Ficin encapsulated in mesoporous metal-organic frameworks with enhanced peroxidase-like activity and colorimetric detection of glucose

Ficin has been reported to possess peroxidase activity, but its applications in some respects have been limited because of its relatively low activity. Herein, a mesoporous metal-organic framework, PCN-333(Fe), was synthesized, which was selected to encapsulate ficin to form ficin@PCN-333(Fe). Compared with ficin, the peroxidase-like activity of ficin@PCN-333(Fe) toward 3,3',5,5'-tetramethylbenzidine (TMB) oxidation was about 3 times increase in the presence of H2O2, and followed classical Michaelis-Menten model. The kinetic parameters showed that stronger affinity and higher catalytic constant (K-cat) of ficin@PCN-333(Fe) to both TMB and H2O2 compared with ficin, and K-cat of ficin@PCN-333(Fe) was increased by 3.65 folds and 3.59 folds for TMB and H2O2. respectively. Taking advantages of higher catalytic property of licin@PCN-333(Fe), we developed a colorimetric method with high sensitivity and selectivity to detect glucose, which displayed a good linear response toward glucose in the range of 05-180 mu M with a limit of detection of 97 nM. Furthermore, ficin@PCN-333(Fe) has been proven to successfully detect glucose in human serum, implying its great potentialities and wide applications as peroxidase mimics. (C) 2020 Elsevier B.V. All rights reserved.