Novel hierarchical composite electrode construction based on magnetic nanoparticles: Application for impedimetric thyroxine hormone determination in human blood samples

As a novel performance, silicon oxide was firstly loaded on Fe3O4 magnetic nanoparticles substrate (Fe3O4@SiO2), and then functionalized with -NH2 group (Fe3O4@SiO2@NH2). The resultant array was reacted with terephthalaldehyde schiff-base to fabricate novel hierarchical magnetic nano-composites. A sensitive sensor involving immobilized gold nanoparticles and nano-composites in electropolymerized polypyrrole was achieved. Cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) techniques were demonstrated the morphology of modified electrode s surface and electrochemical behavior of thyroxine on this platform. We believe that such kind of bio-devices possesses the prominent potential to trace determination of bio-compounds in biological fluids with excellent accuracy and precise analysis. This sensor covered a linear concentration range from 10 to 210 nM of thyroxine with the detection limit of 8 nM.