Nano-p–n junction heterostructure TiO2 nanobelts for the electrochemical detection of anticancer drug and biointeractions with cancer cells

Abstract

Nano-p–n junction heterostructures based on TiO₂ nanobelts with enhanced (001) facets were produced by assembling p-type semiconductor NiO nanoparticles on n-type surface-coarsened TiO₂ nanobelt surfaces. The heterostructures were then used as the sensing electrode for the electrochemical detection of anticancer drugs O⁶-benzylguanine (O⁶BG) and lung cancer cells. O⁶BG exhibited an irreversible diffusion-controlled electrochemical process with an oxidation peak clearly identified at +0.78 V. For lung cancer cells one oxidation peak was found at +1.1 V and two reduction peaks at +0.30, and +0.90 V. These voltammetric features disappeared when O⁶BG was added to the lung cancer cells, which was ascribed to the structural changes of the cell membranes caused by the anticancer drug. These results suggested that nano-p–n junction heterostructures based on TiO₂ nanobelts might serve as promising candidates for biosensing applications of anticancer drugs and tumor cells that will be of significance in diagnostic medicine, cancer diagnosis and molecular biology research.