An automated system for the thermal processing of reagents, the system comprising: a heater block that emits heat; a first elastomeric membrane ; and a second elastomeric membrane positioned adjacent the first elastomeric membrane, wherein a portion of the second elastomeric membrane is sealed to a portion of the first elastomeric membrane to define a first mixing chamber positioned and arranged to receive the heat from the heater block, wherein the first and second elastomeric membranes define a second mixing chamber positioned and arranged to receive the heat from the heater block, and comprising a first piston and a second piston , opposite the heater block, and wherein a compliant layer is positioned under the first elastomeric membrane ,a portion of the complaint layer reversibly closes a section of a channel formed by the first and the second elastomeric membrane upstream from the first and second mixing chambers and another portion of the compliant layer reversibly closes a section of the channel downstream from the first and second mixing chambers, characterized in that the automated system is configured such that, in operation, the first piston is adapted to reversibly depress the first mixing chamber to urge one or more reagents from the first mixing chamber to the second mixing chamber, and such that, in operation, the second piston is adapted to reversibly depress the second mixing chamber to urge the one or more reagents from the second mixing chamber to the first mixing chamber, and in that the first mixing chamber and the second mixing chamber are connected to each other by one or more mixing channels that have a width smaller than the width of the channel upstream from the first mixing chamber and/or the width of a channel downstream from the second mixing chamber. a heater block that emits heat; a first elastomeric membrane ; and a second elastomeric membrane positioned adjacent the first elastomeric membrane, wherein a portion of the second elastomeric membrane is sealed to a portion of the first elastomeric membrane to define a first mixing chamber positioned and arranged to receive the heat from the heater block, wherein the first and second elastomeric membranes define a second mixing chamber positioned and arranged to receive the heat from the heater block, and comprising a first piston and a second piston , opposite the heater block, and wherein a compliant layer is positioned under the first elastomeric membrane ,a portion of the complaint layer reversibly closes a section of a channel formed by the first and the second elastomeric membrane upstream from the first and second mixing chambers and another portion of the compliant layer reversibly closes a section of the channel downstream from the first and second mixing chambers, characterized in that the automated system is configured such that, in operation, the first piston is adapted to reversibly depress the first mixing chamber to urge one or more reagents from the first mixing chamber to the second mixing chamber, and such that, in operation, the second piston is adapted to reversibly depress the second mixing chamber to urge the one or more reagents from the second mixing chamber to the first mixing chamber, and in that the first mixing chamber and the second mixing chamber are connected to each other by one or more mixing channels that have a width smaller than the width of the channel upstream from the first mixing chamber and/or the width of a channel downstream from the second mixing chamber. <EOS>