Microfluidics in space to detect extraterrestrial life signatures and monitor astronaut health

In a new report now published in npj Microgravity, Zachary Estlack and a research team in mechanical engineering and space sciences at the University of Utah and the University of California, Berkeley, developed a microfluidic organic analyzer to detect life signatures beyond Earth and to clinically monitor astronaut health. The team performed extensive environmental tests across diverse gravitational atmospheres to confirm the functionality of the analyzer and its level of technology readiness.

The planetary scientists simulated environments of lunar, Martian, zero and hypergravity conditions typically encountered during a parabolic flight to confirm the functionality of the microfluidic analyzer. The study outcomes pave the way to integrate microfluidic instruments in a range of space mission opportunities.

Microfluidics in space

Microfluidics present a major technical innovation for in vitro biomedical research. The concept is also suited in astrobiology for spaceflight analyses of biological signatures by regulating fluid volumes at the nano-/micro-scale across highly sensitive biochemical investigations, while maintaining a minor physical footprint. As a result, the miniature instruments are specifically appealing to analyze biological imprints of extraterrestrial life.

Planetary scientists have already gathered and studied ice samples in depth from Saturn and Jupiter’s moons Enceladus and Europa with microfluidic devices. Such analytical instruments are also useful to monitor flight crew health. Although the microfluidic bioanalysis systems are still in development, bioengineers aim to improve their gravitational sensitivity and power-efficiency for reconfigurable and compact in-situ space exploration.

Device configuration

Estlack and colleagues developed a microfluidic organic analyzer system (MOA) with an integrated programmable microwave array (PMA) alongside glass microchannels and a laser-induced fluorescence (LIF) detection system. During the development of the organic analyzer, they focused on a Technology Readiness level flight format instrument system to assess the maturity of the device for commercialization, as appropriate for space-flight, to identify the analytes of interest.

This work sheds light on the results of the first two flights in a series of five microgravity flights, to assess the performance of microfluidics under microgravity. The microfluidic valve arrays assisted the preparation and regulation of samples within the instrument, to automatically label, incubate and deliver samples to an integrated capillary electrophoresis chip and detect laser-induced fluorescence within the same setup. In total, the instrument integrated a microfluidic organic analyzer, a microvalve analyzer array containing an integrated chip for laser-induced fluorescence detection, and a sensor suite.

Testing the device under simulated parabolic flights

The research team studied the general functional parameters during the flight to ensure all testing environments were monitored and regulated. As the plane simulation climbed, the pressure dropped and resulted in an overall drop in temperature, which influenced the microfluidic instrument. The changes in operational parameters, however, had minimal impact on the overall performance of the instrument.

Estlack and the team conducted flow rate analyses during lunar, Martian and hypergravity periods of the flight. They noted changes to the initial back flow and peak flow rate with increased gravity. The outcomes of the simulations showed that the gravitational environment had minimal input on the performance of the instrument.

Rating the instruments performance

Based on the capacity for precise volume control under a variety of gravitational conditions, the team conducted automated dilutions to determine the instruments’ performance for future biomarker array testing. They completed three stages of the dilution sequence and recorded them during flight.

During the first two stages, they transferred a buffer and a fluorophore to a storage well in desired ratios. During the final stage, they loaded a microvolume of the diluted fluorophore into built-in detection channels and transferred it past the fluorescence detector via vacuum. The experiments performed under microgravity or Martian gravity corresponded to a specific dilution sequence and showed little variation.

Enhancing the Technology Readiness level on the instruments

The space scientists and bioengineers integrated the results from the first two flights to improve the Technology Readiness of the microfluidic organic analyzer. Their successful performance under microgravity justified their inclusion in spaceflight missions. For instance, with decreasing gravity, the pumping performance of the instrument remained constant, although increased gravity impaired the instrument in the microvalve array region, nevertheless, the organic analyzer remained unaffected throughout varying conditions.

The study outcomes highlighted the suitability of the instrument for applications that detect and determine extraterrestrial chemical and biochemical analytes. The insensitivity of the instrument towards a gravitational field under simulated conditions in the lab justified its suitability for space deployment.

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Outlook

In this way, Zachary Estlack and colleagues studied the technology readiness level of a microfluidic instrument for space missions to explore extraterrestrial biochemical signatures and monitor astronaut health in the future. The lessons learned from this first flight will impact future planned analyses under microgravity and hypergravity, which include investigations of capillary electrophoresis and astronaut crew health monitoring via simulated clinical assays to reveal biomarkers of specific interest.

The outcomes of these studies and the planned future flights will reveal the diverse capacity of the instruments during and after completing the planned space missions.

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