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Abstract: In the present work, using copper as an etching agent, a novel and easy method to prepare porous graphene nanosheet (P-GR) was reported. With a large number of pores, more acidic groups and edge defect sites (EDSs) compared with graphene (GR), the prepared P-GR was used as an electrochemical biosensing platform for the first time. Using voltammetry and amperometry as detection methods, some important electroactive compounds, including dopamine (DA), ascorbic acid (AA), uric acid (UA), epinephrine (EP), guanine (G), adenine (A), xanthine (XA), hypoxanthine (HX), hydrogen peroxide and β-nicotinamide adenine dinucleotide (NADH) were employed to study their electrochemical responses on P-GR modified glassy carbon electrode (P-GR/GCE). The results show that P-GR/GCE exhibits better electrochemical performance to these substances compared with GR modified glassy carbon electrode (GR/GCE) and edge plane pyrolitic graphite electrode (PGE). The remarkable electrochemical advantage of P-GR makes it a promising material in electrochemical biosensing field. [Copyright &y& Elsevier]

Developing electrochemical biosensor, particularly for high sensitive recognizing and detecting tumor marker at low level under benign conditions, is highly desired, but still remains a severe challenge. In this communication, we report a dual-signaling ratiometric method for sensitive detection of carcinoembryonic antigen (CEA) based on gold nanoparticles (Au NPs) functionalized Cu 2 S-CuS/graphene composite (Au-Cu 2 S-CuS/graphene) as the matrix material and carboxyl-Au nanoparticles (Au-COOH) functionalized mesoporous CeO 2 nanoparticles (Au-CeO 2 ) supported toluidine blue (TB) complex as signal label. The oxidation peak current of Cu 2 S-CuS decreases with the increase of CEA concentration, while the oxidation peak current of TB increases. The change of dual signals “Δ I = Δ I TB + |Δ I Cu2S-CuS |” (Δ I TB and |Δ I Cu2S-CuS | are the change values of the oxidation peak currents of TB and Cu 2 S-CuS, respectively) is used as the response signal for quantitative determination of CEA. Notably, the linear range is 0.001 ∼ 100 ng/mL with a detection limit of 0.78 pg/mL (S/N = 3). The ratiometric electrochemical system provides an extremely simple strategy for detecting tumor markers in a reliable, facile, sensitive, and specific manner, which has a promising application for quantitative detection of other tumor markers in clinical diagnosis. [ABSTRACT FROM AUTHOR]