Scientists have discovered how to grow mother-of-pearl in a lab – and reckon it could one day be used to build houses on the moon.
According to a new study, artificial nacre was made using two strains of bacteria and has produced a tough, lightweight material that has the same structure as the real thing.
Professor Anne Meyer from the biology department at the University of Rochester replicated the inner shell layers produced by certain types of molluscs.
The material also makes up the outer layer of pearls – which gives them their lustrous shine coveted by the jewellery industry.
Mother-of-pearl is tougher and stiffer than most plastics, but until now has been incredibly expensive to produce, and involve toxic chemicals.
But the production of bacterial nacre doesn’t require any complex instruments as researchers only have to do is grow bacteria and let it sit in a warm place.
Professor Meyer created alternating thin layers of cement-like crystallised calcium carbonate and sticky polymer before placing it in a beaker containing the bacteria Sporosarcina pasteurii, a calcium source, and urea – the waste product excreted by the kidneys during urination.
This triggers the crystallization of calcium carbonate, which only takes about a day.
Professor Meyer said: “Many people creating artificial nacre use polymer layers that are only soluble in non-aqueous solutions, an organic solvent, and then they have this giant bucket of waste at the end of the procedure that has to be disposed of.
“We’re trying new techniques to make thicker, nacre-like materials faster and that could be the entire material itself.”
The method could lead to new applications of the material in medicine, engineering and could even be used to construct buildings on the moon.
The only necessary “ingredients” for using the artificial mother-of-pearl on the moon would be an astronaut and a small tube of bacteria, according to scientists.
Professor Meyer added: “The moon has a large amount of calcium in the moon dust, so the calcium’s already there.
“The astronaut brings the bacteria, and the astronaut makes the urea, which is the only other thing you need to start making calcium carbonate layers.”
And because the nacre coating protects against chemical degradation and weathering, it holds promise for civil engineering applications like crack prevention and protective coatings for erosion control.
It could also be used in the conservation of cultural artefacts, and in the food industry as a sustainable packaging material.
One of the most beneficial characteristics of the nacre produced in the lab is that it is bio-compatible – made of materials the human body produces or that humans can eat naturally.
This also makes the nacre ideal for medical applications like artificial bones and implants.
Professor Meyer added: “If you break your arm you might put in a metal pin that has to be removed with a second surgery after your bone heals.
“A pin made out of our material would be stiff and tough, but you wouldn’t have to remove it.”