Bioinspired preparation of polydopamine microcapsule for multienzyme system construction

Inspired by the structural organization of mitochondria and the bioadhesive principle, a simple and versatile approach to construct a multienzyme system is developed. More specifically, the multienzyme system is composed of a polydopamine (PDA) microcapsule scaffold and three spatially separated enzymes. The PDA microcapsules are prepared through the rapid, spontaneous self-polymerization of dopamine on the surface of CaCO3 microparticle template, followed by dissolution of the template using EDTA. The wall thickness of the microcapsules can be tuned by the dopamine concentration in an aqueous solution. The three enzymes are respectively immobilized through physical encapsulation in the lumen, in situ entrapment within the wall and chemical attachment on the out surface under extremely mild conditions. As an example, a multienzyme system, containing α-amylase, β-amylase and glucosidase, was constructed to convert starch into isomaltooligosaccharide, and the multienzyme system displays higher catalytic activity and enhanced operational stability. The method developed in this study will establish a powerful platform for the facile construction of multienzyme cascade systems.