Synthesis and functionalization of carbon nanotubes and nanospheres as a support for the immobilization of an enzyme extract from the mushroom Trametes versicolor

In this work, an enzyme extract immobilization over carbon nanomaterials is presented; that is, carbon nanospheres (CNSs), and multi-walled carbon nanotubes (CNTs), using covalent bonds with glutaraldehyde as a crosslinking compound. Carbon nanostructures were obtained by chemical vapor deposition using an iron-cobalt powder alloy prepared by the sol-gel process and using silica powder as support. Acetylene gas was used as carbon carrier to prepare both the CNTs and CNSs. Both nanostructures were oxidized with an acid treatment in order to add functional groups to the surface and subsequently immobilize the enzymes. Carbon nanostructures were characterized using scanning electron microscopy, infrared spectroscopy and Raman spectroscopy to confirm oxidation, immobilization and structural properties. Electrochemical impedance spectroscopy revealed that carbon nanostructures improve the electron transfer of the electrode. Finally, the cyclic voltammetry provided information about the redox process before and after immobilization. Even more, the catalytic activity of the enzymes extract was evaluated showing that CNSs are the best support.