基于红外热成像的PCR温控系统

PCR temperature control system based on thermal infrared imager

电化学实时定量PCR仪中,对热循环3个温度区试剂温度的精度控制至关重要,因为其决定了PCR反应效率。根据非稳态传热原理,热量从基座传递到试剂存在延迟,因此基座上的接触式温度传感器无法直接测得试剂的温度。设计基于红外热成像仪温度检测的温控系统,可以同时对多通道试剂表面的温度进行直接测量,从而准确控制DNA解链-结合-延伸时间,提高DNA扩增效率。为了实现红外热像仪对温度的精确测量,对获取的红外温度进行中值滤波,根据热辐射理论与红外热像仪的测温原理以及公式推导,在线得到被测试剂表面发射率,通过换算从而获得试剂真实温度。实验表明,校准后热像仪测温精度由2.0℃提高到0.3℃;对试剂表面温度的监控使得PCR温控更加准确高效,具有重要意义。

It is very important for ERT-PCR to accurately control the precision of reagent＇s temperature in thermal cycle, because it will determine the efficiency of PCR. According to the theory of unsteady state heat transfer, heat takes time to transfer from block to regent. The temperature control system based on thermal infrared imager can measure a number of target almost simultaneously and accurately control the time of melting, annealing and extension, improve the efficiency of DNA amplification. In order to measure the temperature accurately, the formuals calculating the apparent emissivity of regent are presented based on the theory of infrared radiation and the priciples of temperature measurement by using infrared thermography. After conversion, the accuracy of temperature is enhanced to 0.3℃ from 2.0℃. And it is more reasonable for PCR instrument to set time of constant temperature.