Abstract: Provided are dielectrophoresis (DEP) devices and methods that allow cell sorting to identify, isolate, and/or separate cells of interest based on electrical and physical properties of the cells. Particularly, provided are systems and methods for manipulating particles suspended in a fluid, e.g., cells, micro- or nano-particles, using their electrical signatures. Such methods can be performed using DEP, iDEP, and/or cDEP (contactless dielectrophoresis, where direct contact between the electrodes and the sample is avoided). Typically, an electric field is induced in a sample comprising the target particles and/or cells, such as cancer cells, and the spatial distribution of cells is measured to identify one or more characteristics or properties of the cancer cells. The identified characteristics of the sorted cells can be used to determine drug efficacy and/or resistance with respect to the cells.