Simple and highly sensitive electrogenerated chemiluminescence adenosine aptasensor formed by adsorbing a ruthenium complex-tagged aptamer on single-walled carbon nanotubes

Abstract

A highly sensitive electrogenerated chemiluminescence (ECL) adenosine aptasensor was designed by simply adsorbing a ruthenium complex-tagged aptamer on single-walled carbon nanotubes (SWNTs). A specific anti-adenosine binding aptamer was used as the recognition molecular element and ruthenium(II) complex (Ru1) was used as the ECL signal compound. Ru1-tagged aptamer was utilized as an ECL probe and the ECL probe was non-covalently assembled on the surface of the SWNTs to form an ECL probe/SWNTs composite. Analyte adenosine was bound with the aptamer of the ECL probe on the SWNTs so that the ECL probe was moved away or dropped from the SWNTs, resulting in the decrease of ECL signal. The results showed that the decreased ECL intensity was directly related to the logarithm of adenosine concentration in the range from 1.0 × 10⁻¹⁰ M to 5.0 × 10⁻⁷ M with a detection limit of 5.0 × 10⁻¹¹ M. This work demonstrates that the strategy of simply adsorbing ECL probe/SWNTs composites as a biosensing platform is a promising approach to design ECL aptasensors with high sensitivity and selectivity.