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:
Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania
The strange double life of Dab2
10.01.2017 | University of Miami Miller School of Medicine
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering