← Back to NASA Technology Projects
Completed TRL 3 (started at 2, targeting 3)
In the recent years, the icy worlds of Europa and Enceladus have been the target for future search-for-life missions. Data collection from the Cassini flyby and Hubble Telescope images reveal active vapor plumes on the surface of both bodies that are abundant with salts, organic compounds, and silica nanoparticles – pointing to a subsurface ocean beneath the water ice crust. In such ocean environments, the mechanism to determine molecular signs of life lies in chirality analysis of organics such as amino acids, fatty acids, and biopolymers. By focusing research efforts on both sample pretreatment and biosensing methods, the advancement of selectivity and sensitivity measurements for in-situ amino acid characterization can be achieved. Laser induced fluorescence capillary electrophoresis (LIF-CE) and electrospray ionization mass spectrometry (ESI-MS) are often utilized for their high sensitivity and selectivity under laboratory conditions. However, the sensitivity and reliability of both spectroscopic methods is unreliable for high ionic strength sample analysis. This is due to an increased concentration of electrolytes in the LIF-CE scheme that decreases electroosmotic mobility of the solutions as well as the migration of anions away from the detector. Similarly, the presence of sodium chloride (NaCl) in ESI-MS systems has revealed extensive sodium ion adduction, which decreases the stability of the electrospray while reducing the detected signal-to-noise ratio. Europa and Enceladus are known to have subsurface saltwater concentrations similar to Earth’s oceans (0.6 M NaCl) and thus sample pretreatment methods are essential to retain the sensitivity and selectivity for both spectroscopic biosensing regimes. The preliminary focus of this NSTRF proposal is to create a microfluidic pretreatment device to desalinate and concentrate the ingested sample. The proposed microfluidic device removes excess salt through electrochemical mediated desalination (ECD) which induces ionic separation from the generation of electric field gradients. Furthermore, the proposed device includes an isoelectric focusing (IEF) capability to produce concentrated organic samples after desalination. We plan to safely modify the harvested amphoteric liquid sample by increasing the pH until all present organics become fully deprotonated. Deprotonation along with spatially induced pH gradients will protect the trace organics from ionic separation thus producing an outflow that is both electrolyte-free and concentrated.
The next focus of this NSTRF proposal is to discover both electrochemical and optical biosensing methods to mediate limitations found within spectroscopic sensors. Spectroscopic methods can reveal molecular fingerprints and quantify analytes according to signal intensities, but these methods are limited by noisy background and low sensitivity as well. On the other hand, Field Effect Transistor (FET) biosensing platforms relate the variance in Dirac voltage to analyte concentration in the form of biomolecular doping. FETs are well suited for NASA related exploratory missions as they: require no additional power draw once the gate is activated and allow low-power switching for increased miniaturization capabilities. However, it has been determined that FET biosensors using bulk material as the bridge between the source and drain, experience decreased sensitivity during characterization of high ionic strength samples in the form of electrochemical corrosion, current leakage, and randomized doping. We propose the use of chemical vapor deposition (CVD) grown monolayer graphene to enhance the sensitivity of electrochemical amino acid characterization regardless of ionic strength of the solution. Graphene is a 2D honeycomb lattice of carbon with a sp2 hybridized structure that exhibits robust physical and chemical properties for electrochemical biosensing, such as low intrinsic noise level, biocompatibility, and versatility under the influence of high ionic strength media. With the use of graphene, optical biosensing using surface plasmon resonance detection can be further investigated as a tool for electrolyte-independent amino acid characterization.
Ultimately, the proposed methods will improve both the limit of detection, selectivity, and process efficiency for amino acid detection instrumentation in extraterrestrial missions. The miniaturization of amino acid sample preparation and utilizing graphene for both electrochemical and optical biosensing will provide a simple yet robust solution for integration with existing NASA related payloads.
The proposed work focuses on the advancement of pretreatment operations for aqueous-based microfluidic amino acid detection.In addition to the stated intention, investment in the development of this technology holds a great deal of promise for Earthly needs. The attributes of cost effectiveness and small size ideally suits this technology to humanitarian applications such as scaling up the desalination/concentration process to larger volumes for viable drinking water in underdeveloped regions on Earth. Ultimately, the proposed microfluidic device will improve both the limit of detection and process efficiency for amino acid detection instrumentation in extraterrestrial missions. The miniaturization of amino acid sample preparation will provide a simple yet robust solution for integration with existing NASA related payloads.
Listed on TechPort itself — the most direct way to ask about this specific project.
This is early/mid-stage (TRL 3) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.
None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.