A Rapid Electrochemical Immunosensor Platform for the Sepsis-Associated Host and Pathogen Marker Dual Detection

The study addresses the critical issue of sepsis diagnosis, a life-threatening condition triggered by the body's immune response to infection that leads to mortality. Current diagnostic methods rely on the time-consuming assessment of multiple biomarkers by a series of tests, leading to delayed treatment. Here, we report a platform for developing a point-of-care (POC) device utilizing electrochemical immunosensors for the dual and rapid detection of sepsis biomarkers: Procalcitonin (PCT), Interleukin-6 (IL-6), and C-reactive protein (CRP) as host markers and lipopolysaccharide (LPS) as a pathogen marker. The platform employs 3D microgels that encapsulate the electrochemically active nanoprobes (Carbon dots) for bacterial detection in a lower sample volume (10 μL) and reduced detection time to 10 min, significantly faster than conventional ELISA tests (4-5 h). Cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques were used to assess the electrochemical characterization of biofunctionalized screen printed electrodes (bSPE) and sensor performance, respectively, showing improved sensitivity compared to standard ELISA tests. The developed sensor offers a lower limit of detection (LOD of 3.4 pg/mL for IL-6, 4.36 pg/mL for PCT, and 5.9 pg/mL for CRP) than commercial spectrophotometric ELISA, making it a promising alternative for accurate and timely sepsis diagnosis. Thus, the developed platform could revolutionize sepsis management by enabling early detection and treatment, potentially saving lives.