Carbon Quantum Dot And Graphene Nanocomposites For Electrochemical Detection Of Alpha Fetal Protein

The early detection of cancer biomarker is of great importance in proper prevention, diagnosis and treatment of cancer. In recent years, the applications of nanomaterials espically the carbon nannmaterials have attracted much attention in the field of electrochemical immunosensor. In this work, based on the carbon dots and graphene, novel nanocomposites were synthesized and used in the fabrication of electrochemical immunosensor for a-fetoprotein (AFP).This paper mainly obtained the following results:1. 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 PAMAM-CDs/Au nanocrystal nanocomposites were used to fabricate a simple, label-free and ultrasensitive electrochemical immunosensor for AFP. The proposed immunosensor showed a wide linear detection range from100fg mL-1to100ng mL-1, The detection limit for AFP was0.025pg mL-1. The immunosensor was evaluated for the analysis of clinical serum samples, obtaining a good agreement with enzyme-linked immunosorbent assay (ELISA).2. Poly (diallyldimethylammonium chloride)(PDDA) protected Prussian blue/gold nanoparticles/ionic liquid functionalized reduced graphene oxide (IL-rGO-Au-PDDA-PB) nanocomposites were fabricated and used as signal tag in the detection of AFP. The signals increased linearly with AFP concentrations in the range of0.01-100ng mL-1. The detection limit for AFP was4.6pg mL-1. The immunosensor was applied for the analysis of clinical serum samples, receiving a good agreement with ELISA.