Astronauts could grow their own medicines in space

As human expeditions to destinations beyond Earth advance, medical care tools in the form of lifesaving medications (and optimally available antimicrobials) pose a timely medical challenge: how do astronauts continue to have sufficient numbers of effective medicines during prolonged missions that cannot be easily resupplied? Extraterrestrial conditions degrade drugs much quicker, and the very distance of deep space can scarcely support regular resupplies.

According to a new study by engineers at the University of California, San Diego, there may be a pragmatic answer: on–demand drug production in plants. Researchers believe the crews could end up growing their own therapeutic sources to use as needed on long missions. They developed a simple method that allows the plants to be grown in space-like conditions. Astronomers can repeatedly harvest pharmaceuticals from plants without destroying them or generating large amounts of waste.

Study senior author Nicole Steinmetz said, “With plants, you can grow complex therapeutic compounds using light, water, and soil.”

Plants have already been grown on board the International Space Station (ISS), but complex purification processes have hindered efforts to turn them into pharmaceutical factories. Here, the researchers outline a simplified protocol for generating cowpea mosaic virus (CPMV), one of the most immunogenic plant viruses for cancer therapy and vaccine applications.

Scientists grow plants in lunar soil

The team synthesizes CPMV in Nicotiana benthamiana and black-eyed pea plants. Cultivating these species is easy because they produce large amounts of biomass in a short time, which translates directly into higher product yields. But the technical challenge mainly involves efficiently separating the product from the plant material.

To harvest CPMV along with other pharmaceutical products from the plant, the plants must be physically ground in a blender.

Instead of grinding up the plant tissue, the team used a combination of vacuum infiltration and centrifugation to isolate whole CPMV particles directly from the apoplast, the fluid-filled space outside wine yeast cells. This less harsh approach avoided damage to the cells. Ultrafiltration and diafiltration were then applied to remove impurities from the CPMV, exploiting size differences between the CPMV and the contaminants in solution.

The process was scalable and worked in more than 50 plants. The plants can keep growing and be harvested multiple times, as the leaves are not removed during extraction. The research group eventually sees this process being applied to whole living plants rather than isolated foliage.

Growing Chile Peppers in space

The researchers then put the system through tests to simulate space conditions and assess its performance. They built a random positioning machine that continuously spins the plants to lessen the effects of gravity and recreate microgravity.

A random positioning machine simulates microgravity for growing plants. Photo by Maziar Ghazinejad and Patrick Opdensteinen

Temperature fluctuations and oxidative stress were superimposed on the plants to simulate the environmental effects of space radiation. Interestingly, in some cases, these stressors even enhanced the CPMV yields. This effect is most likely due to CPMV being a plant virus, according to the researchers.

Microgravity led to predictable plant morphology changes; however, temperature switching and ROS stress significantly modified CPMV yields in a time‑dependent manner.

However, the extraction system proved remarkably robust, which may one day assist astronauts in reliably growing and harvesting medicines in orbit or on planetary bases.

“Plants become more susceptible to disease when stressed, which is usually a disadvantage,” Opdensteinen said. “But since our product is derived from a plant virus, we can use that stress response to increase yields.”

First author Patrick Opdensteinen said, “Basically, the product comes out of these cells. This is possible in plants, too.”

The researchers’ ultimate objective is to test their method on real flights during space missions. However, there is still much work to be done before that can happen. The team also intends to continue its research into the effects of deep-space conditions on essential plant functions, including water and nutrient uptake.

CPMV is not only a convenient test case. It holds potential as a therapeutic candidate with direct applicability to immunotherapy and cancer vaccine development. Its production in space may one day give astronauts immediate access to advanced treatments – without waiting for Earthbound resupply missions to arrive.

These results have real-world applications beyond spaceflight, including earthbound molecular farming. In resource-poor settings, where conventional laboratory capacity is low, this more streamlined production approach may benefit local farmers to produce essential drugs from plants grown in their environment.

This research helps shift the focus from viewing plants as merely a source of food and oxygen to recognizing them as living bioreactors capable of sustaining human life in extreme environments. With the combination of biotech and space travel, these scientists are sketching a vision where astronauts pluck therapies off their spacecraft gardens to treat themselves in space, and rural communities pull up similar green-solution systems for inexpensive healthcare through plants.

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