Browsing by Author "Hu, Kai"

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Control-Layer Optimization for Flow-Based mVLSI Microfluidic Biochips
(2014-01-01)
Hu, Kai
;
Dinh, Trung Anh
;
Ho, Tsung-Yi
;
Chakrabarty, Krishnendu
;
交大名義發表
Recent advantages in flow-based microfluidic biochips have enabled the emergence of lab-on-a-chip devices for bimolecular recognition and point-of-care disease diagnostics. However, the adoption of flow-based biochips is hampered today by the lack of computer-aided design tools. Manual design procedures not only delay product development but they also inhibit the exploitation of the design complexity that is possible with current fabrication techniques. In this paper, we present the first practical problem formulation for automated control-layer design in flow-based microfluidic VLSI (mVLSI) biochips and propose a systematic approach for solving this problem. Our goal is to find an efficient routing solution for control-layer design with a minimum number of control pins. The pressure-propagation delay, an intrinsic physical phenomenon in mVLSI biochips, is minimized in order to reduce the response time for valves, decrease the pattern set-up time, and synchronize valve actuation. Two fabricated flow-based devices and five synthetic benchmarks are used to evaluate the proposed optimization method. Compared with manual control-layer design and a baseline approach, the proposed approach leads to fewer control pins, better timing behavior, and shorter channel length in the control layer.
Testing of Flow-Based Microfluidic Biochips: Fault Modeling, Test Generation, and Experimental Demonstration
(2014-10-01)
Hu, Kai
;
Yu, Feiqiao
;
Ho, Tsung-Yi
;
Chakrabarty, Krishnendu
;
資訊工程學系
Recent advances in flow-based microfluidics have led to the emergence of biochemistry-on-a-chip as a new paradigm in clinical diagnostics and biomolecular recognition. However, a potential roadblock in the deployment of microfluidic biochips is the lack of test techniques to screen defective devices before they are used for biochemical analysis. Defective chips lead to repetition of experiments, which is undesirable due to high reagent cost and limited availability of samples. Prior work on fault detection in biochips has been limited to digital ("droplet") microfluidics and other electrode-based technology platforms. The paper proposes the first approach for automated testing of flow-based microfluidic biochips that are designed using membrane-based valves for flow control. The proposed test technique is based on a behavioral abstraction of physical defects in microchannels and valves. The flow paths and flow control in the microfluidic device are modeled as a logic circuit composed of Boolean gates, which allows test generation to be carried out using standard automatic test pattern generation tools. The tests derived using the logic circuit model are then mapped to fluidic operations involving pumps and pressure sensors in the biochip. Feedback from pressure sensors can be compared to expected responses based on the logic circuit model, whereby the types and positions of defects are identified. We show how a fabricated biochip can be tested using the proposed method, and demonstrate experimental results for two additional fabricated chips.