Devices and techniques are described that involve a combination of multidimensional electrokinetic, dielectrophoretic, electrophoretic and fluidic forces and effects for separating cells, nanovesicles, nanoparticulates and biomarkers (DNA, RNA, antibodies, proteins) in high conductance (ionic) strength biological samples and buffers. In disclosed embodiments, a combination of continuous and/or pulsed dielectrophoretic (DEP) forces, continuous and/or pulsed field DC electrophoretic forces, microelectrophoresis and controlled fluidics are utilized with arrays of electrodes. In particular, the use of chambered DEP devices and of a properly scaled relatively larger electrode array devices that combines fluid, electrophoretic and DEP forces enables both larger and/or clinically relevant volumes of blood, serum, plasma or other samples to be more directly, rapidly and efficiently analyzed. The invention enables the creation of“seamless”sample-to-answer diagnostic systems and devices. The devices and techniques