Manufacturing details of the thermal gradient chip and associated hardware. (A) Completed thermal gradient chip wire-bonded to a small printed circuit board for testing. The silicon islands and supporting silicon dioxide support structure are visible in the center. (B) Schematic diagram showing in cross-section several details of the chip manufacturing process. (C) The smaller board is mounted in the larger board shown here, which provides buffering and cable connections between chip and thermal controller. (D) This prototype thermal controller was designed to provide individual control over temperature in 20 silicon islands simultaneously. It was used to carry out thermal isolation and response tests, as well as the hybridization experiments described here.