Special Invited Lecture: Integrated MEMS Sensors

Monolithic ISFET (ion-sensitive field-effect transistor) pH sensor and microelectrode amperometric immunosensor based on the micro fabrication technology have been studied. The Monolithic ISFET sensor, including the differential ISFET/REFET sensing device and the signal-processing circuit integrated on a single chip, was fabricated by standard CMOS and MEMS technology. Polypyrrole were electropolymerized at different voltage on ISFET gate and REFET gate to form ion-sensitive membrane and ion-insensitive membrane. Micro and compatible amperometric immunosensor, composed of micro electrodes and micro reaction pools, was developed by MEMS technology. Bireceptor molecules were immobilized on the sensitive area of the electrode surface by the technology of self-assembled monolayers. The immunosensor was characterized by detection of immunoglobulin G and ¿-fetoprotein. Both kinds of the sensors show attractive advantages, such as miniaturization, compatibility with CMOS techniques, easy to be designed into micro array and enables relatively rapid, reliable and inexpensive field-analysis.