ABSTRACT
Striking demands of immunoassay have urged many investigators to develop immunosensors provided with such requisites as (1) high selectivity, (2) high sensitivity, (3) simplicity, and (4) reproducibility. Since the concept of immunosensors was proposed in the early 1970’s 1 , 2 ), a considerable numbers of papers on immunosensors have been published 3 – 5 ). These immunosensors are categorized into (1)immunosensors without labels and (2) immunosensors with labels. The principles of these immunosensors are schematically illustrated in Figs. 1 and 2. All of these immunosensors depend on molecular recognition of antibody for their high selectivity. Non-label immunosensors are characterized by simple operation, but may not attain sufficiently high sensitivity. In contrast, label immunosensors may provide high sensitivity, although they suffer from lack of simplicity in operation.
