On-Chip Fabrication of Optical Multiple Microsensor Using Functional Gel-Microbead

A novel multiple environments measurement with functional gel-microbead was developed. Optical multiple microsensor was fabricated by connecting gel-microbeads impregnated different indicators. In this paper, Bromothymol blue (BTB) and Bromocresol green (BCG) were employed as pH indicators. BTB and BCG have 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. Gel-microbead is polymerized by UV-ray and adheres to other gel-microbead under an electrolyte solution. Connection of gel-microbeads is operated by only contact. Multiple environments measurement is curried out by detecting the colour and fluorescence intensity of each gel-microbead. We succeeded in fabricating optical multiple microsensor, measuring pH with wide range, and measuring pH and temperature with same gel-microbead.