One of the key aspects of any manned space mission is the ability for scientists to conduct experiments in space. Understanding how different elements and organisms react in microgravity and harsh conditions has been an important part of space exploration.
Now, researchers at the Indian Institute of Science (IISc) and Indian Space Research Organisation (ISRO) have developed a modular, self-contained device to cultivate microorganisms, which could enable scientists to carry out biological experiments in outer space.
In a study published in the peer-reviewed journal Acta Astronautica, the team showed how the device can be used to activate and track the growth of a bacterium called Sporosarcina pasteurii over several days, with minimal human involvement, a news release from IISc explains.
According to the release, understanding how such microbes behave in extreme environments could provide valuable insights for human space missions such as 'Gaganyaan', India's first crewed spacecraft planned by ISRO for 2022-2023.
For years, scientists have explored the use of lab-on-chip platforms, which combine many analyses into a single, integrated chip, for such experiments. There are, however, many other challenges to design such platforms for outer space, as compared to a lab on Earth. “It has to be completely self-contained,” Koushik Viswanathan, assistant professor in the department of mechanical Engineering and a senior author of the study, says in the release. "Besides, you can't simply expect the same operating conditions as you would in a normal laboratory setting."
This particular modular device uses a LED and photodiode sensor combination to track bacterial growth by measuring the optical density or scattering of light, similar to spectrophotometers used in the lab. It also has separate compartments for different experiments. “Each compartment or 'cassette' has a chamber where bacteria, suspended as spores in a sucrose solution, and a nutrient medium can be mixed to kickstart growth, by flicking on a switch remotely,” the release adds, explaining how the device functions.
Data from each cassette is then collected and stored independently. Three cassettes are clubbed into a single cartridge, which consumes just under 1W of power. The researchers hope that a full payload that could go in a spacecraft will contain four such cartridges, capable of carrying out 12 independent experiments.
More importantly, the team also had to ensure that the device was leak-proof and unaffected by any change in orientation. “This is a non-traditional environment for the bacteria to grow. It is totally sealed and has a very small volume. We had to see whether we would get consistent (growth) results in this smaller volume,” Aloke Kumar, associate professor in the department of mechanical engineering, and another senior author of the study, explains. “We also had to make sure that the LED going on and off doesn't generate much heat, which can change the bacterial growth characteristics.”
The researchers using an electron microscope to confirm that the spores grew and multiplied into rod-shaped bacteria inside the device, as they would have under normal conditions in a lab, the news release adds. “Now that we know this proof-of-concept works, we have already embarked on the next step ‒ getting a flight model (of the device) ready,” Viswanathan adds.
This would include optimising the physical space that the device can take up and its performance under stresses such as vibration and acceleration due to gravity. The device can also be adapted for studying other organisms such as worms, and for non-biological experiments. Kumar says the whole idea was to develop a model platform for Indian researchers: "Now that ISRO is embarking on an ambitious human space mission, it has to come up with its own solutions, made at home."
(With inputs from PTI)