Transcript Document

Micromachined Flow-through Polymerase Chain Reaction Chip
Utilizing Multiple Membrane-activated Micropumps
Chih-Hao Wang1, Chia-Sheng Liao2, Gwo-Bin Lee1,2
1Department
of Engineering Science, 2 Institute of MEMS, National Cheng Kung University, Tainan Taiwan 701
Abstract
This study reports a new micromachined flow-through polymerase chain reaction (PCR) chip for applications of rapid pathogen diagnosis. The
PCR chip comprised a micro thermal control module and a microfluidic control module fabricated using MEMS technology. The micro thermal
control module was formed with three individual heating and temperature-sensing sections, each modulating a specific temperature for
denaturation, annealing and extension process, respectively. The membrane-activated micropumps were used to transport sample fluids through
three reaction regions to adjust the time ratio and cycle numbers for PCR. The experimental results showed that S. pneumoniae detection gene
(273 bps) could be amplified successfully using the new flow-through PCR chip. The new PCR chip could be promising for rapid clinical diagnosis
of DNA-based infectious disease.
Design and Fabrication
Experimental
The schematic illustration of a
pneumatic-driven 3-zone flowthrough PCR chip.
Slab-gel electrophoregram for
detection of respiratory tract
infection microorganisms. In
each electrophoregram, there
are DNA ladders (L), products
from a portable PCR system
(C), and conventional PCR
machines (M).
Schematic diagram of the flow-through PCR chip
Simplified fabrication process of the flow-through PCR chip.
(a) Thermal control module, and (b) formation of microfluidic
channels using SU-8 and PDMS casting process.
Primers designed to detect (S. pneumoniae)
(F: forward primer; R: reverse primer)
Conclusions
The movement of the PCR product in the microchannel was dependent on
the time ratio of membrane-activated micropump and cycle numbers.
The micro thermal control module was formed with three individual
heating and temperature-sensing sections, each modulating a specific
temperature for denaturation, annealing and extension process,
respectively.
The PCR chip integrated with the three heaters/sensors and membraneactivated micropumps successfully solve the problems in previous
researches including a fixed time ratio.
Acknowledgements
Photograph of the PCR chip after assembly
Photograph and SEM image of
the micro heaters and sensors
The authors gratefully acknowledge the financial support provided to this
study by the National Science Council of Taiwan (NSC 94-3112-B-006-002)
and by the MOE Program for Promoting Academic Excellence of
Universities (EX-91-E-FA09-5-4).
2006
MML
MEMS design and Micro-fabrication Lab