Advances of Prussian blue and its analogues in (bio)sensors

Abstract

The aim of the present article is to review the current state of knowledge concerning advances of Prussian blue and its analogues in chemical and biological sensors. Despite deposition of these materials has been already discussed, an appearance of recent articles presenting poorly synthesized transition metal hexacyanoferrates, causes review of the synthetic procedures. The significance of Prussian blue for (bio)sensors is provided by its unique catalytic properties: both catalytic activity and selectivity in hydrogen peroxide reduction are >1000 times higher compared to platinum, whereas clinical analyzers and low-invasive monitors are equipped with Pt-based biosensors. Non-iron (nickel, cobalt, cupric etc.) hexacyanoferrates are catalytically inactive, however, they are highly attractive for stabilization of Prussian blue resulting in synthesis of the ‘super-stable’ Prussian blue-based electrocatalyst. The protocol for enzyme immobilization from water–organic mixtures with a high content of organic solvent is discussed. Combination of the most advantageous electrocatalyst (Prussian blue) and the improved immobilization protocol results in elaboration of the advanced biosensors. Their unique sensitivity, selectivity and operational stability (even compared with platinum-based ones) provide application for non-invasive diagnostics.