Synthsis,Modification,Imaging,Anti-tumor Properties Of Rare Earth Based Mesoporous Materials

Rare earth luminescent materials show potential application in bio-labeling and bio-imaging due to the unique characteristics,such as physical and chemical stability,narrow emission bands,high luminescent purity,wide emission wavelength,large Stokes shift,and long lifetime.If luminescent materials have the porous structure simultaneously,they could be utilized as carriers for anti-cancer therapy with imaging-guided properties.The main research content is list as below.Uniform LaF3 and LaCO3F hollow microspheres were successfully synthesized through a surfactant-free route by employing La(OH)CO3 colloidal spheres as a sacrificial template based on Kirkendall effect.The synthetic process consists of two steps:the preparation of La(OH)CO3 precursor via a facile urea-based precipitation and the following formation of lanthanide fluorides hollow microspheres in an aqueous condition under low temperature(50 0C)and short reaction time(3 h),without using any surfactant and catalyst.It is found that the phase and structure of the products can be simply tuned by changing the pH values of the solutions.Time-dependent experiments were employed to study the possible formation process.N2 adsorption/desorption results indicate the mesoporous nature of LaF3 hollow spheres.Yb/Er(Ho)and Yb/Tm doped LaF3 hollow spheres exhibit characteristic up-conversion emissions of Er(Ho)and Tm under 980 nm laser diode excitation,and Eu,Ce/Tb doped LaF3 and LaCO3F emit red,bright yellow-green and near-white light under UV irradiation,respectively.In particular,LaF3:Yb/Er and LaCO3F:Ce/Tb hollow microspheres exhibit high biocompatibility,obvious sustained and pH-dependent doxorubicin(DOX)release properties,suggesting the potential application in imaging and drug release fields.Uniform LaPO4:Ce/Tb mesoporous microspheres have been successfully prepared by a facile mass production co-precipitation process under mild reaction conditions,without using any surfactant,catalyst and further heating treatment.Then,Au nanoparticles were conjugated to polyetherimide(PEI)modified LaPO4:Ce/Tb MMs by the electrostatic interaction.It is found that as-prepared LaPO4:Ce/Tb@Au mesoporous composed of numerous hexagonal nanorods.Upon ultraviolet excitation,LaPO4:Ce/Tb and LaPO4:Ce/Tb@Au MMs exhibit the characteristic green emissions of Tb ions.The MTT assay and DOX release experiments indicate the good biocompatibility and sustained properties.CLSM photographs of cancer cancer cells verify the cell uptake process.In particular,under UV irradiation,a rapid DOX release was achieved due to the photothermal effect of Au NPs deriving from the overlap of the green emission of Tb and the surface plasmon resonance band of gold NPs at about 530 nm.The MTT assay and cellular uptaken images further proved the high toxicity to cancer cells of this drug delivery system,which should be a candidate for cancer therapy carriers due to UV-depdendent drug release and combined imaging properties.Novel Y2O3:Yb/Er-CuxS multifunctional composite were designed by attaching CuxS nanoparticles onto the surface of Y2O3:Yb/Er hollow spheres from a facile and mild co-precipitation and subsequent hydrothermal route.By altering the initial pH values for the synthesis of precursors,the size and structure properties of the final composites can controllably be tuned.Time-dependent experiments indicate that the foamtion of hollow structure is due to Kirkendall effect.The conjugated folic acid(FA)makes the composite recognize the targeted cancer cells and the attached CuxS nanoparticles endow the composite with photothermal function.It is found that the release of DOX from the functional carrier could be controllably released by adjusting the sizes of the samples,release temperature,pH value and near infrared(NIR)radiation.In particular,both photothermal therapy(PTT)and chemotherapy can be simultaneously driven by 980 nm-laser irradiation,which exhibits high anti-cancer efficacy.Moreover,the composite exhibits the clear in vivo red up-conversion luminescence(UCL).This multifunctional nano-carrier can be applicable as bioimaging agent and effective antitumor agent for the synergistic interaction between PTT and the enhanced chemotherapy.Novel multifunctional GdOF:Ln@SiO2(Ln = Yb/Er/Mn)mesoporous capsules were fabricated through a first hydrothermal route followed by a coating of silica and calcination process,which is composed of GdOF:Ln cores and mesoporous silica layer.The target agen(FA),photodynamic agent ZnPc,photothermal agent carbon dots and anti-cancer drug DOX were subsequently attached on the surface of the capsules to achieve a multifunctional anti-cancer system.It was found that due to the co-doped Yb/Er/Mn in GdOF,the markedly enhanced red emission can efficiently transfer energy to the conjugated PDT agent(ZnPc)which produces high singlet oxygen,and the incorporated carbon dots outside the shell can generate obvious thermal effect under 980 nm laser irradiation and also prevent the premature leaking of ZnPc.Simultaneously,the as-produced thermal effect can obviously enhance DOX release,which greatly improves the chemotherapy,resulting in a synergistic therapeutic effect.The system exhibits drastically enhanced therapeutic efficiency against tumor growth,as demonstrated both in vitro and in vivo.Especially,the doped rare earth ions in the host endows the material with excellent UCL imaging,T1 and T2 magnetic resonance imaging(MRI),and computed tomography(CT)imaging properties,thus realizing the target of multi-modal imaging guided multiple therapies.Core-shell up-conversion nanoparticles with DOX molecules,photosensitive Au25(SR)18-(SR refers to thiolate)clusters,and pH/temperature-responsive polymer P(NIPAm-MAA)modified are designed for pH/temperature-stimulated anti-tumor therapy.This system could convert near-infrared light into visible light,and the visible light transfers energy to the Au25(SR)18-clusters for the generation of reactive oxygen species and photothermal effect.Consequently,the thermal effect further stimulated the pH/temperature sensitive polymer in the cancer sites and realized the targeted and controllable DOX release.Meanwhile,the system could be over expressed in different folic acid(FA)receptor positive cells with FA modified.Core-shell structure(TiO2@Y2Ti2O7@YOF:Yb,Tm)was designed for phtotodynamic therapy.Under a single NIR laser irradiation,the highly cytotoxic reactive oxygen species(ROS)required for PDT can be generated due to the energy transfer from YOF:Yb,Tm to theY2Ti2O7 photocatalyst which is responsive to blue emission(visible light).The NIR light induced PDT can efficiently suppress tumor growth,which was evidenced by both in vitroMTT assay and live/dead statement assay.