Graphene oxide derivatives with variable alkyl chain length and terminal functional groups as supports for stabilization of cytochrome c

• Graphene oxide derivatives are suitable scaffolds for cytochrome c immobilization.
• The structure of functional groups of derivatives affect the immobilized protein.
• The immobilized protein exhibit increased tolerance against denaturing agents.
• The immobilized protein exhibit increased thermal and operational stability.

In this study we report the ability of reduced and non-reduced graphene oxide-based nanomaterials (GONs), modified with variable alkyl chain length and terminal functional groups, to act as effective scaffolds for the immobilization of cytochrome c (cyt c) using different immobilization procedures. The GONs/cyt c conjugates are characterized by a combination of techniques, namely atomic force microscopy, X-ray photoelectron and FT-IR spectroscopies as well as thermo-gravimetric and differential thermal analysis. The effect of the structure of functional groups and the surface chemistry of GONs on the immobilization efficiency, the peroxidase activity and the stability of the cyt c was investigated and correlated with conformational changes on the protein molecule upon immobilization. The enhanced thermal stability (up to 2-fold) and increased tolerance (up to 25-fold) against denaturing agents observed for immobilized cyt c, indicates that these functionalized GONs are suitable as nanoscaffolds for the development of robust nanobiocatalysts.