| abstract |
A sensor suitable for the detection of chemical species (e.g. biochemical species) includes a membrane having an ionophore such that gated ion transport may occur through the membrane. The membrane and/or the ionophore is/are such that a dynamic characteristic of conductance through the membrane may be modified when a species to be detected is present. Means are also provided for measuring a dynamic characteristic of conductance through the membrane. The sensor may be used to detect species at very low concentrations and finds application in immunoassay where antibodies are detected with an antigen as ionophore. The dynamic characteristic of conductance measured may be spectral power density, event frequency, auto-correlation function, signal variance, probability density function of current, static lifetime, frequency with which the conductance has a specified value and correlation function of level-crossing times. |