Enzyme Immobilization in Porous Crystals via Cage Encapsulation

Enzyme immobilization within solid or polymer matrices continues to face challenges, such as inhomogeneous protein environments, low loading efficiency, and limited versatility. Here, we present a pre-encapsulation strategy for enzyme immobilization in porous crystals via coordination cage encapsulation. In this approach, enzymes are first confined within the well-defined cavities of spherical coordination cages prior to crystallization. The host cage framework facilitates crystal formation under almost uniform conditions, independently of the surface properties of the enzymes. This isomorphous crystallization enabled the successful immobilization of nine proteins with diverse sizes and properties, achieving high loading efficiencies. The immobilized enzymes retained their native structures and catalytic activities within the crystal, functioning as heterogeneous catalysts with enhanced stability. Furthermore, the co-immobilization of two enzymes in close proximity facilitated cascade reactions, underscoring the potential of coordination cages as effective hosts for enzyme immobilization.