Microfluidic diagnostic chips are (almost) child’s play

Pity us poor Brits and our ox-bow lake of eighties pop-culture – until today I had no idea what Shrinky Dinks were. But now I know… and I also know that code 6 polystyrene sheets (which is what Shrinky Dinks are made of) can be used to make single-run prototypes of microfluidic diagnostic chips, thanks to the innovative thinking of one Michelle Kine:

she whipped up a channel design in AutoCAD, printed it out on Shrinky Dink material using a laser printer, and stuck the result in a toaster oven. As the plastic shrank, the ink particles on its surface clumped together, forming tiny ridges. That was exactly the effect Khine wanted. When she poured a flexible polymer known as PDMS onto the surface of the cooled Shrinky Dink, the ink ridges created tiny channels in the surface of the polymer as it hardened. She pulled the PDMS away from the Shrinky Dink mold, and voilà: a finished microfluidic device that cost less than a fast-food meal.


She hastens to point out that Shrinky Dink microfluidics isn’t perfect–minute ink splatters from the printer, for instance, can give rise to slight irregularities in the finished channels.

Still, glitches like these don’t pose a problem for most applications. And Khine has already found a way around a more serious difficulty: PDMS can absorb proteins, throwing off the results of sensitive tests. She has begun to make chips directly out of the Shrinky Dinks by etching the design into the plastic using syringe tips. As the plastic shrinks, the channels become narrower and deeper–perfect for microfluidics. She can even make three-dimensional chips by melting several etched Shrinky Dinks together. The whole process, from design to finished chip, takes only minutes.

Kudos, Miss Kine. Even if you’re not a microfluidics researcher, this is an impressive example of finding cheap methods for making high-tech devices – the sort of favela-budget hack that takes a technology from university laboratories to the potting sheds of the globe. I wonder what the garage biohacker crowd will make of Kine’s innovation? And what might be the next lab-grade technology to be reproduced at a fragment of the normal price using off-the-shelf stuff from the supermarket? [via BoingBoing]

One thought on “Microfluidic diagnostic chips are (almost) child’s play”

  1. I work with microfluidics and am definitely intrigued by the prospects of the shrinking PS sheets. As a researcher, I’m interested in how controllable the final design is (smoothness, aspect ratio, final dimensions) — this is very important for building . Nice find.

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