Functionalized micro bead with liquid-core Parylene-shell structure

We report on the fabrication, properties and applications of liquid-core Parylene-shell micro bead (LCPS-bead). Functionalized liquid substances and liquid mixtures are usually used as reagents or indicators. When these chemicals are used in biochemical measurements where liquids are often abundant in the ambience, they tend to absorb or mix with the surrounding liquid, and thus change their properties and functionalities. In order to eliminate this disadvantage, we proposed the liquid encapsulated beads. The LCPS-beads were fabricated in two-steps: 1) impregnating porous solid beads with functionalized liquid, 2) encapsulating the beads with Parylene film. We showed that the proposed method provided efficient encapsulating shell to protect the core-liquid from surrounding solvents, thus it enables long time use of the liquid function in the solvents. We demonstrated two applications of the LCPS-beads: micro bead type temperature sensor and pH indicator bead.