When close to each other, bacteria produce and sense certain small molecules called autoinducers. This phenomenon, which is called quorum sensing, depends on the concentration of autoinducers, which depends on the number of bacteria. Using quorum sensing, bacteria can synchronize behaviors such as biofilm formation, bioluminescence, and antibiotic resistance.
Polymer surfaces can be prone to bacterial biofilm formation, which becomes a real problem for medical polymers, especially in intravascular and implantable medical devices. Bacterial biofilms consist of bacteria embedded in a self-produced matrix consisting of polysaccharide, protein and extracellular DNA. Bacterial biofilms are quite resistant to antibiotics and disinfectants, and to the body’s defense responses.
Biofilm formation starts from adhesion of individual bacteria, followed by bacterial growth, colonization, communication, and formation of an extracellular matrix. To prevent bacterial adhesion to polymers one can use different approaches, interfering with one or several of possible adhesion mechanisms through hydrophobic, electrostatic, Van-der-Vaals and other interactions.
The quest to prevent bacterial adhesion led a team of U.K. scientists from the Universities of Nottingham, Birmingham, and Newcastle, to a discovery on the possible use of polymer to affect bacterial communication. The group was headed by Professor Cameron Alexander. The findings, published in Nature Chemistry, stated:
Polymers that can interfere with bacterial adhesion or the chemical reactions used for quorum sensing are therefore a potential means to control bacterial population responses. Here, we report how polymeric ‘bacteria sequestrants,’ designed to bind to bacteria through electrostatic interactions and therefore inhibit bacterial adhesion to surfaces, induce the expression of quorum-sensing controlled phenotypes as a consequence of cell clustering.
The scientists found that in the presence of specifically designed soluble polymethacrylamide derivatives, suspensions of marine bioluminescent bacteria did not adhere to surfaces; instead, they formed clusters as the soluble polymer attached to bacterial receptors. The formation of these clusters induced quorum-sensing communications registered through changes in bioluminescence.
This work opens the way to controlling bacterial behavior by affecting their communication, and can have implications for the emerging field of synthetic biology and biofuels. The research has been featured in Phys.org and Science Daily.
Source: “Bacteria clustering by polymers induces the expression of
quorum-sensing-controlled phenotypes.” Leong T. Lui, Xuan Xue, Cheng Sui, Alan Brown, David I. Pritchard, Nigel Halliday, Klaus Winzer, Steven M. Howdle, Francisco Fernandez-Trillo, Natalio Krasnogor, Cameron Alexander. Nature Chemistry, 2013; DOI:10.1038/nchem.1793
Source: Changing the conversation: Polymers disrupt bacterial communication, Phys.org, November 11, 2013
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