Sensor employing impedance measurements
First Claim
1. A sensor comprising:
- an immobilised affinity component capable of interacting with a predetermined analyte species and being associated with a conducting polymer such that interaction of the affinity component and the analyte induces a change in electrical properties of the polymer, means for applying an AC signal to the polymer, and means for detecting the response of the polymer to the applied signal to detect the induced change, wherein the detecting means comprises means for measuring the impedance of the polymer at a frequency selected to correspond to a peak in the relationship between frequency and impedance change for the polymer and the predetermined analyte.
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Accused Products
Abstract
A sensor uses an immobilized affinity component capable of interacting with analyte species and being associated with a conducting polymer such that the interaction of the affinity component and the analyte induces change in the electrical properties of the polymer. An AC signal is applied to the polymer, and the induced change in impedance resulting from the interaction is measured. The impedance is measured at a frequency or frequencies corresponding to a peak or peaks in the relationship between frequency and impedance change for the polymer and the analyte. The measurement may be made by reference to the imaginary or real component of impedance. The polymer may be in the form of a layer bridging two electrodes between which the impedance is measured. The two electrodes may together define an interdigitated electrode assembly.
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Citations
18 Claims
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1. A sensor comprising:
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an immobilised affinity component capable of interacting with a predetermined analyte species and being associated with a conducting polymer such that interaction of the affinity component and the analyte induces a change in electrical properties of the polymer, means for applying an AC signal to the polymer, and means for detecting the response of the polymer to the applied signal to detect the induced change, wherein the detecting means comprises means for measuring the impedance of the polymer at a frequency selected to correspond to a peak in the relationship between frequency and impedance change for the polymer and the predetermined analyte. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for enhancing the sensitivity of a sensor said method comprising:
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associating an immobilised affinity component capable of interacting with an analyte species with a conducting polymer such that the interaction of the affinity component and the analyte induces a change in the electrical properties of the polymer, applying AC signals to the polymer, and detecting a response of the polymer to the applied signals to detect the induced change, wherein the impedance of the polymer is measured over a wide frequency range, at last one peak in the relationship between frequency and impedance change resulting from exposure of the polymer to the analyte is detected, and the sensor is operated at a frequency or frequencies corresponding to a detected peak or peaks.
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Specification