Characterization of DNA polarizability in alternating electric fields.

The precise separation and manipulation of biomolecules are pivotal across a wide range of life science applications, ranging from sample preparation for DNA sequencing, to the extraction of extracellular vesicles and protein purification. This accurate manipulation fuels progress in diagnostics, therapeutics, and fundamental research.

Dielectrophoresis is a phenomenon in which a non-uniform electric field induces a force on dielectric particles. It is thus a highly versatile tool that allows convenient control over the positioning and movement of cells, viruses, and biomolecules like DNA. The popularity of dielectrophoresis stems from its broad applicability, its non-invasiveness, and high adaptability.

At the heart of dielectrophoresis lies the polarizability of particles/biomolecules, a measure of the particle’s ability to undergo an induced dipole in response to an external electric field through charge induction both within the particle itself and in the electric double layer surrounding the particle. This property is thus intricately linked to the characteristics of both particle and medium. This factor governs how a particle responds to non-uniform electric fields. Therefore, developing a thorough understanding of this factor is critical to achieve precise control over the dynamics of a particle using dielectrophoresis.

Despite the pivotal role that the polarizability of DNA plays in dielectrophoresis based extraction applications, the specific polarizability of DNA molecules remains notably underrepresented in current literature. Understanding this property holds critical importance for the optimization of DNA capture through dielectrophoresis.

This master’s thesis focusses on the development of a setup for the characterization of the polarizability of DNA and other bioparticles through impedance measurements. Accurate impedance measurements will enable the determination of the permittivity and conductivity of biomolecules across a broad frequency range. This approach allows for the determination of the polarizability for DNA molecules hence enabling nanofluidic DNA manipulation for diagnostic applications. Work can also be done on the characterization of different biomolecules and/or bioparticles. The project will be composed of 20% literature study, 60% experimental DNA characterization and 20% thesis writing.