Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Clinging to crevices, E. coli thrive

Rather than being repelled by nanostructured surfaces, as materials scientists have hoped, bacteria with many flagella seem to love them.False-color scanning electron micrograph courtesy of Ronn Friedlander and Michael Bucaro.
Rather than being repelled by nanostructured surfaces, as materials scientists have hoped, bacteria with many flagella seem to love them.

False-color scanning electron micrograph courtesy of Ronn Friedlander and Michael Bucaro.

Abstract:
New research from Harvard University helps to explain how waterborne bacteria can colonize rough surfaces—even those that have been designed to resist water.

Clinging to crevices, E. coli thrive

Cambridge, MA | Posted on April 10th, 2013

A team of materials scientists and microbiologists studied the gut bacterium Escherichia coli, which has many flagella that stick out in all directions. The researchers found that these tails can act as biological grappling hooks, reaching far into nanoscale crevices and latching the bacteria in place.

The scourge of the health care industry, bacteria like E. coli are adept at clinging to the materials used in medical implants like pacemakers, prosthetics, stents, and catheters, spreading slimy biofilm and causing dangerous infections. The findings, published in the Proceedings of the National Academy of Sciences (PNAS) on March 18, suggest that antibacterial materials should incorporate both structural and chemical deterrents to bacterial attachment.

E. coli are equipped with two types of appendages: pili, which are short, sticky hairs, and the whip-like flagella, which are often twice as long as the bacterium itself. Pili had previously been recognized as playing a critical role in the formation of biofilms. These short hairs, up to only a micron in length in E. coli, can stick to surfaces temporarily, while the bacteria secrete a thick slime that holds them permanently in place.

Flagella, on the other hand, typically play a propulsive role, helping bacteria to swim and steer in liquid environments. As it turns out, though, when it's time to settle in one place, flagella also contribute to adhesion on rough surfaces, where the pili would have access to fewer attachment points.

Nanoscale crevices, such as those deliberately built into superhydrophobic materials, often trap air bubbles at the surface, which initially prevent E. coli from attaching at all. The new research shows that the bacteria can gradually force these bubbles to disperse by, essentially, flailing their arms. Once the cracks and crevices are wet, although the cell bodies can't fit into the gaps, the flagella can reach deep into these areas and attach to a vast amount of new surface area.

"The diversity of strategies and methods by which bacteria can adhere reflects their need to survive in a huge variety of environments," says lead author Ronn S. Friedlander, a doctoral student in the Harvard-MIT Division of Health Sciences and Technology. "Of course, if we could prevent biofilms from forming where we didn't want them to, there would be immense benefits in medicine."

Friedlander studies in the lab of Harvard professor Joanna Aizenberg, who holds a joint appointment as Amy Smith Berylson Professor of Materials Science at the Harvard School of Engineering and Applied Sciences and as Professor of Chemistry and Chemical Biology (CCB). Aizenberg's laboratory group has been working to develop extremely slippery surfaces that repel water, dirt, oil, and bacteria.

The surface chemistry of antibacterial materials appears to be just as important as the topography. E. coli flagella have previously been known to adhere to certain proteins on the surface of cells in the gut wall, indicating that the bacteria are capable of bonding with specific molecular matches. But in the 1970s, biologists observing E. coli on microscope slides had also seen something curious: bacteria wheeling about under the coverslip, as if tethered to the glass by a single flagellum. This ability to stick to any surface at all—termed nonspecific adhesion—is part of what makes it easy for bacteria to survive on the surface of medical implants.

Rather than having to find a perfect molecular match, the flagella of E. coli appear to cling to surfaces using a combination of many weak bonds.

"The ideal antibacterial material would be topographically patterned with tiny crevices to limit the amount of surface area that was immediately accessible to bacteria via their pili, but also engineered in terms of its surface chemistry to reduce the ability of the flagella to make bonds within those crevices," says Aizenberg. "Surface structuring alone will not achieve this goal."

In 2012, Aizenberg's group demonstrated a material they call SLIPS (for Slippery, Liquid-Infused Porous Surfaces). It was patterned with nanoscale pores, which were filled with a fluorinated lubricant that was shown to prevent biofilms from attaching.

The findings from this line of research are relevant beyond the field of medicine, as biofilms also pose problems for the food industry, water treatment, ship maintenance, and other industries where slime can clog pipes and filters, corrode metal, or cause contamination. But this latest work also helps to explain, on a basic level, how bacteria succeed at colonizing such a wide variety of environments, including the human gut. Having many flagella, the authors note in their paper, "may be particularly important in an intestinal environment coated with microvilli."

In addition to her appointments at Harvard SEAS and CCB, Aizenberg is Director of the Kavli Institute for Bionano Science and Technology at Harvard; a Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering at Harvard; and Director of the Science Programs at the Radcliffe Institute for Advanced Study; among other roles at the University.

Coauthors included Hera Vlamakis, an instructor in microbiology and molecular genetics at Harvard Medical School; Philseok Kim, a researcher at the Wyss Institute; Mughees Khan, a staff scientist in nanofabrication at the Wyss Institute; and Roberto Kolter, Professor of Microbiology and Immunobiology at Harvard Medical School.

The research was supported in part by the U.S. Office of Naval Research (N00014-11-1-0641), the BASF Advanced Research Initiative at Harvard University, and a National Science Foundation (NSF) Graduate Research Fellowship. The researchers also benefited from the facilities of the Massachusetts Institute of Technology's Microsystems Technology Laboratories and the Harvard Center for Nanoscale Systems, a member of the NSF-supported National Nanotechnology Infrastructure Network (ECS-0335765).


Full bibliographic information

Ronn S. Friedlander, et al., "Bacterial flagella explore microscale hummocks and hollows to increase adhesion," PNAS 110:14, 5624-5629. doi: 10.1073/pnas.1219662110

####

For more information, please click here

Copyright © AlphaGalileo

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 News Press

News and information

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

GLOBALFOUNDRIES Announces Availability of mmWave and RF/Analog on Leading FDX™ FD-SOI Technology Platform: Technology solution delivers ‘connected intelligence’ to next generation high-volume wireless and IoT applications with lower power and significantly reduced cost September 20th, 2017

GLOBALFOUNDRIES Announces Availability of Embedded MRAM on Leading 22FDX® FD-SOI Platform: Advanced embedded non-volatile memory solution delivers ‘connected intelligence’ by expanding SoC capabilities on the 22nm process node September 20th, 2017

Govt.-Legislation/Regulation/Funding/Policy

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

New insights into nanocrystal growth in liquid: Understanding process that creates complex crystals important for energy applications September 14th, 2017

Nanomedicine

Do titanium dioxide particles from orthopedic implants disrupt bone repair? September 16th, 2017

Arrowhead Hosts Investor & Analyst R&D Day to Introduce TRiM(TM) Platform and Lead RNAi-based Drug Candidates September 14th, 2017

Graphene based terahertz absorbers: Printable graphene inks enable ultrafast lasers in the terahertz range September 13th, 2017

Applications for the nanomedTAB are open until September 18th, 2017 September 13th, 2017

Discoveries

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

Announcements

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

GLOBALFOUNDRIES Introduces New 12nm FinFET Technology for High-Performance Applications September 20th, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Military

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

First on-chip nanoscale optical quantum memory developed: Smallest-yet optical quantum memory device is a storage medium for optical quantum networks with the potential to be scaled up for commercial use September 11th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Food/Agriculture/Supplements

Research shows how DNA molecules cross nanopores: Study could inform biosensors, manufacturing, and more September 5th, 2017

Probiotics: Novel biosynthetic tool to develop metallic nanoparticles: This research article by Dr. Nida Akhtar et al has been published in Recent Patents on Drug Delivery & Formulation, Volume 11, Issue 1, 2017 July 20th, 2017

New technology could offer cheaper, faster food testing: Specialized droplets interact with bacteria and can be analyzed using a smartphone April 7th, 2017

Meta-lenses bring benchtop performance to small, hand-held spectrometer: Game-changing nanostructure-based lenses allow smaller devices, increased functionality February 9th, 2017

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