Photochemistry on the Space Station—Aptamer Resistance to Space Conditions: Particles Exposure from Irradiation Facilities and Real Exposure Outside the International Space Station

Abstract

Some microarray-based instruments that use bioaffinity receptors such as antibodies or aptamers are under development to detect signatures of past or present life on planetary bodies. Studying the resistance of such instruments against space constraints and cosmic rays in particular is a prerequisite. We used several ground-based facilities to study the resistance of aptamers to various types of particles (protons, electrons, neutrons, and carbon ions) at different energies and fluences. We also tested the resistance of aptamers during the EXPOSE-R2 mission outside the International Space Station (ISS). The accumulated dose measured after the 588 days of this mission (220 mGy) corresponds to the accumulated dose that can be expected during a mission to Mars. We found that the recognition ability of fluorescently labeled aptamers was not significantly affected during short-term exposure experiments taking into account only one type of radiation at a time. However, we demonstrated that the same fluorescent dye was significantly affected by temperature variations (-21 degrees C to +58 degrees C) and storage throughout the entirety of the ISS experiment (60% of signal loss). This induced a large Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.variability of aptamer signal in our analysis. However, we found that >50% of aptamers were still functional after the whole EXPOSE-R2 mission. We conclude that aptamer-based instruments are well suited for in situ analysis on planetary bodies, but the detection step requires additional investigations.

In situ organic biosignature detection techniques for space applications

“…It was shown that both immobilized and free antibodies retained at least 40% of the binding efficiency after being exposed to freeze-drying, long-term storage, temperature fluctuations, and radiation (Coussot et al, 2019a). Similar experiments with aptamers showed that at least 50% retained their functionality after the entire study (Coussot et al, 2019b). The same study, complemented with ground-based experiments, suggested that radiation has minimal influence on assay performance; however, long-term storage with thermal cycles has a more considerable impact on the sensitivity.…”

“…Multiple studies have investigated the impact of radiation, thermal cycling, and long-time storage on affinity sensors (Le Postollec et al, 2009a;Le Postollec et al, 2009b;Baqué et al, 2011a;Baqué et al, 2011b;de Diego-Castilla et al, 2011;Derveni et al, 2012;Derveni et al, 2013;Vigier et al, 2013;Coussot et al, 2019b). In summary, these studies showed that antibodies and aptamers were resistant to radiation and maintained their performance.…”

“…Although ground-based radiation testing is valuable, it does not capture the reality of varying radiation fluxes, energies, and types during long-term storage and thermal variations. Two studies evaluated affinity sensors (i.e., antibodies and aptamers) that were stored for 566 days outside of the ISS (Vigier et al, 2013;Coussot et al, 2019a;Coussot et al, 2019b). Extensive validation and functionality testing were performed with a previously developed methodology (Coussot et al, 2018a;Coussot et al, 2018b;Coussot et al, 2018c).…”

The Complex Molecules Detector (CMOLD): A Fluidic-Based Instrument Suite to Search for (Bio)chemical Complexity on Mars and Icy Moons

“…Interestingly, a recent report has addressed the resistance of Aps to cosmic rays and other sources of radiation at different energies and doses, using ground-based facilities as well as during the EXPOSE-R2 mission outside the International Space Station (Coussot et al , 2019 ). The authors found that the functionality of the tested aptamers was not affected after being exposed for 588 days to the outer space in EXPOSE-R2, where they accumulated a radiation dose of 220 mGy, equivalent to that expected during a mission to Mars.…”