Direct detection of immunospecies by capacitance measurements

Bataillard, P.; Gardies, Françoise; Jaffrézic‐Renault, Nicole; Martelet, C.; Colin, B.; Mandrand, Bernard

doi:10.1021/ac00172a011

Cited by 162 publications

(61 citation statements)

References 36 publications

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“…This may perhaps be assigned to the antibody-antigen (Ab-Ag) interaction leading to a change in the dielectric/blocking properties of the electrolyteelectrode interface. 49,50 The capacitance value between the RGOant-TiO 2 based immunoelectrode and the electrolyte is 33 0 A d , where 3 0 (F m À1 ) is the permittivity of free space, 3 is the relative dielectric constant, A (m 2 ) is the surface area and d (m) is the distance. The decrease of the measured capacitance due to the increase of the distance between the electrode and electrolyte is thus expected, due to the interaction of Vc with the Ab-Vc.…”

Section: Electrochemical Response Studiesmentioning

confidence: 99%

Reduced graphene oxide–titania based platform for label-free biosensor

et al. 2014

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A label-free biosensor has been fabricated using a reduced graphene oxide (RGO) and anatase titania (antTiO 2 ) nanocomposite, electrophoretically deposited onto an indium tin oxide coated glass substrate. The RGO-ant-TiO 2 nanocomposite has been functionalized with protein (horseradish peroxidase) conjugated antibodies for the specific recognition and detection of Vibrio cholerae. The presence of Ab-Vc on the RGO-ant-TiO 2 nanocomposite has been confirmed using electron microscopy, Fourier transform infrared spectroscopy and electrochemical techniques. Electrochemical studies relating to the fabricated Ab-Vc/RGO-ant-TiO 2 /ITO immunoelectrode have been conducted to investigate the binding kinetics.This immunosensor exhibits improved biosensing properties in the detection of Vibrio cholerae, with a sensitivity of 18.17 Â 10 6 F mol À1 L À1 m À2 in the detection range of 0.12-5.4 nmol L À1 , and a low detection limit of 0.12 nmol L À1 . The association (k a ), dissociation (k d ) and equilibrium rate constants have been estimated to be 0.07 nM, 0.002 nM and 0.41 nM, respectively. This Ab-Vc/RGO-ant-TiO 2 /ITO immunoelectrode could be a suitable platform for the development of compact diagnostic devices.

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Section: Electrochemical Response Studiesmentioning

confidence: 99%

Reduced graphene oxide–titania based platform for label-free biosensor

et al. 2014

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“…Ion-sensitive field-effect transistors (ISFETs) and relatives (EnFETs, BioFETs, etc.) are the canonical examples [6], but similar mechanisms operate in semiconducting nanowires [7], semiconducting carbon nanotubes [8], electrolyte-insulator-semiconductor structures [9][10][11][12], suspended gate thin film transistors [13], and light-addressable potentiometric sensors [14,15]. These field-effect sensors rely on the interaction of external charges with carriers in a nearby semiconductor and thus exhibit enhanced sensitivity at low ionic strength where counterion shielding is reduced; this is explained in a recent review [16] and evidenced by the low salt concentrations often used (e.g., [7,10]).…”

Section: Introductionmentioning

confidence: 99%

Label‐Free Impedance Biosensors: Opportunities and Challenges

2007

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Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label-free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label-free impedance biosensors and identify areas for future research.

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“…In the last decade, simpler antibody assay methods have been proposed in which the binding of antigen to an antibody coated surface is sensed directly. A variety of optical and electronic methods for detection of specific protein binding has been developed, including the use of optical sensor devices such as plasmon resonance, reflectometry, ellipsometric techniques, all of which measure changes in refractive index profile, and capacitors (Bataillard et al, 1988) measuring changes in the dielectric constant after binding. It has also been suggested (Schenck, 1978) that FET devices can be used to detect surface polarization effects due to the formation of the antibodyantigen complex.…”

Section: Introductionmentioning

confidence: 99%