Self-assembly Behavior And Anti-tumor Research Of Metalloporphyrin Nanoparticles

Self-assembly provides an attractive approach to fabricate multifunctional nanostructures from small molecules.The theranostic nanoplatforms self-assembled by metal ions and photosensitizers have attracted great attention in tumor therapy owing to their synergetic photophysical and magnetic properties.Porphyrins are clinically approved and well-documented photosensitizers for treatment of lung cancer,skin cancer and esophageal cancer.Porphyrin-based metal coordination polymers have attracted numerous attention due to their great promise application in phototherapy including photodynamic therapy(PDT)and photothermal therapy(PTT).It has been found that self-assembly process plays a critical role in the antitumor efficiency of the metal organic nanomedicine.This work provides a detailed study of the self-assembly process of MCPs constructed by Mn2+ and TCPP(TCPP:5,10,15,20-tetrakis(4’-carboxyphenyl)porphyrin)in aqueous solution.Unlike traditional nucleation and growth mechanism,we discover that there is a metastable metal-organic intermediate which is kinetically favored in the self-assembly process.And the metastable metal-organic intermediate nanotape structures could convert into thermodynamically favored nanosheets through disassembling into monomers followed by reassembling process.Moreover,the two structurally different assemblies exhibit distinct photophysical performances.The intermediate Mn-TCPP aggregates show good light-induced singlet oxygen 102 generation for PDT while the thermodynamic favored stable Mn-TCPP aggregates exhibit excellent photothermal conversion ability as photothermal agents(PTAs).In addition,we can also obtain stable intermediate aggregates of metal coordination polymers via confined self-assembly and find that the photodynamic effect of intermediate aggregates is obviously better than that of intermediate aggregates in hydrothermal environment.This study could facilitate controlling self-assembly pathway to fabricate complex MCPs with desirable applications.