Exquisitely designed magnetic DNA nanocompartment for enzyme immobilization with adjustable catalytic activity and improved enzymatic assay performance

Abstract The enzymatic activity and practical applications of immobilized enzymes were severely influenced by their location orientation and microenvironment, which played the key roles in maintaining the active conformation and accelerating the reaction process of the desired enzymes. Herein, we presented a general approach to prepare magnetic DNA nanocompartments for encapsulation of metabolic model cascade multi-enzymes, glucose oxidase (GOx) and horseradish peroxidase (HRP), through self-assembly. The enzymes were spatially confined in the well-designed DNA compartments, which were located at the gap areas of magnetic particles. Systematic studies indicated the proximity effect of the multi-enzymes and the high negative charge density microenvironment of the DNA compartments contributed to the high cascade activity together. In addition, the immobilization enzymes within magnetic DNA compartment remarkably increased the overall catalytic efficiency, operational stability, and reusability. The kcat of encapsulation multi-enzymes was 204 s−1, which was 16.6-fold higher than that of free enzymes. The immobilized enzymes were further applied for on-line visual detection of glucose with excellent selectivity, and the immobilized enzymes also showed relative high cytotoxicity towards Hela cells, demonstrating their promising prospect for biocatalysis and cancer starvation therapy.