What is Dielectrophoresis? How it is important to separate, diagnose and control the human blood cells with the diseased cells?

Dielectrophoresis
Actually when a dielectric particle is subjected to a non-uniform electric-field, it
experiences a force. The charge on that particle is not the main cause of this phenomenon, as we might expect. Because non-charged particles also experience the same sort of force when subjected to non-uniform magnetic field. The strength of the force depends upon the medium in which that particle is placed and particle’s electric properties. This force also depends upon the shape and size of the particle.

The consequence of our above interpretation is that as this force is shape and size dependent, so it is reasonable to assume that the two particles with different size/shape experience different magnitude of force when subjected to non-uniform magnetic field. By using this force, it is obvious that we can separate the particles of different sizes with a great accuracy. This force can also be used for orienting the particles with particular shape/size according to requirement.
 
Reason of Dielectrophoresis
Dielectrophoresis occurs when a body is suspended in a non-uniform electric field. Under the action of this non-uniformity of electric field, the body is polarized. In other words, the oppositely charged atomic particles, which constitute that body, are accumulated on the opposite corners of the body. Note that it is not necessary for the body to be already charged before exposure to non-uniform magnetic field. Due to this pole formation, the body experiences a force along the electric field lines. As the field is non-uniform so under the action of this force the body moves along the electric field lines.

                                   Fig (1): Step by Step illustration

Dielectrophoresis Implementation for diagnosing, separating and controlling the viable cells. Dielectrophoresis is a well-established and effective means for the manipulation of viable cells. Various applications have been found, ranging from electro fusion, to individual cell manipulation, and to differential separation from cell mixtures. Its effectiveness, however greatly depends upon the utilization of very low electrical conductivity media.

Actually blood is also a combination of particles. The basic unit of blood is blood cell. The shape/size of blood cells in a blood of a healthy person is almost identical. But when this healthy person is attacked by some disease, then these cells fight a fierce battle with the germs of that disease. As a result of which the shape of blood cell is changed and they become distorted. So, these blood cells are subjected to electric field of particular varying intensity range to exert a force on the unwanted cells to separate them from the pure ones.

This process can also be used to diagnose the disease, by working on the same grounds. Actually as we discussed earlier, that electric field exerts a force depending upon the shape/size. The outcome of this statement is that, the bodies with different shapes interact differently with electric field lines. So from this difference of interaction we can determine the disease’s nature.

Another important implementation is to grow a particular structure on a silicon chip. This structure is grown so carefully by using state of the art techniques. The blood is forced to pass through this chip. Different blood particles interact differently with the structure on the chip depending upon their shape and size. This interaction is recorded by micro-controller embedded onto the chip and hence the disease is diagnosed.