Design Of Piezoelectric Biochip Auto-Detector Applied In Food Safety

Food safety is a common healthy problem worldwide, which is not only related with health and survival of humankind, but also impacts economy and development of society. Food origin disease is the primary issue of food safety. Detection of food origin virus is the pivotal technique in the prevention and control of food origin disease, and it is crucial to the consummation of food safety system. The biosensor technology is a crossing technology involving bioengineering, biochemistry, physics and microelectronics. With the using of new theories and new techniques, the biosensor technology has been greatly developed. Combining the high mass sensitivity of the quartz crystal sensor and the high specificity of the biologic reaction, the piezoelectric biochip has become one of the hotspots in the field of biosensors nowadays. The piezoelectric biochip has many advantages such as quick response, simple and convenient manipulation, high sensitivity, being labeled needlessly and continuous detection. Using piezoelectric biochip in the food safety is a new field. Based on the piezoelectric sensor detection principle, the author designed the piezoelectric biochip detector used in food safety. The paper introduces the definition and the detection theory of the biosensor, the hardware and the software of the whole detector. The instrument uses the piezoelectric quartz crystal immobilizing the biologic probe as sensing element and transduction element, with a reasonable structure for the reaction. The control system adopts the computer and microcontroller framework, and they communicate through the USB interface. AT89S51 microchip system were used to control the peripheral devices under the command of PC, dominating the flowing infusion system, fulfilling the functions such as infusing the specimen, washing the biochip, detecting the frequency, transmitting the data. The software of the computer provides the manipulation interface and the database, controlling the microcontroller to realize the detecting process via the USB, and fulfill the function of displaying the waveform, disposing the data, analyzing the result etc. Programmable logic device was designed as an eight-channel cymometer, measuring frequency signal of eight gates synchronously. The system has the following virtues: convenience, rapid transfer speed, stable quality, favorable expansibility etc. The software was developed under the environment of C++Builder 6.0. It includes system management module, USB data communication module, dada review and analysis module, and database management module. The author has already realized the design of hardware and part of the software module of the whole piezoelectric biochip detector. The equipment can work stably and safely. It has laid a firm foundation for deeper experiment and analyses.