An electrochemiluminescent sensor for dopamine detection based on a dual-molecule recognition strategy and polyaniline quenching

A novel electrochemiluminescence (ECL) sensor was constructed based on a dual-molecular recognition strategy and the quenching effect of polyaniline (PANI) on the ECL emission of graphite-like carbon nitride (g-C3N4). The gold nanoparticle-functionalized g-C3N4 nanosheets (Au-g-C3N4 NS) served as signal probes and as a matrix to immobilize recognition element dithiobis-(succinimidyl propionate) (DSP), capturing dopamine (DA) by the interaction between the amino group of DA and the N-hydroxysuccinimide ester of DSP. Next, 3-aminophenylboronic acid functionalized PANI (APBA/PANI) was incubated onto the electrode based on the interaction between the diol of DA and the boronic acid of APBA to achieve an ECL sensor with a sandwich structure. Due to the excellent quenching effect of PANI on the ECL emission of g-C3N4, the prepared ECL sensor showed a highly sensitive and linear response to DA in the concentration range of 0.10 pM-5.0 nM, with a detection limit of 0.033 pM. Furthermore, the dual-molecular recognition strategy endowed the sensor with high selectivity. The construction strategy described here provides a new analytical method for the specific detection of small biomolecules.