Micro-/Nanofluidic Diffusiophoresis Platform for Simple Concentration and Extraction of Particles Using Ionic Solutions

This paper reports a novel diffusiophoresis-based particle manipulator for the concentration and extraction on-demand using a nanochannel-integrated microfluidic channel network fabricated by the crack-photolithography. The nanochannel regulates the physiochemical environments in the microfluidic channel by suppressing convection flows, making it possible to produce a long-term and stable concentration gradient of target solutes over the microchannel. This unique feature facilitates the rapid and dynamic manipulation of chemically driven transport of particles by simply switching ionic solutions. As a result, this platform successfully achieved about 330-fold concentration of 1- μm -polystyrene particles in 120 min and their extraction in 10 min with a 95% ratio by simply reverting the concentration gradient of the solutions without any electronic power sources and fluidic controllers.