A novel label-free electrochemiluminescence aptasensor based on layered flowerlike molybdenum sulfide–graphene nanocomposites as matrix

A label-free and ultrasensitive electrochemiluminescence (ECL) aptasensor was constructed for the detection of thrombin. Molybdenum sulfide–graphene nanocomposites with good conductivity and large surface area were immobilized on glassy carbon electrode (GCE), and then Nafion was fixed to chemosorb the Ru(bpy)32+ used as luminescence agent. Subsequently, gold nanoparticles (AuNPs) were modified on the electrode to immobilize the thiol-modified thrombin aptamer for fabrication of the thrombin aptasensor. The proposed ECL aptasensor produced the ultrasensitive detection of thrombin with a low detection limit of 3.6 × 10−15 M (S/N = 3) and over a wide target concentration range from 1.0 × 10−14 to 5.0 × 10−9 M. The aptasensor has been successfully applied in the determination of thrombin in human plasma samples of both traumatic and non-traumatic injury patients, indicating its promise in biochemical analysis. The recoveries of thrombin in human plasma samples are between 88.6% and 105.0%, and the RSD values are no more than 3.7%. The results demonstrate that this aptasensor has excellent sensitivity, selectivity and stability.