Optical Temperature Control of Multiple Microheaters Using Digital Micromirror Device

We developed a novel technique for local temperature control of the multiple microheaters on a microchip with a 2D projected pattern of the IR laser using the DMD (Digital Micromirror Device: Texas Instruments). The DMD contains a rectangular array of about 0.5 million hinge-mounted microscopic mirrors or more. Each angle of micromirrors is controlled based on the grayscale picture on the PC monitor. We used it to pattern the IR laser. The reduced projection of the patterned laser beam is irradiated to the evenly divided ITO(Indium Tin Oxide) thin films on the glass plate through the optical lens. Here we applied this method to the immobilization of multiple microorganisms by the thermosensitive hydeogel to assay their individual properties. The hydrogel solution around the irradiated microheater was gelled. In experiment, we confirmed gelation of arbitrarily-selected microheaters, and we succeeded in immobilization of target cells in-situ on a chip.