Sensitive and selective electrogenerated chemiluminescence aptasensing method for the determination of dopamine based on target-induced conformational displacement

Dopamine (DA) is an important neurotransmitter associated with many diseases. It is very significant to detect DA with high sensitivity and good selectivity. Here, a sensitive and selective electrogenerated chemiluminescence (ECL) aptasensing method was developed for the determination of DA based on target-induced conformational displacement. An anti-DA specific aptamer spliting into two ss-DNA (S1 and S2) was used as molecular recognition elements while an ss-DNA labeled with ferrocene (Fc-CS1, complementary to S1) was used as quenching probe. An ECL platform was prepared by dropping the mixture of Nafion, gold nanoparticles (AuNPs) and Ru(bpy)32+ onto glassy carbon electrode (GCE). After hybridization of S1 and Fc-CS1, ds-DNA (S1-CS1-Fc) was self-assembled onto the ECL platform to form an ECL aptasensing platform. In the presence of DA and S2, a S1-S2-DA complex was formed and then Fc-CS1 was released from the electrode surface, resulting in an increase of ECL intensity. DA can be sensitively detected in the range of 1.0 × 10-9 M to 5 × 10-8 M with a lower detection limit of 0.32 nM. This is first report of ECL aptasensing method for the determination of DA based on target-induced conformational displacement. The proposed ECL aptasensing method, exploiting both the aptamer recognition and ECL detection, allows direct detection of DA in diluted serum samples with high sensitivity and good selectivity, which may be further applicable in other neurochemicals assay and biomedical research.