The materials, methods for preparing DNA–invertase conjugate, additional characterization data, and detailed methods for sensor preparation and target detection are described in the Supplementary Information. Briefly, the DNA–invertase conjugates were prepared by using either sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (sulfo-SMCC) or p-phenylene diisothiocyanate (PDITC) as the linker between the DNA and invertase, and were further characterized by both native and sodium dodecyl sulfate polyacrylamide gel electrophoresis (~4–20% gradient). The MBs used for target detection were prepared by immobilization of the biotin-modified DNAs onto the streptavidin-coated MBs and subsequent addition of the functional DNAs and DNA–invertase conjugates. Target detection was conducted by adding the sample solution to the MBs prepared as above, separating the MBs using a magnet, mixing the remaining solution with sucrose, and then measuring the final solution using a commercially available PGM.