Design And Fabrication Of Microfluidic System For Cell Indirect Co-culture

The tumor-targeting drug is a new class of drugs that can specifically recognize tumor cells and make them apoptotic without destroying normal cells around them.The construction of in vitro co-culture system similar to cell microenvironment is of great significance for the study of cytotoxicity of tumor-targeting drugs.The channel network of microfluidic chip is very similar to the vascular system of cells in vivo,which can provide a dynamic,stable and uniform microenvironment for cell culture in vitro.Microfluidic chip,microinjection pump and airtight aseptic culture device together constitute a microfluidic system for dynamic cell culture in vitro,which is of great significance for the study of the mechanism of action of tumor-targeting drug cells.In view of the above contents,this paper carries out the following research:(1)Design and fabrication of cell indirect co-culture microfluidic chip with hierarchical bifurcation channel network.According to Murray's law,a cell culture unit was designed,which was integrated in series and parallel to obtain a structure for cell indirect co-culture.The flow field in the structure was simulated by finite element method.The results showed that the flow velocities in the six culture chambers were the same,and the flow velocities are uniform and stable.Based on the above structure,an indirect co-culture microfluidic chip was designed.Using polydimethyl siloxane(PDMS)as the material,the layers of chips were fabricated by photolithography,dry etching and molding.The oxygen plasma bonding of the chips was completed on the visual alignment equipment.(2)Design and fabrication of a dynamic cell culture device for microfluidic chip.The cell dynamic culture device was designed in split form and consists of a pump box,a control box and a culture box.The key to the design of the incubator was the design of the temperature actuator in the incubator.ITO conductive glass with 23 resistor arrays was fabricated by photolithography and wet etching.The ITO conductive glass was used as the temperature actuator in the incubator.The temperature field in the incubator was analyzed by thermodynamic simulation.The results showed that the temperature distribution on the surface of the temperature actuator was uniform and the central temperature could reach 37 C after 460 s of heating.With polydimethyl methacrylate(PMMA)as the box material,the framework of the cultivation device was built,and the related hardware and control system were equipped according to the required functions.Finally,the insulation material was used to package the device.(3)Research on flow field characteristics in chip culture chamber,stability test of culture device and application of microfluidic control system.Through particle image velocimetry experiment,the flow field distribution characteristics in the cell culture chambers on the chip were obtained,which proved that the same flow velocity could be formed in the cell culture chambers of the microfluidic device,and the velocity was uniform and stable.The temperature and humidity changes in the culture chamber and the number of bubbles in the chip were obtained through stability test experiment,which proved that the culture could be achieved.The device could provide the temperature and humidity environment for cell culture for a long time,and reduce the probability of bubble formation by 53%.Hela cells and L-929 cells were taken as the research objects,and the growth curves of two kinds of cells in the culture chamber were obtained through indirect co-culture experiments,which were consistent with the standard "S" growth curve,and the cell survival rate could reach more than 95%.It proved that the microfluidic control system had practical value.