Cleaning up by speaking to biofilms

BIOMOLECULES that can manage microbial behaviour have been used to successfully coat a range of surfaces, and promise a new method for cleaning industrial equipment.

When making decisions, microbial communities ‘talk’ using a process called quorum sensing. Speech comes in the form of biomolecules called autoinducers, which are released to stimulate or inhibit activity. One such example of a coordinated behaviour is biofilm formation, where microorganisms aggregate in large numbers on a surface. This can be both a blessing and a curse in industry – for example, biofilms on wastewater treatment equipment could help remove contaminants, while biofilms on medical equipment can cause disease.

Now, researchers at Princeton University in the US have been able to apply autoinducer biomolecules as a coating on a range of surfaces.

Senior researcher, Howard Stone, said: “Industrial processes that require treatment for contamination by bacteria typically have biocides added to the bulk solution or in flow processes. However, most bacteria exist as biofilms on surfaces, so the majority of such biocides can be expected to not reach that bacteria. Thus, we developed methods to directly attach molecules such as autoinducers to surfaces where the molecules can activate or inhibit the quorum sensing response in bacteria.”

The researchers used a technique called click chemistry to covalently attach the biomolecules to linker molecules on surfaces that included glass, plastic and metal. The method proved robust and long-lasting, with coatings retaining functionality after five weeks of storage, or following tests such as exposure to flowing water and air-bubbles as found in industrial equipment.

Stone said: “We showed that the molecules work over multiple cycles of flow that deliver and/or clean bacteria from the surface. Thus, we believe that practically all processes where surface-attached bacteria are to be prevented or reduced are targets for our technological advance.”

While the method has only been demonstrated for one bacterium to date, Staphylococcus aureus, the researchers are hopeful that the approach and strategy they have documented can provide a path forward for targeting specific substrates or contaminants. Such applications could include medical implants, industrial pipes or in agriculture.

Stone added: 'We hope to continue the research and work with potential partners who might have applications that would benefit from the approach we are developing at Princeton.'

Nature Microbiology: http://doi.org/f97853