A facile aptamer-based sensing strategy for dopamine through the fluorescence resonance energy transfer between rhodamine B and gold nanoparticles

A facile aptamer-based sensing strategy was developed for dopamine through the fluorescence resonance energy transfer (FRET) between rhodamine B (RB) and gold nanoparticles (AuNPs). The different affinities of unbound and bound aptamers toward AuNPs were employed to modulate the FRET efficiency for signal transfer. Dopamine-binding aptamers (DBA) could protect AuNPs from salt-induced aggregation, resulting in the fluorescence quenching of RB via FRET. Specific binding of DBA with dopamine formed the structured complex, losing the capability to stabilize AuNPs, thus the salt-induced aggregation of AuNPs led to the decrease of fluorescence quenching ability. Correspondingly, the fluorescence intensity of RB recovered along with the dopamine concentration ranging from 26 to 2.90 × 10 3  nM with the detection limit of 2 nM. This method was successfully applied for dopamine determination in swine feeds and chicken livers. Owing to its high sensitivity, excellent selectivity and convenient procedure, this strategy will provide a promising alternative for dopamine screening.