Application of metal-organic framework (MOF)-based enzymatic amplification strategy for the sensitive electrochemical detection of tuberculosis

Abstract

Herein, a small molecule, hemin/G-quadruplex (G4-hemin), was physically embedded into NH2-MIL-53 (Al) to construct a novel metal-organic framework (MOF)-based enzyme (G4-hemin@MOF). Its catalytic activity and stability were investigated in detail by catalyzing a reaction of 3,3′,5,5′-Tetramethylbenzidine (TMB) in the presence of H2O2. The results show that the activity and stability of this new enzyme is better than that of traditional hemin or G4-hemin, and even stronger than that of hemin@MOF (G4-hemin@MOF > G4-hemin > hemin@MOF > hemin). No significant loss in catalytic activity was observed for at least one day. Even after eight days, only a 13.8 % decrease in activity was recorded. An electrochemical biosensor was successfully developed based on a signal amplification strategy utilizing the catalysis of G4-hemin@MOF. The sensor was able to sensitively detect TB in buffer, even in a diluted solution of many proteins. The proposed method offers high selectivity against mismatch sequences of TB, a good linear response range of 10−18 moL L-1 to 10-14 moL L-1 and a low minimum detection limit of 0.330 aM.