Design and Assembly of Continuous Macro-Micro-Porous Metal-Organic Framework Film Assisted by Atomic Layer Deposition for Biosensing

Constructing highly oriented and ordered macro-pores on metal-organic framework (MOF) film can surpass the inherent limitations from micro-pores, promote multiphase adsorption, and expedite electrochemical reaction, but the fabrication remains extremely challenging. Here, continuous macro-micro-porous MOF films are achieved by combining polystyrene microsphere template and induction effect of ZnO nanomembrane prepared by atomic layer deposition. In addition to the intrinsic micro-pores, the fabricated MOF film exhibits oriented and ordered macro-porous structures. Compared with the macro-porous MOF particles and conventional MOF film, the mass diffusion and charge transportation in the macro-micro-porous MOF film are significantly improved, endowing the film with excellent electrochemical activity. The sensor device made from macro-micro-porous ZIF-67 film toward glucose exhibits excellent performance, e.g., high sensitivity, low limit of detection, and fast response, due to rapid glucose molecule diffusion and enhanced exposure of active sites via interconnected macro-porous channels. This work paves the way for the application of MOF film in high-performance biosensor chip and therefore may have great potential in post-Moore period.