Public Release:  New microfluidic chip for discriminating bacteria

American Institute of Physics

Washington, D.C. (September 14, 2010) -- A new "on-chip" method for sorting and identifying bacteria has been created by biomedical engineers at Taiwan's National Cheng Kung University. The technique, developed by Hsien-Chang Chang, a professor at the Institute of Biomedical Engineering and the Institute of Nanotechnology and Microsystems Engineering, along with former graduate student I-Fang Cheng and their colleagues, is described in the AIP journal Biomicrofluidics.

Using roughened glass slides patterned with gold electrodes, the researchers created microchannels to sort, trap, and identify bacteria. The technique uses surface enhanced Raman spectroscopy. This type of spectroscopy, says Chang, "is based on the measurement of scattered light from the vibration energy levels of chemical bonds following excitation in a craggy metal surface, which enhances the vibration energy." Different components like proteins or other chemical components on the surface of bacteria become attached to the craggy gold zone; when excited, these components cause representative peaks at different wavelengths, creating spectral "fingerprints."

Although some species of bacteria could show very similar signatures because the components on their surfaces are almost the same, says Chang, bacteria from different genera are distinguishable using the technique.

"In the future, different species of fungi could also be sorted based on their different electrical or physical properties by optimizing conditions such as the flow rate, applied voltage, and frequency," he says. "This portable device could be used for preliminary screening for the pathogenic targets in bacteria-infected blood, urethral irritation, and of raw milk and for food monitoring."

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The article, " A dielectrophoretic chip with a roughened metal surface for on-chip SERS analysis of bacteria" by I-Fang Cheng (National Cheng Kung University), Chi-Chang Lin (Tunghai University), Dong-Yi Lin and Hsien-Chang Chang (National Cheng Kung University) appears in the journal Biomicrofluidics. http://link.aip.org/link/biomgb/v4/i3/p034104/s1

Journalists may request a free PDF of this article by contacting jbardi@aip.org

ABOUT BIOMICROFLUIDICS

Biomicrofluidics is an online open-access journal published by the American Institute of Physics to rapidly disseminate research in elucidating fundamental physicochemical mechanisms associated with microfluidic and nanofluidic phenomena as well as novel microfluidic and nanofluidic techniques for diagnostic, medical, biological, pharmaceutical, environmental, and chemical applications. See: http://bmf.aip.org/

ABOUT AIP

The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.

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