Copyright © 2011 American Scientific Publishers
All rights reserved
Printed in the United States of America
RESEARCH ARTICLE
Advanced Science Letters
Vol. 4, 1–6, 2011
Application of Microfluidics
Technology in Bioanalysis
B. Liu
1 ∗
, Y. Deng
1 2 ∗
,B.B.Qin
1
, and Z. Y. Li
1
1
State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering,
Southeast University, Nanjing 210096, P.R. China
2
Hunan Key Laboratory of Green Packaging and Application of Biological Nanotechnology,
Hunan University of Technology, Zhuzhou 412008, China
Microfluidics technology which includes continuous-flow microfluidics technology and digital microfluidics tech-
nology is widely used in bioassays today. It holds high promise to facilitate the progress of bioassay by enabling
miniaturization and upgrading of current biological research tools due to its advantages such as low sample
consumption, reduced analysis time, high-throughput and compatible sizes with most biological samples. In this
article, we describe the recent applications of microfluidics in biological researches at the molecular and cellular
levels, including their implementation, and associated design issues. Although the maturity of microfluidics is
not favoured in some reviews about the microfluidics technology, we still predict that the future is bright for this
promising technology at the last section.
Keywords: Microfluidics, PCR, Sequencing Analysis, Drug Delivery, Cell Sorting.
1. INTRODUCTION
Microfluidics technologies can be divided into two classes:
continuous-flow microfluidics technology and digital microflu-
idics technology. Traditional (continuous-flow) microfluidics
technologies are based on the continuous flow of liquid through
microfabricated channels.
1
Continuous-flow systems are inher-
ently difficult to integrate because the parameters that govern
flow field (e.g., pressure, fluid resistance, electric field strength)
vary along the flow-path, making the flow at any location depen-
dent upon the properties of the entire system.
The concept of digital microfluidics (DMF) arose in the
late 1990s and involves the manipulation of discrete vol-
umes of liquids on a surface. Manipulation of droplets can
occur through various mechanisms, including electrowetting,
2
dielectrophoresis,
3
thermocapillary transport
4
and surface acous-
tic wave transport.
5
In the early 2000s, this technology was pop-
ularized by Fair and his coworkers
6
and Kim and his coworkers
7
at Duke and UCLA, respectively.
The microfluidics technique was explained as being a phe-
nomenon driven by surface tension, and was called “elec-
trowetting” or “electrowetting on-dielectric” (EWOD). A detailed
review of electrowetting basics can be found in the work of
Mugele.
8
In addition, work on simulation and modeling of
droplet-based electrowetting has been reported by Biddut and
Homayoun Najjaran.
9
∗
Authors to whom correspondence should be addressed.
Compared to traditional biochips, microfluidic biochips plat-
form is under software-driven electronic control, eliminating the
need for mechanical tubes, pumps, and valves. Moreover, because
each droplet can be controlled independently, these “digital”
systems also have dynamic reconfigurability, whereby groups
of cells in a microfluidic array can be reconfigured to change
their functionality during the concurrent execution of a set of
bioassays.
The advent of microfluidic systems has revolutionized
the methodology for biological researches.
10
Applications of
microfluidic chips in biology are growing fast. In this article, the
recent applications of microfluidic chips in biological researches
at the molecular and cellular levels are overviewed from the per-
spective of biology. As the next-generation platform, microfluidic
chips will certainly open up new avenues for high-throughput
biological analysis, facilitating the understanding of biology at
the molecule-level.
2. ANALYSIS AT MOLECULE LEVEL
Since the discovery of DNA double-helix structure by Watson
and Crick in 1953,
11
molecular level understanding of biol-
ogy started. Especially, with the post genome area coming,
microfluidics based methods will play an important role in high-
throughput genomic studies.
2.1. Polymerase Chain Reaction
Microfluidics technology has been successfully applied for
numerous nucleic acid assay applications. One promising
Adv. Sci. Lett. Vol. 4, No. 1, 2011 1936-6612/2011/4/001/006 doi:10.1166/asl.2011.1202 1