TAU experiment uses CRISPR-Cas to successfully diagnose diseases in space

Astronaut Eytan Stibbe performing the experiment on the International Space Station. Photo: Ramon Foundation and Israel Space Agency.

New method can reliably identify viruses and bacteria infecting crew members

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Tel Aviv University (TAU) researchers recently conducted a unique experiment in the International Space Station to test genetic diagnosis under microgravity conditions using the CRISPR system, a sort of molecular “search engine.” They proved that CRISPR-Cas  can be used to precisely and reliably identify viruses and bacteria infecting crew members during space missions.

The study was led by Dr. Dudu Burstein of TAU’s Shmunis School of Biomedicine and Cancer Research and Dr. Gur Pines of the Volcani Institute. The experiment was conducted in space by astronaut Eytan Stibbe as part of the “Rakia” mission launched to space in April, under the leadership of the Ramon Foundation and the Israel Space Agency.

CRISPR systems are the immune systems of bacteria, protecting them from viruses. Bacteria use CRISPR-Cas systems to locate viral sequences and cleave to them in order to disable them. The systems have recently been used to identify various organisms with extreme precision based on recognition of specific DNA sequences.

The researchers hypothesized that genetic diagnostics using this method, which requires minimal and easily operated equipment, could be suitable for long space missions — for example, at the International Space Station or on future missions to explore the moon and Mars.

“Conditions in space are extremely problematic, and treatment methods are limited, so it is essential to identify pathogens in a rapid, reliable, and straightforward method,” Dr. Burstein explains. “Tests like PCR, which we are now all familiar with, require trained personnel and relatively complex equipment. In the International Space Station, we tested a CRISPR-based detection method developed by Dr. Janice Chen and her colleagues in the laboratory of the Nobel Prize-winning Dr. Jennifer Doudna. First, the DNA is amplified: Each targetted DNA molecule is repeatedly duplicated many times. Then the CRISPR-Cas goes into action: If it identifies the target DNA, it activates a fluorescent molecular marker. The fluorescence lets us know whether the bacteria or viruses of interest are indeed present in the sample. This whole process can be conducted in one tiny test tube, so it can suit well the astronauts’ needs.

Doctoral student Dan Alon and Dr. Karin Mittelman planned the experiment in detail and conducted it countless times in the lab under various conditions. After reaching the desired result, they prepared a kit, including the CRISPR-Cas system and the other components required for detection. Eventually, this kit was launched together with Stibbe to the International Space Station. The results of the experiments conducted by Stibbe were highly successful, and the researchers proved that it is indeed possible to perform precise and sensitive CRISPR-based diagnosis even in an environment with virtually no gravity.

“This is the first step towards the simple and rapid diagnosis of diseases and pathogens even on space missions,” Dr. Burstein concludes. “There is still work to do on the next stages, such as extracting DNA from samples; making the system more efficient, so that it will be able to test a variety of organisms in one test tube; and diagnosing more complex samples. It was inspiring to see our test kit in Eytan’s hands at the Space Station, and we’re even more excited by the possibility that such kits will help future astronauts on their extraterrestrial missions.”

"We're excited by the possibility that such kits will help future astronauts on their extraterrestrial missions."