An Efficient 3-Dimensional Hydrodynamic Focusing Microfluidic Device by means of Locally Increased Aspect Ratio

In this paper, we have designed, fabricated and characterized an efficient 3-dimensional hydrodynamic focusing microfluidic device (3D-HFMD) in numerical and experimental ways. The 3D-HFMD achieved vertical focusing of core sample flow effectively in the pressure driven flow with the help of locally increased aspect ratio of thickness to width without any horizontal separation wall, thereby enabling us to realize 3D focusing after simple horizontal focusing. Extensive numerical analysis shows that the 3D-HFMD enhances the performance of vertical focusing compared with the previous designs over a wide range of the Reynolds numbers, even in the case of a the global aspect ratio less than 0.5. Experimental results from the fabricated 3D-HFMD confirmed that 3D hydrodynamic focusing could be successfully achieved, even when the dimension of the channel was kept consistent with that of general microfluidic channels. The 3D-HFMD suggested in this study could be applied to various integrated biological or chemical microfluidic devices. (C) 2009 Elsevier B.V. All rights reserved.X112022sciescopu