Contents I. Introduction
Large scale integrated microfluidics is a growing field with applications ranging from DNA sequencing [1] to surface modifications of Nano particles [2]. It deals with precise manipulation of fluids at a Nano-liter scale in pressure-driven micro-scale networks (or circuits) of mechanical channels [3]. Typical microfluidic circuits are comprised of single-layered channels and chambers, as well as embedded pressure-controlled monolithic mechanical valves. Circuits fabrication has been previously described in detail by Melin and colleagues [4]. Microfluidics control paradigm utilizes pressure-based or displacement-based perfusion instruments to drive fluids into or from a microfluidic circuit (flow layer), and pressurized on/off channels to actuate or relieve a valve (control layer). Integrated microfluidic circuits with both flow and control layers can be used to automate experiments in a very large scale. For example, Quake and colleagues developed a microfluidic circuit consisting of thousands of micro-fabricated switches for genomic analysis at the single-cell level [5]. Current control platforms for integrated microfluidics-based systems are often application specific, frequently require custom PCB extension boards, do not support instruction sets and are based on microcontrollers which have limited development community and relatively small number of supported libraries [6]. More-importantly, current microfluidic control systems do not support synchronized control from multiple sources simultaneously.
System design. Four microfluidic 6-bits digitally controlled resistors are simultaneously regulated using the proposed control framework in realtime for prescribed flow rate modulation. Hydraulic layout consists of filters, pressure regulators, pressure gauges, passive manifolds and controlled valve terminals. Flow data is recorded and transmitted to the controller for feedback.
