An efficient electrochemical transducer matrix for biosensing devices requires specific characteristics, such as fast electron transfer, stability, high surface area, biocompatibility, and presence of specific functional groups, to facilitate biomolecule attachment. We demonstrate the fabrication of an electrochemical immunosensor based on a highly stable gold nanoparticles-reduced graphene oxide (AuNPs-rGO) composite material as a transducer matrix for label-free and noninvasive detection of salivary oral cancer biomarker interleukin-8 (IL8). The synergy between rGO and AuNPs allowed the immunosensor to exhibit fast response and high sensitivity due to the improved electron transfer behavior of the composite. The immunosensor shows very fast detection (9 min) of IL8 and high sensitivity with an experimental linear dynamic range of 500 fg mL-1 to 4 ng mL-1 and a detection limit of 72.73 ± 0.18 pg mL-1. The fabricated immunosensor exhibits excellent specificity toward the detection of IL8 in human saliva samples. Furthermore, the reusability and stability up to 3 months of the immunosensor demonstrates the commercial potential of this nanoplatform for the detection of other biomarkers of clinical relevance.
Keywords: Immunosensor; cyclic voltammetry; electrochemical biosensor; gold nanoparticles; interleukin-8; reduced graphene oxide.