In this novel enzyme-tagged immunoelectrochemical assay, disposable carbon felt discs serve both as electrodes and as the heterogeneous solid phase. Antibodies are immobilized on the carbon felt via a diaminoalkane-biotin-avidin-biotin bridge. Alkaline phosphatase is used as a label. Bound antibodies are monitored by following the electro-oxidation of aminophenol, produced enzymatically from p-amino-phenyl phosphate by the immobilized alkaline phosphatase at the electrode surface. A model system designed for determination of mouse IgG concentration yielded a calibration curve ranging from 10pg/ml to 100pg/ml. This assay can be performed rapidly and a single determination completed within 20 minutes. The system is useful also for rapid quantitation of a small number (-80 organisms per ml) of bacteria.
- electrochemical sensor