Jacinta Bowler
Where there’s humans there will be biofilms. Hospitals, your water bottle, and even the International Space Station (ISS) all house these difficult to get rid of bacteria or fungi on surfaces.
“They’ve seen these biofilms, and they jeopardise a variety of instruments or equipment,” says MIT mechanical engineer, Professor Kripa Varanasi.
“Space suits, recycling units, radiators, and water treatment facilities. It’s a very important problem that needed to be understood.”
Now researchers from the US have discovered that biofilms on the ISS can be prevented from forming by using what’s called lubricated impregnated surfaces (LIS).
“LIS strongly inhibits biofilm formation compared to stainless steel,” the researchers write in their new paper, published in npj Microgravity.
“Furthermore, this effect is even greater in spaceflight than on Earth, making LIS a promising option for spacecraft use.”
The team used a bacterium called Pseudomonas aeruginosa which can cause hospital-acquired infections like pneumonia. It is also a bacterium which can form biofilms. Biofilms are trickier to remove than a regular clump of bacteria or fungi because they attach to a surface, and then creates a matrix to protect the inner layers of microbes.
Clogs in hoses for the water recovery system on the ISS have sometimes been so severe that they had to be sent back to Earth for cleaning and refurbishing.
To make a surface which prevented the formation of biofilms would protect astronauts and their equipment, as well as saving on costs.
Credit: Space Biofilm Program
The surface the researchers used in this experiment was silicon with nanoscale spikes. In the paper this is called ‘microtopography’ because it looks like a tiny pine forest. This ‘forest’ was then covered in silicon oil, which is held into place tightly due to capillary action.
The team found that this slippery surface prevented the microbes from attaching to the silicon, and therefore forming a biofilm.
In 2019 over three days the surfaces were sent up to the space station, while a control version was kept on Earth. The team found that the LIS was even better at preventing biofilms on space than it was on Earth.
“The results we got were surprising,” said Pamela Flores from the University of Colorado.
On the ground, biofilm formation was reduced by 74 percent, while in space there was an 86 percent reduction.
However, the experiment only ran for three days.
“We don’t know for how long it will be able to keep up this performance, so we definitely recommend a longer time of incubation, and also, if possible, a continuous analysis, and not just end points,” says Flores.
It’s also worth noting that one of the researchers – Kripa Varanasi – is also the founder of a company called LiquiGlide which makes LIS.
But if this is effective, it could be helpful to keep astronauts (and their pipes) healthy, while also helping those of us still on Earth.