Hierarchically-structured immobilized enzyme displaying the multi-functions of bio-membranes

Abstract

In this work, a hierarchically-structured immobilized enzyme is reported, without any damage or chemical modification to proteins involved in the immobilization, while the elution of physically adsorbed proteins was completely avoided. The hierarchical architecture is composed of the protein-encapsulated silica-anodic aluminum oxide (AAO) membrane with a mesoporous nano-particle (MNP) film coated on the membrane surface. This rationally integrated architecture displays size-selective permeability to substrate and product molecules which are much smaller than proteins in size, and allows the bio-catalytic transformation of substrates and the continuous transportation of products, resembling the multiple functions of bio-membranes working in a continuous and controllable process. A scratch test and 20 catalytic cycles indicate the excellent structural and reusable stability of this hierarchical architecture.