A novel lable-free electrochemical immunosensor for carcinoembryonic antigen based on gold nanoparticles–thionine–reduced graphene oxide nanocomposite film modified glassy carbon electrode

• Published in: Talanta (Oxford) 2011-10, Vol.85 (5), p.2620-2625
• Main Authors: Kong, Fen-Ying, Xu, Mao-Tian, Xu, Jing-Juan, Chen, Hong-Yuan
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Antibodies; Biosensing Techniques; Carcinoembryonic antigen; Carcinoembryonic Antigen - analysis; Chemistry; Electrochemical methods; Electrochemistry - instrumentation; Electrodes; Exact sciences and technology; General, instrumentation; Gold; Gold nanoparticles; Graphite - chemistry; Label-free; Metal Nanoparticles; Microscopy, Electron, Scanning; Reduced graphene oxide; Reproducibility of Results; Spectrometric and optical methods; Spectrophotometry, Ultraviolet; Thionine
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2011.08.028

► Gold nanoparticles–thionine–reduced graphene oxide (GNP–THi–GR) nanocomposites synthesized using THi molecules as interlinkers. ► GR has unique electrical conductivity, enlarged active surface area. ► THi has excellent redox activity. ► GNPs has large specific surface area, excellent biocompatibility, extraordinarily catalytic activity, good conductivity. ► The nanocomposites combined with the advantages of the three species suitable for a label-free immunosensor. In this paper, gold nanoparticle–thionine–reduced graphene oxide (GNP–THi–GR) nanocomposites were prepared to design a label-free immunosensor for the sensitive detection of carcinoembryonic antigen (CEA). The nanocomposites with good biocompatibility, excellent redox electrochemical activity and large surface area were coated onto the glassy carbon electrode (GCE) surface and then CEA antibody (anti-CEA) was immobilized on the electrode to construct the immunosensor. The morphologies and electrochemistry of the formed nanocomposites were investigated by using scanning electron microscopy (SEM), ultraviolet–visible (UV–vis) spectrometry, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). CV and differential pulse voltammetry (DPV) studies demonstrated that the formation of antibody–antigen complexes decreased the peak current of THi in the GNP–THi–GR nanocomposites. The decreased currents were proportional to the CEA concentration in the range of 10–500pg/mL with a detection limit of 4pg/mL. The proposed method was simple, fast and inexpensive for the determination of CEA at very low levels.