Metal-organic frameworks in the biomedical sector: properties, challenges, and future frontiers

Nano-metal-organic frameworks (nMOFs) represent a dynamic frontier in nanoscale coordination chemistry, offering exceptional control over composition, structure, and functionality. This review provides a material-chemistry-centric perspective on the evolution of nMOFs from coordination assemblies to practical biomedical materials. We aim to outline the conceptual foundations of nMOFs, with an emphasis on variations in coordination geometry, ligand functionality, synthesis parameters, and their effects on framework morphology, defect chemistry, and stability. Briefly, key synthesis strategies are discussed in the context of how the reaction parameters govern the crystal morphology, size, stability and functionality, and the tunable physicochemical properties, such as surface area, porosity, and high crystallinity, which demonstrate their versatility as viable candidates for drug delivery, biosensing, biocatalysis, imaging, tissue engineering, etc. Special focus is given to the biodistribution, degradation, and clearance of nMOFs to bridge the gap between coordination design and physiological behaviour and to address the major barriers to clinical translation. In addition, this review briefly highlights other applications of nMOFs, including catalysis, gas storage and environmental systems, thereby emphasising the cross-disciplinary relevance of nMOF chemistry. This review provides a comprehensive overview of current research prospects, identifies critical knowledge gaps, and outlines future directions for the development of efficient and functional nMOFs.