Image credit: Kumar, Smith, Pappas 2009
Lately there’s been talk about the DIY Bio movement enabling individuals to do real biology without being part of a university/company lab. Given its potential for low-cost and quick prototyping, microfluidics seems to have promising overlap with DIY Bio. But how would one actually get started with a DIY microfluidics project?
First, what would make a microfluidic method DIY-friendly? At least two things: low cost and an accessible, easy-to-learn technique. Below are a few ideas to get going:
Perhaps the most well-known example of rapid-prototyping for microfluidics is the invention of soft lithography by the Whitesides lab at Harvard using polydimethylsiloxane (PDMS). While this technique is definitely adaptable to the DIY setting, in the last several years researchers have explored a number of materials for making microfluidics that may be even more DIY-friendly:
Double-sided tape: Holmes and Goddard from the University of Manchester show how to make a simple microfluidic channel using double-sided tape, an X-acto knife, and glass slides. Researchers from Genome Data Systems riff off of this idea using a hobbyist’s T-shirt transfer press.
Gelatin: David Beebe’s group describes how to make microfluidic devices out of gelatin— and why you’d want to. They do use a PDMS mold to form the gelatin, but creative DIYers might be able to find a way around this (maybe take inspiration from the cooks who’ve been molding gelatin for years).
Paper: The Whitesides group leads again by developing a technique for making microfluidic devices out of paper, using little more than paper and double-sided tape (is double-sided tape the DIYer’s best friend?). Not content with creating one method, the Whitesides group has also developed additional methods for fabricating paper microfluidics.
Thread: Researchers at Monash University in Australia have used cotton thread and paper for a colorimetric assay — and they used a desktop scanner and Photoshop to read the data! What could be more DIY than that?
PDMS: While it’s not the cheapest material out there, you can also buy PDMS kits (Sylgard 184) in small quantities. A 0.5 kg kit runs ~$50. There are several freely available guides on how to use PDMS for microfluidics.
Methods to Pattern Microfluidic Channels
Most people don’t have a cleanroom with equipment like a spin-coater or mask aligner in their garage. How can you create more complex microfluidic networks or patterns without these? A few ideas:
Shrinky Dinks: In one of the coolest recent approaches, Michelle Khine used Shrinky Dinks to pattern microfluidic devices
Desktop digital craft cutter: Using a relatively inexpensive desktop digital craft cutter, double-sided pressure sensitive adhesive (PSA) tape and laser printer transparency film, Po Ki Yuen and Vasily Goral created lamination-based microfluidics. (Again, double-sided tape rears its head!)
Nylon mesh fabric: Researchers have used nylon mesh fabric to pattern hydrogel gridsto create living cell microarrays.
To learn more (and there’s a lot more out there):
Try a Pubmed search on “low cost microfluidic” — the one I did turned up over 200 entries, many involving rapid-prototyping, low-cost methods that could be adapted to the DIY setting.
Check out the Chips & Tips section of the journal Lab on a Chip — it’s a goldmine for DIY-style techniques.