We aim to develop a new nanotechnology-enabled sensing platform exceeding the sensitivity and selectivity of the current state-of-art (SOA) in portable, low-mass, low-complexity biochemical sensors. This system is a new capability for space exploration/science applications, e.g. exo-life detection in challenging cryogenic environments, including multiplexed arrays in planetary probes, distributed sensor swarms for use with CubeSats, and other platforms, and builds upon our existing efforts at both NASA Glenn Research Center (GRC) and Dartmouth College. Localized surface plasmon resonances (LSPRs) – the collective electron oscillations excited in nano-sized metallic particles (‘nanoantennas’) by incident optical light – have been utilized extensively as sensitive, label-free optical probes for the study of biochemical interactions in both gas and liquid phase, due to their highly confined electric fields and extreme sensitivity to changes in their local environment (e.g. the presence of a target biomolecule.) The ultimate limit of detection – single molecule detection – has been demonstrated with such sensing platforms, and will form the basis of our sensing approach. Yet, the selective capture of rare targets from a complex background near these transducers remains both a challenging problem and necessary step to advance this technology out of the lab and into the field. Therefore, we aim to close this critical knowledge gap in the current proposal, through the development of the tailored nano-recognition elements coupled to sensitive plasmonic nanoantennas. We will primarily focus on exo-life applications – as these are currently the most challenging and least understood – but with further application to astronaut life support, pathogen detection, and water quality monitoring. Field-deployable LSPR-based sensors are currently being explored for terrestrial point-of-care (POC) medical applications by other groups, including our external collaborator for this award at Dartmouth College. These devices are also conducive to the demanding requirements of space exploration, owing to their low-mass, volume, and power consumption, and ruggedization/simplicity in operation. Further, their small size, and relatively low cost with high sensitivity provide capabilities not possible with larger, more complex, centralized instruments (e.g. mass spectrometer). However, LSPR-based sensors (and mass spectrometers) are limited in their demonstrated ability to selectively capture and uniquely identify the target analytes in-situ (in possibly challenging environments), with minimal processing/contamination. This proposal is aimed at enabling this critical step towards a new class of chemical/biochemical measurements for space exploration applications. The goal is to advance the SOA in selective capture and sensitive detection of rare biomarkers in-situ, using small, portable, deployable biosensor platforms, with a particular focus on exo-life detection, and possible extension/application to in-flight astronaut life support (including water quality monitoring, health diagnostics, and pathogen detection).