杏吧原创

笔补肠办颈苍驳听E.coli聽on a trip to Mars could be the best way for humans to survive on the Red Planet.

Initial feasibility studies suggest Mars colonists could use 鈥渓iving鈥� self-healing materials to build habitats, make them air-tight with rubber grown by cells and power them with batteries made of bacteria.

Lynn Rothschild at the NASA Ames Research Center thinks synthetic biology is the key to exploring and colonising other planets like Mars. It could allow key materials and even machinery to be grown locally rather than brought all the way from Earth at stupendous expense.

Her group at NASA has been exploring the feasibility of this approach with the Stanford-Brown iGEM team, a team of undergraduates who design projects for the .

Home grown

Rubber is one key material Mars colonists will need to keep their habitats and spacesuit airtight. On Earth, rubber is either extracted from rubber trees or made from fossil fuels. On Mars, it could instead be produced by genetically modified E. coli.

Several iGEM teams have managed to get E. coli to make rubber by adding genes from the rubber tree. The problem is that聽 the rubber can only be extracted by breaking open the cells, which requires chemicals that Mars colonists will not have.

Rothschild鈥檚 group has now engineered E. coli that have the rubber-making machinery on the outside of their cells, so there鈥檚 no need to break them open. They also created a form of rubber that can be broken down and recycled by the bacteria.

The group has also created self-healing plastics by encapsulating a glue-making bacterium called Bacillus subtilis within them. These bacteria can form spores that can survive long periods with no food. NASA experiments have shown they can survive for at least six years in space.

As long as the plastics are intact, the bacteria should remain dormant. But if cracks expose the spores to light or oxygen, they should awaken, begin feeding on nutrients included in the plastics and start making glue. Once the cracks are sealed, they should become dormant again.

Promising results

鈥淭his technology is promising,鈥� says material scientist Gregory Odegard at Michigan Technological University. Current state-of-the-art self-healing materials have capsules of liquid glue that break and fill cracks if the material is damaged, he says, but this works only once at any one place in the material.

The bacteria could heal repeated cracking events, Odegard says. 鈥淔or deep-space exploration, spare parts will not be available, and repeat healing cycles may be necessary.鈥�

The team is also trying to create batteries made of colonies of E. coli that all pump ions in one direction and therefore generate an electric potential. The idea is to find a replacement for the lithium ion batteries used to store solar energy on the International Space Station. These batteries are heavy, potentially dangerous and would be very difficult to manufacture on other planets.

Rothschild thinks . They could even tweak the organisms they take with them as necessary. For instance, if someone fell ill and needed a drug that wasn鈥檛 available, Earth could transmit the DNA recipe needed to create an organism that could make the drug.