Sandwich-format electrochemiluminescence assay for PDGF-BB using quantum dots-dendrimer nanocomposites as probe.

Abstract This work describes a novel electrochemiluminescence aptasensor for highly sensitive detection of platelet-derived growth factor BB (PDGF-BB) using aptamer functionalized CdS quantum dots–polyamidoamine as probe (CdS QDs–PAMAM–Apt). CdS QDs–PAMAM nanocomposites were synthesized by one-pot synthesis in methanol. The prepared nanocomposites were linked with the NH 2 –aptamer 2 (Apt2) of PDGF-BB to form the CdS QDs–PAMAM–Apt2 probe by glutaraldehyde as coupling reagent. For constructing the aptasensor, MWCNTs–chitosan composites and NH 2 –aptamer 1 (Apt1) with the same base sequence as Apt2 were immobilized on the electrode by the self-assembled method to recognize the target protein PDGF-BB. In the presence of PDGF-BB, the structure of sandwiched format was formed between the Apt1 and the CdS QDs–PAMAM–Apt2 probe, thereby resulting in a proportional increase of ECL emission. Thanks to the efficient and stable ECL emission of CdS QDs–PAMAM dendrimer and the advantage of MWCNTs for accelerating the electron transfer, the highly sensitive detection of PDGF-BB with a detection limit of 0.13 pM was achieved. The linear range is from 0.5 pM to 1 nM. The present protocol was applied to the analysis of PDGF-BB in human serum samples. The recoveries of PDGF-BB in human serum samples are 87.2–113% and RSD values are less than 3.6%.