Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Heat-Based Technique Offers New Way to Measure Microscopic Particles

Abstract:
"A Microfluidic Device for Thermal Particle Detection"

Authors: Ashwin Kumar Vutha, Rensselaer Polytechnic Institute; Benyamin Davaji and Chung Hoon Lee, Marquette University; and Glenn M. Walker, North Carolina State University and the University of North Carolina at Chapel Hill

Published: online March 11, Microfluidics and Nanofluidics

DOI: 10.1007/s10404-014-1369-z

Abstract: We demonstrate the use of heat to count microscopic particles. A Thermal Particle Detector (TPD) was fabricated by combining a 500 nm thick silicon nitride membrane containing a thin-film resistive temperature detector (RTD) with a silicone elastomer microchannel. Particles with diameters of 90 [micrometers] and 200 [micrometers] created relative temperature changes of 0.11 K and -0.44 K, respectively, as they flowed by the sensor. A first-order lumped thermal model was developed to predict the temperature changes. Multiple particles were counted in series to demonstrate the utility of the TPD as a particle counter.

Heat-Based Technique Offers New Way to Measure Microscopic Particles

Raleigh, NC | Posted on March 13th, 2014

Researchers have developed a new heat-based technique for counting and measuring the size of microscopic particles. The technique is less expensive than light-based techniques and can be used on a wider array of materials than electricity-based techniques. The research was performed by faculty at North Carolina State University, the University of North Carolina at Chapel Hill and Marquette University.

"We launched this study purely out of curiosity, but it's developed into a technique that has significant advantages over existing methods for counting and measuring the size of microscopic objects," says Dr. Glenn Walker, senior author of a paper on the work and an associate professor in the joint biomedical engineering program at NC State and UNC-Chapel Hill.

Particle counters are used in a wide variety of industries. For example, physicians use them to count and identify blood and cancer cells while ink manufacturers use them to ensure consistent toner quality. The new thermal technique could also lead to new applications.

The researchers built a device in which an extremely narrow plastic tube rests on a silicon substrate. A wire is connected to a single point beneath the tube. An extremely small current is run through the wire, both generating heat that radiates into the tube and measuring the temperature of the tube and its contents.

When a solution containing microscopic particles is injected into the tube it flows past the wire and the heated area. When the particles pass through this thermal zone they alter the electrical resistance of the wire. This is because the thermal conductivity of a particle will either increase or decrease the temperature in that part of the tube, causing the electrical resistance to go up or down.

Since the researchers know the flow rate of the solution through the tube, they can measure the length of time that the electrical resistance was changed and calculate the size of the objects suspended in the solution.

"So far, we've tested this method effectively with objects in the 200 micron to 90 micron range - at the larger end of the spectrum commonly measured by commercial particle counters," Walker says. "But in theory we'll be able to get down to the 10 micron range and measure individual cells. We're working on that now."

The researchers are also exploring ways to use the technique to detect unwelcome metal particles resulting from machine wear in mechanical devices.

"There are three advantages to our technique," Walker says. "It's simple, it's inexpensive, and it can monitor any kind of particle. Flow cytometry - which uses light - is both expensive and complex, while Coulter counters - which use electricity - only work on objects that don't conduct electricity but are suspended in a solution that is conductive."

####

For more information, please click here

Contacts:
Matt Shipman

919-515-6386

Dr. Glenn Walker
919.513.4390

Copyright © North Carolina State University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Related News Press

News and information

Twisted graphene chills out: When two sheets of graphene are stacked in a special way, it is possible to cool down the graphene with a laser instead of heating it up, University of Manchester researchers have shown September 22nd, 2014

New star-shaped molecule breakthrough: Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created September 22nd, 2014

Iranian Researchers Synthesize Stable Ceramic Nanopowders at Room Temperature September 20th, 2014

Arrowhead to Present at BioCentury's NewsMakers in the Biotech Industry Conference September 19th, 2014

Imaging

IEEE International Electron Devices Meeting To Celebrate 60th Anniversary as The Leading Technical Conference for Advanced Semiconductor Devices September 18th, 2014

FEI Opens New Technology Center in Czech Republic: FEI expands its presence in Brno with the opening of a new, larger facility September 18th, 2014

New NPZ100-403 Piezo Stage from nPoint Inc. September 17th, 2014

New non-invasive technique could revolutionize the imaging of metastatic cancer September 17th, 2014

Development of Algorithm for Accurate Calculation of Average Distance Travelled by Low-Speed Electrons without Energy Loss that Are Sensitive to Surface Structure September 11th, 2014

Microfluidics/Nanofluidics

Dolomite to launch Meros TCU-100 temperature controller at Lab-on-a-Chip & Microarray World Congress September 15th, 2014

First Colloid and Polymer Science Lecture awarded to Orlin D. Velev: Chemical engineer honored for outstanding research in colloid science September 12th, 2014

UO-Berkeley Lab unveil new nano-sized synthetic scaffolding technique: Oil-and-water approach from Richmond's UO lab to spark new line of versatile peptoid nanosheets September 2nd, 2014

Discoveries

Twisted graphene chills out: When two sheets of graphene are stacked in a special way, it is possible to cool down the graphene with a laser instead of heating it up, University of Manchester researchers have shown September 22nd, 2014

New star-shaped molecule breakthrough: Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created September 22nd, 2014

Iranian Scientists Separate Zinc Ion at Low Concentrations September 20th, 2014

Iranian Researchers Synthesize Stable Ceramic Nanopowders at Room Temperature September 20th, 2014

Announcements

Twisted graphene chills out: When two sheets of graphene are stacked in a special way, it is possible to cool down the graphene with a laser instead of heating it up, University of Manchester researchers have shown September 22nd, 2014

New star-shaped molecule breakthrough: Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created September 22nd, 2014

Synthesis of Nanostructures with Controlled Shape, Size in Iran September 22nd, 2014

Iranian Scientists Separate Zinc Ion at Low Concentrations September 20th, 2014

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals

Twisted graphene chills out: When two sheets of graphene are stacked in a special way, it is possible to cool down the graphene with a laser instead of heating it up, University of Manchester researchers have shown September 22nd, 2014

New star-shaped molecule breakthrough: Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created September 22nd, 2014

Synthesis of Nanostructures with Controlled Shape, Size in Iran September 22nd, 2014

Iranian Scientists Separate Zinc Ion at Low Concentrations September 20th, 2014

Tools

IEEE International Electron Devices Meeting To Celebrate 60th Anniversary as The Leading Technical Conference for Advanced Semiconductor Devices September 18th, 2014

FEI Opens New Technology Center in Czech Republic: FEI expands its presence in Brno with the opening of a new, larger facility September 18th, 2014

New NPZ100-403 Piezo Stage from nPoint Inc. September 17th, 2014

Researchers Create World’s Largest DNA Origami September 11th, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE