Featured Research

from universities, journals, and other organizations

Portable diagnostics designed to be shaken, not stirred

Date:
May 9, 2012
Source:
University of Washington
Summary:
A textured surface mimics a lotus leaf to move drops of liquid in particular directions. The low-cost system could be used in portable medical or environmental tests.

As medical researchers and engineers try to shrink diagnostics to fit in a person's pocket, one question is how to easily move and mix small samples of liquid. University of Washington researchers have built and patented a surface that, when shaken, moves drops along certain paths to conduct medical or environmental tests.

"This allows us to move drops as far as we want, and in any kind of layout that we want," said Karl Böhringer, a UW professor of electrical engineering and bioengineering. The low-cost system, published in a recent issue of the journal Advanced Materials, would require very little energy and avoids possible contamination by diluting or electrifying the samples in order to move them.

The simple technology is a textured surface that tends to push drops along a given path. It's inspired by the lotus effect -- a phenomenon in which a lotus leaf's almost fractal texture makes it appear to repel drops of water.

"The lotus leaf has a very rough surface, in which each big bump has a smaller bump on it," Böhringer said. "We can't make our surface exactly the same as a lotus leaf, but what we did is extract the essence of why it works."

The UW team used nanotechnology manufacturing techniques to build a surface with tiny posts of varying height and spacing. When a drop sits on this surface, it makes so little contact with the surface that it's almost perfectly round. That means even a small jiggle can move it. Researchers used an audio speaker or machine to vibrate the platform at 50 to 80 times per second. The asymmetrical surface moves individual drops along predetermined paths to mix, modify or measure their contents. Changing the vibration frequency can alter a drop's speed, or can target a drop of a certain size or weight.

"All you need is a vibration, and making these surfaces is very easy. You can make it out of a piece of plastic," Böhringer said. "I could imagine this as a device that costs less than a dollar -- maybe much less than that -- and is used with saliva or blood or water samples."

In testing, different versions of the UW system could move the drops uphill, downhill, in circles, upside down, or join two drops and then move the combined sample. The type of system is known as a "lab in a drop": all the ingredients are inside the drop, and surface tension acts as the container to keep everything together.

A student tried using a smartphone's speaker to vibrate the platform, but so far a phone does not supply enough energy to move the drops. To better accommodate low-energy audio waves, the group will use the UW's electron beam lithography machine to build a surface with posts up to 100 times smaller.

"There's good evidence, from what we've done so far, that if we make everything smaller then we will need less energy to achieve the same effect," Böhringer said. "We envision a device that you plug into your phone, it's powered by the battery of the phone, an app generates the right type of audio vibrations, and you run your experiment."

Co-authors of the paper are former UW undergraduate Todd Duncombe and former UW graduate student Yegȃn Erdem, both at the University of California, Berkeley; former UW postdoctoral researcher Ashutosh Shastry, now at Corium International in Menlo Park, Calif.; and Rajashree Baskaran, a UW affiliate assistant professor of electrical engineering who works at Intel Corp.

The research was funded by the National Science Foundation, the National Institutes of Health, Intel and the UW's Technology Gap Innovation Fund.


Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Journal Reference:

  1. Todd A. Duncombe, E. Yegân Erdem, Ashutosh Shastry, Rajashree Baskaran, Karl F. Böhringer. Controlling Liquid Drops with Texture Ratchets. Advanced Materials, 2012; 24 (12): 1545 DOI: 10.1002/adma.201104446

Cite This Page:

University of Washington. "Portable diagnostics designed to be shaken, not stirred." ScienceDaily. ScienceDaily, 9 May 2012. <www.sciencedaily.com/releases/2012/05/120509092421.htm>.
University of Washington. (2012, May 9). Portable diagnostics designed to be shaken, not stirred. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2012/05/120509092421.htm
University of Washington. "Portable diagnostics designed to be shaken, not stirred." ScienceDaily. www.sciencedaily.com/releases/2012/05/120509092421.htm (accessed October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) — Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins