Abstract
Manipulation of bio-particles like cells, DNA, and protein is important for biological and medical research. One of fundamental difficulties for the manipulation of bio-particles is that most conventional manipulation devices are orders of magnitude much larger than the bio-partices, which range in size from a few nanometers to micrometers. Therefore, a number of phenomena and forces utilized to manipulate the position-control of particles have been proposed. Most proposed methods have some limitations and disadvantages. In our research, we aim at the developing a manipulation device that has the similar size order as targeted bio-objects and is a non-contact approach to bio-objects. The term AC electrokinetics refers to the movement of particles using AC electric fields. An AC field induces a frequency-dependent dipole on a polarizable particle. The interaction of this dipole and a non-uniform field can give rise to dielectrophoresis (DEP). By specific construction of the electrode geometry which generates the electric field, we could to create electric field morphologies so that the particles experiencing negative dielectrophoresis are “trapped” in isolated field minima. It is the dielectrophoretic field cage, or called DEP trap. Because the DEP force is a gradient force, an extremely high electric field relative to lower electric field surrounding is necessary for a strong DEP trap. The micro pyramid with sharply geometric changes can generate strong electric field gradient by its local high electric field around its tip to a lower electric field surrounding. Based on this concept, we utilize the anisotropic etching to make the micro pyramid array for bio-particles manipulation.