Novel modular pressure and flow rate balanced microfluidic serial dilution networks on printed circuit boards: Designs, Simulations and Fabrication

Abstract

Fast, efficient and more importantly accurate serial dilution is a requirement for many chemical and biological microfluidic-based applications. Over the last decade, a large number of microfluidic devices has been proposed, each demonstrating either a different type of dilution technique or complex system architectures based on various flow source combinations. In this work, a novel serial dilution architecture is demonstrated, implemented on a commercially fabricated printed circuit board (PCB). The proposed single layer, stepwise serial diluter comprises an optimised microfluidic network, where identical dilution ratio per stage can be ensured, either by applying equal pressure or equal flow rates at both inlets. The advantages of the proposed serial diluter are twofold. Firstly, it is structured as a modular unit cell, simplifying the required fluid driving mechanism to a single source for both sample and buffer solution. Thus, this unit cell can be seen as a fundamental microfluidic building block, which can form multistage serial dilution cascades, once combined appropriately with itself or other similar unit cells. Secondly, the serial diluter has been fabricated entirely using commercial PCB technologies, allowing the device to be interfaced with standard electronic components, if more complex miniature point-of-care (PoC) systems are desired, where the small footprint and accuracy of the device is of paramount importance.