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Microfluidic components 2017
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Contents
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Channels
Filters
Mixers
Pumps
Valves
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Microreactors
Surface microfluidics
Droplet reactors
PCR DNA chips
flow control
applications
Basic geometries:straight channel
-separation channel
-mixer
-microreactor
-...
Linear microreactor
R.M. Tiggelaar et al. / Sensors and Actuators A 119 (2005) 196–205
Basic geometries: X,T,Y,H
Applications:
•CE injectors
•mixers
•filters
•reactors
Particle filtering: H-filter
Catalytic microreactor
Younes-Metzler et al:
Applied Catalysis A: General
284 (2005) 5–10
Catalytic microreactor (2)
Younes-Metzler et al:
Applied Catalysis A: General
284 (2005) 5–10
Combine basic shapes to devices
Injector + separation
channel
precolumn reaction +
separation
post-column reaction
Meander-shapes
Adv. Mater. 2012,
DOI: 10.1002/adma.201203252
D. M. Ratner, E. R. Murphy, M. Jhunjhunwala, D. A. Snyder,
K. F. Jensen and P. H. Seeberger, Chem. Commun., 2005, 578
Area needed: 6.3 mm * 6.3 mm
Pumps
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bubble pumps
membrane pumps
diffuser pumps
rotary pumps
electrohydrodynamic
electro-osmotic/electrophoretic
ultrasonic pumps
vacuum pumps
Pumps: actuation mechanism
Peristaltic pump = 3 valves in
series
Pumps without moving parts
Surface tension driven pump
Electro-osmotic pump
Nozzle-diffuser pump,
Olsson, Stemme 1997
Osmotic pump
Thermal ink jet
MEMS Handbook
Passive
• mechanical
• geometric
• hydrophobic
Active valves
pneumatic
thermopneumatic
phase-change
electrostatic
piezoelectri
thermal expansion
Membrane valve, pneumatic actuation
N=20 matrix chip to perform 400 independent PCR reactions,
with in total 2860 in-line microvalves that was controlled by
only two independent pneumatic pressure supplies.
Liu J, Hansen C, Quake SR. Solving the ‘World-to-Chip’ interface
problem with a microfluidic matrix. Anal Chem 2003a;75:4718–23.
Microvalves:
Piezoelectric
actuation, flap valve
Thermal expansion
actuation, torsion valve
Geometric valves
(a)
(b)
Pillar “forest” controls the rate of capillary flow.
Rapid constriction of the flow channel will stop the flow.
Side channel offers timing of flow.
Transducers 2005, p. 1565
(c)
Fluidic diode in PDMS
Microreactors
Small volume good if
expensive and/or dangerous
chemicals
Fast reactions because small
diffusion distances
Large surface area (either
positive or negative effect)
Good temperature control
and fast ramp rates
Besser: J. Vac. Sci. Technol. B 21.2.,
Mar/Apr 2003
Good flow control because of
laminar flow
Simple linear microreactor
Anodic bonding: silicon and glass
Heater electrode
Nitride membrane
Catalyst underneath
Flow channel
Bonded to glass wafer
Microreactor dimensions
Shin & Besser,
Cross-flow reactor in silicon
Fusion
bonding:
silicon-tosilicon
Electrowetting (EWOD)
Hydrophobic
coating
Electrowetting: electrostatically induced reduction in the
contact angle of an electrically conductive liquid droplet on
an insulating hydrophobic surface.
Droplet movement
EWOD ≈ DMF ≈
Digital microfluidics
EWOD materials
ITO =
In:SnO2
transparent
conductor
Parylene
= CVD
deposited
polymer
DMF microreactor
PCR  DNA copy machine
PCR in SU-8
µPCR = rapid thermal ramping
Continuos flow PCR
Thermocycling PCR
Angew. Chem. Int. Ed. 2007, 46, 1 – 5
Simple and complex devices
• 1D devices – flow channels
• 1.5D devices – flow channels with
junctions
• 2.x D devices – flat objects on surface
(height << lateral dimension)
• 2.5D objects – height  lateral size;
open top
• 3D objects – closed spaces (access holes)
Electronic vs. Fluidic
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planar (2D)
small (cm2)
complex
109 elements
15-30 litho steps
• 1-10 $/cm2
• few materials
3D
anything (mm2 => 100 cm2)
simple
few elements
1-5 steps typical
(13 highest so far)
highly variable
novel and exotic materials
Integration; component level
• many operations performed on a chip
 increased automation, easier handling
 smaller signals can be handled
 less waste
 different functions combined on chip
Integration: fluidics
• fabrication yield low
(as with early transistors)
• more difficult design
(as with early ICs)
• no more jobs for analytical chemists
(this was predicted for electronics
engineers in 1960 !)