Microfluidic components 2017 sami franssilaaalto fi Contents Channels

Microfluidic components 2017 sami. franssila@aalto. fi

Contents • • • Channels Filters Mixers Pumps Valves • • 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 • • 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 2003 a; 75: 4718– 23.

Microvalves: Piezoelectric actuation, flap valve Thermal expansion actuation, torsion valve

Geometric valves 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

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: Sn. O 2 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 • 1 D devices – flow channels • 1. 5 D devices – flow channels with junctions • 2. x D devices – flat objects on surface (height << lateral dimension) • 2. 5 D objects – height lateral size; open top • 3 D objects – closed spaces (access holes)

Electronic vs. Fluidic • • • planar (2 D) small (cm 2) complex 109 elements 15 -30 litho steps • 1 -10 $/cm 2 • few materials 3 D anything (mm 2 => 100 cm 2) 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 !)