Layered double hydroxide-hemin nanocomposite as mimetic peroxidase and its application in sensing

A novel mimetic peroxidase, layered double hydroxide (LDH)-hemin nanocomposite, was first prepared by immobilizing hemin between the nanosheets of Fe-Ni LDH obtained through hydrothermal method. It showed an improved peroxidase-like activity to H₂O₂ compared with hemin alone, which was proved by UV-Vis spectroscopy and electrochemical measurements. The electrochemical sensor based on Fe-Ni LDH-hemin nanocomposite exhibited a fast response to H₂O₂ with good linear range of 1-240 μM, a detection limit of 0.3 μM based on a signal-to-noise ratio of 3 and high selectivity. It performed better than the sensors based on HRP and hemin which were prepared in the same conditions. The high performance of the sensor made LDH-hemin nanocomposite a promising mimetic peroxidase to replace natural enzymes.