Microfluidic Label-Free Sensing for Rapid Multiplexed Pathogen Detection in Space Missions

For the success of most space programs involving environmental control and wastewater management, the rapid detection and identification of pathogens under resource limitations is essential. From the basic scientific research standpoint, the capability to monitor and detect microbial responses to microgravity and other low-shear environments in situ would significantly advance the present state of knowledge. Current cell culture or molecular biology based methods are time and labor-consuming, vulnerable to contamination, demand laboratory equipment, and require sophisticated manual preparation such as lysing, staining or labeling. To overcome these barriers, the objective of this project are to develop an integrated microfluidic sensor combining automated sample handling and label-free detection via molecular and plasmonic imaging that acquires molecular fingerprints from the whole organism, surface biomarkers and intra-organism biomarkers, thus achieving multiscale “compartmentalization”. This project is highly interdisciplinary, and the potential impact can be influential to multiple areas on NASA space technology roadmap such as TA06 (Human health, life support and habitation systems), TA08 (Science instruments, observatories, and sensor systems), and TA10 (Nanotechnology). 
We have performed research and development in the following four areas as proposed in the proposal: 
(1) Ultrahigh throughput system for rapid acquisition of molecular fingerprints from biological and nonbiological entities; 
(2) Microfluidic system for convenient and rapid sampling of small quantity of fluids containing potential detection targets; 
(3) Hierarchical nanostructures for functionalized surfaces that can capture target molecules with high specificity, and plasmonic field enhancement for ultrahigh sensitivity; 
(4) Stamping-Surface enhanced Raman scattering (S-SERS) for a minimal-liquid assay of surface contaminants. Overall, the research has resulted in 15+ peer-reviewed journal papers, 10+ conference proceeding papers, and 50+ presentations at conferences and academic seminars/meetings.