Flow Restrictions and Flow Restrictions and Fluid Turbulence in Fluid Turbulence in Microfluidic ChannelsMicrofluidic Channels

By Joseph M. CliftBy Joseph M. Clift

OutlineOutline

IntroductionIntroduction Gate Design and Fabrication of Gate Design and Fabrication of

Gated Channels Gated Channels Fabrication of MixersFabrication of Mixers Conclusions and Future DirectionsConclusions and Future Directions

Why is it important?Why is it important?

Microfluidic devices can be Microfluidic devices can be utilized for a wide range of utilized for a wide range of applications such asapplications such as

BiosensorsBiosensors1,21,2

MicroreactorsMicroreactors1,21,2

Image from http://thebigone.stanford.edu/

Fabrication of GatesFabrication of Gates

Gated channels are Gated channels are produced on produced on Macromedia Macromedia FreehandFreehand™™..

The finished The finished drawings are then drawings are then printed on a printed on a transparency from transparency from high resolution laser high resolution laser printer and cut to fit printer and cut to fit into the petri dishes. into the petri dishes.

Nonlithographic Nonlithographic Fabrication Method Fabrication Method

Microfluidic GatesMicrofluidic Gates

Image taken of three microchannels of distances 165m, 195m, and 205m at 34x.

Image of 195m microchannel at 50x.

200m

200m

Gate DimensionsGate Dimensions

Microfluidic MixersMicrofluidic Mixers

Small cross sections and large linear Small cross sections and large linear flow velocity leads to laminar flowsflow velocity leads to laminar flows

Mixing is essential for biosensors Mixing is essential for biosensors (labeling of samples) and (labeling of samples) and microreactorsmicroreactors

Active mixers – moving stirrersActive mixers – moving stirrers Passive mixers – no moving parts, the Passive mixers – no moving parts, the

cannel geometry generates cannel geometry generates intertwining flows intertwining flows

Nonlithographic Nonlithographic Fabrication of Fabrication of MicromixersMicromixers

Observations of mixing Observations of mixing channelschannels

400 m 100 m

ConclusionsConclusions

Nonlithographic fabrication is a facile Nonlithographic fabrication is a facile and low-cost alternatives for expedient and low-cost alternatives for expedient prototyping.prototyping.

Microgate fabrication exceeded twice Microgate fabrication exceeded twice the resolution of the printers we used.the resolution of the printers we used.

Nonlithographic methods allow for the Nonlithographic methods allow for the fabrication of circular channels with fabrication of circular channels with patterned walls.patterned walls.

Spiral grooves along the walls of Spiral grooves along the walls of micromixers significantly increases the micromixers significantly increases the mixing efficiency. mixing efficiency.

Future DirectionsFuture Directions

Evaluate fluid flow through the Evaluate fluid flow through the microgatesmicrogates

Model the fluid flow in the spiral-Model the fluid flow in the spiral-

grooved micromixersgrooved micromixers

ReferencesReferences

1. Trinidad National Institute of Higher Education compiler. 2001 [cited 2007 Jul 24]. Make Way for Microfluidics! Trinidad: NIHERST. Available from: http://www.niherst.gov.tt/scipop/sci-bits/microfluidics.htm

2. Whatis.com compiler. 2001 [cited 2007 Jul 24]. Microfluidics. Needham, MA: Whatis.com. Available from: http://whatis.techtarget.com/definition/0,,sid9_gci526632,00.html

3. Stephen R. Quake compiler. 2005 [cited 2007 Aug].. Stanford, CA: Quake Group homepage. Available from: http://thebigone.stanford.edu/

AcknowledgementsAcknowledgements

Dr. VullevDr. Vullev Marlon ThomasMarlon Thomas Connie ChongConnie Chong Brent MillareBrent Millare Amy FerrieraAmy Ferriera Elizabeth ZielinsElizabeth Zielins

BRITE BRITE administration administration and membersand members