An autonomous lab on a chip for space flight calibration of gravity-induced transcellular calcium polarization in single-cell fern spores

Multi-Modal Multi-Array Electrochemical and Optical Sensor Suite for a Biological CubeSat Payload

CubeSats have emerged as cost-effective platforms for biological research in low Earth orbit (LEO). However, they have traditionally been limited to optical absorbance sensors for studying microbial growth. This work has made improvements to the sensing capabilities of these small satellites by incorporating electrochemical ion-selective pH and pNa sensors with optical absorbance sensors to enrich biological experimentation and greatly expand the capabilities of these payloads. We have designed, built, and tested a multi-modal multi-array electrochemical-optical sensor module and its ancillary systems, including a fluidic card and an on-board payload computer with custom firmware. Laboratory tests showed that the module could endure high flow rates (1 mL/min) without leakage, and the 27-well, 81-electrode sensor card accurately detected pH (71.0 mV/pH), sodium ion concentration (75.2 mV/pNa), and absorbance (0.067 AU), with the sensors demonstrating precise linear responses (R2 ≈ 0.99) in various test solutions. The successful development and integration of this technology conclude that CubeSat bio-payloads are now poised for more complex and detailed investigations of biological phenomena in space, marking a significant enhancement of small-satellite research capabilities.

BioSentinel: A Biological CubeSat for Deep Space Exploration

BioSentinel is the first biological CubeSat designed and developed for deep space. The main objectives of this NASA mission are to assess the effects of deep space radiation on biological systems and to engineer a CubeSat platform that can autonomously support and gather data from model organisms hundreds of thousands of kilometers from Earth. The articles in this special collection describe the extensive optimization of the biological payload system performed in preparation for this long-duration deep space mission. In this study, we briefly introduce BioSentinel and provide a glimpse into its technical and conceptual heritage by detailing the evolution of the science, subsystems, and capabilities of NASA's previous biological CubeSats. This introduction is not intended as an exhaustive review of CubeSat missions, but rather provides insight into the unique optimization parameters, science, and technology of those few that employ biological model systems.

Lab-on-a-Chip Technologies for Microgravity Simulation and Space Applications

Gravity plays an important role in the development of life on earth. The effect of gravity on living organisms can be investigated by controlling the magnitude of gravity. Most reduced gravity experiments are conducted on the Lower Earth Orbit (LEO) in the International Space Station (ISS). However, running experiments in ISS face challenges such as high cost, extreme condition, lack of direct accessibility, and long waiting period. Therefore, researchers have developed various ground-based devices and methods to perform reduced gravity experiments. However, the advantage of space conditions for developing new drugs, vaccines, and chemical applications requires more attention and new research. Advancements in conventional methods and the development of new methods are necessary to fulfil these demands. The advantages of Lab-on-a-Chip (LOC) devices make them an attractive option for simulating microgravity. This paper briefly reviews the advancement of LOC technologies for simulating microgravity in an earth-based laboratory.

Role of microfluidics in accelerating new space missions

Numerous revolutionary space missions have been initiated and planned for the following decades, including plans for novel spacecraft, exploration of the deep universe, and long duration manned space trips. Compared with space missions conducted over the past 50 years, current missions have features of spacecraft miniaturization, a faster task cycle, farther destinations, braver goals, and higher levels of precision. Tasks are becoming technically more complex and challenging, but also more accessible via commercial space activities. Remarkably, microfluidics has proven impactful in newly conceived space missions. In this review, we focus on recent advances in space microfluidic technologies and their impact on the state-of-the-art space missions. We discuss how micro-sized fluid and microfluidic instruments behave in space conditions, based on hydrodynamic theories. We draw on analyses outlining the reasons why microfluidic components and operations have become crucial in recent missions by categorically investigating a series of successful space missions integrated with microfluidic technologies. We present a comprehensive technical analysis on the recently developed in-space microfluidic applications such as the lab-on-a-CubeSat, healthcare for manned space missions, evaluation and reconstruction of the environment on celestial bodies, in-space manufacturing of microfluidic devices, and development of fluid-based micro-thrusters. The discussions in this review provide insights on microfluidic technologies that hold considerable promise for the upcoming space missions, and also outline how in-space conditions present a new perspective to the microfluidics field.

BioSentinel: A Biofluidic Nanosatellite Monitoring Microbial Growth and Activity in Deep Space

Small satellite technologies, particularly CubeSats, are enabling breakthrough research in space. Over the past 15 years, NASA Ames Research Center has developed and flown half a dozen biological CubeSats in low Earth orbit (LEO) to conduct space biology and astrobiology research investigating the effects of the space environment on microbiological organisms. These studies of the impacts of radiation and reduced gravity on cellular processes include dose-dependent interactions with antimicrobial drugs, measurements of gene expression and signaling, and assessment of radiation damage. BioSentinel, the newest addition to this series, will be the first deep space biological CubeSat, its heliocentric orbit extending far beyond the radiation-shielded environment of low Earth orbit. BioSentinel's 4U biosensing payload, the first living biology space experiment ever conducted beyond the Earth-Moon system, will use a microbial bioassay to assess repair of radiation-induced DNA damage in eukaryotic cells over a duration of 6-12 months. Part of a special collection of articles focused on BioSentinel and its science mission, this article describes the design, development, and testing of the biosensing payload's microfluidics and optical systems, highlighting improvements relative to previous CubeSat life-support and bioanalytical measurement technologies.

Testing Lab-on-a-Chip Technology for Culturing Human Melanoma Cells under Simulated Microgravity

The dynamic development of the space industry makes space flights more accessible and opens up new opportunities for biological research to better understand cell physiology under real microgravity. Whereas specialized studies in space remain out of our reach, preliminary experiments can be performed on Earth under simulated microgravity (sµg). Based on this concept, we used a 3D-clinostat (3D-C) to analyze the effect of short exposure to sµg on human keratinocytes HaCaT and melanoma cells A375 cultured on all-glass Lab-on-a-Chip (LOC). Our preliminary studies included viability evaluation, mitochondrial and caspase activity, and proliferation assay, enabling us to determine the effect of sµg on human cells. By comparing the results concerning cells cultured on LOCs and standard culture dishes, we were able to confirm the biocompatibility of all-glass LOCs and their potential application in microgravity research on selected human cell lines. Our studies revealed that HaCaT and A375 cells are susceptible to simulated microgravity; however, we observed an increased caspase activity and a decrease of proliferation in cancer cells cultured on LOCs in comparison to standard cell cultures. These results are an excellent basis to conduct further research on the possible application of LOCs systems in cancer research in space.

Nanosatellites for Biology in Space: In Situ Measurement of Bacillus subtilis Spore Germination and Growth after 6 Months in Low Earth Orbit on the O/OREOS Mission

We report here complete 6-month results from the orbiting Space Environment Survivability of Living Organisms (SESLO) experiment. The world's first and only long-duration live-biology cubesat experiment, SESLO was executed by one of two 10-cm cube-format payloads aboard the 5.5-kg O/OREOS (Organism/Organic Exposure to Orbital Stresses) free-flying nanosatellite, which launched to a 72°-inclination, 650-km Earth orbit in 2010. The SESLO experiment measured the long-term survival, germination, metabolic, and growth responses of Bacillus subtilis spores exposed to microgravity and ionizing radiation including heavy-ion bombardment. A pair of radiation dosimeters (RadFETs, i.e., radiation-sensitive field-effect transistors) within the SESLO payload provided an in-situ dose rate estimate of 6-7.6 mGy/day throughout the mission. Microwells containing samples of dried spores of a wild-type B. subtilis strain and a radiation-sensitive mutant deficient in Non-Homologoous End Joining (NHEJ) were rehydrated after 14, 91, and 181 days in space with nutrient medium containing with the redox dye alamarBlue (aB), which changes color upon reaction with cellular metabolites. Three-color transmitted light intensity measurements of all microwells were telemetered to Earth within days of each 24-hour growth experiment. At 14 and 91 days, spaceflight samples germinated, grew, and metabolized significantly more slowly than matching ground-control samples, as measured both by aB reduction and optical density changes; these rate differences notwithstanding, the final optical density attained was the same in both flight and ground samples. After 181 days in space, spore germination and growth appeared hindered and abnormal. We attribute the differences not to an effect of the space environment per se, as both spaceflight and ground-control samples exhibited the same behavior, but to a pair of ~15-day thermal excursions, after the 91-day measurement and before the 181-day experiment, that peaked above 46 °C in the SESLO payload. Because the payload hardware operated nominally at 181 days, the growth issues point to heat damage, most likely to component(s) of the growth medium (RPMI 1640 containing aB) or to biocompatibility issues caused by heat-accelerated outgassing or leaching of harmful compounds from components of the SESLO hardware and electronics.