| Summary: | 碩士 === 國立中興大學 === 生醫工程研究所 === 99 === Compared with the working medium, cell is easily to encounter an electric field induced polarization. Hence a positive dielectrophoretic force, which is generated due to an unbalanced electric field, will drive the cell toward the area of high electric field density. In this study, the finite element analysis software COMSOL is used to investigate the influence of an electric field on cell behavior for a better design of the dielectrophoretic electrode. Accordingly, a dielectrophoretic device that contains several micro electrodes for producing unbalanced electric field is fabricated using microelectromechanical fabrication technique. The proposed device is then used for the detection of cell adhesive force on PDMS and PLA.
It is observed that those cells cultured on PDMS firmly stick on the material without any movement under the actions of different dielectrophoretic force. However, the dielectrophoretic force due to a 6 V applied potential is enough to move those cells having cultured on the PLA for 4 and 6 hr. When the culture period is increased to 8 hr, a higher applied potential of 16V is required to move the cells. The cells cultured on the PLA for 24 hr are not relaxed by the dielectrophoretic force even a higher potential is applied. Theoretically, a higher applied voltage can induce a larger driving force to move the cultured cells. For the PLA scaffold, a higher potential is required to move those cells having longer culture time. While for the PDMA scaffold, the cells cultured on it have a much higher adhesive force such that the dielectrophoretic force generated by the proposed device cannot lift the cells from the scaffold. A higher applied potential results in the unwanted cell lysis.
The contact angles of PDMS and PLA are measured to be 92.21and 83.11, respectively. It indicates that the PLA surface is more hydrophilic than PDMS. In general, cells should have a better adhesion on PLA scaffold. However, the experimental results in this study reveal that cells have better adhesion on the PDMS scaffold. It is presumed that other properties of the scaffold influence the cell adhesion more than its hydrophilic-hydrophobic property.
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