Biomedical Engineering Reference
In-Depth Information
(Berkeley), which has been able to integrate glass PCR chips with PDMS microvalves and other
processing functions such as CE (
Figure 4.21
). A four-layer glass-PDMS-glass-glass hybrid
device integrated microvalves, microheaters, temperature sensors, 380-nL reaction chambers,
and the channels for CE where the amplicons (reaction products) are separated and detected by
luorescence ater 30 cycles of RT-PCR (in 45 minutes, allowing for attomolar detection sensitiv-
ity, equivalent to ~11 template RNA molecules).
In the continuous-low architecture, introduced in 1998 by Andreas Manz's group, then at
London's Imperial College of Science, the nucleic acid solution lows through a microluidic
channel with alternating hot and cold regions, thereby producing ampliication (
Figure 4.22
). A
rich variety of designs (ranging from serpentines to spirals to it as many meandering channels
(a)
(b)
(c)
Sample
Glass
manifold
PDMS
membrane
Ti/Pt
heater
Ti/Pt RTD
Heater/
electrophoretic
wafer
Cathode
Waste
PCR chamber
Valve
access
PDMS valve
CE channel
RTD
wafer
Anode
1 cm
FIGURE 4.21
Integrated.RT-PCR.and.CE.on.a.chip..(From.Nicholas.M..Toriello,.Chung.N..Liu,.and.
Richard.A..Mathies,.“Multichannel.reverse.transcription-polymerase.chain.reaction.microdevice.for.
rapid.gene.expression.and.biomarker.analysis,”.
Anal. Chem.
.78,.7997-8003,.2006..Reprinted.with.
permission.of.the.American.Chemical.Society.)
90°
80°
70°
60°
90°
80°
70°
60°
20
21
22
23
24
20
21
22
23
24
25
26
27
28
29
30
25
26
27
28
29
30
(a)
(b)
Melt line
FIGURE 4.22
Continuous-low.PCR..The.“melt.line”.shows.the.point.where.the.sample.has.a.rela-
tively.high.amplicon.concentration.(a,.DYZ1;.and.b,.CYP2C9*3.targets)..The.random.dark.ellipsoids.
within.the.channels.are.slow-moving.bubbles..(From.Niel.Crews,.Carl.Wittwer,.Robert.Palais,.and.
Bruce. Gale,. “Product. differentiation. during. continuous-low. thermal. gradient. PCR,”.
Lab Chip
. 8,.
919,.2008..Reproduced.with.permission.from.The.Royal.Society.of.Chemistry.)
