Researchon Key Issues Of Cell Culture System With Real-time Dynamic Microscope Imaging In Space

Continuously improving cell culture experiments in space and simulating testson earthhas become one of the most efficient methods to explore the fundamental reasons, whichcould cause complex and negative influencesto our human from cellular level to the wholebody system.Thus in order to guarantee the stability of the whole cell culture process,building a full set of cell culture system with space environmental adaptability has beenacknowledged as one of the most significant equipment to explore the space life science.Compared with the environment on earth, the universe has its own special characters,such as micro-gravity, strong radiation, ultra-low temperature and high vacuum condition.Therefore, space life science has gained its most widespread attention and become one ofthe most popular research fields all over the world. When trying to design the cell culturesystem, extra considerations must be conducted to overcome some obstacles, such as thehuge cost, limited time, limited volume of the device, limited room for operation and so on.So we need to take anoverall consideration of various factors, such as the integration of thedevice, the heat transmission, the mechanical properties, etc. What’s more, the real-timemicroscope monitoring of some physical changes, like the morphological changes and themovements of the cells, could give much better evidences to explain some specialphenomena during the cell cycle in space. Hence, a highly-integrated visible lightmicroscope imaging system is also a necessity.So based on the former investigation of the development of space cell culture devicesboth at home and abroad, we determined to develop a highly-integrated and full-automatedcell culture system.With the features of high thoughtput, small size and high efficiency, microfluidic chipsare utilized as the cultivation platform finally. To optimize the micro-channel and thestructure of the cultivation chamber, finite element analysis software was applied for the inner flow and thermal simulation of the microfluidic chips. To achieve the accuratetemperature control around37℃±0.5℃, a low-power consumption micro-controllerMSP430was adopted and incorporated with PID feedback algorithm (ProportionIntegration Derivation). And instead of using peristaltic micropump，a piezoelectricdiaphragm micropump was used to meet the requirement of accuracy and low velocity ofcell culture perfusion, together with its corresponding controller mp6-OEM. Finally, wefinished intermittent dynamic perfusion culture of SH-SY5Y. To facilitate the assembling ofmicrofluidic chip, illumination source and Paltierthermoelectric cooler, we made aspecialized chip box using photosensitive resin by3-D additive manufacturing technology.On the other hand, we designed a multi-channel microscope system to monitor thedynamic morphological changes and the movements of the cells.We utilized FPGAas thecore microprocessor of the imaging system, CCD as the photosensitive device. Thecomplete front-end solution for CCD imaging was employing the analog-to-digitalconvertor AD9923A. Then the video data was transmitted to PC for real-time monitoringthrough PCI-e bus. At last, all of the function modules were assembled and integrated in acompete structure designed with space adaptability to accomplish the cell culture withreal-time dynamic microscope imaging in space.