Enhancement of multiple parallel assay operations with cross contamination avoidance in a given biochip
08 Sep 2014-pp 1-7
About: The article was published on 2014-09-08. It has received None citations till now. The article focuses on the topics: Biochip.
Citations
More filters
[...]
TL;DR: In this paper , a cross-referencing digital microfluidic biochips (DMFBs) with an efficient module placement design can be declared as a multifunctional chip or not, and a chip design which incorporates parallelism for enhancing performance in terms of assay completion time while performing multiple types of bioassays.
Abstract: Digital Microfluidic Biochips (DMFBs) perform many biochemical reactions requiring relatively less cost and very less amount of space. DMFBs that use cross-referencing addressing requires less number of pins, therefore, less manufacturing cost. However, it suffers from a problem called electrode interference, i.e., unwanted droplet operation because of an extra activated cell. DMFBs also suffer from a problem called cross-contamination, i.e., mixing of droplets with unwanted residues of droplets containing different chemicals which results in incorrect diagnosis. In this article, our objective is whether a cross-referencing DMFB with an efficient module placement design can be declared as a multifunctional chip or not. We propose a chip design which incorporates parallelism for enhancing performance in terms of assay completion time while performing multiple types of bioassays. We also propose a novel method, which automatically selects a new cross-contamination free path while routing from the source to the sink. We have included an on-chip washing scheme. The whole method ensures no Electrode Interference.
1 citations
References
More filters
[...]
TL;DR: To understand the opportunities and limitations of EWD microfluidics, this paper looks at the development of lab-on-chip applications in a hierarchical approach.
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.
1,037 citations
[...]
TL;DR: This paper studies the effects of varying droplet aspect ratios on linear-array droplet mixers, and proposes mixing strategies applicable for both high and low aspect ratio systems, and presents a split-and-merge mixer that takes advantage of the ability to perform droplet splitting at these ratios.
Abstract: The mixing of analytes and reagents for a biological or chemical lab-on-a-chip is an important, yet difficult, microfluidic operation. As volumes approach the sub-nanoliter regime, the mixing of liquids is hindered by laminar flow conditions. An electrowetting-based linear-array droplet mixer has previously been reported. However, fixed geometric parameters and the presence of flow reversibility have prevented even faster droplet mixing times. In this paper, we study the effects of varying droplet aspect ratios (height ∶ diameter) on linear-array droplet mixers, and propose mixing strategies applicable for both high and low aspect ratio systems. An optimal aspect ratio for four electrode linear-array mixing was found to be 0.4, with a mixing time of 4.6 seconds. Mixing times were further reduced at this ratio to less than three seconds using a two-dimensional array mixer, which eliminates the effects of flow reversibility. For lower aspect ratio (≤0.2) systems, we present a split-and-merge mixer that takes advantage of the ability to perform droplet splitting at these ratios, resulting in a mixing time of less than two seconds.
484 citations
[...]
TL;DR: In this paper, an alternative mixing strategy is presented based on the discretization of liquids into droplets and further manipulation of those droplets by electrowetting, where interfacial tensions of the droplets are controlled with the application of voltage.
Abstract: Mixing of analytes and reagents is a critical step in realizing a lab-on-a-chip. However, mixing of liquids is very difficult in continuous flow microfluidics due to laminar flow conditions. An alternative mixing strategy is presented based on the discretization of liquids into droplets and further manipulation of those droplets by electrowetting. The interfacial tensions of the droplets are controlled with the application of voltage. The droplets act as virtual mixing chambers, and mixing occurs by transporting the droplet across an electrode array. We also present an improved method for visualization of mixing where the top and side views of mixing are simultaneously observed. Microliters of liquid droplets are mixed in less than five seconds, which is an order of magnitude improvement in reported mixing times of droplets. Flow reversibility hinders the process of mixing during linear droplet motion. This mixing process is not physically confined and can be dynamically reconfigured to any location on the chip to improve the throughput of the lab-on-a-chip.
367 citations
[...]
TL;DR: This study shows that both electrowetting on dielectric and dielectrophoresis are effective for droplet generation and manipulation, and demonstrates: (1) the presence of a wetting contribution to dielectophoresis; and (2) contact angle reduction is merely an observable consequence of, not a condition for, the occurrence of electrowsetting onDielectric.
Abstract: Electrically controlled droplet-based labs-on-a-chip operate under the principles of electro-capillarity and dielectrophoresis. The microfluidic mechanics of manipulating electrified droplets are complex and not entirely understood. In this article, we analyse these operating principles, especially electrowetting on dielectric (a form of electro-capillarity) and dielectrophoresis, under a unified framework of droplet electrohydrodynamics. We differentiate them by their electric origins and their energy transduction mechanisms. Our study shows that both electrowetting on dielectric and dielectrophoresis are effective for droplet generation and manipulation. In addition, our study demonstrates: (1) the presence of a wetting contribution to dielectrophoresis; and (2) contact angle reduction is merely an observable consequence of, not a condition for, the occurrence of electrowetting on dielectric. Simulations are used extensively in this article to illustrate device operation, to expose underlying physics, and to validate our conclusions. Simulations of electrically driven droplet generation, droplet translocation, droplet fusion, and droplet fission are presented.
292 citations
[...]
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.
221 citations
Related Papers (5)
[...]