Particle Trapping Using Dielectrophoresis

Chemotherapy is a method used to treat cancer; drugs enter the body to kill cells that can reproduce quickly. However, these drugs cannot differentiate between cancer cells and non-cancer cells, resulting in many side effects. We are conducting research on site specific drug delivery, in which drugs will only treat targeted cells. The drug must be enclosed in a polymer capsule until it reaches the desired location. We must determine the changes in the environment that will open the capsule; this will prevent the drug from being released too soon or too late.

The vesicle is observed in solution using a microscope. Because of the vesicle’s small size, even a drop of liquid used to change the properties of the solution can push the vesicle out of our field of vision. To solve this problem, we must use a method to trap the vesicles; dielectrophoresis is a phenomenon in which a force acts on a particle in a non-uniform electric field.  With negative dielectrophoresis, the force acts towards regions of low electric field and thus, traps the particle in those regions. The dielectrophoretic force counteracts the forces due to other factors such as drag, Brownian motion, gravity, and buoyancy to give a net force of zero.

We will create various electrode geometries to run simulations on COMSOL Multiphysics. Using fluid dynamics and electrostatics, we will determine the dielectrophoretic force required to trap a particle for our selected geometries, which will allow us to decide the optimal geometry for continuing research.