Key points from article :
Team incorporated various chemicals into the 3-D printing process.
Chemicals act as signals to activate certain responses in biologically engineered microbes.
Biomedical tools can control living organisms by producing therapeutic compounds.
Colors take several hours to develop as the bacteria grow, and then remain stable once they are in place.
Designers are able to control and pattern the growth of living systems through a computational algorithm.
Team used genetically modified E. coli bacteria in the tests.