Abstract
Metal nanoparticles have unique electrochemical and optical properties depending on their conditions, such as size, shape or aggregation, and are extensively expected as an advanced sensor in various fields. We have developed a microfluidic device capable of generating a stable concentration gradient in microchannel as a reaction field for nanoparticles. In this device, nanoparticle solution is seeded in the concentration gradient. The aggregation of gold nanoparticles (15 nm in diameter) in NaCl aqueous solution was employed as a sample. It was confirmed that a continuous change in the color of solution reflecting the degree of aggregation in accordance with NaCl concentration.
