Cytokine proteins are one of the most important early indicators of infection and immune response, and therefore serve as an excellent diagnostic tool for monitoring health. The objective of this project is to develop an easy-to-use handheld diagnostic sensor, with the NSBRI Smart Medical Systems Team, for the rapid detection of several cytokine levels in saliva. This lightweight and non-invasive monitor for the routine detection of cytokine levels would play an important role in astronaut health-care during long-duration space missions, and would be an immediate asset to the medical community on Earth.

Current affinity-based technologies used to detect cytokines, such as the enzyme-linked immunosorbent assay (ELISA), are time consuming and labor intensive, requiring trained technicians and bulky equipment not suitable for space flight. The specific aim of this project is to develop a miniature immunosensor that will deliver fast and sensitive results (within minutes). This prototype will contain a microfluidic consumable integrated with automated sample preparation and a reusable optical readout device.

I will accomplish this aim by optimizing the sensor’s three state-of-the-art key features: 1) Adaptation of an affinity-based assay that uses up-converting phosphor (UCP) reporter technology (SRI International, USA) for the sensitive detection and quantification of several cytokine profiles [1]; 2) Modification of micro-pillared capillary structures on the microfluidic chip (Åmic, Sweden) to provide direct fluidic control over critical assay parameters [2]; 3) Development of an optical detector, to detect and amplify UCP signal on the microfluidic chip. This research will produce a convenient and affordable diagnostic test that could also be used to implement virtually any affinity-based assay on a common platform for Earth and space-based medical care.

The first task of the project was to develop a reliable immunoassay using recombinant IFN-y cytokine protein. This was accomplished using two types of assay platforms, a nitrocellulose membrane and a microcapillary chip. Currently in progress, the second task was to implement an automated sample preparation into the microfluidic chip. The third task was to develop and assemble a handheld read-out device to read the immunoassay. Preliminary design and product specifications for this optical detector read-out device were proposed.