Stydy Of The Laser Induced Fluorescence Technology For Detecting Microorganisms

Chinese manned space program has developed to the stage, which needs theastronauts’ long-term resident in the space station. There are a large number ofmicroorganisms in the space station when it is in orbit. And it is really a serious issuethat we must pay attention to, because lots of microorganisms had been detected inthe Mir Space Station and the International Space Station. On one hand, thesemicrobes will affect the health of astronauts. On the other hand, some microbes canalso erode the material of the station, which may lead hardware failures. Studies showthat in the space micro gravity environment, microbial mutation may increase, and thetoxicity enhances. In this special environment, effective response to microbialcontamination is prevention, and rapid detection is the premise. In order to meet thedemand of fast and in situ microbial detection in the space station, a system based onPCR technology is designed and realized in this thesis. The main research contentsand results are as follows:1) Some common methods of detecting microbial are compared, and the most fittingone for space is real-time PCR technique.2) Ansys Workbench is used for finite element simulation of temperature field ofmicro fluidic chip PCR, static PCR chip, and micro channel type PCR chip.Thesimulation results show that, three kinds of chips can all meet the requirement of PCRamplification temperature. By experiments, and considering the amplificationefficiency, the automation and so on, the final selection is micro channel type PCRchip.3) The weight and volume of space load is subject to strict constraints. In the courseof the study, the thought of miniaturization and automation has followed t. In thisthesis, the PCR reactor is micro channel type PCR chip based on the idea of microfluidic chip, and the piezoelectric pump technology is used for liquid transport.4) Photomultiplier is usually used for the real-time PCR instrument. But it onlyprovides light intensity information without the location of the light. So EMCCD isused in this thesis, which is high sensitive for weak light detection. By designing thedriving clock and signal processing, the EMCCD can work in the multiplicationmodel. And it can satisfy the requirements of multiple real-time PCR.5) Calibration of the detection sensitivity of the EMCCD system, which can meet thedemand of detecting excited fluorescence. The correct template, the error template and no template experiments are carried out to verify the feasibility of the system. Aneasy integrated automatic air microorganism sampler is designed for the system.Microbial detection system based on PCR technology is designed in this subject,which can not only provide technical support for the biological safety of the Chinesespace station, but also can be used for microbial detection of customs, field hospitals,public health security which need portable, fast occasions microbial detectioninstrument．So it also has great civil value.