Dielektrophorese

Dielektrophorese is a phenomenon where polarizable particles suspended in a non-uniform electric field experience a net force. This force arises from the interaction of the induced dipole moment of the particle with the electric field gradient. Unlike electrophoresis, which relies on the net charge of a particle, dielektrophoresis works on neutral particles as long as they are polarizable. The direction and magnitude of the dielectrophoretic force depend on the dielectric properties of the particle and the surrounding medium, as well as the frequency and strength of the applied electric field.

When a particle is placed in a non-uniform electric field, the field induces a dipole moment within the particle. If the particle's permittivity is higher than that of the medium, the induced dipole aligns with the field, and the particle is attracted towards regions of higher field strength. Conversely, if the particle's permittivity is lower than the medium, the induced dipole aligns against the field, and the particle is repelled from regions of higher field strength. This force can be used to manipulate and separate particles based on their dielectric properties.

Dielektrophoresis has found numerous applications in various scientific and technological fields. It is widely used in biological and chemical analysis for manipulating cells, proteins, DNA, and other biomolecules. In microfluidics, dielectrophoresis is employed for cell sorting, counting, and trapping. It also plays a role in the development of biosensors and lab-on-a-chip devices. Furthermore, dielektrophoresis has been explored for applications in materials science, such as particle assembly and manipulation of nanoparticles. The ability to control and move particles without direct physical contact makes dielektrophoresis a powerful and versatile technique.