Enzyme‐Loaded Fe ³⁺ ‐Modified Polydopamine Microparticles: Bioreactor Systems for Operating Biocatalytic Cascades, Enantioselective Transformations and Sensor Applications

We report on the synthesis of Fe 3+ ‐modified porous polydopamine microparticles acting as peroxidase mimicking frameworks. The nanozyme microparticles catalyze the H 2 O 2 oxidation of dopamine to aminochrome, or the oxidation of NADH to NAD + . Loading of the Fe 3+ ‐polydopamine microparticles with enzymes yields bioreactor systems enabling the operation of biocatalytic cascades in confined microenvironments. This is exemplified with the loading of glucose oxidase (GOx) in the Fe 3+ ‐modified polydopamine (Fe 3+ ‐PD), enabling the operation of the GOx/Fe 3+ ‐PD catalytic cascade, or by the integration of acetylcholine esterase (AChE) and choline oxidase (ChOx) in the Fe 3+ ‐PD framework, enabling the operation of the AChE/ChOx/Fe 3+ ‐PD cascade. In addition, the synthesis of chiral Fe 3+ ‐modified poly(L‐DOPA) and Fe 3+ ‐modified poly(D‐DOPA) particles leads to the chiroselective H 2 O 2 catalyzed oxidation of L/D‐DOPA.