Lactate is an important downstream product of glycolysis in living cells, and its level is highly related with diseases. On the basis of amorphous metal-organic frameworks (aMOFs), a multienzyme system consisting of lactate oxidase (LOx) and horseradish peroxidase (HRP) was established for intracellular lactate detection. By coencapsulation in aMOFs with proximity, LOx and HRP were delivered into cells, serving as artificially constructed organelles, exhibiting high activity and selectivity for the intracellular detection of the important metabolite lactate, which improved the signal to noise ratio by ∼650-fold. As demonstrated by both experimental and simulation results, the high efficiency was attributed to the short distance between the two types of enzymes coencapsulated in aMOFs. The concept of constructing multienzyme systems in this study shows promise for the detection of various intracellular metabolites.
Keywords: enzyme cascade; enzyme catalysis; lactate; metal−organic frameworks; tumor cell detection.