Electrochemical sensor based on surface modification of graphene nanosheets with gold nanoparticles for determination of 5-fluorouracile anticancer drug

In this paper, we selected electrochemical strategy to determination of 5-fluorouracile by graphene-Au NPs nanocomposites-modified glassy carbon electrode (GN/Au NPs/GCE). 5- Fluorouracil (5-FU) is an anti-neoplastic agent, it has been used for the treatment of solid tumors of the breast and rectum [1]. It is also used in treatment of colorectal cancer, and pancreatic cancer. High over voltage of drugs, especially cancer drugs, at a bare electrode suggested necessary modification of electrodes with conductive materials such as polymers, electroactive mediator and nanocomposites [2, 3]. Graphene together with its, various derivatives, such as graphene oxide, graphene nanoribbon, chemically reduced graphene oxide [4, 5] has shown fascinating advantages in electrochemistry such as electrochemical devices and capacitors due to its remarkable electrochemical properties. Especially, a chemically reduced graphene nanosheet (cr-Gs) is popular and robust in bioelectrochemistry communities because of its easy functionalization, rich surface chemistry, and biocompatibility [6-8]. Many efforts have been devoted to improve the capability of cr-Gs through association of cr-Gs with metallic nanoparticles. Gold nanoparticles are always considered as an advanced candidate due to their amazing surface properties and quantum-mechanical rules with diameters less than 10 nm [9, 10]. For example, graphene-Au NPs (GN/Au NPs) nanocomposites have been used as substrates of surface enhanced Raman scattering (SERS), hydrogen peroxide sensor and monolayer graphene fabrication [11-13]. On the basis of the outstanding properties of GN/Au NPs nanocomposites in electronics and chemistry, it is highly desired to be used as the sensing platform in electrochemical biosensors for sensitive detections. Herein, the electrochemical behavior of 5-FU was investigated employing cyclic voltammetry (CV), chronoamperometry (CA) and 262 electrochemical impedance spectroscopy (EIS). After optimization of experimental conditions, the electro-oxidation peak currents for 5-FU at pH 9.0 phosphate buffer solution was found to vary linearly with its concentrations in the range of 0.1–50.0 μM using differential pulse voltammetry (DPV) method. The detection limit is 0.04 μM. Furthermore, GN/Au NPs/GCE was successfully applied for the analysis of 5-FU in blood serum samples with recovery 100.5% and 99.23% respectively. The modified electrode showed good stability and repeatability.