Advances and challenges of metal-organic frameworks in controlled drug delivery

Metal-organic frameworks (MOFs) are a class of crystalline porous materials, which have become the main platform for drug delivery research because of their high specific surface area, adjustable pore size and high drug loading capacity. The selection of organic ligands, adjustment of metal nodes and post-synthetic modification enable precise control over drug loading, release kinetics and targeting specificity. These features overcome key limitations of traditional carriers, such as low loading capacity, easy inactivation and difficult biocompatibility. In addition, combining MOFs with stimulus-responsive polymers or photothermal agents has led to multifunctional systems that integrate therapeutic and diagnostic imaging, thereby enabling theranostic application. This review analyzes MOF surface engineering, stimulus response behavior, cytotoxicity and long-term biological interaction in detail. It also briefly describes the application of MOFs in various drug delivery modes, aiming to provide fundamental insights and guide the development of intelligent and adaptive drug delivery platforms for future biomedical applications.