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Preparation Of Microfluidic Chip Based On Graphene And Its Study On Single Cell Behaviors

Posted on:2019-04-13Degree:MasterType:Thesis
Country:ChinaCandidate:X H WangFull Text:PDF
GTID:2348330542973635Subject:Measuring and Testing Technology and Instruments
Abstract/Summary:PDF Full Text Request
Microfluidics is a method of precisely controlling and manipulating microfluidic fluids with dimensions ranging from tens to hundreds of micrometers.As the size of the microfluidic chip channel is generally in the tens to hundreds of micrometers,roughly the same as the single cell size,can precisely control the fluid from the space and time,and save a lot of reagents and cells,with unparalleled advantages to traditional cell behavior research technology.So the development of microfluidic technology provides new ideas and methods for the study of single cell behaviores.The biophysical characterizations in single cell can effectively elucidate the function and status of cells and reveal the difference of cell monomer.It's of great significance for the differentiation and pathology of cells and the early diagnosis and treatment of disease.Biological impedance detection technology had been widely used in the study of cell physiology,and was also the basis for constructing cell impedance sensors.The classical cell impedance electrode is a planar gold electrode.Although,it could be a goodish conduction of electrical impedance changes,it is often need to add some specific chemical modification(antibodies)on the gold electrode,in order to achieve the location of the cells on the specific gold electrode.As well as,Two-dimensional plane electrode could only able to sense the extension and migration of the cell in the plane direction(XY axis),but it does not reflect the movements and changes of the cell in the longitudinal(Z axis),which is not comprehensive for the impedance analysis of the cell's three-dimensional structure.As cell surface is full of micro/nanoscale filamentous pseudopods,if the electrode material and the interface are matched with the size of the filamentous pseudopods on the cell surface from the point of view of the bionic,it will increase the interaction between the cell surface and the electrode material interface,and provide more contact points and greater contact force for the extraction of electrical signals,which will greatly enhance the electrical impedance signal of cells,distinguish and monitor carcinogenesis process of cancer cell more obvious.Based on this,we have developed a microfluidic chip with single/double cells cambered microgrooves by micro-electro-mechanical system(MEMS)processes,the gold and graphene materials were modified on the inner surface of the three-dimensional structure of microgrooves by a series of chemical modification and physical deposition methods.And the conductive film was patterned into many single sensing units.Simultaneous CCD recording and electrical signals extractionallow for the research of cells at different stages.The results were statistically analyzed and compared,the specific studies are asfollows:1.A microfluidic chip was designed to capture single/double cells.A conventional cell impedance microfluidic chip based on two-dimensional planar gold electrode was prepared through a series of micro-nano processing technology.And a series of characterization of the surface morphology were carried out.It was followed by a primary magnetron sputtering process to modify the gold material on the inner surface of the three-dimensional structure of the microgroove.the continuous gold film was cut pieces according to the designed sensing units by a laser dicing with a given energy density.A three-dimensional gold interface of single/double cells impedance microfluidic chip was formed,and similarly a series of characterization chip surface morphology were carried out.2.A single/double cells impendance microfluidic chip of three-dimensional graphene bionic interface was formed by a series of micro-nano processing technology and chemical modification and reduction.The continuous conductive graphene film is etched into a discrete capture sensing unit with a certain energy density of femtosecond laser.The graphene interface and the microscopic morphology,the electrochemical activity,conductivity of the capture microcolumns were investigated and characterized by a series of observations and some electrical impedance tests on various trace solutions.3.A cell impedance test platform was built,a series treatments were carried out for the prepared three kinds of microfluidic chip.The metastatic(MDA-MB-231)and less-metastatic(MCF-7)breast cancer were injected into three microfluidic chips by syringe pump respectively.Single/double cells were captured separately at the corresponding of electrode locations,the inverted microscope with CCD and the impedance meter obtain real-time single and double cells surface morphology and electrical impedance waveform information.At the same time,the cells in the chip were cultured for a certain time interval,the electrical impedance and morphology informations of single/double cells in the whole physiological cycle were obtained,and the corresponding relationship between them was further analyzed.And several repeated experiments and statistical analysis of the related parameters were carried out.Finally,the relationship between the electrical impedance signal and the surface morphology of the single cell was simultaneously obtained by the three-dimensional graphene interface in real time.4.The channel flow rate of the the microfluidic chip and the electric field changes of the three kinds of chips with captured cells is calculated theoretically by the finite element calculation software COMSOL,respectively.The equivalent circuit model of three-dimensional graphene interface and two-dimensional gold interface with captured cell were built,respectively.The parameters of each part were analyzed and compared,and the specific theoretical advantages of the graphene interface were obtained.
Keywords/Search Tags:microfluidic chip, micro-electro-mechanical system(MEMS), single cell capture, electrical cell impedance sensor(ECIS), three-dimensional graphene interface
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