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A PDMS BASED INTEGRATED PCR MICROCHIP FOR
GENETIC ANALYSIS
Sandeep Kumar Jha, You-Cheol Jang, Rohit Chand, Kamrul Islam
Department of Nanoscience & Engineering, Myongji University, Yongin, 449728, Republic of Korea
Yong-Sang Kim
Department of Nanoscience & Engineering, Myongji University & Department of Electrical Engineering, Myongji
University, Yongin, 449728, Republic of Korea
Keywords: PDMS, PCR Microchip, SMAD4, Lab-on-a-chip, ITO microheater.
Abstract: An integrated continuous-flow microfluidic chip was fabricated on glass substrate with PDMS based
microchannels, cell lysis and PCR modules. Gold-microelectrodes were used to produce electrochemical
cell lysis, while, indium-tin-oxide (ITO) microheater was used for thermal cycling of PCR reaction. The
fabricated device was used for 20 cycles of PCR amplification of pancreatic cancer DNA marker (SMAD4)
from non-tumorigenic MCF10a human cell lines. The 193 bp PCR amplicon obtained through on-chip PCR
was confirmed in case of MCF 10a cells through agarose gel electrophoresis, whereas no product was
detected in case of tumorigenic MCF7 cells. The total time required for entire reaction was less than 90 min.
Therefore, we propose that such microchip can be helpful in predicting the risk of cancer by analysis of
genetic tumor markers from human samples and can also be used for other genetic analysis involving PCR
reaction.
1 INTRODUCTION
Early detection of metastasis has always remained as
elusive as necessity. Such detection often involves
invasive tissue biopsy or expensive and unreliable
tumor marker antigen study. However, the probable
occurrence of a certain forms of cancer can be
predicted as early as gastrulation using genetic
markers. SMAD4 is one such gene, which is either
deleted or mutated in more than one third of
pancreatic cancer patients (Dixit and Juliano, 2008).
These genetic markers can be identified by using
Polymerase chain reaction (PCR), which is a widely
used molecular biology technique for amplifying
specific regions of DNA using DNA polymerase
enzyme. The PCR technique is also applicable in
cloning, genotyping, drugs discovery, forensic,
environmental and ever growing application areas. A
majority of PCR applications involves analysis with
whole cells and requires the extraction of template
DNA prior to PCR. These steps are time consuming
and labor extensive and require expensive chemicals
and instrumentation.
Since, further miniaturization of this technique
is possible, we propose in this regard, a continuous-
flow PCR chip on glass substrate using indium-tin-
oxide (ITO) heater and microchannels laid in
polydimethylsiloxane (PDMS). As, cell lysis is an
important step for extraction of DNA prior to PCR
analysis, for this reason, we also integrated a cell
lysis device on the same chip. While, PDMS was
chosen for microfluidic devices fabrication as it can
easily and repeatedly be fabricated by the molding
method and requires no channel pretreatment as in
case of materials such as Poly(methyl methacrylate)
(PMMA); ITO heater electrodes were the choice for
thermal cycling due to ease of its fabrication and
linear variation of its temperature by application of
DC power.
2 EXPERIMENTAL
The Micro chip consisted of two parts (Fig. 1). The
273
Kumar Jha S., Jang Y., Chand R., Islam K. and Kim Y..
A PDMS BASED INTEGRATED PCR MICROCHIP FOR GENETIC ANALYSIS.
DOI: 10.5220/0003288202730275
In Proceedings of the International Conference on Biomedical Electronics and Devices (BIODEVICES-2011), pages 273-275
ISBN: 978-989-8425-37-9
Copyright
c
2011 SCITEPRESS (Science and Technology Publications, Lda.)