Quartz Crystal Based Microgravimetric Immunobiosensors

Piezoelectric crystal immunosensors have attracted considerable interest in the last few years since the monitoring of a specific substance is central in many applications. These sensors work on the principle of measuring a small change in resonant frequency of an oscillating piezoelectric crystal due to change in mass on the sensor surface. Because of their low cost and high Q-factors, these miniaturized sensors show fast response time, high sensitivity, and are suitable for mass production using standard fabrication techniques. Arrays of such sensors could be fabricated to cover ranges of a particular sensing property and have the potential for seamless integration with CMOS-based electronics. The present article demonstrates a type of piezoelectric crystal immunosensor using simple design of frequency oscillator and monitoring circuitry for biomedical applications. The basic criterion for immobilizing biomolecules (receptor etc.) on sensor surface for immunoassay application is briefly discussed.