Myoglobin immobilized on Fe3O4@SiO2 magnetic nanoparticles: Direct electron transfer,enhanced thermostability and electroactivity

Myoglobin (Mb) has been successfully immobilized in alternation with oppositely charged poly(dimethyldiallylammonium chloride) via the sequential layering approach on the biocompatible Fe₃O₄@SiO₂ nanoparticles. The bound Mb could be easily separated by an external magnetic field and used as less costly, more stable, and reusable alternatives to the soluble ones. Direct electron transfer between the immobilized Mb and the electrode was observed. Moreover, the immobilized Mb provided remarkable thermostability up to 70 °C and high electroactivity with the apparent Michaelis–Menten constant (k_M) of 45 μM.