Microfluidics

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Microfluidic Chip

Microfluidics refers to a set of technologies that control the flow of minute amounts of liquids or gases — typically measured in nano- and picoliters — in a miniaturized system.

Just as a computer chip has carefully-arranged wires that electricity moves around, a microfluidic chip has tiny channels etched onto it that fluids move around. In a biochemistry laboratory, a chemist might pipette some solution out of a flask, mix it with a reagent, fractionate it, or perform other operations on it. The interesting thing is that most of these processes are just a matter of moving liquids around, so they can be replicated with microfluidics. The advantage is that microfluidics is much cheaper, safer and requires less skill. Room-sized diagnostic testing equipment can be shrunk down to the size of a postage stamp. This is also called "lab-on-a-chip".

Applications are as vast as they are revolutionary, and include -

• Medical diagnostics and blood tests
• Medical and chemical research - testing for genes, chemical separation and reactions
• Environmental sensing - testing water quality, air quality, monitoring for environmental toxins
• Testing for plant diseases
• Testing soils (biosensor example here)
• mining
• developing biofuels
• and many more.

Microfluidics in Open Source Ecology

We are interested in very cheap, open-source ways of making microfluidic chips. There are plenty of groups working on this; it's a matter of gathering the information.

DIY microfluidics methods

• How to make a microfluidic chip using double-sided sellotape, glass slides and a scalpel: [1]. This requires inlet and outlet holes in the slide; perhaps these could be made with a laser cutter?
• Complex 3D microfluidic devices made with alternating layers of paper and double-sided tape: [2]. The tape was cut using a laser cutter. The paper was treated with photoresis (a light-sensitive polymer) and exposed to UV light when masked with a transparency with a pattern printed onto it. Cost of fabricating a chip = $0.03.
• Disposable microfluidic devices created using regular wax paper
• Shrinky Dink® microfluidics - academic paper here

Channel designs

Are there online repositories of channel designs for different purposes?

Micado is open-source software for designing microfluidic chips.

Materials and Equipment Used

Consumables:

• blotter paper
• regular paper
• wax paper, shrinky-dink
• transparency film
• cotton thread
• sewing needles
• wood sticks
• Jell-O
• beeswax?

Equipment:

• syringes
• cell phone cameras
• plastic lenses for cheap microscopes
• Laser cutter, see Low-cost rapid prototyping of flexible microfluidic devices using a desktop digital craft cutter

George Whitesides, Harvard University

In his legendary career in chemistry, George Whitesides has been a pioneer in microfabrication and nanoscale self-assembly. Now, he's fabbing a diagnostic lab on a chip.

Further Reading

• Wikipedia: Microfluidics and Lab-on-a-chip
• DIY Bio
• Diagnostics For All
• Daktari