Coordination-induced self-assembly based carbon dot dendrimers as efficient signal labels for electrochemiluminescent immunosensor construction

In this work, an "on-off" electrochemiluminescent immunosensor for bone alkaline phosphatase (BALP) detection was constructed based on the carbon dot dendrimers (CD DRs) as signal labels and Pt nanoparticles functionalized Ni-phenolic coordination spheres (Pt@Ni-PCS) as quenching labels. The prepared CD DRs with low cytotoxicity were synthesized via coordination-induced self-assembly of carboxyl groups-rich N-doped carbon dots and zirconium oxygen clusters, of which the ECL efficiency was 2-fold enhancement than that of discrete N-doped carbon dots. Benefiting from the efficient quenching effect of Pt@Ni-PCS toward Zr-CD DRs/triethylamine-based ECL system, the prepared immunoassay for BALP detection exhibited a broad linear range with 1 pg/mL to 50 ng/mL and a low limit of detection of 24.9 fg/mL. Importantly, this highlights coordination-induced self-assembly as a tool for carbon dots enrichment to construct efficient ECL nanocomposites, which conceptualizes a pathway to expand the application of carbon dots in clinical ECL analysis technology.