Capacitive sensor and method of use
AssigneeAltratech Limited
InventorsTimothy Cummins, Brian O'Farrell
Life of this patent
Estimating the term…
Abstract
An analyte in a liquid sample is detected using a capacitive sensor having electrodes and a sensor surface, and a signal processor. The sample is dried to reduce its liquid content, and capacitive measurements are made after the drying and preferably also before the drying. The sample may include particles, and the analyte is part of or attached to the particles, and the particles provide a major part of the capacitance change compared to absence of particles. In another example the particles are degenerative and form an integral mass upon application of heat, enhancing the extent of capacitance change.
Claims18
A method of detecting nucleic acid analytes in a liquid sample using a capacitive sensor having inter-digitated electrodes covered by an insulating protective layer, said insulating protective layer providing a sensor surface, the sensor surface comprises a PNA probe fixed on the sensor surface, said probe being selected to bind to the nucleic acid analyte and a processor linked with the electrodes,
- the method comprising steps of:
- bringing the liquid sample into contact with said sensor surface, wherein the liquid sample includes beads attached to nucleic acid analytes, and said beads provide a major part of a capacitance change in which there is an increase in capacitance with increasing number of beads,
- drying the liquid sample,
- measuring capacitance of the dried sample by fringe-field sensing in which there is a fixed capacitance portion in the insulating protective layer, and a variable transducer portion in the air or analyte above the insulating protective layer, and
- using said measurement to provide data concerning the analyte.
Dependencies are inferred from the claim text.