A Microfluidic Device For Single Cell Micropipette Aspiration Based On Wheatstone Bridge

A series of biological functions or behaviors of cells are considered to be closely related to changes in cellular mechanical properties.Therefore,the deformation and mechanical properties of single cells are often used as important indicators in cell mechanics analysis.Since the mechanical properties of each cell are quite different,in order to get more accurate information on the characteristics of cell mechanics,an effective experimental analysis platform is needed for the analysis of single cell mechanics.Microfluidic technology has been widely used in the study of single cell mechanical properties owing to its microminiaturization,small volume of reactant,sample miniaturization,accurate control of fluid and good biocompatibility.The existing methods can be classified into two categories: non-contact methods based on the principle of micro vortex or stagnation point flow;contact methods based on micro traps or dynamic micro.However these methods have some shortcomings of complexity,instability,difficult to achieve high flux capture,and inconvenience to directly analyze single cell mechanical properties.In the work,a microfluidic device for single cell micropipette aspiration based on Wheatstone bridge has been designed.Firstly,a microfluidic device is designed for single cell micropipette aspiration and mechanical properties analysis according to the principles of Wheatstone bridge,fluid mechanics and microfluidics technology.In the microchannel,the parameters such as flow resistance,flow rate and differential pressure are calculated,which theoretically confirm the possibility and capacity of micropipette aspiration and mechanical properties analysis.Secondly,in order to accurately understandthe flow field and other related information in the microchannel,and to verify the reliability of the model calculation,thecharacteristics of fluid mechanics in the microfluidic chip is simulated with COMSOL.Comparing the simulation results with the theoretical results proves the reliability of the theoretical results and correctness of the differential pressure calculated from the theoretical model.Finally,an experimental system based on the microfluidic chip is designed and established in this paper,including a programmable injection pump,a microscope,a charge coupled device camera and a computer.Then microsphere capturing and cells aspiration experiments are carried out to achieve microsphere capturing and single cell micropipette aspiration,and the mechanical properties of single cell is further analyzed.In this paper,the designed microfluidic device for single cell micropipette aspiration based on Wheatstone Bridge provides a new platform for the investigation of single cell mechanical properties.