Abstract
A novel on-chip environment measurement with functional gel-tool was developed. Environment measurement gel-tool was fabricated by connecting the gel-microbeads impregnated with indicators in a microchip. In this paper, Bromothymol blue (BTB) and Bromocresol green (BCG) were employed as pH indicators. BTB and BCG have the different indicator range. Rhodamine B is temperature sensitive fluorescent dye and is used for temperature measurement. Gel-microbead is made by salting-out of hydrophilic photo-crosslinkable resin and is manipulated by optical tweezers. Moreover, gel-microbead is polymerized by UV illumination. The connection of gel-microbeads is performed by contact of gel-microbeads under UV illumination in an electrolyte solution of a certain concentration. Multiple environments measurement gel-tool included with several indicators is realized by assembly of the gel-microbeads impregnated with different indicators. This technique can be employed for compensation of the dependence of the indicator on environment except for the target environment. Environment measurement is performed by detecting the color and the fluorescence intensity of each gel-microbead. We succeeded in the on-chip fabrication of the environment measurement gel-tools such as wide range pH measurement gel-tool and pH and temperature measurement gel-tool in a microchip.
