A system for manipulating electric fields within a microscopic fluid channel includes a fluid channel with an inlet and an outlet to support fluid flow, at least one controllable electric field producer that applies a non-uniform and adjustable electric field to one or more regions of the fluid channel, one or more sensors that measure one or more parameters of a fluid flowing through the fluid channel, and a controller with hardware and software components that receives signals from the one or more sensors representative of values of the one or more parameters and, based on the parameter values, drives one or more actuators to adjust the electric field produced by the plurality of electric field producers. A complex fluid including at least two components flows through the fluid channel, where at least one of the at least two components comprises particles controllable by the non-uniform and adjustable electric field.