An impedimetric aptamer-based sensor for sensitive and selective determination of cardiac troponin I

Herein, a sensitive impedimetric aptasensor was presented for cardiac troponin I (cTnI) sensing. The construction of the aptamer-based impedimetric sensor was started by modifying the indium tin oxide (ITO) glasses with thiol functional groups to enable the binding of gold nanoparticles (AuNPs) onto ITO surface. This ITO/AuNPs substrate was then biointerfaced with thiol modified Tro6 aptamer, which ended up by binding cTnI on Tro6 apatamer. The concentration of cTnI was determined by recording the impedance before and after conjugation of cTnI with the Tro6 aptamer by using hexacyanoferrate (II)/(III) as the redox probe. The impedimetric aptasensor response is directly related to the logarithmic value of cTnI concentrations from 0.1 pgmL(-1) to 10 ngmL(-1) with detection limit of 0.055 pgmL(-1). The demonstrated sensitive aptasensor was successfully used to determine cTnI in human blood serum sample.