Design Of A Microfluidic Chip And Study Of The Application On Cell-stretching Manipulation

Biomedical study based on manipulation techniques of biological cells andanalysis of microfluidic-chip systems has been one of most advanced science andtechnologies in the world. It has been sufficiently proved that the biomechanicalparameters of cells are related to their biological functions, and happening anddevelopment of some diseases are attributed to the change of biomechanical parameters.This article discusses how to use microfluidic chips and dielectrophoresis (DEP)technologies to test the cells’ biomechanical performance after medical treatmentdirectly on cell level, and thus realize a quick evaluation of the new medicines. Via theDEP force generated by the interaction between the electrical field and the cells, we canstretch the normal and lesion cells separately, and measure the biomechanicalparameters of them, such as strains, Poisson’s ratio, Young’s modulus, elastic constants,viscoelastic, adhesion, etc. Following this, measure the biomechanical parameters of thelesion cells which were treated with drugs. Compare the parameters with the former two,so as to monitor the efficacy of drugs. This system can be applied to the field of drugresearch and development, which will accelerate the speed of drug screening, obtain asmuch as information of the most of drugs in the study of once time, in order to improvethe efficiency of early research, enhance confidence in late stage of drug study, so as toshorten the development cycle of new drugs. The research focus of this paper is asfollows.(1) The basis study of cell stretching chips based on the theory of dielectrophoresis:theory of dipole moment, the dielectric and the principle of relative dielectric constant,the principle of dielectrophoresis chip, controlling factors of dielectrophoresis chip,calculations the dielectrophoresis forces of spherical and ellipsoidal cells.(2) The processing of design and fabrication of microfluidic chips for cellstretching manipulation: design and simulation of chips for cell stretching, the choice ofmaterials for chip fabrication, fabrication processing of PDMS channel, fabricationprocessing of microelectrodes, bonding process of PDMS channel and glass substrates.(3) Study of the cell stretching experiments using of the microfluidic chips integrated with microelectrodes: the establishment of the experimental system, theorigin and nature of NB4cells, the selection of voltage and frequency used for cellsstretching manipulation, stretching NB4cells before and after drug treatment.(4) The results of cell stretching manipulation and discussion: process theexperimental data to obtain the strain versus time curve and the strain versus thedielectrophoretic force curve, by compare the differences between cells without drugtreatment and cells treated with drugs. Through analyzing these two curves of NB4cellsto detect the efficacy of drugs.In summary, this paper achieved stretching operation for NB4cells by designedmicrofluidic chip. Focuses on studying the relationship between the curves of NB4cells,one cure is the strain versus time and the other is the strain versus dielectrophoresisforce. The results show that: the maximum strain of NB4cells without drug treatmentwithin180s is0.06-0.09and the maximum strain of NB4cells treated with drugs was0.18. It can be drawn the conclusion that NB4cells treated with drugs are stiffer thanthat treated without drugs. Analysis the curve of strain versus dielectrophoresis force:the strains of the two kinds of cells increase with force. The strain of NB4cells withoutdrugs treated increases faster than that treated with drugs. This data also shows the drugtreated NB4cells are stiffer than NB4cells without drug treatment. The aboveexperimental results show that drugs play a role on cells.