Multilevel Microfluidic Systems and Methods

A method of mixing materials in a microfluidic device, comprising:

• flowing a first material through a first flow channel formed in a first layer of a substrate;
• flowing the first material through a first isolation valve, wherein the first isolation valve is disposed along the first flow channel, comprises a first portion of a control channel formed in a second layer of the substrate adjacent to the first layer, and is configured to control flow through the first flow channel into a first chamber;
• flowing the first material from the first flow channel into the first chamber;
• flowing a second material through a second flow channel formed in a third layer of the substrate adjacent to the second layer;
• flowing the second material through a second isolation valve, wherein the second isolation valve is disposed along the second flow channel, comprises a second portion of the control channel formed in a second layer of the substrate, and is configured to control flow through the second flow channel into the second chamber;
• flowing the second material from the second flow channel into the second chamber;
• actuating the control channel so as to inhibit flow through the first and second isolation valves;
• flowing the first material from the first chamber through an interface valve into the second chamber, so as to mix the first material with the second material, wherein the interface valve comprises a portion of an interface channel formed in a fourth layer of the substrate adjacent to the third layer, and is configured to control between the first chamber and the second chamber.