It sounds a little creepy, but it is possible that genetically modified bacteria could be used to build self healing walls and a whole lot of other cool stuff.
“When two genetically modified bacterial cells come in close proximity, these proteins come together and keep the cells attached to each other. By surrounding each cell with this sticky, elastic material, bacterial cells will cluster together to form a living slime.”
So once you get a good magic formula, they are quick to grow, the materials are cheap and everything is biodegradable.
The author works in a lab, he’s an academic. You will have to wait for him to get his shit together and starts a company before you can invest. More information in the video below.