Microfluidic systems

A microfluidic device for controllably transporting material among a plurality of intersecting microscale channels, the device comprising:

• a body structure;
• a channel network disposed in the body structure, the channel network comprising a plurality of intersecting microscale channels, the plurality of intersecting microscale channels comprising n microscale channel intersections, and x channel termini which are unintersected by a microscale channel and which channel termini are located in or on the body structure of the device, wherein n is greater than or equal to x, provided that x is at least 3 and n is at least 4;
• an electrokinetic material transport system comprising an electrical power supply electrically coupled to each of the at least 3 unintersected channel termini, wherein the system controls the power supply such that the power supply supplies a separate electrical potential simultaneously to at least three of the unintersected termini of the plurality of microscale channels, the electrical potential supplied at the unintersected channel termini controlling material transport at the at least 4 intersections, wherein said controlling material transport comprises flowing material into each of the at least 4 intersections through at least two channel segments, or out of each of the at least 4 intersections through at least 2 channel segments, wherein the material is flowed simultaneously through the at least two channel segments.