microfluidics lecture

MicrofluidicsNANS 511Peter Zhou

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Microfluidic Devices

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Other Applications of Microfluidics

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Why Microfluidics• Predictable fluid behavior• Accurate spatial control • Reduced sample volume• Lower cost• Parallel processing

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Microfluidic Devices Engineering

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Bernoulli’s Equation• Based on energy balance

• Quick and easy way to determine stream conditions, given that the fluid flow regime is stable

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Bernoulli’s Equation

𝑃1𝜌𝑔 +

𝑉 12

2𝑔 +𝑍1=𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡

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Dimensionless Numbers• Dimensionless numbers characterizes certain properties of flow• It also helps with scaling up or down the process• Reynolds Number

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Dimensionless Numbers• Peclet Number • Compares the transverse mass transfer rate to the diffusion rate• Want to minimize the effects of diffusion

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Dimensionless Numbers• Capillary Number • Compares the viscous effect to the surface tension effect

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Class ExerciseYou are asked to design a microfluidic channel of a cylindrical shape to funnel incoming fluids. The fluid flow rate was determined to be 1E-9 m3/s. The channel is 2 micron in diameter. The density and the viscosity of the fluid are 1000 kg/m3 and 1E-3 Pa.s, respectively. Determine the fluid velocity and Reynolds number.

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Solution

1. = 636

2. Not the behavior you want in a microfluidic device

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Mechanical Application• With sophisticated microfluidic channels, sophisticated

controller and actuators are needed• Pumps, valves, etc

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Microfluidic Devices Engineering Microfluidics in Nanoscience

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Diagnostic and Imagining Applications• Lab-on-Chip devices

• Glucose meter • Pregnancy test

• Organ-on-Chip• Colorimetric assays

• pH paper

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Microfluidics Paper-based Analytical Devices (μPAD)• μPAD• Inexpensive• Easily Disposed• Independent of lab machines• Biologically Compatible

Paper Towels

Technicl

oth

Chromatography Paper

$0.00 $1.00 $2.00 $3.00 $4.00 $5.00 $6.00 $7.00

Cost of different types of paper

Per Unit Area Cost

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Microfluidics based Analytical Devices (μPAD)• Photolithographic technique for patterning paper

• Channel width of 186 microns and barrier width of 248 microns• Well defined geometry compared to wax technique

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Microfluidics based Analytical Devices (μPAD)

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• Microfluidics is a fast and a cost effective method of processing analytes compared to conventional methods• Fundamentals of designing a microfluidic chamber• Evaluated flow velocity and determined the flow regime

• Many different applications in imaging and diagnostics and many more to come• What about nanofluidics?• Even smaller in scale, surface charges plays a role in system behavior

Use of Microfluidic Devices Engineering Microfluidics in Nanoscience

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Questions?

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Referencehttp://www.custompartnet.com/wu/images/rapid-prototyping/inkjet-printing.png

Microfluidic Devices in Nanotechnology. Hoboken, US: Wiley, 2010. ProQuest ebrary. Web. 31 March 2016.

Nature Protocols 8, 1459–1474 (2013) doi:10.1038/nprot.2013.082Published online 11 July 2013

Nature Physics 6, 433–437 (2010) doi:10.1038/nphys1637Received 22 September 2009 Accepted 05 March 2010 Published online 18 April 2010

Microfluidics. Somerset, US: Wiley-ISTE, 2013. ProQuest ebrary. Web. 31 March 2016.

Martinez, A. W., Phillips, S. T., & Whitesides, G. M. (2009). Diagnostics for the Developing World: Microfluidic Paper-Based Analytical Devices. Analytical Chemistry, 82(1), 3-10. Retrieved April 6, 2016.

Jakubek, A. M. (n.d.). Music-Powered Lab-On-A-Chip Promises Easier Health Screening. Retrieved April 06, 2016, from http://www.popsci.com/gear-amp-gadgets/article/2009-07/musical-chip-means-portable-flu-kits-are-just-around-corner