In this work, beta-NaYF4:Yb,Er upconversion (UC) film was successfully prepared on silicon (Si) substrate via self-assemble method for the first time. The chemical composition and surface morphology of the UC film were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), X-ray power diffraction (XRD), and scanning electron microscopy (SEM) measurements. To investigate the effects of KH-560 primer film and chemical reactions on the UC luminescence properties of beta-NaYF4:Yb,Er UC film, decay profiles of the 540 nm and 655 nm radiations were measured. Furthermore, tribological test was applied to qualitatively evaluate the adhesion of the UC film. The results indicate that the UC film has been successfully prepared on Si substrate by covalent chemical bonds. This work provides a facile way to synthesize beta-NaYF4:Yb,Er UC film with robust adhesion to the substrate, which can be applicable for other UC films. (C) 2016 Elsevier B.V. All rights reserved.

Hypoxia is a major cause of treatment resistance in breast cancer. Single-walled carbon nanotubes (SWCNTs) exhibit unique properties that make them promising candidates for breast cancer treatment. In the present study, a new functionalized single-walled carbon nanotube carrying oxygen was synthesized; it was determined whether this material could increase chemosensitivity and radiosensitivity of human breast cancer cell lines, and the underlying mechanisms were investigated. MDA-MB-231 cells growing in folic acid (FA) free medium, MDA-MB-231 cells growing in medium containing FA and ZR-75-1 cells were treated with chemotherapy drugs or radiotherapy with or without tombarthite-modified-FA-chitosan (R-O2-FA-CHI)-SWCNTs under hypoxic conditions, and the cell viability was determined by water-soluble tetrazolium salts-1 assay. The cell surviving fractions were determined by colony forming assay. Cell apoptosis induction was monitored by flow cytometry. Expression of B-cell lymphoma 2 (Bcl-2), survivin, hypoxia-inducible factor 1-α (HIF-1α), multidrug resistance-associated protein 1 (MRP-1), P-glycoprotein (P-gp), RAD51 and Ku80 was monitored by western blotting. The novel synthesized R-O2-FA-CHI-SWCNTs were able to significantly enhance the chemosensitivity and radiosensitivity of human breast cancer cell lines and the material exhibited its expected function by downregulating the expression of Bcl-2, survivin, HIF-1α, P-gp, MRP-1, RAD51 and Ku80.

In this work, amino-functionalized NaYF4:Yb,Er upconversion nanoparticles (UCNPs) were synthesized by a hydrothermal method.

β-NaYF4:Yb3+/Er3+ microcrystals codoped with Cr3+ ions were prepared for the first time via a facile hydrothermal method. The influence of doping concentration of Cr3+ ions on growth and upconversion (UC) luminescence properties of β-NaYF4:Yb3+/Er3+ microcrystals were investigated in detail. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL) spectra were used for characterization. The results demonstrated that the morphology and size of β-NaYF4:Yb3+/Er3+ microcrystals were influenced by doping concentration of Cr3+ ions, the possible mechanism was proposed. The UC intensity of β-NaYF4:Yb3+/Er3+ microcrystals was significantly enhanced by doping of Cr3+ ions. In contrast to β-NaYF4:Yb3+/Er3+ microcrystals without doping of Cr3+ ions, the green and red emission intensities of the microcrystals codoped with 15 mol% Cr3+ ions were enhanced by 16 and 7 times, respectively. The enhancement of the UC intensities should be ascribed to the distortion of local symmetry around Er3+ ions, the UC mechanism was discussed. This work will be helpful for improving the UC intensity of other lanthanide-doped UC nano- and micro-crystals.

Yb3+ and Er3+ ions co-doped α-NaYF4:Yb3+, Er3+ nanocrystals were successfully synthesized via a facile hydrothermal method using citric acid (CA) as chelating ligand and NaNO3 as mineralizer. The influences of the CA/RE (RE = Y+Yb+ Er) molar ratio, reaction time, reaction temperature and the NaNO3/RE molar ratio on the crystal phases and shapes of as-prepared products have been well investigated. The possible formation mechanism has been discussed in detail and an aggregation growth theory has been proposed. X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and photoluminescence (PL) spectra were used to characterize the products. Under 980 nm excitation, the emission intensities of the as-prepared nanocrystals were much stronger than that of the nanocrystals modified by ethylenediaminetetraacetic acid (EDTA). Additionally, the as-prepared products maintained spherical shape and high degree of monodispersion, which is expected to be suggestive for the preparation of other complex rare earth fluoride compounds.

Objective To study the in vivo and in vitro effects of adding oxygen carbon nanotubes (CNTs) to chemotherapy for breast cancer. Methods MCF-7 and SK-BR-3 breast cancer cells were co-cultured with paclitaxel and then exposed to oxygen-CNTs under hypoxic conditions. Cell proliferation, viability, and apoptosis rate were analyzed. Hypoxia-inducible factor-1 alpha (HIF-1α) expression was measured using reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Nude mice were used as a human breast cancer model to explore the impact of oxygen-CNTs on the in vivo chemotherapeutic effect of paclitaxel. Results Oxygen-CNTs had no significant effects on the growth of breast cancer cells under normoxia and hypoxia. However, in the hypoxic environment, oxygen-CNTs significantly enhanced the inhibitory effect of paclitaxel on cell proliferation, as well as the apoptosis rate. Under hypoxia, downregulation of HIF-1α and upregulation of caspase-3, caspase-8, caspase-9, LC3 and Beclin-1 were observed when paclitaxel was combined with oxygen-CNT. Furthermore, addition of oxygen-CNTs to chemotherapy was found to significantly reduce tumor weight in the tumor-bearing mice model. Conclusions Oxygen-CNTs can significantly increase the chemotherapeutic effect of paclitaxel on breast cancer cells. Oxygen-CNTs may be a potential chemosensitizer in breast cancer therapy.

目的:研究叶酸修饰稀土改性载氧碳纳米管在低氧环境下对乳腺癌细胞株放疗敏感性的影响.方法:使用水溶性四唑盐法(WST-1)方法研究叶酸修饰稀土改性载氧碳纳米管对MDA-MB-231细胞与ZR-75-1细胞生长的作用,使用细胞集落形成实验研究其在低氧环境下对无叶酸培养基中MDA-MB-231细胞、有叶酸培养基中MDA-MB-231细胞及ZR-75-1细胞放疗敏感性的影响.利用流式细胞术研究叶酸修饰稀土改性载氧碳纳米管联合放疗干预MDA-MB-231乳腺癌细胞株的凋亡率的改变.利用Western Blot实验观察Bcl-2、survivin、Hif-1α、Rad51及Ku80表达水平的改变.结果:在常氧及低氧环境下,叶酸修饰稀土改性载氧碳纳米管在低于1 00 μg/ml的浓度时对乳腺癌细胞株生长无明显影响.在低氧环境下,放疗联合叶酸修饰稀土改性载氧碳纳米管组相比于单纯放疗组细胞克隆形成率有不同程度的降低,以无叶酸培养基中MDA-MB-231细胞组降低最为明显,照射剂量在2、4、6、8Gy时其细胞克隆形成率均显著降低(P＜0.05).流式细胞术显示叶酸修饰稀土改性载氧碳纳米管联合放疗后可使MDA-MB-231乳腺癌细胞株的凋亡率增加.Western Blot实验显示Bcl-2、Survivin、Hif-1α、Rad51及Ku80表达水平均降低.结论:叶酸修饰稀土改性载氧碳纳米管可在体外低氧环境下增强乳腺癌细胞株对放疗的敏感性.

Using a facile hydrothermal method, hexagonal beta-NaYF4:Yb3+ 20 mol%, Er3+ 1 mol% crystals with predictable size and morphology were synthesized and the upconversion (UC) luminescence properties were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectra were used to characterize the samples. The results indicated that the size and morphology of the crystals can be precisely controlled by tuning the values of the initial reaction solution and the molar ratio of NaNO3 to RE3+ (RE = Y + Yb + Er), and the mechanism was proposed. The UC luminescence properties of beta-NaYF4:Yb3+/Er3+ crystals were found to strongly depend on the crystal morphologies and sizes. The peak area ratio of green to red (RIG) increased from 0.29 to 1.03 with pH values increasing from 3 to 10, and increased from 1.03 to 1.26 with the increase of molar ratio of NaNO3 to RE3+ from 0 to 90. The emission colors were tuned from pure green to orange yellow. This study provides a facile way to synthesize beta-NaYF4:Yb3+/Er3+ crystals with predictable morphology and size, and tunable luminescence properties, which can be applicable for other rare earth fluoride compounds. (C) 2014 Elsevier B.V. All rights reserved.