Optical Interference of TiO2 Nanotube Arrays for Drug Elution Sensing

TiO2 nanotube arrays with a highly-ordered porous structure have attracted a significant amount of attention for their use as interferometric biosensors, and in this study, TiO2 nanotube arrays were implemented in a porous sensing chip for such applications. The interference spectrum was converted into the optical thickness using the Fourier transform, and drug elution was detected through a change in the optical thickness in real time. The sensitivity to the drug improved through the fabrication and optimization of TiO2 nanotube arrays with various structures. The TiO2 nanostructure with a diameter of similar to 110 nm and a length of similar to 3.579 mu m achieved the best performance. The optimum structure was obtained at 60 V, similar to 40 min, and 0.50 wt% of NH4F 8.16 vol% of water in ethylene glycol, and the thickness and pore diameter of the porous TiO2 arrays were measured and confirmed via FESEM and spectroscopic liquid infiltration. The elution of ibuprofen from the TiO2 nanotube arrays exhibited a change in the optical thickness of 5 nm for about 28.5 hr.