Download A Fully-Integrated Microfluidic Chip for RNA

A Fully-Integrated Microfluidic Chip for RNA-Virus Detection
Fu-Chun Huang1, Chia-Sheng Liao2, Gwo-Bin Lee1,2
1Department of Engineering Science, 2Institute of Micro-Electro-Mechanical-System Engineering
National Cheng Kung University, Tainan, Taiwan 701
 Abstract
90
80
Temperature (oC)
The study reports a new fully-integrated microfluidic device
capable of performing Reverse-Transcription Polymerase Chain
Reaction (RT-PCR), transportation of amplified molecular samples,
capillary electrophoresis (CE) separation and on-line detection of
RNA-based virus. Using three major technologies, including
molecular biology, micro-fabrication and micro-fluidics, we
develop an innovative micro-total-analysis-system (μ-TAS) for
rapid clinical diagnosis. We have successfully demonstrated the
detection of the Dengue-2 virus using the hand-held system in a
shorter period with less consumption of samples and reagents. The
system can perform high heating (20℃/sec) and cooling (10℃/sec)
rates. The integrated system has successfully carried out the
detection of Dengue-2 virus samples.

Experimental
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70
60
(2)
(3)
(4)
50
40
30
20
0
100
200
300
400
Time (sec)
500
600
(A)
(B)
(A) Typical PCR thermal cycles generated by the PCR chip.
(B) SEM images. (1) A SU-8 mold of two optical fibers and one
microchannel, (2) PDMS replication from the SU-8 mold. (3) SU-8
mold of a pneumatic pump, and (4) PDMS replication of the micropump.
 Design and fabrication
RT-PCR
reagents
(1)
PCR
reagents
after RT-PCR
High Voltage Power Supply
Computer
Microfluidic chip
PMT
RT/PCR
reaction
chamber
capillary
electrophoresis
RNA
Transmission line
chip
optical fiber Hg lamp
photomultiplier
Optical fiber
computer
Microfluidic
Temperature control
Focus lens
tube
control module
module
Band-pass filter
Schematic representation of the fully-integrated microfluidic chips for
(A)
(B)
RNA virus detection.
(A) Schematic representation of the experimental setup for CE detection.
Note that excitation and emitted lights are transmitted by buried optic
fibers.
(e) SU-8 mold formation
(a) Lithography
(B) The PCR and microfluidic control systems.
sample
preparation
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872
70
(b) Platinum deposition
60
(c) Gold deposition
511
50
Fluorescent signal
(mV)
(f) PDMS replication
603
310
281
40
271
30
(d) Insulation layer setup
(g) O2 plasma bonding
Simplified fabrication process for the fully- integrated microfluidic
chip.
20
72
118
194 234
10
0
Leads of heaters
and sensors
PCR reagents
RT/PCR reaction
chamber
2.5
Capillary
electrophoresis
Peristaltic micropneumatic pump
RT-PCR reagents
Optical fiber
channel
Photograph of the fully-integrated microfluidic chip after assembly.
3
3.5
4
4.5
5
Time (min)
Electrophoregrams of amplified RNA product of Dengue II virus and
Hae III digested x-174 DNA markers.
 Conclusions
Fully-integrated microfluidic chips capable of performing DNA
amplification from RNA virus, sample transportation, capillary
electrophoresis separation, and on-line optical detection have been
developed.
The developed system consumes less reagent and sample volumes, and
provides higher heating/cooling rates with a more precise temperature
control.
The proposed microfluidic chip is a powerful tool for the detection of
DNA/RNA samples and has significant potential for implementation in
micro total analysis systems.
2006
MML
MEMS design and Micro-fabrication Lab