Device for controlling particle distribution in an evaporating droplet using radial electroosmotic flow

Abstract

Provided is a device for controlling a particle distribution in a droplet including particles. The device includes: a first electrode for developing an electric field in the vicinity of the droplet; and a second electrode for developing the electric field that is fixed to a substrate, is insulated from the first electrode, and located at about the center of the droplet. A micro electrode system including a circular electrode placed along a droplet rim and a point electrode at about the center of the bottom is used to cause radial electroosmotic flow, thereby obtaining a uniform solute distribution after complete evaporation of the droplet. The direction and strength of the radial electroosmotic flow can be varied and the radial electroosmotic flow is periodically applied. Particles used to obtain uniformity are selected from the group consisting of a polymer, an organic substance, an inorganic substance, a metal, and a biomolecule. The particles can be neutral, negatively charged or positively charged.