Abstract: Microfluidic Sensor System to Investigate Cell-Secreted Biomarkers

Atopic dermatitis (AD), a long-lasting skin inflammatory condition, can present itself as early as infancy and affects approximately 9.6 million US children [1]. While therapies are available for alleviating symptoms, the numerous complex mechanisms causing AD make it difficult to predict and prevent disease severity. Interferon gamma (IFN-γ) and interleukin-31 (IL-31) are two peripheral blood mononuclear cell (PBMC)-secreted biomarkers with promising correlations with AD; studies have shown that children with AD have decreased IFN-γ and increased IL-31 cell-secretions [2] [3]. While both biomarkers are quantifiable using ELISA, electrochemical (EC) biosensors present as a promising alternative for faster detection and enhanced sensitivity. Currently, there is no tool capable of detecting both biomarkers simultaneously. In this project, we present a design for a microfluidic, electrochemical (EC) biosensor for the detection of IFN-γ and IL-31. We identified that streptavidin magnetic beads (MBs) offer increased surface area for biotinylated aptamers, and we used the aptamer-MB conjugates as the sensing probes in the design. Furthermore, we present a potential microfluidic design that would allow for continuous monitoring of stimulated PBMC cells. Under continuous monitoring, scientists can study cell secretion changes under various stimulants, thus improving our understanding of AD progression. Our result demonstrates that multiplex detection of these two biomarkers is possible. We view our design as the starting point for a versatile tool applicable in diagnostic and research settings. For example, a commercialized biosensor could aid physicians in identifying a child’s risk of AD, even when the child does not present symptoms at the time of check-up. Furthermore, by modifying the MBs with different aptamers or antibodies, this biosensor can also be used to better diagnose and study other diseases.