Development Of Flowing QCM And Automatic DNA Analysis System

Quartz crystal microbalance (QCM) transfers the mass signal of thesamples (substance) to the frequency signal via the piezoelectric effect ofthe quartz crystal. It has of many advantages such as high sensitivity andmonitoring in real time, and it is widely used in biomedicine, chemicalanalysis, and environment detection. The development of QCM biosensorinvolves various disciplines such as biology, chemistry, physics,computer, electronics and so on. Based on improving the ordinarystatic-detecting QCM biosensor, this paper developed a flowingautomatic QCM system, which possessed multifunctions such as flowingdetection, temperature controlling and automatic DNA analysis. Thesystem consists of multi-channel flow system, temperature controllingsystem and automatic controlling system of DNA detection. The maincontents as follows:(1) The whole flowing automatic QCM system was developed,including the design and manufacture of multi-channel sample cell,flowing reaction cell, flowing channel and system cabinet. The sampleflowed into the reaction cell under the driving of peristaltic pump andgravity, the frequency shift of quartz crystal was detected in real time.After reaction, the waste and detergent solution were discharged byperistaltic pump.(2) In order to realize the temperature controlling in DNA detectionprocess, the temperature control system was developed. The core isSCU(Single Chip Micyoc). And it is used the DS18B20chip as themeasurement temperature sensor and PN junction diode as the controltemperature sensor. At the same time, The linear relation of temperatureand voltage on PN junction diode was adopted to realize the temperaturecontrol in minimal range of±0.1℃.(3) The development of the automatic control software of DNAhybridization analysis. According to the process of sample injection,immobilization, hybridization and washing in DNA detection, the man-machine interface and control software were designed and written.The serial communication protocol of QCM can realize the automaticcontrolling of DNA detection process.(4) The flowing automatic QCM system was used in DNA detection.DNA immobilization and hybridization detection were performed. Theresults suggested that the system was of good stability and repeatability.