Lumped-Element Modeling for Rapid Design and Simulation of Digital Centrifugal Microfluidic Systems

Since the 1990s, centrifugal microfluidic platforms have evolved into a mature technol‐ ogy for the automation of bioanalytical assays in decentralized settings. These “Lab-ona-Disc” (LoaD) systems have already implemented a range of laboratory unit operations (LUOs) such as sample loading, liquid transport, metering, aliquoting, routing, mixing, and washing. By assembling these LUOs in highly functional microfluidic networks, including sample preparation and detection, a sizable portfolio of common test formats such as general chemistry, immunoassays/ protein analysis, nucleic acid testing, and cell counting has been established. The availability of these bioanalytical assay types enables a broad range of applications in fields such as life-science research, biomedical point-ofcare testing and veterinary diagnostics, as well as agrifood, environmental, infrastruc‐ tural, and industrial monitoring. Recently, a new method of the so-called “event-triggered” flow control has been developed which is independent of the spin rate. These valves, which function in a handshake mode as opposed to the typically batchwise liquid transfers on the “Lab-on-a-Disc” (LoaD) platform, assume a similarly pivotal role as relays and transistors in digital electronics, allowing conditional, logical (flow) control elements. This chapter will describe the modeling of this new generation of “digital” centrifugal microfluidic systems with lowdimensional, lumped-element simulations which have already been instrumental to the modern success story of modern microelectronics.