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ISGEN: In-Situ Genetics Experiments on Nanosatellites
 

Fully automated, in-situ, miniaturized systems (1.5 - 15 kg) will measure, and provide life support for, model micro-organisms: C. elegans, Drosophila, yeast, E. coli.

Benefit
For safe, long-duration space missions, the debilitating effects of the environment such as bone density loss, muscle atrophy, and a stressed immune system must be addressed. In terrestrial medicine, powerful recent advances in therapeutics have come from detailed understanding of biological mechanisms and pathways at the molecular level. The low-cost, small-size, autonomous secondary payload approach provides a means to study biological changes of fundamentally well-understood microorganisms and mammalian cells at the gene/protein level. Such knowledge will be key to the development of effective countermeasures to the deleterious effects of long-duration space travel. Flying many missions using this low-cost 2°-payload-compatible technology will lead to better understanding of the biological effects of the spaceflight environment, particularly radiation, enabling countermeasure development: a critical need for safe long-duration space missions.

Research Overview
The ISGEN project is designing and developing miniature biological stasis, growth, and analysis systems along with the necessary life support (culturing) capabilities to study gene and protein expression in model small/micro organisms. The system is fully self-contained and autonomous, telemetering results to Earth, requiring no specimen return. The main project components are technology-demonstration subsystems including quantitative fluorescent imagers, microfluidic networks, liquid arrays for the replicate study of multiple genetic constructs, and miniature environmental control and power management systems.

At the core of the ISGEN platform is an integrated analytical “cassette”, ~ 2" x 4" x 8". It includes:

  • pumps, valves, microchannels, filters, membranes, and wells to maintain the biological viability of various microorganisms.
  • an integrated thermal control system.
  • a suite of sensors.
  • a miniaturized optical detection system.
  • 8 – 24 integrated “microwells.”

The miniaturized system telemeters genetic changes in micro-organisms

Each 20 – 50 µL microwell contains a population of a model organism, with the option to include replicates and/or genetic variants in the different wells. A permeable membrane covering each well provides gas exchange, and an optical surface on the other face allows (imaging) fluorescence, luminescence, or absorbance-based assay of gene or protein expression, as well as population enumeration via counting or optical density measurement.

Right: The miniaturized system telemeters genetic changes in micro-organisms.

Each ISGEN cassette has its own hermetic headspace with electrical feedthroughs for power and data linking, plus integral thermal management. The headspace contains bags of support medium and a humidified air volume to exchange with the microwells via a permeable membrane. CO2 scrubbing and/or O2 generation are provided as necessary, and sensors record total pressure, pO2, pCO2, RH, temperature, and radiation. Outside the “wet” headspace are the light source and detector for optical assay, front-end signal conditioning, control and data handling, nonvolatile storage, power conditioning/backup, 3-axis accelerometer, and thermal dissipation/insulation materials/connections.

Model organisms will be studied on nanosatellites

The headspace contains bags of support medium and a humidified air volume to exchange with the microwells via a permeable membrane. CO2 scrubbing and/or O2 generation are provided as necessary, and sensors record total pressure, pO2, pCO2, RH, temperature, and radiation. Outside the “wet” headspace are the light source and detector for optical assay, front-end signal conditioning, control and data handling, nonvolatile storage, power conditioning/backup, 3-axis accelerometer, and thermal dissipation/insulation materials/connections.

The ISGEN technology modules will enable small gene/protein array analyzers, small spacecraft systems that can be carried as secondary payloads on planned missions, and specific Model organisms will be studied on nanosatellitesreference-experiment protocols designed for the study of genetic changes arising from the unique space environment. Near-term plans include support for mammalian cell cultures, to allow characterization of gene/protein profiles of these highly relevant systems.

Right: Model organisms will be studied on nanosatellites

Background
Advances in miniaturization of key technologies coupled with the emergence of nascent secondary-payload launch capabilities for small spacecraft offer new, low-cost approaches to space biology research. Leveraging this, in-situ genetic studies offer a powerful investigative tool suitable for use with small model organisms; compared to traditional discrete-measurement cell biology, this “broadband” approach to understanding biological change is attractive for the following reasons:

  • large amounts of data are obtained from relatively modest biology experiments.
  • genetic characterization is an accepted “gold standard” for many biological investigations.
  • multiple replicates are integral to the measurement strategy.
  • reducing reliance on human-tended architectures enhances reliability and accuracy.
  • uses sophisticated microanalytical methods and small-platform computational power.
  • costly sample return is eliminated.

Small satellites provide ready access to a range of space environments. Multiple flights are possible and probable, enabling a test/learn/redesign iterative approach and allowing replicate experiments. Autonomous small spacecraft technologies are now quite capable, with appropriate command-&-control, communications, and power management systems. In addition, the secondary payload approach is relatively low in cost and provides ideal partnering and collaborative opportunities.