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Author

Karl F. Biihringer

Bio: Karl F. Biihringer is an academic researcher from University of Washington. The author has contributed to research in topics: Electrowetting & Microfluidics. The author has an hindex of 1, co-authored 1 publications receiving 35 citations.

Papers
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01 Jan 2003
TL;DR: A broadly applicable approach to optimally control digital microfluidic systems, i.e., software algorithms that generate a sequence of control signals for moving one or many droplets from start to goal positions in the shortest number of steps, subject to constraints such as minimum required separation between droplets, obstacles on the array surface, and limitations in the control circuitry.
Abstract: In digital microfluidic systems, analyte droplets (volume typically c 1~1) are transported on a planar electrode array by dielectrophoretic and electrowetting effects. While recent work has demonstrated feasibility mainly with single droplets on small arrays, these systems hold promise for commercial-scale applications by simultaneously moving many droplets on large arrays. This paper introduces a broadly applicable approach to optimally control digital microfluidic systems, i.e., software algorithms that generate a sequence of control signals for moving one or many droplets from start to goal positions in the shortest number of steps, subject to constraints such as minimum required separation between droplets, obstacles on the array surface, and limitations in the control circuitry.

36 citations


Cited by
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Proceedings ArticleDOI
06 Mar 2006
TL;DR: This work develops the first systematic droplet routing method that can be integrated with biochip synthesis, which minimizes the number of cells used fordroplet routing, while satisfying constraints imposed by throughput considerations and fluidic properties.
Abstract: Recent advances in microfluidics are expected to lead to sensor systems for high-throughput biochemical analysis. CAD tools are needed to handle increased design complexity for such systems. Analogous to classical VLSI synthesis, a top-down design automation approach can shorten the design cycle and reduce human effort. We focus here on the droplet routing problem, which is a key issue in biochip physical design automation. We develop the first systematic droplet routing method that can be integrated with biochip synthesis. The proposed approach minimizes the number of cells used for droplet routing, while satisfying constraints imposed by throughput considerations and fluidic properties. A real-life biochemical application is used to evaluate the proposed method.

228 citations

Journal ArticleDOI
TL;DR: This work proposes a system design methodology that attempts to apply classical high-level synthesis techniques to the design of digital microfluidic biochips and develops an optimal scheduling strategy based on integer linear programming and two heuristic techniques that scale well for large problem instances.
Abstract: Microfluidic biochips offer a promising platform for massively parallel DNA analysis, automated drug discovery, and real-time biomolecular recognition. Current techniques for full-custom design of droplet-based “digital” biochips do not scale well for concurrent assays and for next-generation system-on-chip (SOC) designs that are expected to include microfluidic components. We propose a system design methodology that attempts to apply classical high-level synthesis techniques to the design of digital microfluidic biochips. We focus here on the problem of scheduling bioassay functions under resource constraints. We first develop an optimal scheduling strategy based on integer linear programming. However, because the scheduling problem is NP-complete, we also develop two heuristic techniques that scale well for large problem instances. A clinical diagnostic procedure, namely multiplexed in-vitro diagnostics on human physiological fluids, is first used to illustrate and evaluate the proposed method. Next, the synthesis approach is applied to a protein assay, which serves as a more complex bioassay application. The proposed synthesis approach is expected to reduce human effort and design cycle time, and it will facilitate the integration of microfluidic components with microelectronic components in next-generation SOCs.

172 citations

Journal ArticleDOI
TL;DR: A polynomial-time algorithm for coordinating droplet movement under such hardware limitations is developed and described, and a layout-based system that can be rapidly reconfigured for new biochemical analyses is introduced.
Abstract: This paper describes a computational approach to designing a digital microfluidic system (DMFS) that can be rapidly reconfigured for new biochemical analyses. Such a “lab-on-a-chip” system for biochemical analysis, based on electrowetting or dielectrophoresis, must coordinate the motions of discrete droplets or biological cells using a planar array of electrodes. The authors have earlier introduced a layout-based system and demonstrated its flexibility through simulation, including the system's ability to perform multiple assays simultaneously. Since array-layout design and droplet-routing strategies are closely related in such a DMFS, their goal is to provide designers with algorithms that enable rapid simulation and control of these DMFS devices. In this paper, the effects of variations in the basic array-layout design, droplet-routing control algorithms, and droplet spacing on system performance are characterized. DMFS arrays with hardware limited row-column addressing are considered, and a polynomial-time algorithm for coordinating droplet movement under such hardware limitations is developed. To demonstrate the capabilities of our system, we describe example scenarios, including dilution control and minimalist layouts, in which our system can be successfully applied.

164 citations

Journal ArticleDOI
TL;DR: This paper presents general hardware-independent models and algorithms to automate the operation of droplet-based microfluidic systems and an approach toward automatic mapping of a biochemical analysis task onto a DMFS is investigated.
Abstract: This paper presents general hardware-independent models and algorithms to automate the operation of droplet-based microfluidic systems. In these systems, discrete liquid volumes of typically less than 1 $muhboxl$ are transported across a planar array by dielectrophoretic or electrowetting effects for biochemical analysis. Unlike in systems based on continuous flow through channels, valves, and pumps, the droplet paths can be reconfigured on demand and even in real time. Algorithms that generate efficient sequences of control signals for moving one or many droplets from start to goal positions, subject to constraints such as specific features and obstacles on the array surface or limitations in the control circuitry, are developed. In addition, an approach toward automatic mapping of a biochemical analysis task onto a DMFS is investigated. Achieving optimality in these algorithms can be prohibitive for large-scale configurations because of the high asymptotic complexity of coordinating multiple moving droplets. Instead, these algorithms achieve a compromise between high runtime efficiency and a more limited nonglobal optimality in the generated control sequences.

149 citations

Journal ArticleDOI
TL;DR: A general-purpose system that uses simple algorithms and yet is versatile is described that has been able to successfully coordinate hundreds of droplets simultaneously and perform one or more chemical analyses in parallel.
Abstract: In this paper we present an approach to coordinate the motions of droplets in digital microfluidic systems, a new class of lab-on-a-chip systems for biochemical analysis. A digital microfluidic system typically consists of a planar array of cells with electrodes that control the droplets. The primary challenge in using droplet-based systems is that they require the simultaneous coordination of a potentially large number of droplets on the array as the droplets move, mix, and split. In this paper we describe a general-purpose system that uses simple algorithms and yet is versatile. First, we present a semi-automated approach to generate the array layout in terms of components. Next, we discuss simple algorithms to select destination components for the droplets and a decentralized scheme for components to route the droplets on the array. These are then combined into a reconfigurable system that has been simulated in software to perform analyses such as the DNA polymerase chain reaction. The algorithms have ...

77 citations