Droplet routing for digital microfluidic biochips based on microelectrode dot array architecture

A digital microfluidic biochip (DMFB) is a device that digitizes fluidic samples into tiny droplets and operates chemical processes on a single chip. Movement control of droplets can be realized by using electrowetting-on-dielectric (EWOD) technology. DMFBs have high configurability, high sensitivity, low cost and reduced human error as well as a promising future in the applications of point-of-care medical diagnostic, and DNA sequencing. As the demands of scalability, configurability and portability increase, a new DMFB architecture called Microelectrode Dot Array (MEDA) has been introduced recently to allow configurable electrodes shape and more precise control of droplets. The objective of this work is to investigate a routing algorithm which can not only handle the routing problem for traditional DMFBs, but also be able to route different sizes of droplets and incorporate diagonal movements for MEDA. The proposed droplet routing algorithm is based on 3D-A* search algorithm. The simulation results show that the proposed algorithm can reduce the maximum latest arrival time, average latest arrival time and total number of used cells. By enabling channel-based routing in MEDA, the equivalent total number of used cells can be significantly reduced. Compared to all existing algorithms, the proposed algorithm can achieve so far the least average latest arrival time

Cross-Reference Ewod Driving Scheme And Cross-Contamination Aware Net Placement Technique For Meda Based Dmfbs

Droplet based digital microfluidics is a popular emerging technology for laboratory experiments. However, certain limitations exist in specific cases for implementation that require further enhancement. Pin-count minimization and cross-contamination avoidance between droplets of different bio-molecules during droplet routing are primary design challenges for biochips. A competent architecture namely Microelectrode Dot Array (MEDA) has recently been introduced as a new highly scalable, field programmable and reconfigurable dot array architecture which allows dynamic configuration. This work considers the cross contamination problems in pin constrained biochips based on MEDA architecture. In order to reduce the cross-contamination problem, in this work we present a MEDA architecture based cross-reference driving scheme that allows simultaneous driving of multiple droplets and thereby propose a suitable net placement technique applicable for MEDA architecture. The objectives of this proposed technique include reducing the crossovers with intelligent collision avoidance, minimizing the overall routing time and increasing grouping number to reduce the total pin-count. Simulation results thus presented in this paper indicate the efficiency of our algorithm for practical bioassays