Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New lab-on-a-chip measures mechanics of bacteria colonies

02.07.2009
Researchers at the University of Michigan have devised a microscale tool to help them understand the mechanical behavior of biofilms, slimy colonies of bacteria involved in most human infectious diseases.

Most bacteria in nature take the form of biofilms. Bacteria are single-celled organisms, but they rarely live alone, said John Younger, associate chair for research in the Department of Emergency Medicine at the U-M Health System. Younger is a co-author of a paper about the research that will be the cover story of the July 7 edition of Langmuir.

The new tool is a microfluidic device, also known as a "lab-on-a-chip." Representing a new application of microfluidics, the device measures biofilms' resistance to pressure. Biofilms experience various kinds of pressure in nature and in the body as they squeeze through capillaries and adhere to the surfaces of medical devices, for example.

"If you want to understand biofilms and their life cycle, you need to consider their genetics, but also their mechanical properties. You need to think of biofilms as materials that respond to forces, because how they live in the environment depends on that response," said Mike Solomon, associate professor of chemical engineering and macromolecular science and engineering, who is senior author of the paper.

Mechanical forces are at play when our bodies defend against these bacterial colonies as well, Younger says.

"We think a lot of host defense boils down to doing some kind of physical work on these materials, from commonplace events like hand-washing and coughing to more mysterious processes like removing them out of the bloodstream during a serious infection," he said. "You can study gene expression patterns as much as you want, but until you know when the materials will bend or break, you don't really know what the immune system has to do from a physical perspective to fight this opponent."

Researchers haven't studied these properties yet because there hasn't been a good way to examine biofilms at the appropriate scale.

The U-M microfluidic device provides the right scale. The channel-etched chip, made from a flexible polymer, allows researchers to study minute samples of between 50 and 500 bacterial cells that form biofilms of 10-50 microns in size. A micron is one-millionth of a meter. A human hair is about 100 microns wide.

Such small samples behave in the device as they do in the body. Tools that require larger samples don't always give an accurate picture of how a particular substance behaves on the smallest scales.

The researchers found that the biofilms they studied had a greater elasticity than previous methods had measured. They also discovered a "strain hardening response," which means that the more pressure they applied to the biofilms, the more resistance the materials put forth.

If doctors and engineers can gain a greater understanding of how biofilms behave, they could perhaps design medical equipment that is more difficult for the bacteria to adhere to, Younger said.

The experiments were performed on colonies of Staphylococcus epidermidis and Klebsiella pneumoniae, which are known to cause infections in hospitals.

The new microfluidic device could also be used to measure the resistance of various other soft-solid materials in the consumer products, food science, biomaterials and pharmaceutical fields.

The paper is called, "Flexible Microfluidic Device for Mechanical Property Characterization of Soft Viscoelastic Solids Such as Bacterial Biofilms." The first author is Danial Hohne, a recently-graduated Ph.D. student in the Department of Chemical Engineering.

The research is funded by the National Institutes of Health, the National Institute of General Medical Sciences, the U-M Center for Computational Medicine and Biology and the Department of Emergency Medicine.

For more information:

Michael Solomon:
http://www.engin.umich.edu/dept/cheme/people/solomon.html
John Younger:
http://sitemaker.umich.edu/younger/the_younger_lab
Michigan Engineering:
The University of Michigan College of Engineering is ranked among the top engineering schools in the country. At more than $130 million annually, its engineering research budget is one of largest of any public university. Michigan Engineering is home to 11 academic departments and a National Science Foundation Engineering Research Center. The college plays a leading role in the Michigan Memorial Phoenix Energy Institute and hosts the world class Lurie Nanofabrication Facility. Michigan Engineering's premier scholarship, international scale and multidisciplinary scope combine to create The Michigan Difference.

Nicole Casal Moore | EurekAlert!
Further information:
http://www.umich.edu
http://www.engin.umich.edu/

More articles from Health and Medicine:

nachricht 'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers
16.02.2018 | National University of Science and Technology MISIS

nachricht New process allows tailor-made malaria research
16.02.2018 | Eberhard Karls Universität Tübingen

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>