Microfluidic Platform for Multiplexed Cell Sampling and Time-Resolved SPR-Based Cytokine Sensing

Recent advancements of in vitro diagnostic systems for cell analysis such as cell chips and organ-on-a-chip systems have provided the opportunity to investigate dynamic cellular responses in microenvironments of increased physiological relevance. Among others one crucial parameter in cell analysis is related to the activation of intracellular pathways and the release of signaling molecules following exposure to bioactive substances. Based on the principle of diaphragm valves we have developed pneumatically-activated micropumps to conduct time-resolved immunoassays that quantify the release of stress markers into the supernatant. Micropumps play a critical role in the development of a fully integrated microfluidic system, because they make it possible to manipulate and transport solutions at the microliter to nanoliter scale in microchannels. While washing, labeling and regeneration steps are performed using our developed automated fluid handling system, the quantitation of IL-6 release by human fibroblasts is accomplished using surface plasmon resonance (SPR) spectroscopy. Our automation and miniaturization effort is expected to improve assay reliability, speed, and efficiency, all of which are considered crucial parameters when monitoring rapid transient cell responses.