The researchers created a form of concrete made of living beings that can repair itself, “reproduce” and could help us in the next missions to other planets.
The field of engineered living materials is very thriving in recent times. The materials, in addition to the classical inorganic matrix, contain within them organisms, typically bacteria, to provide properties that respond to the surrounding environment. Recent examples include materials that respond to changes in pressure, light or kill dangerous bacteria. In most cases, however, we are dealing with thin materials applied to structural elements.
Wil Srubar, a materials scientist at the University of Colorado, Boulder, and his colleagues lay the foundations for a revolution. In research published in the journal Matter, the group presented a material consisting of sand, a hydrogel that helps contain water and nutrients, and a kind of photosynthetic cyanobacteria. The particular mixture provides calcium carbonate to the bacteria that create a kind of shell around them, a bit like when shells are formed. Afterwards, the shell dries and remains in the material, hardening it like mortar.
In conditions of high humidity, the material can also reproduce. By breaking a brick in half and adding sand and the gelatinous mixture, the bacteria double the volume of the material in 6 hours, going from one brick to two. If repeated the experiment you get 4 bricks starting from the initial two and so on. The process on which the reproduction is based is very interesting for potential applications. Even if the new material will not build self-erecting houses, it could soon lead to the construction of components that can heal themselves when damaged.
Live concrete could even offer astronauts bound to Mars a way to build structures with local materials. Adventurers could in fact bring only bacterial cultures and use local material to harden, saving a lot of space and weight, which are fundamental aspects during interplanetary missions.
