Improved and simple sealing of microfluidic structures

An innovative way for covering and sealing microfluidic devices is proposed. After giving an overview to a variety of commonly used techniques, the problem of tightness (to fluids and gases) is discussed, and a simple yet effective solution, based on a lid that has an optimized pre-curved shape, is introduced. The curvature significantly enhances uniformity of pressure distribution; evidence is presented by computer simulation as well as through fluidic measurements, showing water tightness up to nearly one bar. The method used for finding the optimized shape is briefly presented. Although the method proposed is usable with virtually any material and size, examples are given in materials and scales typical for microfluidics. The technique is fully compatible to mass production techniques for polymer materials; a water tight example for an injection molded lid and base, held together by a clamping mechanism that easily can be replaced by laser welded points, is presented.