Radiation-resistant: New technology opens new avenues for biopharmaceuticals in space flight

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An instrument on the International Space Station can now grow E. coli in space, opening up a new path for biomanufacturing drugs during long-term space flight. A study published in the journal npj Microgravity used a ground simulator of a space station instrument to grow E. coli, proving that E. coli can be grown in a way that is more suitable for space travel than existing alternatives. If microorganisms can be grown well in space, astronauts can use them to make drugs on demand.

"This could be critical for survival on long-duration missions, where resupply is impossible," said senior author Richard Bonocola, a faculty member in the Department of Biological Sciences at Rensselaer Polytechnic Institute. "Here we were asking: Is there a better way to grow microbes in space? And we found that with shear forces, there very well could be." With the exciting results, the team hopes to conduct similar experiments on the space station. While starting with the workhorse of molecular biology, Escherichia coli, the team hopes to eventually use the instrument to grow radiation-resistant microbes.

This could protect drugs being developed from the ever-present radiation of space during the manufacturing process. Bacteria like E. coli need oxygen to grow, and the gold standard way to aerate bacteria in liquid growth media is to use an orbital shaker, a machine that shakes a platform horizontally on which containers of liquid rest. Shakers rely on gravity to spin the liquid contents, which rise and fall inside the flask, mixing oxygen with the liquid, and instruments like the one sent to the space station in July 2019 do a better job.

Inspired by the research of Rensselaer professor Amir Hirsa, the NASA-built instrument uses shear, a force that occurs at the boundary of two objects pushing in opposite directions, similar to the forces that occur at a fault line between tectonic plates. The instrument uses a syringe to dispense a drop of liquid that forms a bubble. One side of the bubble is attached to a stationary ring, while the other side is attached to a thin ring that can rotate. The rotating ring creates shear forces on the surface of the bubble, causing its contents to rotate. The shear instrument is currently being used to conduct Hirsa's experiments, studying the effects of shear stress on amyloid fibrils.

Amyloid fibrils are clusters of proteins associated with neurodegenerative diseases such as diabetes, Alzheimer's and Parkinson's. On Earth, Bonocora used a knife-edge viscometer, an instrument designed by Hirsa's team in which a metal tube tip spins across the surface of a liquid in a dish, similar to the spinning rings in space-based instruments, to simulate shear forces. The experiment tested how bacteria grew when aerated with a knife-edge viscometer and an orbital oscillator when the two instruments were used at different speeds. At higher speeds, bacteria aerated through the knife-edge viscometer showed growth rates close to those of the orbital oscillator.

Even at lower rates, shear forces produced more growth than in bacterial samples without mechanical ventilation. This is a viable way to grow microorganisms, and the new research is opening a new path that now needs to be considered in a more realistic environment, such as aboard the space station. "Space pharmaceutical production is a critical component of our efforts to safely send humans into the depths of the solar system, and this research is foundational to achieving that goal," said Curt Brayman, dean of the College of Science. "The successful collaboration between Rick and Amir's teams demonstrates our long-standing connection to space exploration and is one of many examples of the 'low wall' culture of interdisciplinary research that we are proud to foster at Rensselaer."

Boco Park | Research/From: Rensselaer Polytechnic Institute

Reference journal: npj Microgravity

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