Microchip System for Patterning Cells on Different Substrates via Negative Dielectrophoresis

Seeding cells on a planar substrate is the first step to construct artificial tissues in vitro. Cells should be organized into a pattern similar to native tissues and cultured on a favorable substrate to facilitate desirable tissue ingrowth. In this study, a microchip system is designed and fabricated to form cells into a specific pattern on different substrates. The system consists of a microchip with a dot-electrode array for cell trapping and patterning and two motorized platforms for providing relative motions between the microchip and the substrate. AC voltage is supplied to the selected electrodes by using a programmable micro control unit to control relays connected to the dot-electrodes. Nonuniform electric fields for cell manipulation are formed via negative dielectrophoresis (n-DEP). Experiments were conducted to create different patterns by using yeast cells. The effects of different experimental parameters and material properties on the patterning efficiency were evaluated and analyzed. Mechanisms to remove abundant cells surrounding the constructed patterns were also examined. Results show that the microchip system could successfully create cell patterns on different substrates. The use of calcium chloride (CaCl$_2$) enhanced the cell adhesiveness on the substrate. The proposed n-DEP patterning technique offers a new method for constructing artificial tissues with high flexibility on cell patterning and selecting substrate to suit application needs.