Coadsorption optimization of DNA in binary self-assembled monolayer on gold electrode for electrochemical detection of oligonucleotide sequences

Ferrario, A.; Scaramuzza, Matteo; Pasqualotto, E.; Toni, A. De; Paccagnella, A.

doi:10.1016/j.jelechem.2012.11.029

Cited by 10 publications

(13 citation statements)

References 42 publications

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“…The co-assembly of short-chain thiols with thiol-modied probe DNA (i.e., probe DNA/thiols mixed SAMs) on gold for constructing a DNA sensor can increase the H E and H D greatly because it may reduce DNA non-specic adsorption and align the DNA SAMs more for reducing the spatial hindrance for hybridization. [9][10][11][12][13][14][15] Thus, the construction of DNA sensors based on probe DNA/thiols mixed SAMs on gold and studies on their hybridization ability becomes a hotspot. For example, the coassembly of thiol-modied poly(ethylene glycol) (PEG) and probe DNA can not only reduce DNA non-specic adsorption but also make the surface more biocompatible and resist the adsorption of protein on the DNA SAMs, which allows for the measurement of target DNA in a real sample (e.g., serum).…”

Section: Introductionmentioning

confidence: 99%

Size-fitting effect for hybridization of DNA/mercaptohexanol mixed monolayers on gold

Zhang

et al. 2014

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In this article we proposed a simple hexagonal model for exploring the hybridization of thiol-modified probe DNA self-assembled monolayers (SAMs) on gold with target DNA molecules in solution. The size-fitting coefficient d(c)/d(t) from the model was used to discuss the principle for DNA optimal hybridization, where d(c) was the channel diameter among three adjacent probe DNA molecules on gold and dt was the gyration diameter of the target DNA molecules in solution. Experimentally we investigated the hybridization effect (hybridization efficiency H(E) and hybridization density H(D)) of thiol-modified probe DNA (DNA base amount m = 15, 25 or 35)/mercaptohexanol (MCH) mixed SAMs on gold in 1 M electrolyte solution by chronocoulometry (CC) and electrochemical impedance spectroscopy (EIS). The surface coverage Γ(m) of the probe DNA on gold was adjusted by changing the mixed concentration ratio of probe DNA with MCH (C(DNA)/C(MCH)) in the assembly solution. Results indicated that with the increase of C(DNA)/C(MCH), H(E) decreased gradually; H(D) first increased and then decreased, which arrived at the biggest at C(DNA)/C(MCH) = 1 for all the probe DNA/MCH mixed SAMs (m = 15, 25, 35). The optimal Γ(m) for achieving the biggest H(D) in DNA hybridization decreased with the increase of m from 15 to 35. The experimental conclusions obtained by CC and EIS measurements verified each other. Combining the simple model with our experimental results, we ascertained that d(c)/d(t) decreased with the increase of m, which showed a good linear relationship. These conclusions provided an important reference and guidance for controllably constructing DNA sensors with optimal performance.

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Section: Introductionmentioning

confidence: 99%

Size-fitting effect for hybridization of DNA/mercaptohexanol mixed monolayers on gold

Zhang

et al. 2014

Analyst

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“…For DNA hybridization sensors, it is indeed well established that the sensor output, whether optical3, 13, 14 or electrochemical15–18 in nature, initially increases with the probe coverage but quickly falls off above a certain coverage because the hybridization efficiency decreases due to steric hindrance at the surface 3. 13–17…”

Section: Introductionmentioning

confidence: 99%

“…With this method, the probe and the diluent are both present in the same immobilization solution, and various authors have shown that, in such a case, the DNA surface density can be modulated by changing the DNA‐to‐diluent ratio in solution 3. 10, 13, 17, 18, 39, 40 However, the influence of the ionic strength in the one‐step coadsorption methods has not been systematically investigated.…”

Section: Introductionmentioning

confidence: 99%

Optimization of the Probe Coverage in DNA Biosensors by a One‐Step Coadsorption Procedure

et al. 2013

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Analytical performance (selectivity, sensitivity, limit of detection) of a sensor is ultimately connected to the interfacial architecture of the sensing surface that needs to be optimized. Self‐assembly of a mixed monolayer of thiolated probes and diluent onto gold surfaces used in the design of biosensing platforms is nowadays commonly performed by a two‐step immobilization procedure. In this work, the merits of a one‐step coadsorption procedure are emphasized, and it is shown that the ionic strength is a very efficient tool to fine control the surface concentration of the immobilized probe. Probe densities were obtained by alternating current voltammetry or fluorescence measurements depending on the type of labeling of the probes. With unlabeled DNA sequences, chronocoulometric measurements were performed in the presence of dissolved hexaammineruthenium(III) cations. The maximum probe density achievable at high ionic strength by the one‐step coadsorption procedure is limited by steric constraints and depends on the structure of the sequence. Various thiolated DNA sequences (single‐stranded DNA, double‐stranded DNA, linear, hairpin, quadruplex) coadsorbed with a common diluent, 4‐mercaptobutan‐1‐ol, were used to discuss the structural factors affecting the maximum surface densities obtained for the different types of probe. Application of the one‐step coadsorption procedure to the optimization of the analytical performance of a protein aptasensor is illustrated by building a sensor for the detection of thrombin on the basis of the thrombin binding aptamer sequence.

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“…30,31 Surface plasmon resonance (SPR) studies probing binding in real-time indicate that both kinetics and percent binding depend on the probe converge. 34 Studies controlling the probe density show the optimum coverage of the probe to obtain efficient binding is in the 2.5 × 10 12 to 4.5 × 10 12 ssDNA/cm 2 range with 31,35,36 or without MCH backfill. 34 In an interesting study, interprobe distance was fine-tuned using a DNA origami scaffold to show that an optimal distance for efficient binding to achieve sensitivity of 1 fM was ∼9 nm, 37 equivalent to a coverage of ∼1.6 × 10 12 ssDNA/cm 2 .…”

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Electrochemical Characteristics of a DNA Modified Electrode as a Function of Percent Binding

Tevatia¹,

Prasad

Saraf

2019

Anal. Chem.

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Electrochemical characteristics of immobilized double-stranded DNA (dsDNA) on a Au electrode were studied as a function of coverage using a home-built optoelectrochemical method. The method allows probing of local redox processes on a 6 μm spot by measuring both differential reflectivity (SEED-R) and interferometry (SEED-I). The former is sensitive to redox ions that tend to adsorb to the electrode, while SEED-I is sensitive to nonadsorbing ions. The redox reaction maxima, R max and Δmax from SEED-R and SEED-I, respectively, are linearly proportional to amperometric peak current, I max. The DNA binding is measured by a redox active dye, methylene blue, that intercalates in dsDNA, leading to an R max. Concomitantly, the absence of Δmax for [Fe(CN)6]4–/3– by SEED-I ensures that there is no leakage current from voids/defects in the alkanethiol passivation layer at the same spot of measurement. The binding was regulated electrochemically to obtain the binding fraction, f, ranging about three orders of magnitude. A remarkably sharp transition, f = f T = 1.25 × 10–3, was observed. Below f T, dsDNA molecules behaved as individual single-molecule nanoelectrodes. Above the crossover transition, R max, per dsDNA molecule dropped rapidly as f –1/2 toward a planar-like monolayer. The SEED-R peak at f ∼ 3.3 × 10–4 (∼270 dsDNA molecules) was (statistically) robust, corresponding to a responsivity of ∼0.45 zeptomoles of dsDNA/spot. Differential pulse voltammetry in the single-molecule regime estimated that the current per dsDNA molecule was ∼4.1 fA. Compared with published amperometric results, the reported semilogarithmic dependence on target concentration is in the f > f T regime.

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Coadsorption optimization of DNA in binary self-assembled monolayer on gold electrode for electrochemical detection of oligonucleotide sequences

Cited by 10 publications

References 42 publications

Size-fitting effect for hybridization of DNA/mercaptohexanol mixed monolayers on gold

Size-fitting effect for hybridization of DNA/mercaptohexanol mixed monolayers on gold

Optimization of the Probe Coverage in DNA Biosensors by a One‐Step Coadsorption Procedure

Electrochemical Characteristics of a DNA Modified Electrode as a Function of Percent Binding

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