An Electrochemically Controlled Microcantilever Biosensor

Nagai, Yoshihiko; Carbajal, Jorge Dulanto; White, John H.; Sladek, Robert; Grütter, Peter; Lennox, R. Bruce

doi:10.1021/la400975b

Cited by 17 publications

(29 citation statements)

References 37 publications

(81 reference statements)

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“…In some applications, a partially coated sensor surface is desired [21][22][23]. Peterson et al [24] have shown that surfacetethered single stranded DNA, when in a low surface density regime, is desired as probe hybridization proceeds with relatively fast kinetics.…”

Section: Introductionmentioning

confidence: 99%

“…Many other studies have shown that sub-monolayer coverage of tethered DNA probes leads to optimal hybridization efficiencies for DNA binding on gold [25,26], on gold nanowires [27], or for protein binding [28]. Nagai et al [23], using microcantilever sensors, demonstrated that maximal surface stress changes between single stranded oligonucleotides and hybridized probes are achieved at a probe density of ca. q = 0.3 (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Selectivein situpotential-assisted SAM formation on multi electrode arrays

et al. 2016

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The selective modification of individual components in a biosensor array is challenging. To address this challenge, we present a generalizable approach to selectively modify and characterize individual gold surfaces in an array, in an in situ manner. This is achieved by taking advantage of the potential dependent adsorption/desorption of surface-modified organic molecules. Control of the applied potential of the individual sensors in an array where each acts as a working electrode provides differential derivatization of the sensor surfaces. To demonstrate this concept, two different self-assembled monolayer (SAM)-forming electrochemically addressable ω-ferrocenyl alkanethiols (C) are chemisorbed onto independent but spatially adjacent gold electrodes. The ferrocene alkanethiol does not chemisorb onto the surface when the applied potential is cathodic relative to the adsorption potential and the electrode remains underivatized. However, applying potentials that are modestly positive relative to the adsorption potential leads to extensive coverage within 10 min. The resulting SAM remains in a stable state while held at potentials <200 mV above the adsorption potential. In this state, the chemisorbed SAM does not significantly desorb nor do new ferrocenylalkythiols adsorb. Using three set applied potentials provides for controlled submonolayer alkylthiol marker coverage of each independent gold electrode. These three applied potentials are dependent upon the specifics of the respective adsorbate. Characterization of the ferrocene-modified electrodes via cyclic voltammetry demonstrates that each specific ferrocene marker is exclusively adsorbed to the desired target electrode.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Selectivein situpotential-assisted SAM formation on multi electrode arrays

et al. 2016

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“…In recent years, several nano and micromechanical structures have been described as possible biosensor platforms. [1][2][3][4][5] Here we focus on cantilever-based sensors which have been used for the mechanical detection of a vast variety of biological targets such as DNA, [6][7][8][9][10][11][12][13][14][15] antigens, 16 proteins, 17,18 bacteria, [19][20][21] and viruses. 22 The most common detection principles in these mechanical sensors due to biological binding effects are changes in surface stress [23][24][25][26][27] and mass.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity measurement of a cantilever-based surface stress sensor

Haag

Schumacher

Grütter

2016

The Journal of Chemical Physics

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A detailed analysis of the temporal surface stress evolution for potential-driven adsorption of ions is discussed. A gold-coated cantilever is used to simultaneously measure the change in surface stress as well as the current response during an applied potential step. In this electrochemical configuration, the cantilever acts as the working electrode, a platinum wire as the counter electrode, and the Ag/AgCl (sat. KCl) electrode as the reference electrode. To study the time-dependent signal and the sensitivity of the cantilever response, the frequency of the potential step applied to the cantilever is varied from 1 s to 0.1 ms. First, a comparison between a strong adsorbing (chloride Cl) and a weak adsorbing ion (perchlorate ClO) in a 1 mM solution is presented. Next, the linear relationship between surface stress and charge density is measured for these fast potential steps. The slope of this fit is defined as the sensitivity of the system and is shown to increase for shorter potential pulses. Finally, the behaviour of the surface stress and current for consecutive applied potential steps is studied.

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“…In such applications, especially in nanotechnology, it is crucial to improve the molecular level quality and reproducibility of monolayers and shorten the functionalization time. Applied potential has been shown to enhance deposition of alkanethiol SAMs [6][7][8], immobilization [9] and hybridization [10,11] of DNA as well as conformational modulation of DNA layers [12,13], introducing new possibilities for molecular level control of surface functionalization. Additionally, Ma and Lennox have shown that a moderate anodic potential (from +200 mV to +600 mV vs Ag/AgCl) applied to an Au electrode, induced a rapid and complete adsorption of thiol molecules [6].…”

Section: Introductionmentioning

confidence: 99%