Engineers Create Knife That Can Cut a Water Droplet in Half

ORIGINAL: Gizmodo

Andrew Liszewski

October 3, 2012

Sometimes science truly is indistinguishable from magic: a team of engineers at Arizona State University has created a knife that can actually cut water. Cut it clean in two parts, no little droplets, no mess. Just like a piece of chorizo.

What kind of sorcery is this? Was this forged by Elvish blacksmiths?

The knife was actually made by Dr. Antonio García and his team. García, a Chemical, Biological & Materials Engineering associate professor at the College of Engineering in Tempe, wanted to find a new class of metal that would allow completely clean bioseparations.

The core of the blade is two 0.020-inch thick zinc and copper sheets. After forging it, it was cleaned with acetone, ethanol, deionized water and then air-dried with nitrogen. Then the researchers dipped it in “a 10 nanomolar aqueous solution of silver nitrate for approximately 20 seconds.” Finally, they added the magic element, dipping it in a 1 nanomolar solution of substance called HDFT.

This seemingly magic material and manufacturing method can revolutionise biomedicine, allowing the separation of proteins and biological fluids “without troubling satellite drop formation.” This will allow for faster and more efficient analysis of biochemical liquid substances.

To test it, they got a water droplet and put it on a Teflon surface, pinned by wire loops. As you can see in the video, the experiment was a complete—and amazing—success. [Plos One via El Mundo (In Spanish)]