Design And Research Of Cell Adsorption Chip For Patch Clamp System

Cells can conduct intracellular and intercellular signaling through ion-transmembrane flow.Patch clamp techniques are commonly used to measure ion channel currents and membrane potentials,and are widely used in electrophysiology and life sciences,but traditional glass microelectrodes in the patch clamp experiment,there is a problem that the production and operation are difficult,the efficiency is low,and the movement is easy to cause the sealing effect with the target cells to be poor.In recent years,microfluidic chips have been widely used in patch clamp research with their unique advantages of precise fluid control,easy operation of single cells,and good biocompatibility.However,the conventional microfluidic patch clamp cell adsorption chip has problems of high adsorption difficulty,low cell utilization rate,and complicated process preparation.Therefore,a patch clamp cell adsorption chip with simple structure,convenient operation and high throughput will greatly facilitate the measurement of cell membrane potential.Based on the principle of fluid dynamics,a microscopic,simple and efficient cell adsorption chip for the patch clamp experimental system is designed.The specific research contents and results are as follows:(1)Theoretical analysis: Chip structure was designed in combination with cell size and the requirements of patch clamp experiment on cell adsorption,and the flow velocity,flow resistance and pressure drop in the micro channel were analyzed based on Poiseuille's law to determine the dependence of negative pressure required by adsorption channel on the flow velocity.Through theoretical analysis,this paper determines the design scheme of the "snake channel" and the patch clamp capture channel of the main channel using the arc and the straight line to adopt the transition structure from fine to coarse.The calculation results indicate that the completion of cell adsorption requires the application of a negative pressure at the patch clamp capture port;There is a linear relationship between the input flow rate(flow rate)and the minimum applied negative pressure value;As the distance between the capture unit and the main channel entrance becomes closer,the linear coefficient becomes smaller(-1611,-1724,-1551,-1349,-11,18,-868);The closest and farthest capture unit from the main channel entrance has a linearity difference of half.(2)Numerical simulation: Using the finite element multiphysics analysis software comsol to establish a simulation model of microfluidic chip capture cells,simulating the flow velocity,pressure drop and particle motion trajectory in the channel.The results show that near the cell capture channel port of the chip,the pressure of the fluid drops sharply and the flow rate increases significantly,and the affected area accounts for about 1/3 of the main channel;The trajectory of particle motion in the simulation further verified the phenomenon that cells in this region are easily adsorbed.In a simulation with a flow rate of 3 mm/s and 20 microparticles randomly placed,it can be observed that the capture of cells is dependent on the applied negative pressure,and the optimal negative pressure is-1000 pa.(3)Experimental verification: The cell adsorption experiment platform was built by using the prepared microfluidic chip,and the effectiveness of the chip on the adsorption of microspheres with different particle sizes was verified by polystyrene microsphere capture experiments.The stable adsorption of cells under flow interference was achieved by cell adsorption experiments,and the applied negative pressure values were consistent with the theoretical calculations.The cell adsorption chip designed for the patch clamp experimental system in this paper has successfully achieved stable adsorption of single cells in theoretical analysis,simulation and cell experiments.And some key result parameters are consistent with each other,showing good feasibility,providing a convenient and convenient platform for patch clamp experiments such as cell membrane potential measurement and control.