Study Of Polymer Substrate MEMS Technology On Biomedical Application

MEMS technology is a kind of micro manufacture technology which developed along with silicon micro manufacture technology. By process such as photolithograph, we can manufacture device of micro or nano dimension. Flexible MEMS and Bio-MEMS have appeared in MEMS domain recent several years. Device of micrometer dimension on flexible substrate can be manufactured by flexible MEMS technology, and these devices have the virtue that they can bear impact and can be curved; in vitro diagnostic device and in vivo device can be manufactured by Bio-MEMS technology.With developing of organic compound technology, recent year people developed kinds of polymer material, which has good fabrication character and good biocompatibility. These organic compounds are used widely in medical domain. This thesis mainly focuses on fabricating bioelectrode array on organic compound PI substrate and application of epoxy based SU-8 in breast cancer MCF-7 cell culture.Retinal Prosthesis is a therapy method that through implant micro electrode array on retina of blind people, using electric signal stimulate retina, and cause the blind to see vision. In Retinal Prosthesis, bioelectrode array, as the bridge between artificial instrument and nature neuron, is most important to transmittance of electric signal. We manufacture bioelectrode array using MEMS technology, for the resolution on retina is of micro dimension. Now some two dimensional bioelectrode arrays have been developed.With further research to cell culture, people find that cell cultured in three dimensional structure of micro or nano dimension differs from ones that cultured in two dimensional structures. Bio - MEMS has the nature advantages in in vivo device manufacture for its small dimension.First subject of this thesis is that we developed a kind of 3-D bioelectrode array used in retinal prosthesis. Using common MEMS technology such as sputtering, RIE, photolithography, electroforming, etc, combine with character of PI(Polyimide), we manufactured a kind of 3-D bioelectrode array on flexible substrate successfully. We solved the problems in process technology, which include adhesion force between PI and wire, electrode biocompatibility protection, emerge of electrode, and peeling apart of flexible substrate. Differ from two dimensional bioelectrode array, 3-D bioelectrode array electrodes protrude from substrate surface and can contact with tissue more fully. Our bioelectrode array is flexible because we use polyimide as the substrate. Impedance test result indicates that the impedance of single electrode is from 22 kΩto 8 kΩwhen frequencies vary from 20 Hz to 10 kHz. The impedance of our bioelectrode is small, as a result, it consume less energy on bioelectrode array when electric signal pass through it. It is suitable to use three dimensional bioelectrode arrays as a tool of researching retinal neural signals.The other subject of this thesis is that we manufactured SU-8 grooves, pentacle and gear structures of micro dimension with different deep wide ratio using MEMS technology. We cultured breast cancer MCF-7 cells in micro structures. Configuration observation, MTT check and flow cytometry were used to check effect of microstructures on breast cancer MCF-7 cells to research potential application in tumor therapy of micro structures.