“…Nanostructured metal oxides such as ZnO, Fe 3 O 4 , SnO 2 , CeO 2 , In 2 O 3 and others have recently aroused much interest as immobilizing matrices for chemo-biosensor development due to their interesting nanomorphological, functional, biocompatible and catalytic properties. [17][18][19][20] Further chemical doping with appropriate elements (Fe, Cr, Co, Mn, Ni, etc.) is widely used as an effective method to tune surface states, energy levels of semiconductors and transport performance of carriers, and enhance the electrical, electrochemical and magnetic properties of materials.…”