A Numerical Simulation Study For Generation And Control Of Biochemical Signals In A Microfluidic Shear Device

The relationship between cell microenvironment and cell information regulation is one of the hotspots in the cell biology research.It is difficult to carry out in vivo research directly because the cell microenvironment is very complicated.Therefore,the in vitro study of cells has become a common method in cell biology research.The microfluidic shear device based on microfluidic technology can generate the desired biochemical signals and shear stress,which has become an important platform for simulating cell dynamic biochemical microenvironment in recent years.In order to study the quantitative relationship between extracellular microenvironment and cellular information regulation,it is very important to quantitatively generate dynamic biochemical signal solutions in the microchannel.In the study of generating biochemical signals by microfluidic shear device,the influence of attenuation of biochemical signals during transmission is neglected,and the analysis and control of loading biochemical signal process are lacking.Therefore,it is necessary to quantitatively analyze the loading process of biochemical signal in microfluidic shear device and find the method to reduce the error of loading biochemical signals.In this thesis,the numerical simulation of the quantitatively loading and control process of the biochemical signals in the microfluidic shear device is carried out.The main contents are as follows:(1)the fundamental fluid mechanics in the rectangular microfluidic channel is analyzed by solving the Taylor-Aris dispersion equation;(2)based on the characteristics of the transmission system of the rectangular microfluidic channel,the PID controller is designed and the quantitatively loading process of the low frequency biochemical signals is simulated numerically;(3)a further simulation study has been conducted on the ‘remote' regulation of the intracellular calcium signal in the vascular endothelial cells by controlling extracellular ATP signals.It is concluded that low-frequency biochemical signals can pass through the microfluidic channel without waveform distortion under the different micro-flows,transmission distances and signal waveforms.Based on the PID controller,the biochemical signals in the microfluidic shear device can be quantitatively generated and controlled,and the low frequency interference can be reduced in principle.Furthermore,desired ATP signals can be quantitatively loaded into the cells in the microfluidic shear device so as to control the intracellular calcium signals in vascular endothelial cells.This work provides a theoretical feasibility and methodological base for further experimental study of the quantitative relationship between dynamic microenvironment and cellular function by effectively using the microfluidic shear device.