Polyamidoamine dendrimers-capped carbon dots/Au nanocrystal nanocomposites and its application for electrochemical immunosensor

In this work, polyamidoamine dendrimers capped-carbon dots (PAMAM-CDs) were fabricated by one-step microwave assisted pyrolysis of citric acid (CA) and PAMAM, where the formation of CDs and the surface passivation were accomplished simultaneously. The obtained graphitic PAMAM-CDs, with abundant amine groups, were employed as reducing and capping agents for the formation of PAMAM-CDs/Au nanocrystal nanocomposites. The resulting nanocomposites exhibited excellent conductivity, stability and biocompatibility on the surface of electrode and were designed as an immobilized matrix for sensitive immunosensing of alpha-fetoprotein (AFP). The proposed immunosensor showed a wide linear detection range from 100 fg mL(-1) to 100 ng mL(-1). The detection limit for AFP was 0.025 pg mL(-1). Importantly, the immunosensor was evaluated for the analysis of clinical serum samples, obtaining a good correlation with enzyme-linked immunosorbent assay (ELISA). The results indicated that the immunosensor provided a possible application for the detection of AFP in clinical diagnosis. (C) 2013 Elsevier B.V. All rights reserved.