Research And Development Of Online Microscopic Imaging System For Artificial Blood Vessel Under Microgravity

Astronauts are facing the severe challenge of space microgravity environment when performing long-term space missions,and cardiovascular dysfunction is one of the main manifestations of microgravity environment affecting astronauts’health.In order to ensure astronauts’health in space orbit,it is very important to study the impact of space microgravity on human blood vessels.Because the real microgravity environment is difficult to obtain,the"simulated microgravity method"which makes the artificial blood vessel cells produce weight loss effect through a clinostat on the ground is one of the common and effective experimental methods.In a large number of experimental has studied on artificial blood vessels using clinostat to simulate microgravity,there is a common problem called"off-line detection",that is,when detecting artificial blood vessels,the artificial blood vessels placed in the detection device have already been separated from the microgravity environment provided by clinostat,which will lead to certain uncertainty and non-objectivity in the experimental results.In order to solve the problem of"off-line detection",an experimental device integrating artificial blood vessel culture function,microgravity simulation function,on-line microscopic imaging function and remote real-time interaction function was developed in this paper,so that the artificial blood vessel under microgravity could be"on-line detected"in real time.For the culture environment required by artificial blood vessels,the system established an automatic control system of temperature,relative humidity and CO₂concentration.Through PID automatic control algorithm,the automatic controlled of three parameters of temperature,relative humidity and CO₂concentration in artificial blood vessel culture environment was realized.The temperature can be stabilized to37℃,the relative humidity can be stabilized at 95%and the CO₂concentration can be stabilized at 5%.The clinostat used to simulate microgravity was manufactured in the form of 3D printing.The rated speed of the clinostat was controlled by PWM electrical signal,which simplified the manual motor speed regulation structure in the traditional clinostat.The actual speed of the clinostat was accurately measured by the speed measurement device composed of Hall sensor and magnet,so that the speed of the clinostat can be accurately controlled and fed back.The special micro objective lens in the micro imaging device of the system had the characteristics of short working distance.Its optical system was designed by ZEMAX,the electronic microscopic ocular was composed of CMOS sensor,and the fixed and connecting structure was manufactured in the form of 3D printing.The micro imaging device was firmly fixed with the artificial blood vessel to avoid mechanical shaking caused by the working process of the clinostat.The magnification and optical resolution of the micro imaging device were actually measured by"image pixel method"and"resolution plate method"respectively.In order to improve the quality of remote real-time interaction and reduce network delay,the architecture of remote interaction software was according to pub/sub architecture,and MQTT protocol was used as message interaction protocol.By deploying back-end agent services,developing message publishing software and configuring graphical message subscription clients,the local or remote low latency interaction function of artificial blood vessel experimental data under microgravity was fully realized.The performance and reliability of remote real-time interactive software were measured and verified by"interactive delay test method".In summary,the research and development of on-line microscopic imaging system for artificial blood vessels under microgravity not only simplified the process of traditional artificial blood vessel experiment under microgravity and realized the"on-line microscopic detection"of artificial blood vessels under microgravity,but also realized the low delay real-time message interaction mode based on the Internet of things communication technology,which brought convenient operation to the experimenters,it also enabled the whole process of artificial blood vessel experiment under microgravity to be remotely monitored and recorded.The research and development of the system provided a special experimental device for researchers in the field of aerospace medicine to study artificial blood vessels under microgravity.