Methods and devices for enhanced biochemical sensing

Abstract

A method and application for detecting and measuring the presence of a binding target material employs a semiconductor device having a receptor-covered surface topgate, separated by a dielectric layer from a substrate. Receptors attached to this surface exhibit a chemical selectivity function. Binding occurs in a test solution, with charge associated with the target material modulating at least one device characteristic. According to the present invention, measurement may occur under dry conditions, at a time and location different from when binding occurred, thus substantially eliminating problems associated with ionic shielding and reference electrodes, so prevalent with prior art wet measurement techniques. Preferably the device includes a backgate to which a bias may be applied to restore the device's pre-binding characteristics. Measurement of the restorative backgate bias provides a signal indicating binding of the desired target material. The present invention eliminates the reference electrode commonly found in prior art devices and methods. Beads, conjugates and other objects may be used to enhance charge and thus promote sensitivity. Alternatively a distributed channel bipolar device may be used as a sensor. Sensors according to the present invention may be batch produced and combined in arrays with same or differing receptors to provide rapid measurements, including differential and confirmational testing. Such an array may be combined with an electrophoresis gel material to provide enhanced sensitivity, real-time analysis of drifted charged electrophoresis molecules.