Abstract
Dielectrophoresis (DEP) is a physical effect that generates a force on a polarisable particle when it experiences a non-homogeneous electric field. It has been shown in earlier research that its measure allows finding the electrical properties of that particle, including the electric permittivity and conductivity. Prior approaches have applied DEP-based techniques to measure the electric properties of one or several cells at a time. However, the protocols they usually use suffer from several problems, among which are the poor statistical significance due to the small number of cells monitored, the relatively high level to noise ratio, the duration of the measurement or the loss of information during the data processing. This thesis presents the work I have achieved in an effort to solve part of these problems. The approach was two-sided: part of the work was dedicated to the development of a new automate that measures the DEP force on a large population of cells with a low level of noise, and another part was dedicated to the development of new theoretical approaches in order to obtain lower bias and higher signal to noise levels from the data processing. For these purposes, the protocol and material used previously in the measurements of DEP force were studied, with particular attention to the microwell-based technique used at the University of Surrey from which an automatic procedure was developed in a series of consecutive improvements. The automate and software obtained at the end of this work were able to quickly measure the DEP spectrum and study it in a way that provided novel or more accurate information about the cells electrical properties.