Construction And Applications Of Functional Supramolecular Nanosystems Based On Pillar[n]arenes

In recent years,functional supramolecular nanosystems based on noncovalent interactions have become a research hotspot in the field of biology,chemistry,and functional materials,since these supramolecular nanosystems hold potential applications in nanomaterials due to their outstanding defined morphology,stimuli-responsiveness,photophysical property,biological and catalyst activities.As a new class of macrocyclic hosts,pillar[n]arenes have become an important building block for the construction of functional supramolecular nanosystems with their unique characteristics.At present,the supramolecular nanosystems based on water-soluble pillar[n]arenes have shown good applications prospects in targeted drug delivery,photoelectric conversion,sensors,etc.,and have attracted more and more attentions.In this thesis,we have developed two novel functional supramolecular nanosystems based on the excellent host-guest property of water-soluble pillar[n]arenes,and investigated their potential applications for fabricating targeted drug delivery and artificial light-harvesting systems.The main content consists of the following two parts:In the first part,we successfully constructed supramolecular polymersomes based on the host-guest interaction of a water-soluble pillar[5]arene(WP5)with good biocompatibility and a biodegradable cationic poly(glutamamide)s(polymer 1).Besides,mitoxantrone(MTZ)which is one of the hydrophilic anticancer drug can be encapsulated into the obtained polymersomes to achieve MTZ-loaded polymersomes.Importantly,since the surface of the polymersomes are modified with biotin ligands,these polymersomes demonstrated excellent targeting ability,and the anticancer drug can be specifically delivered to cancer cells which have overexpressed biotin receptors on the surface.When the MTZ-encapsulated polymersomes are endocytosed by cancer cells,the polymersomes would disassemble because of the acidic microenvironment of the cancer cells,and the MTZ encapsulated in the polymersomes can be efficiently released.At the same time,the targeted polymersomes could not only improve the anticancer efficiency of MTZ,but also effectively reduce systematic toxicity on normal cells,suggesting their potential applications for targeted drug delivery.In the second part,we successfully constructed two kinds of highly efficient light-harvesting systems in aqueous solution.a salicylaldehyde azine derivative(G)was designed and synthesized,it can be assembled into spherical nanoparticles in the presence of water-soluble pillar[6]arene(WP6)which can remarkably improve the aggregation-induced emission(AIE)of G and make it an excellent donor.Furthermore,the obtained supramolecular nanoparticles can successfully encapsulate the hydrophobic dye Nile Red(NiR)which act as acceptors in its hydrophobic core,and realize energy transfer from donors to the acceptors,which can be confirmed by fluorescence decay and quantum yield experiments.And the system shows ultrahigh antenna effect and energy transfer efficiency.In addition,we further constructed another artificial light-harvesting system using the nanoparticles to achieve efficient energy transfer from energy donors to Eosin Y(ESY).This system realizes a simple and efficient mimick of photosynthesis,and provides a good foundation for further research on photoelectric conversion and energy storage.In summary,two kinds of functional supramolecular nanosystems have been successfully constructed in this thesis based on water-soluble pillar[5,6]arenes,and their applications for fabricating targeted drug delivery and artificial light-harvesting systems have been investigated,providing some reference for the development of functional supramolecular nanosystems.