| Coordinating Multiple Droplets in Planar Array Digital Microfluidic Systems |  |
| E. J. Griffith and S. Akella |
| Workshop on the Algorithmic Foundations of Robotics |
| Utrecht/Zeist, Netherlands |
| July, 2004 |
| International Journal of Robotics |
| November, 2005 |
Abstract
Workshop on the Algorithmic Foundations of Robotics
This paper presents an approach to coordinate the motions of droplets
in digital microfluidic systems used for biochemical analysis. A digital microfluidic
system typically consists of a planar array of cells with electrodes that control the
droplets. The primary challenge in using droplet based systems is that they require
the simultaneous coordination of a potentially large number of droplets on the array
as the droplets move, mix, and split. This paper describes a general-purpose system
that uses simple algorithms and yet is versatile. First, a semi-automated approach
to generate the array layout in terms of components is explained. Next, simple
algorithms to select destination components for the droplets and a decentralized
scheme for components to route the droplets on the array are discussed. These are
then combined into a reconfigurable system that has been simulated in software to
perform DNA polymerase chain reaction and other analyses. The algorithms have
been able to successfully coordinate hundreds of droplets simultaneously and perform
one or more chemical analyses in parallel. Since it is challenging to analytically
characterize the behavior of such systems, methods to detect potential instabilities
are proposed.
International Journal of Robotics
In this paper we present an approach to coordinate the motions of
droplets in digital microfluidic systems, a new class of lab-on-a-chip
systems for biochemical analysis. A digital microfluidic system typically
consists of a planar array of cells with electrodes that control
the droplets. The primary challenge in using droplet-based systems is
that they require the simultaneous coordination of a potentially large
number of droplets on the array as the droplets move, mix, and split.
In this paper we describe a general-purpose system that uses simple
algorithms and yet is versatile. First, we present a semi-automated
approach to generate the array layout in terms of components. Next,
we discuss simple algorithms to select destination components for
the droplets and a decentralized scheme for components to route the
droplets on the array. These are then combined into a reconfigurable
system that has been simulated in software to perform analyses such
as the DNA polymerase chain reaction. The algorithms have been
able to successfully coordinate hundreds of droplets simultaneously
and perform one or more chemical analyses in parallel. Because it
is challenging to analytically characterize the behavior of such systems,
simulation methods to detect potential system instability are
proposed.
BibTeX
Workshop on the Algorithmic Foundations of Robotics
| @INPROCEEDINGS{griffith2005a, |
|
author |
= |
{Eric J. Griffith and Srinivas Akella}, |
| title |
= |
{Coordinating Multiple Droplets in Planar Array Digital Microfluidic Systems}, |
| editor |
= |
{Michael Erdmann and David Hsu and Mark Overmars and Frank van der Stappen}, |
| booktitle |
= |
{Algorithmic Foundations of Robotics VI}, |
| pages |
= |
{219--234}, |
| year |
= |
{2005}, |
| } |
International Journal of Robotics
| @ARTICLE{griffith2005c, |
|
author |
= |
{Eric J. Griffith and Srinivas Akella}, |
| title |
= |
{Coordinating Multiple Droplets in Planar Array Digital Microfluidic Systems}, |
| journal |
= |
{International Journal of Robotics Research}, |
| volume |
= |
{24}, |
| number |
= |
{11}, |
| pages |
= |
{933--949}, |
| month |
= |
{November}, |
| year |
= |
{2005}, |
| } |
Media
Video
Note that these videos were recorded with an earlier version of the software.
Therefore, droplets need only have 1 and 2 electrodes between them
when moving in a line or around a corner, respectively. The general system
behavior remains consistent with these videos, however.
Droplet Mixing
 |
This is a video of two different types of droplets being mixed in a mixing unit. The
droplets enter from two sources on the left side of the array, proceed to the work area
and subsequently the mixing unit. Once they are mixed, they leave the array at a
sink on the right side.
|
| AVI |
DNA Polymerase Chain Reaction - Continuous Mode
 |
This video demonstrates a simulated DNA Polymerase Chain Reaction. We are
assuming the droplets are routed off-chip for the heating. The simplified analysis
graph for the reaction is shown below. Here, the system is operating in continuous
mode, where sources supply input droplets continuously at regular intervals. |
| AVI |
|
DNA Polymerase Chain Reaction - Unstable Continuous Operation
 |
This video demonstrates a simulated DNA Polymerase Chain Reaction. We are
assuming the droplets are routed off-chip for the heating. The simplified analysis
graph for the reaction is shown below. Here, the system is operating in continuous
mode, where sources supply input droplets continuously at regular intervals, but the
input droplets are supplied at too great of a rate. |
| AVI |
|
Multiple Simultaneous Reactions - Continuous Mode
 |
This video demonstrates a simulated DNA Polymerase Chain Reaction (suqare droplets) happening in
parallel with another, fictional reaction (diamond droplets). We are
assuming the droplets are routed off-chip for the heating for the PCR. The simplified analysis
graph for the reaction is shown below. Here, the system is operating in continuous
mode, where sources supply input droplets continuously at regular intervals. |
| AVI |
|
DNA Polymerase Chain Reaction - Batch Mode
 |
This video demonstrates a simulated DNA Polymerase Chain Reaction. We are
assuming the droplets are routed off-chip for the heating. The simplified analysis
graph for the reaction is shown below. Here, the system is operating in batch mode,
where the input droplets are supplied when the output
droplets have left the array. Also, each mix/split operation
produces one waste droplet (diamond droplets). |
| AVI |
|
Download
- Paper: PDF (WAFR) PDF (IJRR)
- BibTeX: bib (WAFR) bib (IJRR)
- Abstract: PDF (WAFR) PDF (IJRR)
- Movies:
- PCR - Continuous Mode: AVI
- PCR - Unstable Continuous Operation: AVI
- Multiple Simultaneous Reactions - Continuous Mode: AVI
- PCR - Batch Mode: AVI
