Label-free electrochemical aptasensor for sensitive thrombin detection using layer-by-layer self-assembled multilayers with toluidine blue-graphene composites and gold nanoparticles

► The aptasensors exhibited low detection limit and wide linear range to thrombin. ► The Tb-Gra nanocomposites combined the advantages of graphene and toluidine blue. ► The aptasensors showed good fabrication reproducibility and sufficient stability.