An electrochemical troponin T aptasensor based on the use of a macroporous gold nanostructure

A specific troponin T (TnT) binding aptamer was identified and immobilized on an electrodeposited macroporous gold nanostructure using poly(ethylene glycol) 600, to fabricate a novel and ultrasensitive TnT aptasensor. The transducer surface on the gold disk electrode was characterized by field emission scanning electron microscopy, and immobilization of the aptamer was monitored by open circuit potential measurements. Binding of TnT by the aptamer was monitored by differential pulse voltammetry using ferro/ferricyanide as the redox probe. The aptamer has a high affinity and specificity, and the electrode is sensitive and selective. Best operated at a working potential of 0.23V (vs. Ag/AgCl), the electrode can detected TnT in the 0.05 to 5.0ngmL(-1) concentration range with a 23pgmL(-1) detection limit. The method was applied to the determination of TnT in 99 spiked human serum samples, and the diagnostic sensitivity and specificity were 94 and 95%, respectively.