Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
(e)
Air
Air
Mixed
region
Air
Air
Air
FIGURE 3.61
A. PDMS. vacuum. pump.. (From. Kazuo. Hosokawa,. Kae. Sato,. Naoki. Ichikawa,. and.
Mizuo.Maeda,.“Power-free.poly(dimethylsiloxane).microluidic.devices.for.gold.nanoparticle-based.
DNA.analysis,”.
Lab Chip
.4,.181-185,.2004..Reproduced.with.permission.from.The.Royal.Society.
of.Chemistry.)
Sample well
a
Flow chamber
Diffusion membrane
Pressure
Control channel
Fluid
Air
Sample well
b
Flow chamber
Diffusion membrane
Vacuum
Control channel
FIGURE 3.62
Gas-permeation.micropump..(From.Mark.A..Eddings.and.Bruce.K..Gale,
“A.PDMS-
based. gas. permeation. pump. for. on-chip. luid. handling. in. microluidic. devices,”.
J. Micromech.
Microeng.
.16,.2396-2402,.2006..Figure.contributed.by.Bruce.Gale..Reproduced.with.permission.
from.the.Institute.of.Physics.)
3.8.4.3 Three-Valve PDMS Peristaltic Micropumps
he Quake microvalves (
Figure 3.38a
) were irst reported in 2000. he same
Science
article also
reported the operation of three valves in series to obtain a peristaltic pump (see
Figure 3.38b
in Section 3.8.1.4) that achieved a pumping rate of 2.35 nL/s at zero backpressure; these pumps
could be operated at 25 Hz (75 Hz each valve). In 2003, the Mathies group presented peristaltic
pumps constructed with their “doormat” microvalves (
Figure 3.63
), featuring pumping rates up
to 50 nL/s at zero backpressure. (he pumping rates do not necessarily relect the performance
of the pump, because it can be easily increased by increasing the area of the valve seal; the
Mathies group investigated diaphragm pump dimensions between 1000 and 6000 μm, which is
equivalent to displacement chamber volumes ranging between 67 and 2050 nL.)
An interesting variation of the “doormat” design (it can be constructed with an all-SU-8
mold) has been presented by Satoshi Konishi's group of Ritsumeikan University in Kyoto
(Japan). Here the valve seat is circularly symmetric, which facilitates the ejection of the luid out
of the valve seat as the PDMS membrane attempts to seal with the valve seat in the valve-closing
phase of the pumping cycle (
Figure 3.64
). he reported pumping rates were low (~1.2 nL/s at
