Bacteria are generally free-floating critters, but they can bind together to create biofilms communities, making their homes in metal pipes and teeth cavities, and they are generally unwelcome visitors where they lurk. They wreak havoc on systems from hospitals to power structures, contaminating food and water, trashing energy efficiency, and causing infections.
The new substance, created by researchers at Harvard, was inspired by the the pitcher plant (you can read about its inception and initial uses here). It features an immobilized liquid film to trick the bacteria into thinking they had nowhere to attach and grow. Their study was published this week in the journal Proceedings of the National Academy of Sciences. In the past, researchers have tried using antiseptics and textured surfaces to stem the biofilms, but those fixes were temporary – zombie bacteria can return from the dead with just a few dormant cells and restart their communities. Recently, another project used a super-resolution microscope to peer into the architecture of biofilms. The bacterial communities can build a protein shell around themselves like the walls of a building.
The technology to create the hybrid smooth surface is appropriately called SLIPS (or Slippery Liquid-Infused Porous Surfaces). This is how it works: the SLIPS is made up of thousands of super-thin stacks that hold a liquid lubricant in place. The liquid forms a smooth flat layer at the top of the stacks. That’s what makes the structure so slick, creating an environment that’s so slippery that the bacteria have nothing to grip on to. It can even prevent ice and snow from building up on it.
The researchers reported that SLIPS worked, reducing the formation of three of the most notorious, disease-causing biofilms--including potentially-lethal E. coli--by 96-99% over a 7-day period. That figure was 35 times more than the next best option: a surface treated with polyethylene glycol. The researchers describe this result as going beyond state-of-the-art technology, because no other surface can maintain its material without being toxic. In addition, SLIPS is durable. It’s able to stay intact during a week of being submersed in super-salty water, and can stand up to acids and UV radiation.
They say that the technology, which can heal itself, can work inside the human body, which may make it an ideal addition to implanted medical devices like pacemakers or artificial knees. Other applications could include graffiti-proof walls and friction-free water pipes. Future research could look into the physical mechanisms of how the biofilm-busting material works. For example, scientists would like to know if the bacteria can attach before sliding off, or if they just float above the surface.