Microperoxidase-11@PCN-333 (Al)/three-dimensional macroporous carbon electrode for sensing hydrogen peroxide

In this work, a novel hydrogen peroxide (H2O2) biosensor was developed based on the microperoxidase-11 (MP-11) encapsulated in metal-organic frameworks, PCN-333 (Al) (PCN stands for porous coordination network), which was grown on the three-dimensional (3D) kenaf stem-derived porous carbon (3D-KSC) firmly and uniformly. The ball-flower-like PCN-333 (Al) with mesopores of 5.5 nm was especially suitable for encapsulating MP-11 (1.1 x 1.7 x 3.3 nm). Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to characterize the 3D-KSC electrode and the 3D-KSC/PCN-333 (Al)@MP-11 electrode. UV-vis spectroscopy was used for characterizing the encapsulation of MP-11 in the 3D-KSC/PCN-333 (Al) electrode. Cyclic voltammetry and differential pulse voltammetry were used to characterize the electrochemical behaviors and performance of the biosensor. The results showed that the encapsulated MP-11 molecules showed a better performance than free enzyme. Under the optimized experimental conditions, the resulted H2O2 biosensor exhibited a wide linear range from 0.387 mu M to 1.725 mM and a low detection limit of 0.127 mu M with good stability and high selectivity, which was superior to some H2O2 biosensors. (C) 2016 Elsevier B.V. All rights reserved.