A new biological safety lock could help protect the world's ecosystems from the potential harms of synthetic organisms.

These types of organisms are helping produce biofuels and providing insight into disease, but they can disrupt natural ecosystems if not properly handled, Harvard Medical School reported. Contamination can occur if lab dishes or industrial vats break or if someone who has been in contact returns home with them on their clothes.

To combat this, researchers modified Escherichia coli bacteria to require an amino acid that cannot be found in nature. This meant the bacteria could not survive outside of a lab setting. Two recent studies were the first to use synthetic nutrient dependency as a biocontainment strategy for synthetic organisms.

"We now have the first example of genome-scale engineering rather than gene editing or genome copying," said George Church, Robert Winthrop Professor of Genetics at Harvard Medical School and core faculty member at the Wyss Institute. "This is the most radically altered genome to date in terms of genome function. We have not only a new code, but also a new amino acid, and the organism is totally dependent on it."

The findings mean safer E. coli strains that could be used in biotechnology applications with less fear of contamination.  In current samples the number of E. coli able to survive without being fed the synthetic amino acid are at undetectable levels. The researchers grew a group of 1 trillion E. coli cells and found that after two weeks none had escaped.

"As part of our dedication to safety engineering in biology, we're trying to get better at creating physically contained test systems to develop something that eventually will be so biologically contained that we won't need physical containment anymore," Church concluded. "we can use the physical containment to debug it and make sure it actually works."

The findings were published in a recent edition of the journal Nature.