A Point-of-care Diagnostics Logic Detector Based on Glucose Oxidase Immobilized Lanthanide Functionalized Metal-organic Frameworks
In this work, a novel lanthanide functionalized metal organic frameworks enzyme (L-MOFs-enzyme) composite has been first prepared via a surface attachment strategy between Eu3+@UMOF and glucose oxidase (GOx). Here, Eu3+@UMOF can be used as a support for GOx immobilization and also a responsive fluorescent center towards glucose (Glu). The resultant material not only presents a fascinating luminescent properties based on the 5D0→7F2 transition of Eu3+ and the catalytic performance of enzyme, but also some advantages of MOF-enzyme composites, including better stability, and great fluorescent selectivity and sensitivity towards Glu (detection limit = 0.2 μM). Besides, the composite exhibited an excellent selectivity and sensitivity towards Glu in the serum and urine under room temperature and neutral conditions, which break the limitation of specific catalytic conditions of enzymes. Taking all the advantages of the L-MOF-enzyme composite, a point-of care (POC) diagnostics logic detector which can fluorescent detect of Glu in urine was designed. From the three outputs of the logic detector (L, M and H), we can intuitively self-diagnosis of the three range of Glu concentrations that as the inputs of the detector (0.1 μM~10 μM, 10 μM~10 mM, > 10 mM) by naked eye. The logic detector allows us, especially diabetics, to instantly detect glucose levels in the urine without going to the hospital for complicated inspections. It is the first attempt using L-MOFs combined with GOx to construct a POC diagnostics logic detector for fluorescent detecting of Glu.