Synthesis, characterization, and biosensing application of ZnO/SnO2 heterostructured nanomaterials

In this work, zinc oxide/tin oxide (ZnO/SnO2) heterostructured nanomaterials were synthesized by hydrothermal method. Transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction measurements revealed that the product was composed of ZnO nanowires and SnO2 nanobranches. The novel ZnO/SnO2 heterostructured nanocrystals were for the first time used as a supporting matrix to explore a novel immobilization and biosensing platform of redox proteins. UV-visible absorption investigation indicated that hemoglobin (Hb) intercalated well in the ZnO/SnO2 heterostructured nanocrystals retained its native structure. Comparative experiments have confirmed that the ZnO/SnO2-based biosensor not only had enhanced direct electron transfer capacity but also displayed excellent electrocatalytic properties such as higher sensitivity and wider linear range to the detection of hydrogen peroxide in comparison with the ZnO- and SnO2-based biosensors.