Enhanced electrogenerated chemiluminescence behavior of C3N4 QDs@ C3N4 nanosheet and its signal-on aptasensing for platelet derived growth factor

•C3N4 QDs@C3N4 nanosheet nanocomposite was prepared by a simple oxidation method.•It exhibits stronger and more stable ECL response owning to more surface defect.•A signal-on ECL aptasensor for PDGF-BB was fabricated using the nanocomposite.•This work opens up the application of g-C3N4 nanocomposite in signal-on aptasensing.

A novel g-C3N4 nanosheets embedded with C3N4 QDs nanocomposites (QD@CNNS) was prepared by simple oxidation using hydrogen peroxide and UV light irradiation. This nanocomposite exhibits more stable and stronger electrochemiluminescent (ECL) behavior compared with CNNS. Coupling this nanocomposite with Fc-labeled aptamer, a signal-on aptasensor for platelet derived growth factor BB (PDGF-BB) is fabricated. Initially, the Fc-labeled aptamer binds onto QD@CNNS via π-π conjugation and electrostatic interaction, quenching ECL emission from QD@CNNS. The introduction of target efficiently recovers the ECL signal by the formation of PDGF-BB/aptamer complex. The ECL intensity is proportion to the concentration of PDGF-BB in the range of 0.02-80 nM with a detection limit of 0.013 nM. This work demonstrates a simple synthesis method to obtain QD@CNNS with excellent ECL behavior, and opens up the application of g-C3N4 nanocomposite in signal-on aptasensing.