Scientists in the United States developed a living, green material made of sand and bacteria, displaying both structural load-bearing and biological functions.

The study, presented on Wednesday in the journal Matter, described a scaffold out of sand and hydrogel for the bacteria to grow in. The hydrogel retains moisture and nutrients for the bacteria to proliferate and mineralize, a process similar to the formation of seashells in the ocean.

The hydrogel-sand brick is not only alive, but also reproductive. By splitting the brick in half, the bacteria can grow into two complete bricks with the help of some extra sand, hydrogel and nutrients, according to the study.

The researchers demonstrated that one parent brick could reproduce up to eight bricks after three generations, displaying the capability of exponential material manufacturing.

"We use photosynthetic cyanobacteria to biomineralize the scaffold, so it actually is really green," said the paper's senior author Wil Srubar at the University of Colorado Boulder.

The method provides a green alternative to modern building materials, as concrete is the second most-consumed material on Earth after water.

Srubar's team envisions introducing different functional bacteria to the material platform to create new materials with biological functions, such as the ones that sense and respond to toxins in the air. The living material may also be used to build structures where there are limited resources like the desert or even another planet like Mars.