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Home  > Raw materials & technologies  > Applications  > Protective & Marine coatings  > Green slime works against bacteria

Saturday, 22 February 2020
Raw materials & technologies, Applications, Protective & Marine coatings

Green slime works against bacteria

Tuesday, 14 August 2012

Faces stare at the green slime, running down the wall, rain clouds darken the sky; sounds like the scenery of a dark fantasy film - or a viscous painting of a wall against bacterials.

The new coating prevents 99 % of harmful bacteria from forming on surfaces

Source: Harvard University

The new coating prevents 99 % of harmful bacteria from forming on surfaces

Source: Harvard University

Alexander K. Epstein, of the Harvard University in Cambridge, US and his colleagues report that Slippery Liquid-Infused Porous Surfaces (SLIPS) prevent three of the most notorious, disease-causing biofilms: 99.6 % of Pseudomonas aeruginosa biofilm attachment over a 7-d period, as well as Staphylococcus aureus (97.2 %) and Escherichia coli (96 %), under both static and physiologically realistic flow conditions.

It shows approximately 35 times the reduction of attached biofilm versus best case scenario, state-of-the-art PEGylated surface, and over a far longer timeframe.

The researchers screened for and excluded as a factor cytotoxicity of the SLIPS liquid, a fluorinated oil immobilised on a structured substrate.

Self-cleaning surfaces

The coating technology works in both a static environment and under flow, or natural conditions, making it ideally suited for coating implanted medical devices that interact with bodily fluids.

The inability of biofilm to firmly attach to the surface and its effective removal under mild flow conditions (about 1 cm/s) are a result of the  nonadhesive, "slippery” character of the smooth liquid interface, which does not degrade over the experimental timeframe. The chemist showed that SLIPS-based antibiofilm surfaces are stable in submerged, extreme pH, salinity, and UV environments. They are low-cost, passive, simple to manufacture, and can be formed on arbitrary surfaces.

Not surprisingly, the research has been supported in part by the Department of Defense Office of Naval Research.

Outlook on the understanding of design tricks

In future studies, the researchers aim to better understand the mechanisms involved in preventing biofilms. They are particularly interested in whether any bacteria transiently attach to the interface and then slip off, if they just float above the surface, or if any individuals can remain loosely attached.
"Biofilms have been amazing at outsmarting us,” said Aizenberg. "And even when we can attack them, we often make the situation worse with toxins or chemicals.

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