Microfluidics Microbial Activity MicroAssay: An Automated In Situ Microbial Metabolic Detection System

Area of Science:

• Astrobiology
• Microbiology
• Planetary Science

Background:

• Direct extant life detection instrumentation has been absent from space missions since the 1970s.
• Advancing new technologies for future space missions is crucial for life detection.
• Metabolism-indicator redox dyes offer a promising avenue for detecting microbial activity.

Purpose of the Study:

• To develop, optimize, and test a semi-automated prototype for detecting extant microbial life.
• To evaluate the sensitivity and robustness of redox dye/buffer combinations for life detection.
• To assess the performance of the developed system using astrobiological analog samples.

Main Methods:

• Developed and optimized the microfluidics Microbial Activity MicroAssay (μMAMA) system.
• Evaluated six redox dye/buffer combinations for sensitivity and robustness.
• Tested the system's response to metabolic activity in high-Arctic analog samples and Mars regolith simulant.

Main Results:

• Identified Biolog Inoculating Fluid (IF)-C and AlamarBlue buffered in IF-0a (aB-IF0a) as optimal dye/buffer combinations.
• Detected metabolic activity from as few as 10^2 cells/mL with optimal combinations.
• Demonstrated efficacy across a broad range of physiochemical conditions (pH, temperature, salinity, perchlorate) and in the presence of Mars regolith simulant.
• Successfully detected extant active cold-adapted microbial life from high Arctic analog sites.

Conclusions:

• The μMAMA system, utilizing optimized redox dyes, can detect extant microbial life.
• The system demonstrates high sensitivity and broad environmental tolerance, suitable for diverse planetary conditions.
• Its small size and potential for automation make μMAMA a viable instrument for future landed life detection missions.