Several Hybrid Systems Based On Covalent Organic Polymers And Coordination Polymers(or MOFs) For Detection And Controlled Drug Release

Environment and food safety as well as diseases treatment as two major research fields related to human health,have attracted great attention of researchers.With the rapid development of material science,porous organic polymers and organic-inorganic porous materials have shown great potential in the fields of biomedicine,sensing,adsorption and separation.Especially,as two kinds of the well-developed porous polymers,covalent organic polymers?COPs?and metal organic frameworks?MOFs?are flourishing in detection,sensing,controllable drug delivery,cancer therapy and many other fields due to the desirable properties of tunable compositions,easy-modification,and controllable size/morphology as well as other attracting advantages.Therefore,this paper is devoted to preparing functional porous organic polymers and organic-inorganic porous composites based on COPs and MOFs to promote the solution of the scientific problems related to human health,such as environmental and food safety,targeted drug delivery as well as cancer therapy.Firstly,three kinds of COPs with high stability,large surface area and high porosity were synthesized and prepared as the fibers of solid phase microextraction,providing high-performed porous organic materials and detection strategy for the efficient separation and analysis of organic pesticides in food and opening up a new research direction for the maintenance of food safety.Secondly,we made efforts in the design and synthesis of optical detection materials.A new type of fluorescent coordination polymer was synthesized by selecting pillararene as the building blocks and its application in sensing and detection was systematically studied,which enriched the existing optical detection materials and provided a new strategy for improving environmental safety problems.Finally,multifunctional organic-inorganic porous composites were designed by incorporating easy-modified,biocompatible and high loaded MOFs with excellent pillararenes,inspiring the development of targeted drug delivery and cancer therapy.This paper can be summed up as the following four parts:?1?In this part,three kinds of novel COPs-hydrazone COPs,cross-linked COPs and PAF/IL composites were designed and served as the fibers of solid phase microextraction?SPME?,respectively.These fibers were used to SPME of organic pesticide residues in food samples and their adsorption and separation effects were investigated.Notably,these COPs materials showed better adsorption and separation effect on organic pesticides than that of commercial materials and the present strategy demonstrated desirable detection performance.?2?In this part,a fluorescent pillarene coordination polymer?CP5-PCP?was initially prepared by a simple hydrothermal synthesis method,in which dicarboxylic acid-containing copillar[5]arene?CP5?was used as the building block and Cr³⁺as central metal node.Then,the luminescent property and mechanism of CP5-PCP were investigated in detail.In addition,this fluorescent CP5-PCP could be used as a multifunctional sensor for the detection of Fe³⁺,acetone and nitrophenol organic pollutants.It is worth mentioning that the application of pillararenes-based coordination polymers is not limited to the above studies due to the unique properties of pillararenes and coordination polymers,such coordination polymers have great potential in sensing,adsorption,controllable drug delivery and so on.This research can not only inspire the design of macrocyclic coordination polymers,but also promote the development of multifunctional porous materials through the synergy of supramolecular chemistry and coordination chemistry.?3?Pillararenes as a class of attractive supramolecular compounds play an important role in the controllable drug delivery,the coorperation of pillararenes and MOFs are expected to obtain multifunctional biomedical materials by combining the advantages of supramolecular chemistry and coordination chemistry.In this paper,a multifunctional therapeutic nanoplatform was initially fabricated according to the core-shell construction concept of layer-by-layer self-assembly.Concretely,Fe₃O₄ magnetic nanoparticles were used as the core and UiO-66 MOF was grown in situ on the surface of magnetic nanoparticles for the delivery of anticancer drug 5-fluorouracil?5-Fu?,then,twokindsofpillararenes-carboxylatopillar[6]arene?WP6?and carboxylatopillar[5]arene?WP5?pseudorotaxanes were used as nanovalves for the pH/Ca²⁺/Zn²⁺/temperature responsive 5-Fu release.In vitro release experiments demonstrated that WP6-based nanoplatform?Fe₃O₄@UiO-66@WP6?possessed the expected effect of sustained release due to the stronger host-guest interaction between WP6 and the stalk components.Subsequently,cytotoxicity test proved that Fe₃O₄@UiO-66@WP6 had good biocompatibility and better therapeutic effect compared with single 5-Fu.Such synergistic Fe₃O₄@UiO-66@WP6 therapeutic nanoplatform integrated magnetic separation,magnetic resonance imaging,multistimuli responsive drug delivery in one system,which was beneficial for the timing and local treatment with high efficiency.?4?In this part,polypyrrole?PPy?with good biocompatibility and photothermal performance served as the substrate for the growth of UiO-66 MOF,integrating chemotherapy and photothermal therapy in one pot.Then,WP6 nanovalves were anchored on the surface of PPy@UiO-66 MOF nanohybrids?PU NPs?through the dynamic host-guest interaction between WP6 and stalk components modified on the surface of PU NPs,endowing the whole composites?PPy@UiO-66@WP6?with passive targeting capability in response to the pathological microenvironment?pH/temperature?.Furthermore,folic acid conjugated polyethyleneimine?PEI-Fa?was modified on the outermost layer of PPy@UiO-66@WP6 through electrostatic interactions to prepare PPy@UiO-66@WP6@PEI-Fa?PUWPFa?nano-therapy system.The as-synthesized PUWPFa nano-therapy system integrated folic acid-mediated active targeting,supramolecular nanovalves-mediated passive targeting,PPy-based photothermal therapy and MOF-based chemotherapy in one system.The photothermal effect and the controlled drug release performance of the PUWPFa composites were investigated in detail.Experimental results showed that the PUWPFa system had a good photothermal conversion efficiency of 38.69%and the existence of the nanovalves ensured the targeted drug release at elevated temperature and acidic environment of cancer cells,indicating that controlled drug release and chemophotothermal therapy complemented each other in the present nano-therapy system.Significantly,in vivo and in vitro experiments exhibited that the as-prepared PUWPFa composites showed better therapeutic performance than single photothermal therapy or chemotherapy.Meanwhile,PUWPFa composites had no obvious toxic and side effects on normal organs?heart,liver,spleen,lung and kidney?of xenograft female mice models.