ANALYTE SPECIFIC CHEMICAL SENSOR

An analyte specific chemical sensor for determining an analyte in a test medium. The sensor comprises a sensing surface which is coated with reversible competitive recognition units (RCRUs) each of which contains as constituent components at least one receptor and at least one ligand, one of which components is an analyte analogue. In these RCRUs the receptor and the ligand are a priori connected to each other, directly or indirectly, in such configuration that even when, for example, an analyte analogue ligand is displaced from the receptor by an analyte ligand, the analogue will still be retained in relatively close proximity to the receptor. In addition, the relative positions of the receptor and the ligand in the RCRU are such that when no analytes are present or when the analyte concentration is at a low level, they are affinity conjugated by a specific affinity interaction. The fluctuations of analyte concentrations in the test sample affect the chemical occurrences at the RCRUs, and consequently the physico-chemical characteristics of the components thereof. The changes in the analyte concentration are monitored, according to the present invention, by continuously measuring the changes of the above physico- chemical characteristics induced by occurrences at the RCRUs, namelythe inner association and dissociation thereof. Such physico-chemical characteristics may be, for example, photochemical, e.g. light absorption, light emission, light scattering and light polarization; electrochemical; and piezoelectrical.