Holy Mother! Scientists find environmentally safe way to create mother of pearl

Mother of pearl or nacre is one of nature’s hardest and stiffest materials. It is the hard iridescent coating found on the outside of pearls and the inside of certain mollusc’s shells. Scientists have always looked for a way to recreate it and they have succeeded. [caption id=“attachment_6510891” align=“alignnone” width=“1280”] The combination of the bacteria Sporosarcina pasteurii, a calcium source, and urea triggers the crystallization of calcium carbonate, pictured above in extreme close up. Image credit: University of Rochester[/caption] Teams from the University of Cambridge, the CNRS lab, and ETH Zurich have, previously, recreated nacre. However, the manufacturing processes have either been too energy intensive or have used harsh chemicals. Anne Meyer, a biologist from the University of Rochester, New York has developed a way to produce nacre which is safer for the environment and inexpensive using bacteria. The synthetic nacre has the toughness of natural nacre, while also being stiff and bendable.

In a study published in the SMALL journal, Meyer has described the method used. The technique involves mixing urea with Sporosarcina pasteurii bacteria and a calcium source, then dipping a glass slide into the solution. A reaction between the urea and bacteria causes a thin layer of calcium carbonate to crystallize onto the slide. That slide is then placed in a beaker containing a solution of the bacteria Bacillus licheniformis. After that beaker has been left in an incubator for a period of time, the bacteria forms a layer of sticky polymer on top of the existing calcium carbonate layer. The method used to create the novel material could lead to new applications in medicine, engineering — and even constructing buildings on the moon.