The Study Of Microfliudic Chips Based On Coulter Theory

Cell counting is of great importance for understanding cell growth, biomass measurements and environment monitoring, etc. Coulter microfluidic chips have become a research hotspot, owing to its advantages of fast, efficiency, miniaturization and low power consumption. Our study aims to design a simple and easy processing Coulter’s microchips. Microfluidic behaviors were investigated by numerical simulation and finite element analysis based on fluid dynamics and diffusion theory. It reveals the principle of microfluidic behaviors along with the variation of channel sizes and pressures, etc. It provides a new way of optimizing the parameters and micro fabricating microparts of microfluidic devices.Firstly, a Coulter microchip based on hydrodynamic focusing was designed and simulated to microfluidic velocity, influenced by channel size and fluid property. Microfluidic concentration diffusion with different parameters was then studied based on convection and diffusion theory. The main conclusions as following:If the aspect ratio of a channel’s length and width was fixed,, microfluidic flow velocity will increase linearly with increasing pressure. At the aspect ratio of1, the flow velocity is the fastest. The bigger is the fluidic viscosity, the slower is the velocity.The fluidic diffusion coefficient and inlet pressure have a great influence on fluidic concentration diffusion. The pressure along a channel from inlet to outlet decreased gradually, resulting in fluidic diffusion. The velocity ratio between two sheath flows is a dominat factor of location and width of a fluidic sample in the channel exit. The location fitting formula is: x=0.8633-Ratio+0.3739Secondly, micro-particles were used as an ideal model to study cell’s behavior in a microfluidic channel., Particle’s pathway varied along the sample location in the channel exit, indicating the possibility of hydrodynamic focusing. Under the constant sample flow ratio, the ratio of two sheath flows determines particle’s pathway and its velocity. It can be used to eliminate particles aggregation.Lastly, the bulk concentration of3D laminar flow mixer was simulated.. Both diffusion and mixture of concentration are due to pressure, diffusion coefficient and channel length. With the channel extension, the pressure will decrease, so that concentration diffusion takes place. The agreement of2D and3D simulation results shows significance of this research towards the potential of microfluidic devices.