Graphene Conductive Polymer Paper-Based Biosensor for Interleukin-6 Detection in Human Serum

Abstract Biosensing technology has advanced significantly in recent years because of its wide applications in healthcare and biomolecule detection. However, fabricating a biosensor that will be rapid, sensitive, inexpensive, simple, and selective can be challenging. In this study, we fabricated a paper-based biosensor using conductive polymers (CPs) and graphene to detect Interleukin-6 (IL-6) in human serum. Cross-sectional scanning electron microscopy (SEM) was carried out and the images indicated that flat graphene nanoflake (GNF) sheets are connected to the fibrous structure of cellulose. We used 20 μL of human serum and 2 μL of IL-6 antigen concentration to measure the electrical impedance spectroscopy (EIS) using Autolab potentiostat (PGSTAT302N). A typical three-electrode method was preferred over the two-electrode method for better accuracy, and the sensor was connected through an adapter to the potentiostat. The paper-based biosensor detected in the range of 2 pg/mL to 20 μg/mL (the solution was prepared by serial dilution method), and the charge transfer resistance (Rct) increases linearly with the concentration (899 Ω–964 Ω). The limit of detection (LOD) of IL-6 detection was ∼16 pg/mL for our biosensor. Thus, using a portable, simple, sensitive, and inexpensive paper-based biosensor can be a great platform to detect early-stage cancer biomarkers.