초록 |
Particle manipulation is essentially required in a wide range of microfluidic applications such as particle counting and sorting. Particle focusing is a key techology to develop highly efficient microfluidic cytometer. Various particle focusing schemes have been proposed, which can be categorized into active and passive methods. The passive method, not relying on any external force, has attracted much attention since the throughput is usually much higher and its implementation is relatively simpler as compared to the active methods. Recently, our group have developed a novel passive technique to manipulate micro-/naoparticles utilizing the viscoelastic properties of polymer solutions, which can achieve highly efficient particle focusing in an extremely simple straight channel. We demonstrated that microparticles are aligned along the channel centerline in a square channel by the combined effect of elastic and inertial force in dilute polymer solutions. In addition, we recently demonstrated the image cytometry of non-spherical particles in a cross-slot channel utilizing the viscoelasticity-driven particle focusing. In this presentation, I will also introduce the recent progress in viscoelastic microfluidics, particularily focusing on the particle focusing in nanoparticle colloidal dispersion. |