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The 19th Asia and South Pacific Design Automation Conference

Session 3B  Advances in Microfluidic Biochips
Time: 15:50 - 17:30 Tuesday, January 21, 2014
Location: Room 301
Chairs: Tsung-Yi Ho (National Cheng Kung University, Taiwan), Juinn-Dar Huang (National Chiao Tung University, Taiwan)

3B-1 (Time: 15:50 - 16:15)
TitleA Network-Flow-Based Optimal Sample Preparation Algorithm for Digital Microfluidic Biochips
Author*Trung Anh Dinh, Shigeru Yamashita (Ritsumeikan University, Japan), Tsung-Yi Ho (National Cheng Kung University, Taiwan)
Pagepp. 225 - 230
Keyworddigital microfluidic biochips, sample preparation, minimum-cost maximum-flow
AbstractSample preparation, which is a front-end process to produce droplets of the desired target concentrations from input reagents, plays a pivotal role in every assays, laboratories, and applications in biomedical engineering and life science. The consumption of sample/buffer/waste is usually used to evaluate the effectiveness of a sample preparation process. In this paper, we present the first optimal sample preparation algorithm based on a minimum-cost maximum-flow model. By using the proposed model, we can obtain both the optimal cost of sample and buffer usage and the waste amount even for multiple-target concentrations. Experiments demonstrate that we can consistently achieve much better results not only in the consumption of sample and buffer but also the waste amount when compared with all the state-of-the-art of the previous approaches.
Slides

3B-2 (Time: 16:15 - 16:40)
TitleExploring Speed and Energy Tradeoffs in Droplet Transport for Digital Microfluidic Biochips
AuthorJohnathan Fiske, *Daniel Grissom, Philip Brisk (University of California, Riverside, U.S.A.)
Pagepp. 231 - 237
KeywordMicrofluidics, Cyber-Physical System, Droplet Transport
AbstractThis paper transforms the problem of droplet routing for digital microfluidic biochips (DMFBs) from the discrete into the continuous domain, based on the observation that droplet transport velocity is a function of the actuation voltage applied to electrodes that control the devices. A new formulation of the DMFB droplet routing problem is introduced for the continuous domain, which attempts to minimize total energy consumption while meeting a timing constraint. Henceforth, DMFBs should be viewed as continuous, highly integrated cyber-physical systems that interact with and manipulate physical quantities, as opposed to inherently discrete and fully synchronized devices.
Slides

3B-3 (Time: 16:40 - 17:05)
TitleGeneral Purpose Cross-Referencing Microfluidic Biochip with Reduced Pin-Count
Author*Jackson Ho Chuen Yeung, Evangeline F.Y. Young (The Chinese University of Hong Kong, Hong Kong)
Pagepp. 238 - 243
KeywordDMFB, microfluidics, biochip, routing
AbstractThe number of control pins used is a major factor affecting the manufacturing cost of Digital Microfluidic Biochip (DMFB). Pin-count on a DMFB can be reduced by sharing of control pins between electrodes. Most existing works on reducing pin-count are problem specific. Problem specific optimizations result in DMFB that can only perform certain specific bioassays. Cross-Referencing DMFB has a full array layout that is fully reconfigurable for any bioassay. Conventional Cross-Referencing DMFB uses m + n number of pins. We have devised a non-problem specific pin assignment methodology that uses only √2(√m + √n) number of pins. The resulting DMFB are still fully reconfigurable. We have developed a droplet router specifically for cross-referencing DMFB with shared control pins. All real bioassay tested can be routed using a fixed and problem independent control pin mapping. Reduction on pin count ranges from 50 % to 67 %.

3B-4 (Time: 17:05 - 17:30)
TitleWash Optimization for Cross-Contamination Removal in Flow-Based Microfluidic Biochips
AuthorKai Hu (Duke University, U.S.A.), *Tsung-Yi Ho (National Cheng Kung University, Taiwan), Krishnendu Chakrabarty (Duke University, U.S.A.)
Pagepp. 244 - 249
Keywordwash optimization, flow-based biochip, cross-contamination
AbstractRecent advances in flow-based microfluidics have enabled the emergence of biochemistry-on-a-chip as a new paradigm in drug discovery and point-of-care disease diagnosis. However, these applications in biochemistry require high precision to avoid erroneous assay outcomes, and therefore are vulnerable to contamination between two fluidic flows with different biochemistries. Moreover, to wash contaminated sites, the buffer solution in flow-based biochips has to be guided along pre-etched channel networks. This constraint makes washing in flow-based microfluidics even harder. In this paper, we propose the first approach for automated wash optimization for contamination removal in flow-based microfluidic biochips. The proposed approach targets the generation of washing pathways to clean all contaminated microchannels with minimum execution time. A path dictionary is first established by pre-searching physically implementable paths in a given chip layout. When wash targets and occupied microchannels are defined, the proposed methods determine an optimized path set with the least washing time by calculating the priorities of wash targets. Two fabricated biochips are used to evaluate the proposed washing method. Compared to an ad hoc baseline method, the proposed approach leads to more efficient washing in all cases.
Slides