While widely used for terrestrial medical applications, handheld blood analyzers are not suitable for space missions due to the short shelf-life of their measurement cartridges as well as their lack of clinical-grade accuracy and sensitivity. Therefore, scientists researching the impact of spaceflight on humans often have access only to pre- and post-flight data. This also means that astronauts do not have a simple and reliable method to accurately, and in real time, monitor key health parameters during spaceflight. Clearly, an in situ measurement capability can provide significant benefits both to operations and spaceflight factors research, as well as in decision-making in managing astronauts’ health.
Photonic integrated circuit (PIC)-based biochemical sensors offer enhanced robustness and assay longevity compared with conventional portable analyzers. Under NASA Small Business Technology Transfer (STTR) funding, Silicon Valley-based Intelligent Fiber Optic Systems
Corporation (IFOS) and Stanford University are developing an innovative, miniaturized lab-on-a-chip device to directly monitor astronaut health during missions, using ~3 drops of body fluid sample such as blood, urine, and potentially other body fluids like saliva, sweat, or tears.
The first-generation system comprises a miniaturized biosensor based on PICs (including Vertical Cavity Surface Emitting Laser (VCSEL), photodetector and optical filters, as shown in Figure 1) and biochemical assay that generates a fluorescent optical signal change in response to the target analyte. This approach will enable simultaneous, multiplexed measurement capability using integrated microfluidic circuitry or standard microfluidic sample slides from the medical industry (Figure 2).
The initial focus is on measurement of total protein concentration in blood and urine, the level of which can be indicative of liver and kidney conditions, infections, and bone marrow disorders. In experiments, a prototype lab-on-a-chip device demonstrated measurement performance better than gold-standard benchtop instruments including large benchtop spectrophotometer colorimetric assays. As shown in the model in Figure 2, the sensor capabilities will be extended to multiplex detection of other body fluids from which a number of analytes will be explored in accordance with NASA Human Research Program Exploration Medical Capability Element priorities. As an additional benefit, the envisioned PIC-based handheld biosensor platform (Figure 3) is an efficient and fieldable generic optical transducer that can be used cross-functionally to monitor water quality and other critical environmental parameters in space vehicles.
Johnson Space Center (JSC) in Houston, TX is interested in this technology due to its wide potential benefits to human spaceflight missions. IFOS is working with JSC's Human Research Program to explore technology infusion opportunities ranging from International Space Station (ISS) deployment, to future deep-space missions including Mars transit.
In parallel, to support wider commercialization here on Earth, IFOS participated in NASA's inaugural I-Corps™ program, in which the project team performed more than 100 in-person interviews with prospective customers, users, and stakeholders. The data collected indicates compelling business opportunities in personalized medicine and at-home diagnostics, both of which IFOS is now pursuing.