Interfacial engineering of MOF-electroactive microorganism biohybrids: Extracellular electron transfer and...

The inadequate efficiency of extracellular electron transfer (EET) between electroactive microorganisms (EAMs) and abiotic electrodes represents a fundamental limitation on the energy conversion efficiency of bioelectrochemical systems (BES). Most current strategies aimed at enhancing EET focus on optimizing isolated components-either materials or microorganisms-often neglecting the multiscale regulation of the biotic-abiotic interface. This oversight hinders efforts to fundamentally overcome the thermodynamic and kinetic constraints associated with the EET process. Metal-organic frameworks (MOFs), characterised by their precisely tunable pore structures and designable redox-active centres, offer promising materials for reconfiguring synergistic biotic-abiotic interfaces and addressing these challenges. However, direct evidence for MOF-microbe orbital coupling remains limited, making it a key research gap rather than a confirmed mechanism. We systematically examine the latest advancements in the coupling system of MOFs and EAMs. We analyse the functional evolution of MOFs, which transition from serving as passive protective shells for microorganisms to acting as active regulators of extracellular electron transfer in EAMs. Furthermore, we elucidate the synergistic regulatory mechanisms inherent in this coupling system. Unlike existing reviews that predominantly summarise synthesis methods and performance characterisation results of MOFs, this review critically addresses the core challenges and engineering barriers encountered in the practical application of this system within real-world environments, with a particular focus on interface engineering. We integrate practical applications of this system across several cutting-edge fields and reveal the underlying principles of interface engineering that enhance system stability and resistance by comparing the constitutive relations of various coupled systems. Finally, in light of the current challenges faced by these biohybrid systems, we delineate potential avenues for future breakthroughs.