BACKGROUNDThe substrate materials of enzyme electrodes strongly affect bioelectrocatalytic activity. TiO2 nanotube arrays (NTAs) show good affinity to glucose oxidase (GOx) but low conductivity. TiN NTAs show good conductivity but low affinity to GOx. Nitrogen-doped TiO2 (N-TiO2) NTA with good hydrophilicity and conductivity was designed to prepare a GOx/N-TiO2 NTA enzyme electrode to promote bioelectrocatalytic performance. RESULTSN-TiO2 NTA had a well-ordered nanoarray structure with slightly distorted pore mouth and wrinkled nanotube wall. N-TiO2 NTA exhibited decreased charge transfer resistance and similar contact angle to TiO2 NTA, presenting high electrical conductivity and good hydrophilicity. GOx/N-TiO2 NTA exhibited highly increased current response at a potential of -0.45 V, presenting good bioelectrocatalysis towards glucose. A GOx/N-TiO2 NTA enzyme electrode was used to fabricate a glucose biosensor, showing a high sensitivity of 733.17 mu A mM(-1) cm(-2) and a linear range of 0.05-0.85 mmol L-1 and low detection limit of 2.9 mu mol L-1 for glucose determination. It exhibited high selectivity in the presence of common interfering substances and was used to determine glucose in serum. It also had good reproducibility and long-time storage stability. In addition, the GOx/N-TiO2 NTA enzyme electrode was used to fabricate a glucose fuel cell, showing maximum power density of 23.92 mu W cm(-2) as well as good bioelectrocatalytic stability. CONCLUSIONHigh bioelectrocatalytic activity and stability of GOx/N-TiO2 NTA proved that N-TiO2 NTA could act as a reasonable supporting substrate material for enzyme electrodes for various bioelectrocatalytic applications. (c) 2015 Society of Chemical Industry