A Simple, Stable and Picomole Level Lead Sensor Fabricated on DNA-based Carbon Hybridized TiO2 Nanotube Arrays

An electrochemical lead sensor is developed on DNA-based vertically aligned conductive carbon hybridized TiO2 nanotube arrays (DNA/C-TiO2 NTs). The designed DNA/C-TiO2 NTs sensor is superior in determination of lead with high sensitivity, selectivity and repeatability, as well as wide pH adaptability, fast electro-accumulation capacity for lead and easy regeneration. Such remarkable characteristics for lead sensing are attributed to the immobilization of abundant target biomolecules, DNA, and the enhanced bioelectrochemical activity. The controllable carbon hybridization of the TiO2 NTs increases the conductivity of the electrode, while retaining the tubular structure, biocompatibility, and hydrophilicity. The results show that the lead sensor possesses a wide linear calibration ranging from 0.01 to 160 nM with the detection limitation at a picomole level (3.3 pM). The application of the present sensor is realized for determination of Pb2+ in real water samples.