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Direct Electrical Transduction of Antibody Binding to a Covalent Virus Layer Using Electrochemical Impedance.
- Source :
-
Analytical Chemistry . 8/1/2008, Vol. 80 Issue 15, p5695-5705. 11p. - Publication Year :
- 2008
-
Abstract
- Electrochemical impedance spectroscopy is used to detect the binding of a 148.2 kDa antibody to a "covalent virus layer" (CVL) immobilized on a gold electrode. The CVL consisted of M13 phage particles covalently anchored to a 3 mm diameter gold disk electrode. The ability of the CVL to distinguish this antibody ("p-Ab") from a second, nonbinding antibody ("n-Ab") was evaluated as a function of the frequency and phase of the measured current relative to the applied voltage. The binding of p-Ab to the CYL was correlated with a change in the resistance, reducing it at low frequency (1-40 Hz) while increasing it at high frequency (2-140 kHz). The capacitance of the CYL was virtually uncorrelated with p-Ab binding. At both low and high frequency, the electrode resistance was linearly dependent on the p-Ab concentration from 20 to 266 nM but noise compromised the reproducibility of the p-Ab measurement at frequencies below 40 Hz. A "signal-to-noise" ratio for antibody detection was computed based upon the ratio between the measured resistance change upon p-Ab binding and the standard deviation of this change obtained from multiple measurements. In spite of the fact that the impedance change upon p-Ab binding in the low frequency domain was more than 100 times larger than that measured at high frequency, the S/N ratio at high frequency was higher and virtually independent of frequency from 4 to 140 kHz. Attempts to release p-Ab from the CVL using 0.05 M HCl, as previously described for mass-based detection, caused a loss of sensitivity that may be associated with a transition of these phage particles within the CVL from a linear to a coiled conformation at low pH. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00032700
- Volume :
- 80
- Issue :
- 15
- Database :
- Academic Search Index
- Journal :
- Analytical Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 34121094
- Full Text :
- https://doi.org/10.1021/ac8008109