Apoferritin‐templated biosynthesis of manganese nanoparticles and investigation of direct electron transfer of MnNPs–HsAFr at modified glassy carbon electrode

Manganese nanoparticles (MnNPs) were created within horse spleen apoferritin (HsAFr) cavity nanotemplates. Transmission electron microscopy revealed the particle size to be 6 nm. Intrinsic fluorescence data showed that the mineralization acted as a quencher of the HsAFr fluorescence, and extrinsic fluorescence data revealed that the hydrophobic binding site at the surface of HsAFr was not changed. Finally, the MnNP‐HsAFr was immobilized onto multiwalled carbon nanotubes entrapped into chitosan (CS) matrices by through sequential 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide–N‐hydroxysuccinimide and glutaraldehyde coupling. The MnNPs–HsAFr immobilized on CNT‐CS/GC electrode was characterized by cyclic voltammetry. This charge transfer coefficient (α) and the exchange current (i0) of MnNPs–HsAFr immobilized on modified electrode in 0.1 M phosphate solution (pH 7.5) were found to be 0.57 and 0.48 μA, respectively.