Adjustable trapping position for single cells using voltage phase-controlled method.

We present an advanced technique improving upon the micron-sized particle trap integrated in biochip systems using a planar structure to generate an adjustable trapping position by utilizing voltage phase-controlled (VPC) method and negative dielectrophoresis (nDEP) theory in high conductivity physiological media. The designed planar and split structure is composed of independent components of measuring and trapping micro-electrodes. Through different voltage configurations on the device, the trapped position of single particles/cells was selected and adjusted in vertical and horizontal directions. The numerical simulations verify our theoretical predictions of the effects at the various voltages. It shows that the trapped position can be adjusted in the vertical (0 to 26 μm) and horizontal (0 to 74 μm) directions. In experiments, the single particles/cells is captured, measured, and then released, with the same process being repeated twice to demonstrate the precision of the positioning. The measurement results determined that particles at various heights result in different magnitude values, while the impedance error is less than 5% for the proposed electrode layout. Finally, the experiments are performed to verify that a particle/cell can be precisely trapped on the selected site in both the vertical and horizontal directions.