MgFe-layered double hydroxide modified electrodes for direct electron transfer of heme proteins

In this study, the Fe-based layered double hydroxides (Mg3Fe LDH) were used to immobilize heme proteins including hemoglobin (Hb), myoglobin (Mb) and horseradish peroxidase (HRP) for fabrication of heme/Mg3Fe LDH film on glassy carbon electrode (Mg3Fe-heme/GCE). The possible role of iron in framework of LDH to promote direct electron transfer (DET) of heme proteins was investigated using an LDH containing non-iron as a reference. Hb was selected as a model protein for studying the electrocatalytic activity of immobilized heme in LDH film. The Mg3Fe-Hb/GCE displayed an enhanced electrocatalytic reduction towards H2O2. The biosensor showed a very low detection limit (0.036 μM) and apparent Michaelis–Menten constant (7.98 μM). This work outlines that Fe-based LDH modified electrode provides a promising platform for immobilization of heme proteins and development of sensitive biosensors.

► Low-cost Fe-based LDHs were facilely synthesized by the coprecipitation method.
► Direct electron transfer of heme were achieved at the heme-LDH modified electrodes.
► The biosensor displayed an enhanced electrocatalytic reduction towards H2O2.
► The biosensor showed a low detection limit and apparent Michaelis–Menten constant.