基于NTC热敏电阻器的实时PCR仪数据采集器设计

摘要

实时聚合酶链反应(PCR)是一种通过热循环与荧光信号检测方法实现特定DNA片段的快速复制与定量检测的技术.PCR反应过程中,热循环温度控制精度决定了PCR反应效率,从而直接影响定量检测的精度.根据非稳态传热原理,热量从基座传递到试液需要一定的时间,为了检测这一延迟时间对温控的影响,基于NTC热敏电阻器,采用USB总线和FPGA技术,以USB控制器和FPGA为核心控制模块.AD7663为模数转换芯片,实现数据采集器的设计,并采用多线程技术和缓冲队列方法实现连续数据采集.通过理论与实验相结合,准确测量了试液升降温过程中的延迟时间,对实时PCR仪温度控制具有重要意义.%Real-time polymerase chain reaction (PCR) is a method for rapid replication and quantitative detection of specific DNA fragment through thermal cycle and fluorescent signal detection. The precision of temperature control in thermal cycle determines PCR efficiency, and also affects the precision of quantitative detection. According to the theory of unsteady state heat transfer, heat takes time to transfer from block to test solution. In order to know the influence of the delay time on temperature control, a data acquisition has been designed using USB bus and FPGA technology based on NTC thermistor, and continuous data acquisition is achieved through multi-threading technology and buffering queues. By the combination of theory and experiment,the delay time of heat transfer has been measured successfully.