Research On Biochemical Environmental Parameters Detection And Mechanical Stimulation Control Technology Of Bioreactor

Tissue defects caused by trauma,congenital diseases,aging,etc.are very common in clinic,but traditional treatment methods are not effective.The repair of tissue defects is still a major problem in clinical medicine today.Tissue engineering technology is one of the most promising therapeutic measures.In vitro culturing of engineered tissue requires a bioreactor that can accurately simulate the biochemical and mechanical environment.However,the current bioreactor is difficult to meet the demand,and it is still in the stage of laboratory application and clinical research.Only by fully considering the synergy of the mechanical environment and the biochemical environment can a better culture effect be achieved.Therefore,it is urgent to develop a bioreactor that can accurately simulate the specific tissue mechanics and biochemical microenvironment.Firstly,the historical background and significance of the research on mechanical bioreactor are expounded.The biomechanics research in tissue engineering technology is analyzed.The research status of bioreactor monitoring technology,evolutionary algorithm of simulating cell behavior and mechanical bioreactor control technology are discussed.The research focus of this thesis is pointed out.In order to achieve the aseptic and intelligent monitoring of environmental parameters of tissue engineering bioreactor,a general sensor unit design of bioreactor monitoring system suitable for various tissue and cell culture was built.In this thesis,three important environmental parameters of p H,DO and CO₂ are selected,and the corresponding sensor detection principle was analyzed in detail.Combined with the need for disinfection and online measurement of the sensor in the bioreactor monitoring system,the selection of sensor is determined.The calibration method is given to ensure the accuracy of the sensor.In response to the requirements for accurate and intelligent detection of biochemical environmental parameters of tissue engineering bioreactors,a data acquisition unit based on ADC+STM32 hardware architecture was developed.Firstly the design of IV signal conditioning circuit,signal acquisition and conversion circuit,data processing circuit and data transmission circuit is completed,and then the software design of the system is given.The thesis introduces the completion of software program design in the main program module,data processing and transmission module,and the system intelligent monitoring cloud platform is discussed.Finally,the experiment is carried out based on the developed data acquisition platform.The experimental results show that the data acquisition unit developed in this thesis can realize the intelligent monitoring of the bioreactor biochemical environmental parameters.In the process of tissue culture in vitro,applying corresponding mechanical stimulation can obtain better culture effect,but the best mechanical stimulation scheme needs to be obtained through a large number of culture experiments,which has a long experiment period and high cost.In response to this problem,a cellular automata(CA)based cellular evolution algorithm under mechanical stimulation is proposed in this thesis.Firstly,the dynamic differential equations of the relationship between cell growth and environmental limiting factors and self-limiting factors were deeply studied,and the functional relationship between cell concentration and matrix concentration is deduced,two-dimensional cell growth space is constructed.Based on the cell growth mechanism,cell neighbors and nutrients,the evolution rules are established,and the cellular automata simulation evolution algorithm based on improved dynamic differential equation is proposed.The simulation experiment results show that the algorithm proposed in this thesis can accurately simulate the in vitro culture process of cells under mechanical stimulation,and the experiment period is shortened,which provides a reference for the best mechanical stimulation scheme required for tissue culture.After determining the optimal mechanical stimulation program,precise mechanical stimulation control is very important for the effect of in vitro tissue culture,and the accuracy of bioreactor mechanical stimulation control is affected by many factors.In this thesis the structure of the bioreactor servo system is analyzed in detail,the control model of each link of the servo system is deduced,the error source of the bioreactor servo control system is studied,and the two-quality servo system model considering friction interference is established.The controller design based on fuzzy adaptive PID algorithm is given.The simulation results show that the method proposed in this thesis can effectively improve the anti-interference of the system control and the accuracy of the mechanical stimulation control.