed experimental procedures were listed in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

New Surface-Enhanced Raman Sensing Chip Designed for On-Site Detection of Active Ricin in Complex Matrices Based on Specific Depurination

Tang

Sun

Lui

et al. 2016

ACS Appl. Mater. Interfaces

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Quick and accurate on-site detection of active ricin has very important realistic significance in view of national security and defense. In this paper, optimized single-stranded oligodeoxynucleotides named poly(21dA), which function as a depurination substrate of active ricin, were screened and chemically attached on gold nanoparticles (AuNPs, ∼100 nm) via the Au−S bond [poly(21dA)−AuNPs]. Subsequently, poly(21dA)−AuNPs were assembled on a dihydrogen lipoic-acid-modified Si wafer (SH−Si), thus forming the specific surface-enhanced Raman spectroscopy (SERS) chip [poly(21dA)−AuNPs@SH−Si] for depurination of active ricin. Under optimized conditions, active ricin could specifically hydrolyze multiple adenines from poly(21dA) on the chip. This depurination-induced composition change could be conveniently monitored by measuring the distinct attenuation of the SERS signature corresponding to adenine. To improve sensitivity of this method, a silver nanoshell was deposited on post-reacted poly(21dA)−AuNPs, which lowered the limit of detection to 8.9 ng mL −1 . The utility of this wellcontrolled SERS chip was successfully demonstrated in food and biological matrices spiked with different concentrations of active ricin, thus showing to be very promising assay for reliable and rapid on-site detection of active ricin.

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“…19 After observing the interesting effect of low pH, we initially attributed it to a simple electrostatic model. In this work, we emphasized also on the effect of DNA conformation, which allowed us to explain the difference between poly-A and poly-C spacer, 26 and also the adsorption of non-thiolated DNA.…”

mentioning

confidence: 99%

Parallel Polyadenine Duplex Formation at Low pH Facilitates DNA Conjugation onto Gold Nanoparticles

Huang

Liu

2016

Langmuir

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DNA-functionalized gold nanoparticles (AuNPs) have been extensively used in sensing, drug delivery, and materials science. A key step is to attach DNA to AuNPs forming a stable and functional conjugate. While the traditional salt-aging method takes a full day or longer, a recent low-pH method allows DNA conjugation in a few minutes. The effect of low pH was attributed to protonation of adenine (A) and cytosine (C), resulting in an overall lower negative charge density on DNA. In this work, the effect of DNA conformation at low pH is studied. Using circular dichroism (CD) spectroscopy, parallel poly-A duplex (A-motif) is detected when a poly-A segment is linked to a random DNA, a design typically used for DNA conjugation. A DNA staining dye, thiazole orange, is identified for detecting such A-motifs. The A-motif structure is ideal for DNA conjugation since it exposes the thiol group for directly reacting with gold surface while minimizing non-specific DNA base adsorption. For non-thiolated DNA, the optimal procedure is to incubate DNA and AuNPs followed by lowering the pH. The i-motif formed by poly-C DNA at low pH is less favorable for the conjugation reaction due to its unique way of folding. The stability of poly-A and poly-G DNA in low pH is examined. An excellent stability of poly-A DNA is confirmed, while poly-G has lower stability. This study provides new fundamental insights into a practically useful technique of conjugating DNA to AuNPs.3

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Instantaneous and Quantitative Functionalization of Gold Nanoparticles with Thiolated DNA Using a pH-Assisted and Surfactant-Free Route

Cited by 520 publications

References 49 publications

DNA origami based assembly of gold nanoparticle dimers for surface-enhanced Raman scattering

DNA origami based assembly of gold nanoparticle dimers for surface-enhanced Raman scattering

New Surface-Enhanced Raman Sensing Chip Designed for On-Site Detection of Active Ricin in Complex Matrices Based on Specific Depurination

Parallel Polyadenine Duplex Formation at Low pH Facilitates DNA Conjugation onto Gold Nanoparticles

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