▎ 摘　　要

The technology of ink-jet printing has been an appealing alternative to traditional photolithography for fabricating flexible and elastic circuits, having low-cost and ease of control. In this work, a novel, unique and sensitive immunoassay designed based on application of silver nanoparticles-reduced graphene oxide nano composite (Ag/RGO) ink for fabrication of paper based immunosensor, Cysteamine coped gold nanopartides (CysA/Au NPs) as a signal amplification element for determination of CA15-3 protein. Fully electrochemically methodology was applied to prepare a new transducer based on the Ag/RGO surface which provides high surface area for CA15-3 antibody immobilization in high amount. Under optimized experimental conditions, the Ag-RGO/CysA-Au NPs based immunosensor shows good specificity and sensitivity. The obtained LLOQ of immunosensor for CA 15-3 biomarker was 15 U/mL as well as calibration curve was linear in the range of 15-125 U/mL. The technique was successfully employed assay of CA15-3 biomarker in unprocessed human plasma samples.