An ultrasensitive non-enzymatic amperometric glucose sensor based on a Cu-coated nanoporous gold film involving co-mediating

In this work, we constructed an ultrasensitive non-enzymatic amperometric glucose sensor based on a Cu-coated nanoporous gold film (Cu/NPGF) for the first time, which comprised two pairs of electron mediators, Cu(II)/Cu(III) and Au/Au(I). The nanoporous gold film with high roughness (R=136) was prepared by anodic potential step and the very thin Cu coating into/on the nanoporous Au was electrodeposited at constant current. In comparison with electrodeposited Cu on a smooth gold surface and with the nanoporous Au, the prepared Cu/NPGF showed significantly enhanced electrocatalytic activity for the oxidation of glucose around 0.1 V due to its nanoporous structure and the pronounced co-mediating of Cu(II)/Cu(III) and Au/Au(I), as well as their coupling Cu(III) + Au = Cu(II)+Au(I). The Cu functionalized NPGF electrode also exhibited an extraordinary performance in sensing glucose with a wide linear range (2 mu M-8.11 mM), short response time (3 s), ultrasensitivity (3643 mu AmM-1 cm(-2)), low detection limit (0.59 mu M), good anti-interference and anti-toxicity, long-term stability (over 3 weeks), and satisfactory quantification of glucose concentration in human serum. We expect that functionalization of nanoporous gold films will provide a new platform for electrochemical sensors. (C) 2014 Elsevier B.V. All rights reserved.