Functional characterization of a conducting polymer-based immunoassay system.
Experiments have been performed to characterize the electrical properties and functionality of a poly(3-hexylthiophene)-coated platinum electrode developed as a sensor for immunoassay read-out. Admittance measurements were performed on the coated electrodes as a function of frequency. The admittance spectra obtained show that the sensor is capacitive in nature. A circuit model is presented for comparison to other conducting polymer systems. Dynamic sensor response is characterized by oxidizing the polymer via a hydrogen peroxide-iodide pathway. Hydrogen peroxide is introduced either by direct injection or through a glucose-glucose oxidase reaction to determine electrode functionality and sensitivity. Sensor response to chemical oxidation is measured as a function of frequency and applied signal amplitude. System response is linear in frequency from 1 Hz to 70 Hz and in excitation amplitude up to approximately 600 mV. System sensitivity is analyzed based on oxidant generation from the enzyme-initiated pathway, sensor baseline drift, and the noise band on the quiescent sensor current.
Fare
T L
TL
Ohmicron Medical Diagnostics, Newtown, PA 18940, USA. thomas-fare@maca.sarnoff.com
Cabelli
M D
MD
Dallas
S M
SM
Herzog
D P
DP
D015374:Biosensing Techniques; D004553:Electric Conductivity; D004566:Electrodes; D004573:Electrolytes; D005949:Glucose Oxidase; D007118:Immunoassay; D018189:Immunomagnetic Separation; D011108:Polymers
D004573:Electrolytes; D011108:Polymers; D005949:Glucose Oxidase