Pillar[5]arene-Based Supramolecular Assemblies Application In Artificial Light-Harvesting Systems And Biological Therapy

With the development of nanotechnology,supramolecular assemblies as a new type of material using non-covalent interactions have attracted more and more attention.In recent years,supramolecular chemistry has developed rapidly and has important implications in the field of biomedicine,energy,catalysis,and sensing.Supramolecular macrocycles have been widely used in the preparation of functional materials due to their unique structures,easy functionalization,abundant host-guest complexation capabilities,and dynamic and modular properties.Some guest molecules have been used to construct smart supramolecular system due to their ability to selectively bind to specific host macrocycles.In recent times,due to the impact of the global energy crisis,studies towards artificial light-harvesting systems driven by macrocycles-based host-guest interactions have gradually been revealed and developed rapidly.Although macrocycle-based functional materials have been fabricated and exhibit impressive potential applications,almost all of them have a lot of drawbacks,for example,the constructed light-harvesting system has low energy transfer efficiency.In addition,cancer is the leading cause of death and a significant barrier to increasing life expectancy in countries around the world.Worldwide,it is estimated that in 2020,there will be 19.3 million new cancer cases and nearly 10.0million cancer deaths.Unlike most conventional platforms with suboptimal therapeutic capabilities,supramolecular cancer nanotherapy has unparalleled advantages in early diagnosis and personal therapy,has broad potential in clinical translation and application.Based on the above research background,a series of pillar[5]arene-based supramolecular assemblies were prepared by host-guest self-assembly,and their applications in catalysis,fingerprint imaging,cancer treatment and other related aspects were studied.The details are summarized as follows:(1)We present a novel and highly efficient artificial light-harvesting system through directly embedding CsPbBr₃ quantum dots(QDs)inside a supramolecular self-assembly of thymine functionalized-pillar[5]arene(PTY)and an eosin Y-based derivative(EYB)for photocatalytic cross-coupling hydrogen evolution reaction.In this system,guest molecule EYB can self-assemble with host PTY through host-guest interaction to form PTYéEYB.The thymine group in the host PTY can coordinate with Pb²⁺ions to further form CsPbBr₃ quantum dots.CsPbBr₃ quantum dots confined in the PTYéEYB interlayer overcome the long-standing unsolved self-quenching problem.In addition,the donor CsPbBr₃ QDs exhibit a broad spectral absorption in the UV-visible range,and their emission shows good spectral overlap with the absorption of EYB,thus realizing an efficient energy transfer process from CsPbBr₃ quantum dots to the nearby acceptor EYB with an energy transfer efficiency of 96.5%.More importantly,the combination exhibited excellent photocatalytic activity in cross-coupling hydrogen evolution reactions,and the product yield was more than 2.5 times that obtained using eosin Y alone.Our research opens up a new avenue for utilizing perovskite QDs with broad spectral absorption as the energy donor to construct efficient light-harvesting systems for solar energy conversion.(2)We present a near-infrared(NIR)emissive artificial light-harvesting system with two-step high-efficiency sequential resonance energy transfers by the in situ growth of MAPb Br₃ quantum dots into the supramolecular self-assembly of carboxyl-functionalized pillar[5]arene coordination polymer and two different fluorescent dyes,eosin Y and Nile blue,for realizing the NIR fluorescent imaging of sweat pores on latent fingerprints(LFPs).When EYB and Ni B were sequentially entrapped into the supramolecular assembly,the energy was transferred from the MAPb Br₃ QDs to EYB and then to Ni B with NIR emission through two-step sequential highefficiency FRET.Furthermore,the fluorescence of this system was found to be stable in non-aqueous solvents but easily quenched by the small quantities of water secreted from human sweat pores,allowing high-resolution imaging of sweat pores in LFPs using NIR fluorescence imaging technology.Our strategy will open up a new way of building an efficient sequential perovskite-based artificial lightharvesting system with NIR emission,which can be used for third-level fingerprint imaging at crime scenes and other potential applications such as sensing and diagnosis.(3)Herein,we developed an acid-activated mitochondria-targeted DNAzyme supramolecular micelles has been developed by encapsulating the DNAzyme into supramolecular assembly of carboxyl functionalized-pillar[5]arene(denoted as CP5)and guest molecule Mn porphyrin derivatives(Mn TPPCN)carrying nitric oxide(NO)donor and triphenylphosphonium(TPP).Such supramolecular micelles(T-DNAzyme@CP5éMn TPPCN)allow to effectively co-deliver DNAzyme,NO and Mn TPPCN into mitochondria for selective and highly efficient gene-silencing therapy and photodynamic therapy(PDT).Notably,in such a supramolecular micelles system,T-DNAzyme@CP5éMn TPPCN easily accumulated in tumors and subsequently responded to the acidic tumor microenvironment,and the carried DNAzyme realizes intelligent release for cleavage of abnormal m RNA in cancer cell.Meanwhile,the carried NO donor undergoes breakdown under red light irradiation to produce NO for inhibiting cellular respiration,allowing more O₂ in tumor cells to generate singlet oxygen(~1O₂),thereby profoundly enhancing photodynamic therapy(PDT).Our work paves an extremely simple way to integrate DNAzyme with PDT for efficient and selective mitochondria-targeted cancer therapy.(4)In this work,we successfully fabricated a supramolecular nanoplatform(T-LOX@CP5éMn TPPCN)with mitochondria targeting and tumor microenvironment regulation for enhanced photodynamic therapy(PDT).Once the supramolecular micelles accumulating in tumors and subsequently responding to the reductive microenvironment,the carried LOX for depleting excess lactic acid in cancer cells and generating O₂ under the catalysis of Mn TPPCN to adjust the tumor hypoxic microenvironment and support the profound enhancement of PDT.Meanwhile,the carried NO donor undergoes breakdown under red light irradiation to produce NO for inhibiting mitochondrial respiration for reversing the hypoxic tumor microenvironment and enhancing photodynamic therapy.The results show that the supramolecular micelles have a good tumor therapeutic effect after intravenous administration in mice.Our study opens up a new avenue for designing pillar[5]arene-based host-guest interactions for targeting mitochondria,enhancing PDT,and tuning the tumor microenvironment for effective precise cancer therapy.