Fabricatiion of 3D microfluidic networks with a hybrid stamp

We report on a novel methodology for fabricating multilayer, high aspect ratio, 3D microfluidic structures with through-layer vias that can be bonded between two hard substrates. It is realized by using a plastic plate embedded PDMS stamp in soft lithography to obtain flat and open PDMS structures that can be stacked to form multiplayer 3D microfluidic networks in high yield without severe structure distortion. Our method also allows the control of the curvature of the channel sidewalls and the shape of channel cross section that may open up profound applications in electrokinetics, microoptics, and inertia microfluidics.