Fei Su

Bio: Fei Su is an academic researcher from Intel. The author has contributed to research in topics: Biochip & Digital microfluidics. The author has an hindex of 24, co-authored 41 publications receiving 2246 citations. Previous affiliations of Fei Su include Duke University.

Microfluidics-Based Biochips: Technology Issues, Implementation Platforms, and Design-Automation Challenges

Abstract: Microfluidics-based biochips are soon expected to revolutionize clinical diagnosis, deoxyribonucleic acid (DNA) sequencing, and other laboratory procedures involving molecular biology. In contrast to continuous-flow systems that rely on permanently etched microchannels, micropumps, and microvalves, digital microfluidics offers a scalable system architecture and dynamic reconfigurability; groups of unit cells in a microfluidics array can be reconfigured to change their functionality during the concurrent execution of a set of bioassays. As more bioassays are executed concurrently on a biochip, system integration and design complexity are expected to increase dramatically. This paper presents an overview of an integrated system-level design methodology that attempts to address key issues in the synthesis, testing and reconfiguration of digital microfluidics-based biochips. Different actuation mechanisms for microfluidics-based biochips, and associated design-automation trends and challenges are also discussed. The proposed top-down design-automation approach is expected to relieve biochip users from the burden of manual optimization of bioassays, time-consuming hardware design, and costly testing and maintenance procedures, and it will facilitate the integration of fluidic components with a microelectronic component in next-generation systems-on-chips (SOCs).

Droplet Routing in the Synthesis of Digital Microfluidic Biochips

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.

High-level synthesis of digital microfluidic biochips

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.

Unified high-level synthesis and module placement for defect-tolerant microfluidic biochips

Abstract: Microfluidic biochips promise to revolutionize biosensing and clinical diagnostics. As more bioassays are executed concurrently on a biochip, system integration and design complexity are expected to increase dramatically. This problem is also identified by the 2003 ITRS document as a major system-level design challenge beyond 2009. We focus here on the automated design of droplet-based microfluidic biochips. We present a synthesis methodology that unifies operation scheduling, resource binding, and module placement for such "digital" biochips. The proposed technique, which is based on parallel recombinative simulated annealing, can also be used after fabrication to bypass defective cells in the microfluidic array. A real-life protein assay is used to evaluate the synthesis methodology.

Architectural-level synthesis of digital microfluidics-based biochips

Abstract: Microfluidics-based 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 fluidic components. We propose a system design methodology that attempts to apply classical architectural-level synthesis techniques to the design of digital microfluidics-based biochips. We first develop an optimal scheduling strategy based on integer linear programming. Since 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 used to evaluate the proposed method.

Digital microfluidics: is a true lab-on-a-chip possible?

Abstract: The suitability of electrowetting-on-dielectric (EWD) microfluidics for true lab-on-a-chip applications is discussed. The wide diversity in biomedical applications can be parsed into manageable components and assembled into architecture that requires the advantages of being programmable, reconfigurable, and reusable. This capability opens the possibility of handling all of the protocols that a given laboratory application or a class of applications would require. And, it provides a path toward realizing the true lab-on-a-chip. However, this capability can only be realized with a complete set of elemental fluidic components that support all of the required fluidic operations. Architectural choices are described along with the realization of various biomedical fluidic functions implemented in on-chip electrowetting operations. The current status of this EWD toolkit is discussed. However, the question remains: which applications can be performed on a digital microfluidic platform? And, are there other advantages offered by electrowetting technology, such as the programming of different fluidic functions on a common platform (reconfigurability)? To understand the opportunities and limitations of EWD microfluidics, this paper looks at the development of lab-on-chip applications in a hierarchical approach. Diverse applications in biotechnology, for example, will serve as the basis for the requirements for electrowetting devices. These applications drive a set of biomedical fluidic functions required to perform an application, such as cell lysing, molecular separation, or analysis. In turn, each fluidic function encompasses a set of elemental operations, such as transport, mixing, or dispensing. These elemental operations are performed on an elemental set of components, such as electrode arrays, separation columns, or reservoirs. Examples of the incorporation of these principles in complex biomedical applications are described.

Microfluidic Large-Scale Integration: The Evolution of Design Rules for Biological Automation

Abstract: Microfluidic large-scale integration (mLSI) refers to the development of microfluidic chips with thousands of integrated micromechanical valves and control components. This technology is utilized in many areas of biology and chemistry and is a candidate to replace today’s conventional automation paradigm, which consists of fluid-handling robots. We review the basic development of mLSI and then discuss design principles of mLSI to assess the capabilities and limitations of the current state of the art and to facilitate the application of mLSI to areas of biology. Many design and practical issues, including economies of scale, parallelization strategies, multiplexing, and multistep biochemical processing, are discussed. Several microfluidic components used as building blocks to create effective, complex, and highly integrated microfluidic networks are also highlighted.

The building blocks of magnonics

Abstract: Novel material properties can be realized by designing waves' dispersion relations in artificial crystals. The crystal's structural length scales may range from nano- (light) up to centimeters (sound waves). Because of their emergent properties these materials are called metamaterials. Different to photonics, where the dielectric constant dominantly determines the index of refraction, in a ferromagnet the spin-wave index of refraction can be dramatically changed already by the magnetization direction. This allows a different flexibility in realizing dynamic wave guides or spin-wave switches. The present review will give an introduction into the novel functionalities of spin-wave devices, concepts for spin-wave based computing and magnonic crystals. The parameters of the magnetic metamaterials are adjusted to the spin-wave k-vector such that the magnonic band structure is designed. However, already the elementary building block of an antidot lattice, the singular hole, owns a strongly varying internal potential determined by its magnetic dipole field and a localization of spin-wave modes. Photo-magnonics reveal a way to investigate the control over the interplay between localization and delocalization of the spin-wave modes using femtosecond lasers, which is a major focus of this review. We will discuss the crucial parameters to realize free Bloch states and how, by contrast, a controlled localization might allow to gradually turn on and manipulate spin-wave interactions in spin-wave based devices in the future.

The building blocks of magnonics

Abstract: Novel material properties can be realized by designing waves’ dispersion relations in artificial crystals. The crystal’s structural length scales may range from nano- (light) up to centimeters (sound waves). Because of their emergent properties these materials are called metamaterials. Different to photonics, where the dielectric constant dominantly determines the index of refraction, in a ferromagnet the spin-wave index of refraction can be dramatically changed already by the magnetization direction. This allows a different flexibility in realizing dynamic wave guides or spin-wave switches. The present review will give an introduction into the novel functionalities of spin-wave devices, concepts for spin-wave based computing and magnonic crystals. The parameters of the magnetic metamaterials are adjusted to the spin-wave k -vector such that the magnonic band structure is designed. However, already the elementary building block of an antidot lattice, the singular hole, owns a strongly varying internal potential determined by its magnetic dipole field and a localization of spin-wave modes. Photo-magnonics reveal a way to investigate the control over the interplay between localization and delocalization of the spin-wave modes using femtosecond lasers, which is a major focus of this review. We will discuss the crucial parameters to realize free Bloch states and how, by contrast, a controlled localization might allow us to gradually turn on and manipulate spin-wave interactions in spin-wave based devices in the future.

Advances in engineered surfaces for functional performance

Abstract: Surface phenomena play a decisive role in the behaviour of engineering parts; their understanding and control are fundamental to the development of many advanced fields, such as: electronics, information technology, energy, optics, tribology, biology and biomimetics. Engineered surfaces rely on the control of surface characteristics to obtain a desired functional performance. This paper reports the advances in the state of the art considering the relationships between the properties of functional surfaces, their applications and the technologies to engineer surfaces.