Titanium dioxide nanotube based sensing platform for detection of mycobacterium tuberculosis volatile biomarkers methyl nicotinate and p-anisate

This research presents a metal functionalized titanium dioxide (TiO₂) nanotube based sensor developed for detection of volatile biomarkers (methyl p-anisate and methyl nicotinate) associated with tuberculosis (TB). In this work self-aligning TiO₂ nanotubes were fabricated, and functionalized with cobalt for specific binding to the volatile biomarkers of interest. Mimics of the volatile biomarkers were dissolved in water at variable concentrations, and nitrogen gas was flowed through the biomarker solutions and delivered to the sensor. A potentiostatic scan was used to measure current across the device under constant potentials ranging from -1.0 volts to 1-volts methyl nicotinate and methyl p-anisate. The sensor response showed a 3 × 10⁵ change in current for methyl nicotinate, and 7.61 × 10⁶ change in current for methyl p-anisate when compared to baseline. The sensor also showed little response to five other VOCs (acetone, ethanol, methanol, benzene, and phenol) which suggest the sensor is functionalized to be specific for the target VOCs associated with TB. Results showed detection of the volatile biomarkers yield orders of magnitude change in current which is detected easily. The sensor is simple to operate, responds in minutes, and has potential applications in non-invasive diagnosis of TB and other diseases that have distinct volatile biomarkers.