A novel label-free electrochemiluminescence immunosensor for oral cancer marker monitoring based on luminol-functionalized PPy/AgNPs nanocomposite

This study was performed to develop a developed label-free electrochemiluminescence (ECL) immunosensor for the selective and sensitive detection of interleukin-8 (IL-8) antigen as a biomarker in oral cancer. The ECL immunosensor relied on an anti-IL-8 antibody conjugated to a luminol-functionalized polypyrrole-silver nanoparticle (PPy/AgNPs) nanocomposite. The PPy/AgNPs nanocomposite promoted both the immobilization of the antibody and the ECL signal formed by luminol. The immunosensor exhibited a low LOD (3.9 fg/mL), a broad linear range (10 −3 to 10 3 pg/mL), excellent specificity, and significant stability and repeatability. Results showed that the recoveries ranging from 92.00 % to 99.30 % and relative standard deviation from 3.62 % to 4.22 % indicated successful application to spiked human saliva and serum samples, confirming the immunosensor's performance and efficiency in complex biological fluids. The excellent selectivity and sensitivity of the proposed IL-8 immunosensor, coupled with its stability, low cost and ease of use, exhibited its substantial potential for early oral cancer diagnosis and disease monitoring.