Novel dual-sensor for creatinine and 8-hydroxy-2'-deoxyguanosine using carbon-paste electrode modified with molecularly imprinted polymers and multiple-pulse amperometry

Abstract

We present a novel amperometric dual-imprinted sensor for simultaneous determination of creatinine (Cre) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in human urine and serum. The sensor used multiple-pulse amperometric detection in flow injection analysis (MPA-FIA). Copper oxide nanoparticles were coated with the Cre molecularly-imprinted polymer (CuO@MIP), using methacrylic acid as the functional monomer and N, N′-(1,2-dihydroxyethylene) bis-acrylamide as cross-linker. For 8-OHdG sensing, we embedded platinum nanoparticles in reduced graphene oxide and then coated it with guanosine poly-dopamine MIP (PtNPs-rGO@MIP). A carbon-paste electrode (CPE) was then formed containing both nanocomposites to give the dual MIP sensor (CuO@MIP and PtNPs-rGO@MIP/CPE). We developed a dual-potential waveform as a function of time, with Edet.1 (+0.4 V/150 ms) to determine Cre selectively and Edet.2 (+0.6 V/250 ms) to analyze both compounds simultaneously (Cre and 8-OHdG). Subtracting the two signals at 0.6 V and 0.4 V (using a correction factor), respectively, from each other allowed for quantifying 8-OHdG without interference from Cre. The MIP sensor has a linear range of 0.5–150 μM for creatinine and 0.005–50 μM for 8-OHdG, with limits of detection in nano-molar level. The proposed method is successfully applied for the simultaneous determination of Cre and 8-OHdG in urine and serum samples.