Covalent functionalization of zinc oxide nanowires for high sensitivity p-nitrophenol detection in biological systems

High-quality zinc oxide (ZnO) nanowires were synthesized using the atmospheric chemical vapor deposition technique and were appropriately characterized. Subsequently, the nanowire surface was covalently grafted with 1-pyrenebutyric acid (PBA) fluorophore, and surface-sensitive X-ray photoelectron spectroscopy and Fourier transform infrared-attenuated total reflectance spectroscopy were utilized to confirm the functionalization of 1-pyrenebutyric acid on the nanowire surface. Additionally, photoluminescence (PL) measurements were used to evaluate the optical behavior of pristine nanowires. Through fluorescence quenching of 1-pyrenebutyric acid by p-nitrophenol, a detection limit of 28 ppb was estimated. Based on these findings, ZnO nanowires functionalized with 1-pyrenebutyric acid are envisaged as extremely sensitive platforms for the ultra-trace detection of p-nitrophenol in biological systems.

► High quality synthesis of ZnO nanowires through a CVD process and characterization.
► Covalent functionalization with fluorescent receptor to produce novel hybrid organic–inorganic system.
► Surface sensitive XPS results are analyzed to deduce proof of covalent functionalization.
► Detection limit of 28 ppb estimated for sensor through fluorescence studies.
► Highly sensitive and selective sensing platform design is proposed based on empirical findings.