Click chemistry on azide-functionalized graphene oxide

Chemical functionalization of graphene oxide represents a major challenge in chemical engineering with the aim of both improving the properties of the material while generating versatile platforms with a broad range of applications. The development of electrochemical (bio)sensors requires the controlled and rational immobilization of molecules as a key step in the enhancement of analytical performance. Click chemistry reactions represent an important strategy for the covalent linking of different compounds on a substrate via complementary azide or alkyne groups. The mild reaction conditions allow the preservation of the properties of biomolecules, while the orientation towards green chemistry enables a new range of biomedical applications. The azide group was inserted in the graphene oxide backbone by chemical functionalization and the resulting product was characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy and electrochemical impedance spectroscopy. The successful synthesis of the graphene-azide platform was also validated by electrochemical methods performed after clicking ethynylferrocene, an electroactive model molecule. The results show that this new approach is a versatile method for the covalent immobilization of biomolecules.