Integrated bio-switches: novel biosensing devices highly suitable to actuators

Enzyme switch is a novel biosensing device based on the conductometric measurements of polyaniline film covered with oxidase enzyme and peroxidase. In this study, basic characteristics of enzyme switches were investigated. Furthermore, immunochemical switch for human serum albumin (HSA) determination was developed based on an indirect competitive enzyme immunoassay and enzyme switch principle. HSA was determined successfully by using this sensing device. Since enzyme switch is based on the electro-conductivity change, it can be inserted into electric circuits as a variable resistor. Enzyme switch was connected via simple electric circuit to actuators (pumps etc.), and the actuators could be directly controlled by enzyme switch without the use of AD/DA converters and PCs. Finally 9 channel 3-D paired electrodes were prepared and 9 enzyme switches were integrated on one chip. The response characteristics of this integrated enzyme switch were investigated.