Interface-regulated Fabrication Of Gold Nanorod-porphyrin MOF Composite For Phototherapy

Phototherapy including photodynamic therapy and photothermal therapy hold great promises for precise tumor theranostics due to their effective and non-invasive modality.However,the efficiency of photosensitizers is too low to be widely used in clinical treatment.The preparation of composite to achieve Photodynamic therapy and photothermal therapy is an undoubtedly important way to improve the efficacy of phototherapy.Photodynamic therapy based on porphyrin photosensitizer has received significant attention due to its high light absorption efficiency and yield of singlet oxygen.It has been found that the nanostructures of porphyrin molecules assembled can broaden the absorption spectrum and extend the retention time in vivo.The gold nanorods have good biocompatibility and high efficiency of photothermal conversion,which achieve the delivery of porphyrins and generate photothermal therapy.It is noteworthy that the surface plasmon resonance of gold nanorods can significantly increase the yield of singlet oxygen from photosensitizer,which provides an opportunity to further enhance the photodynamic therapy effect of porphyrin photosensitizers.In order to develop a novel phototherapy material with high load and stable structure,we designed a gold nanorod-porphyrin metal organic framework?GNR@TCPP-MOF?structure composite.The interface compatibility problem of metal nanoparticle and MOF was solved by surface modification.Different gold nanorod-porphyrin MOF composites were prepared by seed growth method,and the phototherapy effect of the composites was tested.Based on this,the following design research contents were carried out in this subject:1.We selected tetracarboxyphenyl porphyrin?TCPP?as the organic linker for constructing MOF.In order to solve the interfacial compatibility between gold nanorods and porphyrinic MOF,we used a carboxyl thiol molecule as an intermediate bridge connecting the two materials.First,the surface of the gold nanorods were functionalized with 11-mercaptoundecanoic acid?MUA?.Then,GNR@TCPP-MOF with different morphology was fabricated by the solvothermal method using the functionalized gold nanorods?MUA-GNR?,TCPP and zirconium chloride.And the effects of gold nanorod concentration,reaction time and temperature on the gold nanorod-porphyrin MOF were studied.In this process,the contradiction between easy oxidation etching at high temperature of gold nanorods and the need of porphyrinic MOF to react at high temperature was solved.The morphologies,structures and optical properties of GNR@TCPP-MOF materials were systematically analyzed by SEM,TEM,EDS,XRD,UV-vis absorption and other characterization methods,and it was found that the introduction of gold nanorods had a great influence on the morphology and size of porphyrinic MOF,but the crystalline structure of porphyrinic MOF had not been changed.The GNR@TCPP-MOF nanocomposites showed good photothermal performance and the great efficiency of singlet oxygen production with local electric field enhancement,and exhibited rapid and efficient photodynamic therapy in cell phototoxicity assays.2.The resulted GNR@TCPP-MOF nanocomposites showed poor fluorescence imaging in vitro.We introduced metal porphyrin with magnetic resonance imaging function to construct gold nanorod-porphyrin multifunctional nanocomposites.Firstly,a paramagnetic metal porphyrin MnTCPP was prepared by using"two-step"and a core-shell GNR@MnTCPP-MOF structure of the same morphology and size was constructed.Because MnTCPP has poor photosensitivity,in order to improve the photodynamic therapeutic effect of GNR@MnTCPP-MOF composites,ZnTCPP with higher singlet oxygen yield was further introduced,and the bimetallic doped gold nanorod-porphyrin MOF composites were prepared by the same method.The obtained gold nanorod-porphyrin MOF from different proportions of doped metalloporphyrin had the same morphology and size.We investigated the photosensitive properties and MRI properties of different proportions of GNR@Mn/ZnTCPP-MOF composites,the result showed that GNR@MTCPP?1:1?-MOF performed good MRI imaging effect with a relaxation rate of 5.847 mM^-1·s^-1 and excellent singlet oxygen production.And 87.15%cells killing efficiency was verified in cell phototoxicity experiments.The composite indicated excellent universality for tetracarboxyphenyl porphyrin and provided a basis for further construction of multifunctional gold nanorod-porphyrin composite.