Assembly Behavior Of Water-Soluble Porphyrin J-Aggregation And Its Optical Diagnosis And Treatment

Molecular self-assembly technology is a powerful tool for constructing various functional nanomaterials by transforming a system from a disordered state to a highly ordered state through a bottom-up approach.Porphyrins are an important class of substances involved in life processes.Due to their macrocyclic structure containing conjugated π-electrons and molecular rigidity,porphyrins have become important structural elements in the field of molecular selfassembly.In the self-assembly of porphyrins,there are two typical stacking patterns(Jaggregation or H-aggregation),but different aggregation patterns can eventually obtain assemblies with different structures and functions.In recent years,self-assemblies of porphyrins have shown great application prospects in biomedical treatment and supramolecular chirality.However,it is still a major problem to regulate the way of self-assembly and aggregation of porphyrins in biological aqueous systems.In this thesis,a series of novel water-soluble porphyrins,which exhibit J-aggregation behavior in water,were synthesized by introducing different numbers of cationic side chains or changing the linker groups.As water-soluble nano-photosensitizers,these J-aggregated assemblies have been applied in cancer treatment,and provide a basis for further understanding and designing novel functional supramolecular systems.In Chapter 2,the co-assembly of cationic porphyrins(1 and 2)with biological phosphoric acid molecules in aqueous phase was investigated.By reducing the number of cationic side chains,the polyphosphate-induced porphyrin aggregation mode changes from H-aggregation to J-aggregation,and the structure of the assembly also changes from helical fibers to twodimensional nanosheets.It is of great interest in supramolecular chemistry to modulate the nanostructures of porphyrin assemblies by modulating the mode of porphyrin aggregation.In Chapter 3,the synthesized cationic porphyrin(3)was designed to form a unique dynamic J-aggregates in water,which can co-assemble with nucleotides to form chiral supramolecular assemblies.Among them,guanine riboside triphosphate(GTP)assembles supramolecular chiral signals that are different from other triphosphate nucleotides.However,non-aggregated states are unable to form the chiral supramolecular assemblies by the pathways described above.This confirms the path-dependent formation of this chiral supramolecules,which provides a guideline for understanding and modeling the assembly of complex biological chiral supramolecular systems.In Chapter 4,a novel cationic porphyrin(P1)was designed and synthesized.The transition from molecularly-dissovled state to J-type self-aggregation in was achieved by changing the linking groups of the side chains to the phenyl porphyrins.Based on this aggregation mode and the side chain terminal charges,an ultrathin nanosheet structure(～2 nm)was constructed.Compared with the photodynamic effects of the assemblies with different morphologies,the singlet oxygen generation of the ultrathin 2D structure was significantly boosted.The ultrathin nanosheets demonstrated excellent PDT/PTT synergistic therapeutic effect through good tumor site enrichment.