Abstract

Fluidically-Coupled Electrochemical Immunosensing of Interleukin-6 in as a Biomarker for Traumatic Brain Injury and Covid-Related Cytokine Storms

Paul Bohn, Arthur J. Schmitt Professor of Chemical and Biomolecular Engineering and Professor of Chemistry and Biochemistry, University of Notre Dame

A highly sensitive, label-free immunosensing platform based on interdigitated electrode arrays (IDEAs) has been developed for the detection of IL-6, a critical cytokine biomarker for inflammation and trauma. The IL-6 IDEA sensor exhibits a LOD in PBS that is comparable to other label-free sensors and ELISA-based electrochemical immunosensors, and it achieves linear ranges at IL-6 concentrations across 4 orders of magnitude for all fluids. Thus, the IL-6 IDEA sensor is an excellent candidate for clinical application as a POC tool, given its simple assembly, ease of operation, straightforward analysis, and good sensitivity for IL-6 in physiological fluids. Furthermore, preliminary experiments on non-optimized structures show that operation in generator-collector redox cycling mode can produce significant amplification factors. The performance of the IL-6 IDEA sensor was also explored in both CSF and serum. The IDEA sensor is less sensitive to IL-6 in CSF and serum than in in PBS, which is expected due to the presence of interferents, such as cellular debris, proteins, lipids, etc. Although LODs in CSF and serum were higher, the IL-6 IDEA electrochemical immunosensor can reliably detect IL-6 across 4 orders of magnitude at clinically relevant concentrations in CSF and serum. CSF is the preferred physiological fluid for biomarker detection due to its exceptionally low concentration of non-target interferents relative to blood plasma or serum.