Abstract
Monitoring cardiac troponin I (cTnI) is of great value in the clinical diagnosis of acute myocardial infarction (AMI). In this paper, a highly sensitive electrochemical aptamer sensor was demonstrated by using polystyrene (PS) microspheres as the electrode substrate material, combined with Prussian blue (PB) and gold nanoparticles (AuNPs) for the sensitive and label-free determination of cTnI. PS microspheres were synthesized by emulsion polymerization and then dropped onto the glassy carbon electrode, PB and AuNPs were electrodeposited on the electrode in corresponding electrolyte solution step by step. The PS microsphere substrate provided a large surface area for loading mass of the biological affinity aptamers, while the PB layer improved the electrical conductivity of the modified electrode and the electroactive AuNPs exhibited excellent catalytic performance for subsequent electrochemical measurements. In view of the above-mentioned sensing platform, the fabricated label-free electrochemical aptamer sensor showed a wide detection range of 10 fg/mL ~ 1.0 µg/mL and a low limit of detection of 2.03 fg/mL under the optimal conditions. Furthermore, this biosensor provided an effective detection platform for the analysis of cTnI in serum samples. The introduction of this sensitive electrochemical aptamer sensor provides a reference for clinical sensitive detection of cTnI.