Droplet-trapping film can lead to less painful blood tests

Summary:A thin, flexible film that wraps around a single drop of liquid could prevent evaporation, allowing diagnostics to be performed with just one droplet of blood.

A thin, flexible film that wraps around a single droplet could prevent evaporation, allowing diagnostics to be performed with a single drop of blood.

And that means: no more big needles. ScienceNOW reports.

The film, invented by Ya-Pu Zhao and colleagues from the Chinese Academy of Sciences, could take the shape of a tiny container just a few millimeters wide.

The apparatus consists of a conductive base covered with an elastic layer of a silicone compound called polydimethylsiloxane (PDMS).

  1. When liquid is dripped on the PDMS, the film wraps around the droplet. And that’s because of surface tension, the same force that causes water to curl upward along the side of a glass.
  2. To release the trapped droplet, a thin electrode is inserted. Together with the conductive base, this creates an electric field that causes the film and droplet to vibrate, forcing the PDMS layer to unwrap.

"The vibration of the droplet makes it look like it is tap dancing while the flexible film seems like its dancing skirt," the researchers write. Watch a video of the tap dancing water (it’s 50 times slower than in real life).

Since the container allows the droplets to be transported without evaporating or becoming contaminated, the new tech could enable blood tests that use just one drop.

Not only would this reduce time and discomfort, it could also deliver tiny quantities of encapsulated drugs to diseased cells – which avoids having to administer potentially harmful drugs to the entire body.

The study was published in the Proceedings of the Royal Society A today.

[Via ScienceNOW]

Images: Wang et al.

This post was originally published on Smartplanet.com

Topics: Innovation


Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York. Follow her on Twitter.

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