Metal-organic framework (MOF)-based nanomaterials for biomedical applications.

Metal-organic frameworks (MOFs) are compounds consisting of metal ions or clusters coordinated to organic ligands to form one-, two-, or three-dimensional structures. They are a subclass of coordination polymers (CPs), with the special feature that they are often porous. The organic ligands are sometimes referred to as second building structs. The new porous materials have paid great attention because of the variety of advantages such as tunable components, structural diversity, high loading performance and favorable biodegradability. In this review, we highlighted the recent progress on the drug delivery application of MOFs, especially emphasizing the application of pH-responsive delivery as well as magnetic-guided drug delivery systems (DDSs). Subsequently, the applications of MOFs in magnetic resonance imaging (MRI), optical imaging (OI), X-ray computed tomography (CT) imaging and multimodality imaging will be discussed. Finally, we will provide an overview for the photodynamic therapy and the toxicity feature of MOFs.