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Moving Nano-particles Can Be Tough, But A Pitt Professor Found A Way

University of Pittsburgh
As the reagent density changes the flow of particles begins placing them where they can be concentrated for testing or assembly.

Researchers and laboratory scientists are increasingly trying to move cells and nano-particles through smaller and smaller channels.

“You want to get fluid pumped through something that’s the width of your hair,” said Anna Balazs, University of Pittsburgh chemical and petroleum engineering professor. “So one of the challenges is first just how to pump fluid through and then how to direct particles … to a specific location.”

Being able to move extremely small particles with precision and collect them in one location is key to building structures on the nano-scale, as well as collecting particles in large enough quantities for them to be accurately detected by sensors. 

If lab scientists have to wait for the particles or blood cells to move from point A to point B in a closed system on their own, it could take hours and they might not ever get to point B in concentrations high enough to be detected.

Pumps that mechanically create pressure to move fluids, such as blood from a reservoir to a collection point do not work well when trying to pass materials through such small tubes or channels. In addition, pumps work best when there is an outlet for the fluid they are moving, which means the sample quickly runs out.

Scientists have tried to coat the particles on one side to get them to move through the tiny tubes, but it is hard to control their direction of travel and by coating them you might change their properties.

"You don't have 'nano-tweezers' to go in there and pick up each particle and put it down," Balazs joked.

Credit University of Pittsburgh
University of Pittsburgh
These three depections show how the process works over time.

So Balazs and her team thought maybe they could create a conveyor belt-type system to deliver the particles to their destination.

They put the particles or blood cells to be moved into a fluid that contains a material that reacts with a coating on the surface of the tiny channel. 

The reaction between the first material, known as a reagent, and the second material coating the channel causes the fluid to be sucked into the channel and dumped onto the spot where the scientist wants the particles to be deposited.

“In our system, you can actually keep everything in a chamber and it’s going to end up at the place where you want it,” post-doctoral researcher Henry Shum said. “So you can leave it and go out for lunch and when you come back all the particles will be where you want it.”

The Pitt team partnered with researchers at Penn State University who made the system. By publishing the findings in the journal Nature Communications, the researchers said a company could use the technology to improve a commercially available test.

Balazs said it’s basically just a transportation system.

“And what we want to do in the future is put little traffic lights in,” she said.  “So you deliver to one place for a certain amount of time and then it moves on to the next location and the analysis gets done for another kind of assay. And it all gets done autonomously.”

When they get that figured out, it might be the next article the team publishes.

In this week’s Tech Headlines:

  • As if it wasn’t already there, the NHL is making a leap into the digital age this playoff season. The league is making three iPad Pros available for coaches on every bench and officials will also have them to review coaches’ challenges. Video replay coaches have also been given new macs for the locker room. It’s part of a collaboration with Apple. The iPads, which were tested late in the regular season, provide real-time video capabilities to show players how they're performing. Arizona Coyotes coach Dave Tippett said teams need to be able to challenge goals quickly and he thinks the added technology will help. The NFL has had Microsoft Surface Tablets on sidelines for the past three seasons.
  • One of the men who was instrumental in creating the internet and the modern personal computer, has died. Robert W. Taylor was 85 when he lost his long fight with Parkinson's disease last week. Taylor was working for the Pentagon's Advanced Research Projects Agency in 1966 when he shepherded the creation of a single computer network to link researchers around the country.  The network eventually evolved into the internet. A few years later, Taylor was working for the team at Xerox that helped create the first personal computer.

The Associated Press contributed to this report.