Immobilisation of cobaltferritin onto gold electrode based on self-assembled monolayers.

The iron storage protein, ferritin, has a cavity of ∼7 nm in diameter in which iron is oxidised and stored as a hydrated oxide core. Electron transfer is known to be an important step in the sequestering of iron by cellular ferritin. The cavity was used as a nanocontainer to grow cobalt nanoparticles. The immobilisation of ferritin on the electrode surface is essential for various bioelectronic applications. A cobaltferritin-immobilised electrode based on self-assembled monolayer (SAM)-modified gold electrode was developed. The cobaltferritin-immobilised SAM-modified electrode was characterised by electrochemical and atomic force microscopy (AFM) techniques. The results indicated that cobaltferritin was selectively immobilised onto succinimidyl alkanedisulfide-modified Au electrode by the covalent interaction between cobaltferritin and the terminal functional groups of the SAMs. The cobaltferritin immobilised modified electrode showed a direct electron transfer reaction between cobaltferritin and the electrode. The electrochemically regulated uptake and release of cobalts for cobaltferritin immobilised on the SAMs were demonstrated. The results obtained in this study indicate that cobaltferritin has potential for a biomaterial in nanoscale synthesis for potential magnetic, catalytic and biomedical-sensing applications.