Metal–Organic Frameworks And Covalent Organic Frameworks For Tumor Photodynamic Therapy Application

Metal–organic frameworks(MOFs)are a type of crystalline hybrid material composed of metal ions and organic linkers.Owing to their adjustable structure,easy modification,permanent pores,and good biocompatibility,MOFs have been used in biomedicine.As a promising alternative to MOFs,covalent organic frameworks(COFs)are purely organic crystalline porous materials that should be more biocompatible and suitable for biomedical applications.Photodynamic therapy(PDT)is a highly effective,non-invasive,and highly selective method for cancer therapeutics.PDT based on nanomaterials overcomes many shortcomings of traditional PDT and thus has more future development potential.In the first part of this thesis,the recent progress in MOF-based nanomaterials for tumor PDT was summarized,including the design strategies for MOF-based PDT nanomaterials,and challenges faced in the use of MOF-based PDT.In the second part of this thesis,the host-guest nanomaterial 2I-BODIPY@ZIF-90 synthesized by simple in situ self-assembly method for precise PDT applications was reported.2I-BODIPY@ZIF-90 was selectively taken up by tumor cells due to pH driving,released from endosomes and lysosomes due to proton sponge effect subsequently,and localized to mitochondria finally.Under illumination,2I-BODIPY@ZIF-90 induced mitochondrial membrane potential decrease and leads to cell death.In the third part of this thesis,the PDT applications of COF-based nanomaterials LZU-1-BODIPY-2I and LZU-1-BODIPY-2H were reported.Two BODIPY molecules with amino groups were successfully modified to the nanoscale COF LZU-1 surface through bonding defect functionalization(BDF)method.The resulting nanoparticles had well-defined chemical composition,excellent stability,negligible dark toxicity,and extremely high phototoxicity in vitro and in vivo.From mechanism,the nanoparticles were taken up by cancer cells through energy-dependent endocytosis and caused cell death through mitochondrionand lysosome-associated pathways.These studies will offer the potential for wider application of MOFs and COFs in the biomedical field.