Electrophoretically deposited reduced graphene oxide platform for food toxin detection

Abstract

Reduced graphene oxide (RGO) due to its excellent electrochemical properties and large surface area, has recently aroused much interest for electrochemical biosensing application. Here, the chemically active RGO has been synthesized and deposited onto an indium tin oxide (ITO) coated glass substrate by the electrophoretic deposition technique. This novel platform has been utilized for covalent attachment of the monoclonal antibodies of aflatoxin B1 (anti-AFB1) for food toxin (AFB1) detection. The electron microscopy, X-ray diffraction, and UV-visible studies reveal successful synthesis of reduced graphene oxide while the XPS and FTIR studies suggest its carboxylic functionalized nature. The electrochemical sensing results of the anti-AFB1/RGO/ITO based immunoelectrode obtained as a function of aflatoxin concentration show high sensitivity (68 μA ng(-1) mL cm(-2)) and improved detection limit (0.12 ng mL(-1)). The association constant (ka) for antigen-antibody interaction obtained as 5 × 10(-4) ng mL(-1) indicates high affinity of antibodies toward the antigen (AFB1).

Reduced graphene oxide–titania based platform for label-free biosensor

“…24 Briey, 1.5 g of graphite powder was pre-oxidized by reacting it with a mixture of 40 mL of 98% H 2 SO 4 , 5 g K 2 S 2 O 8 and 5 g of P 2 O 5 for 4 h at 80 C. The obtained suspension was washed with deionized water 4-5 times and dried at 50 C under vacuum. The pre-oxidized graphite was deoxidized by adding a mixture of concentrated H 2 SO 4 : H 3 PO 4 (180 : 13) with constant stirring.…”

“…The reduction of GO was performed using the two-step reduction procedure reported in previous work. 24 On its dispersion in deionized water, the pH of the solution was increased to $10 using 5 wt% sodium carbonate solution and sodium borohydride (NaBH 4 ) (400 mg) was directly added into the 200 mL GO suspension (1 mg mL À1 ) under magnetic stirring and kept at 80 C for 1 h, resulting in a color change from brown to black. The solid product was then puried with water and ethanol washing, followed by drying and re-dispersion in H 2 SO 4 at 120 C. This was then re-ltered through a 0.22 mm Dura pore membrane to yield RGO.…”

“…14 RGO has been utilized for the detection of aatoxin B1 using an electrochemical technique. 24 The metal oxide nanoparticles (MOsN) based nanocomposites with carbonaceous materials, including RGO, have been found to display improved electronic properties that play a vital role in the fabrication of electrochemical biosensors. [25][26][27][28] It has been reported that the use of MOsN and GO nanocomposites may result in improved biosensor efficacy compared to when a single component is used.…”

Nanostructured palladium-reduced graphene oxide platform for high sensitive, label free detection of a cancer biomarker

“…The intense peak at 11.4 corresponds to the (002) reection plane and the peak at 42 corresponds to the (001) reection plane of GO. 30 It is noteworthy that the diffraction peak at 26.4 corresponding to graphite is very weak, indicating the complete conversion of graphite into GO through the oxidative treatment (Fig. 2i).…”

“…The Mg 2+ ions adsorbed on the nanostructure provide adequate positive surface charges to enable a uniform lm deposition. 30 The deposited lm was removed from the suspension and washed with DI water followed by drying.…”