Analytical Sciences

Abstract − Analytical Sciences, 25(2), 235 (2009).

Preparation of Two-dimensionally Ordered Microbeads Structure Dispensed with an Ink-jet and Its Application to ELISA
Yoriko INOUE, Moeka NISHIWAKI, Yuki KUDO, Nobuko SEINO, Tatsuro NAKAGAMA, and Katsumi UCHIYAMA
Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
In order to the increase sensitivity of enzyme-linked immunosorbent assay (ELISA) using micro-droplet reaction system formed by ink-jet, we employed small dots of two-dimensionally well-ordered structure of polystyrene (PS) microbeads (710 ± 25 µm in diameter) formed on the surface of polydimethyl siloxane (PDMS). An aqueous suspension of polystyrene microbeads (5 µm) was ejected on the PDMS plate with ink-jet. The PS beads were automatically assembled by capillary force accompanied with solvent evaporation. The evaporation rate was controlled by ambient relative humidity. The assembled beads were solidly immobilized on the surface of PDMS surface. The dots of well-ordered structure were stable against vigorous washing. ELISA using the structure as a reaction location was three times more sensitive than the material without the structure due to the increase of the surface area and consequent increase of the amount of antibody.