Dielectrophoretic particle chromatographie (DPC) at preparative scale (SPP 2045)
Dielectrophoretic particle chromatography (DPC) is a separation method for a variety of microparticles, these can be of biological, synthetic or natural origin. By influencing the particles with inhomogeneous electric fields, specific residence times or separation rates for different particles are obtained. The method is suitable for the analysis and separation of microparticles. In addition, the scalability of electrode-based dielectrophoresis using low-cost printed circuit boards (PCB) is investigated.
In current publications, most DEP separators are microfluidic devices and are consequently only capable of handling volume flows in the µLh-1 or lower mLh-1 range. These separators work by either using selective trapping of particles or spatial separation of different particles. This type of operation can be feasible for highly valuable products as proteins or cells and can be even considered as high throughput. However, for less valuable products or high quantities an increase in throughput is necessary. Since the DEP force scales with the gradient of the electric field squared, it is important to maintain the magnitude of the gradient during the scale up of the device. For microfluidic setups scale up by numbering up is considered as an option, but since the fabrication of microfluidic devices often requires clean-room techniques and small setups are challenging to handle, setups with larger dimensions are a focus of current research. One way to up-scale DEP separators up, is by using macroscopic insulating structures as glass beads, meshes or alumina foams to scatter the electric field and thus generate local field minima and maxima. This approach is called insulator-based dielectrophoresis (iDEP). The high-throughput iDEP approaches, however, need high voltages since the electrodes themselves are separated by the insulator which additionally blocks the fluid pathway resulting in an increased pressure drop. The insulating material is also challenging to clean after processing the materials. In contrast, electrode-based DEP (eDEP) often use electrode arrays to generate inhomogeneous electric field. eDEP separators are not used as high throughput separators yet as large electrode arrays are expensive and time consuming to fabricate within the clean-room.
The aim of our work is to develop novel tools for addressing both separation tasks, high selectivity and high throughput. The former should be used by developing a novel chromatographic technique which is utilizing dielectrophoresis to generate trap and release cycles as this was analytically shown to be favorable for high selectivity. Although chromatographic techniques are rare in the field of DEP; they might be an option for realizing highly specific separations. As a second step the upscaling of eDEP devices should be addressed, since this is a bottleneck of current electrode-based approaches. Additionally, when scaling up, the specific costs for the setups should massively decrease to favour the applicability of macroscopic eDEP devices.
Project-relevant publications
J. Giesler et al. (2022). Electrophoresis. https://doi.org/10.1002/elps.202200131
J. Giesler et al. (2021). Scientific Reports 11(1), 16861. https://doi.org/10.1038/s41598-021-95404-w
J. Giesler et al. (2020). Micromachines 11(1), 38. https://doi.org/10.3390/mi11010038
Contact:
Giesler, Jasper, M. Sc.
Room UFT 2110
Fon: 0421- 218 - 63495
