Titania Nanotube Array Sensor for Electrochemical Detection of Four Predominate Tuberculosis Volatile Biomarkers

Detection of specific breath-based volatile organic biomarkers (VOBs) directly associated with a pulmonary disease like tuberculosis presents itself as a potential non-invasive, and point-of-care (POC) medical diagnostic technique. In this work, highly ordered titania nanotubular arrays (TNA) synthesized through electrochemical anodization and functionalized with cobalt, was utilized as a robust sensing platform for electrochemical detection (amperometric mode) of four prominent tuberculosis volatile biomarker. The limit of detection of the sensor was determined to be similar to 0.018 ppm VOBs, with the sensor exhibiting higher selectivity toward the VOBs over other organics commonly found in breath. The sensor response theory modeled using Butler-Volmer kinetics at high overpotentials (Tafel behavior) corroborates well with experimentally derived signal responses. Of the four VOBs examined, methyl p-anisate exhibits the maximum current response (81 mu A), while methyl nicotinate demonstrates the fastest reaction kinetics, or response time (35 seconds). The development of functionalized 1D nanostructured metal oxide semiconductor based sensors demonstrates enhanced sensor response with rapid detection times appropriate for POC disease diagnosis. (C) 2016 The Electrochemical Society.