Enhanced electrochemical aptasensor integrating MoS/CuS-Au and SI-RAFT for dual signal amplification in cTnI detection.

Cardiac troponin I (cTnI) is known to be among the prominent diagnostic bio-marker for acute myocardial infarction (AMI). In this paper, we proposed an electrochemical aptasensor with nanomaterial MoS/CuS-Au as the substrate material and perillaldehyde (PA) as the surface-initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization monomer by mediating the in-situ deposition of silver metal on the electrode surface for ultrasensitive detection of cTnI. The substrate material MoS/CuS-Au not only accelerated the rate transfer between electron, but also provided more active sites for aptamers introduction. The perillaldehyde (PA) monomers were modified onto the electrode by surface-initiated reversible addition fragmentation chain transfer polymerization (SI-RAFT), and the signal was amplified in one step by reducing silver ions to metallic silver deposited in situ on the upper of the electrode surface. Under optimum reaction conditions, this aptasensor achieved a detection limit down to 10.83 fg·mL. The proposed aptasensor without additional natural enzymes or biological tags, had a promising potential for use in the diagnosis of early acute myocardial infarction (AMI).