Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New method manipulates particles for sensors, crime scene testing

08.06.2010
Researchers at Purdue University have developed a potential new tool for medical diagnostics, testing food and water for contamination, and crime-scene forensics.

The technique uses a combination of light and electric fields to position droplets and tiny particles, such as bacteria, viruses and DNA, which are contained inside the drops.

Other methods using either light or electric fields separately are able to position droplets or the particles they contain, but the new "hybrid optoelectric" device is able to do both, making it potentially practical for sensors and industrial processes, said mechanical engineering doctoral student Aloke Kumar.

Ordinarily, the particles inside droplets are detected when they randomly fall on a sensor's surface. However, the new method could improve sensor efficiency by actively moving particles to specific regions on an electronic chip for detection or analysis.

"This new hybrid technique is universal in the sense that we can manipulate a range of droplet and particle sizes, going all the way from microliter drops to particles a few nanometers long," said Steven T. Wereley, a professor of mechanical engineering who is working with Kumar.

The method offers promise for future "lab-on-a-chip" technology, using electronic chips to analyze biological samples for medical and environmental applications. Sensors based on the technique could make possible a new class of chemical analyses, or assays, with point-of-care devices in a doctor's office or hospitals.

Such sensors might be used to quickly analyze blood, urine and other bodily fluids for a range of applications, including drug screening; paternity testing; detecting coronary artery disease, tumors and various inherited diseases including cystic fibrosis; and detecting infectious diseases and bacteria, viruses and fungi that are difficult to culture using conventional laboratory methods.

"This technique also would be good for DNA tests, such as those used on the TV program 'CSI,' to identify crime suspects using only a small blood sample," Wereley said. "The idea is to use a chip to quickly carry out laboratory procedures called polymerase chain reaction and capillary electrophoresis. The new technology also should be good for testing food and water for pathogens such as E. coli or salmonella."

Critical to the technology are electrodes made of indium tin oxide, a transparent and electrically conductive material commonly used in consumer electronics for touch-screen displays. Liquid drops are positioned on the electrodes, and the infrared laser heats up both the electrodes and the droplets. Then electric fields in the electrodes cause the heated liquid to produce a "microfluidic vortex" of circulating liquid. This vortex enables researchers to position the particles in the circulating liquid by moving the infrared laser. The particles accumulate only where the laser is shined.

"Sensors are one of the immediate applications of this technology," said Kumar, who may continue the work as a postdoctoral researcher at the Oak Ridge National Laboratories, where he will complete a two-year Eugene Wigner Fellowship starting this month. "We should be able to improve the efficiency of sensors at least 10 times."

Findings were detailed in a research paper appearing June 1 in the journal Langmuir. The paper was written by Kumar, Wereley and former Purdue doctoral student Han-Sheng Chuang, now a postdoctoral researcher at the University of Pennsylvania. The research is based at the Birck Nanotechnology Center at Purdue's Discovery Park.

Purdue has filed a U.S. patent application on the design.

The technique might be used to manufacture sensors and other devices by modifying a phenomenon called the coffee-ring effect, which causes residue to form when liquid evaporates. Because the particles in the residue form only where the infrared laser shines, the procedure might be used to precisely position particles to create structures and circuits for biosensors and electronics.

"We have successfully used this technique to create spatially controlled microassemblies, and we hope that this would interest other research groups looking into the coffee-ring effect," Kumar said.

The work has been supported with funding from the National Science Foundation and the Micro/Nano Fluidics Fundamentals Focus (MF3) Center at the University of California, Irvine.

Emil Venere | EurekAlert!
Further information:
http://www.purdue.edu
http://www.purdue.edu/newsroom/research/2010/100607WereleyHybrid.html

Further reports about: Biosensors DNA Sensors coffee-ring effect electric field manufacture sensors

More articles from Power and Electrical Engineering:

nachricht Multicrystalline Silicon Solar Cell with 21.9 % Efficiency: Fraunhofer ISE Again Holds World Record
20.02.2017 | Fraunhofer-Institut für Solare Energiesysteme ISE

nachricht Six-legged robots faster than nature-inspired gait
17.02.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>