Assembly of MOF Microcapsules with Size-Selective Permeability on Cell Walls

The assembly of metal-organic frameworks (MOFs) into microcapsules has attracted great interest because of their unique properties. However, it remains a challenge to obtain MOF microcapsules with size selectivity at the molecular scale. In this report, we used cell walls from natural biomaterials as non-toxic, stable, and inexpensive support materials to assemble MOF/cell wall (CW) microcapsules with size-selective permeability. By making use of the hollow structure, small pores, and high density of heterogeneous nucleation sites of the cell walls, uniform and continuous MOF layers could be easily obtained by inside/outside interfacial crystallization. The prepared MOF/CW microcapsules have excellent stability and enable the steady, slow, and size-selective release of small molecules. Moreover, the size selectivity of the microcapsules can be adjusted by changing the type of deposited MOF.