Microfluidic System for Automatic Cell Culture

1
Microfluidic System for Automatic Cell Culture
Chun-Wei Huang, Song-Bin Huang, Gwo-Bin
Lee Department of Engineering Science, National
Cheng Kung University, Tainan, Taiwan
Abstract
The current study presents a new cell chip
capable of automating cell culture process. This
microfluidic cell culture system comprising
micropumps, microvalves, microchannels, a cell
culture area and several reservoirs is fabricated
by using micro-electro-mechanical-systems (MEMS)
process. A new pneumatic micropump requiring only
one electromagnetic valve (EMV) is developed to
transport fluids. With this approach, the control
circuit and peripheral apparatus are greatly
simplified. Several reservoirs are used to place
sample fluids such as cell culture medium,
phosphate-buffered saline (PBS) and trypsin
solutions. The pneumatic micropump allows the
solutions to flow only in one direction. The
uni-directional feature of the micropump can
prevent the whole culture process from
contamination. Moreover, a new check-valve is
also used to prevent the culture solutions from
flowing back into the microchannels. A typical
cell culture process for human lung cancer cells
(A549) is successfully performed on the developed
microfluidic system.
Microfluidic cell culture system
Experimental
Schematic illustration of the automatic cell
culture system. It is composed of a cell culture
area, four micropumps, four micro check-valves,
microchannels, and four reservoirs.
(a) A photograph of the pneumatic micropump
integrated with the micro flow sensor, air
chambers and the fluid microchannel. (b) The
relation between the back pressure and the flow
rate. At a zero flow rate, the micropump has a
maximum back pressure of 16.5 mm-H2O (or 0.02
psi).
Pneumatic micropump hydrophobic microvalve
(a) Photograph of the automatic cell culture
chip. (b) Two micro check-valves are activated
simultaneously. (c) CCD image shows that the ink
can be successfully stopped.
Cell culture
(a) Schematic illustration of the pneumatic
micropump consisting of three air chambers with
different volumes and a flow stopper. (b)
Cross-sectional view of the actuation mechanism
of the micropump. When compressed air fills the
chambers, the flow stopper is pushed downward
first. Then, the membranes of the micropump are
pushed downward sequentially, and the fluid is
pumped to the left-hand side. (c) SEM images of
the SU-8 template (upper) and the PDMS replica
(lower).
(a) Growth curve of the cultured A549 cell. The
cells grew exuberantly from day 1 to day 3 with a
growth rate around 3. The growth rate reduces to
less than 2 from day 3 to day 5. (b) CCD images
from daily observation of cell growth, from Day 0
to Day 5.
(a) Schematic illustration of the micro
check-valve. (b) Cross-sectional view of the
actuation mechanism of the microvalve. Before the
micropump is activated, the liquid is blocked by
the microvalve. When the micropump is activated,
the microvalve is lifted due to the hydrodynamic
force generated by the micropump and the liquid
can flow through the microvalve. (c) SEM images
of the SU-8 template (left) and the PDMS replica
(right).
2006
MML
MEMS design and Micro-fabrication Lab