硅烷改性铕配合物的制备与发光性能研究

荧光稀土配合物具有良好的荧光特性,但是简单的配合物由于较低的光、热稳定性而限制了其应用。以氨丙基硅烷偶联剂与邻苯二甲酰氯反应制备改性配体,并与铕离子进行配位制备改性稀土配合物,通过天线效应敏化稀土离子发光,从而实现能量传递和最终的材料发光。考察了不同条件下对稀土配合物的产率和荧光发射强度的影响;测量了配合物的红外光谱、紫外光谱,并推测了配合物的稳定结构;通过荧光光谱测定了配合物的荧光发射强度。结果表明,改性配合物表现出了更强的铕离子的荧光特征峰,说明了铕离子的第一激发态能级和改性配体的三重态能级之间有更好的匹配。     

稀土铕有机配合物的研究进展及其应用

目的 介绍稀土铕有机配合物的原理、分类、应用及其最新研究进展,为高性能稀土铕配合物的研发提供一定的思路和依据。方法 通过查阅国内外学者近年来对稀土铕有机配合物的各种研究文献,对稀土铕有机配合物的主配体种类及应用进行整理总结。结果 稀土铕有机配合物的主配体有四大类,即β-二酮类、羧酸及羧酸盐类、有机高分子类与超分子大环类,该配合物主要应用于荧光材料、发光材料、磁性材料和生物等四大领域。结论 铕有机配合物的荧光性能良好,且高分子类配合物易加工成型;有机高分子类铕配合物可以结合Eu3+和高分子的优点,在提高其与聚合物材料相容性的前提下,有望成为一种新型的功能材料。     

稀土有机配合物荧光材料的研究进展

概述稀土有机配合物的荧光发光机理,即有机配体通过对稀土离子的敏化作用,并将其跃迁的能量传递给稀土离子供其发光;列举芳香胺类、β-二酮类和多胺多羧酸类等新型的有机配体结构。提出稀土有机配合物材料的研究与应用应致力于研发高性能有机配体,并着手解决极易被水猝灭和量子产率不高等问题。认为合成平面刚性强并对稀土离子进行有效保护的新型有机配体,可以有效增强稀土有机配合物的荧光强度以改善其应用范围。     

紫外荧光剂Eu-xGd-(1-x)(BZA)-3Phen发光性质及机理研究

选用β-二酮配体苯甲酰丙酮(BZA)作为第一配体,再选用适当的协同配体邻菲咯啉(Phen),掺杂惰性稀土离子钆(Gd3+),合成了EuxGd(1-x)(BZA)3Phen红色荧光剂。通过元素组成、红外光谱、紫外光谱、热性能、荧光性能对其进行了表征,并研究了该掺杂配合物体系的发光机理,利用分子间能量传递模式解释了惰性稀土离子对EuxGd(1-x)(BZA)3Phen的"共发光效应"。结果表明,这是一类性能优良、成本较低的铕配合物。     

一种双β-二酮化合物及其铕配合物的制备与表征

以4-正丁基苯乙酮和对苯二甲酸二甲酯为主要原料,通过Claisen缩合反应合成了1种具有双β-二酮结构的化合物1,4-双(4-正丁基苯基-1,3-丙二酮基)苯,并通过IR、UV、1 H-NMR对其结构进行了表征。将该双β-二酮与邻菲罗啉、稀土金属铕离子合成新的铕三元配合物,通过IR、UV、TG-DTG及荧光发射光谱对配合物结构和性能进行表征。荧光测试结果表明,室温下新型铕三元配合物在紫外光激发下表现出中心离子的特征荧光发射光谱,发射峰在612nm处,属5 D0→7F2跃迁带,峰型尖锐,单色性好,是一种性能优良的红光发光材料,具有较好的应用前景。     

含稀土配合物的甲基丙烯酸甲酯荧光性能研究

含稀土有机配合物的高分子材料综合了稀土材料和高分子材料的优异性能,在制备光学器件方面有广泛的应用前景.本文制备了含铕的噻吩甲酰三氟丙酮(TTA)和二苯甲酰甲烷(DBM)配合物的聚甲基丙烯酸甲酯(PMMA)体系,并考察了配合物含量、配体、小分子掺杂剂和PMMA分子量对体系荧光性能的影响.分析表明要想获得高效发光的稀土配合物高分子体系需要选用对称性较差,含氟取代基较多的配体,并找到合适的配体或小分子掺杂剂的含量,且尽量增大基体的分子量.     

2,2-联吡啶-6,6-二羧酸与稀土配合物的合成及性能

利用2,2-联吡啶-6,6-二羧酸作为配体,合成了稀土配合物[Ln2(bpydc)3·3H2O]·H2O·3CH3OH(1,Ln=Eu,Tb,Yb,Gd;Hbpydc=2,2-联吡啶-6,6-二羧酸)。使用单晶X射线衍射仪、傅里叶红外光谱、紫外吸收光谱、荧光光谱以及磷光光谱等对其进行了表征和配体与发光中心的能级匹配程度的测定,探讨了配合物的荧光性能与能量传递效率。结果表明:配合物具有两种不同环境的配位中心,促使配合物在空间上具有层状堆积结构;Eu(Ⅲ)与Tb(Ⅲ)配合物分别在612与548nm处有强烈的红色与绿色荧光发射,特征荧光敏化效果明显;配体三重态能级26666cm-1与稀土离子Eu3+(5D0,17300cm-1)、Tb3+(5D4,20500cm-1)最低激发态能级匹配,存在明显天线效应,具有优良的能量传递效率。     

Eu-SSA-phen/MCM-41杂化发光材料的合成与表征

采用水热法合成改性MCM-41介孔分子筛;采用液相沉淀法合成了以磺基水杨酸及邻菲罗啉作为双配体的铕的配合物,找到其发光效果最好的配比,即n(Eu)∶n(SSA)∶n(phen)=1∶2∶1,并将发光效果最好的稀土配合物组装到改性后的MCM-41中,合成了稀土配合物(Eu)/改性MCM-41杂化发光材料,采用紫外光谱分析、元素分析、小角XRD、红外光谱、荧光光谱和TGA对其结构和荧光性质进行了研究。结果表明,组装体具有MCM-41典型结构并且在组装之后仍保留了MCM-41的孔道结构;其荧光光谱具有Eu3+的特征荧光发射,发光强度大于纯配合物。改性MCM-41后组装稀土配合物的发光效果更佳,热稳定性更好,更有利于实际应用。     

一种新型铕三元配合物的制备与荧光性质研究

合成了1个邻菲罗啉衍生物DmPPhen,作为第二配体,以α-噻吩三氟甲酰丙酮作为第一配体制备了1种新颖的三元稀土铕(Eu)配合物发光材料。利用红外光谱、元素分析及核磁氢谱分析了配合物的组成与结构。在常温下研究了配合物的荧光性质,结果表明配合物有很好的荧光性质。     

SiO_2/稀土Eu(Ⅲ)配合物核-壳复合粒子的制备及发光性能研究

采用St ber法制备了粒径为40~60nm的单分散纳米SiO2微球,以氧化铕为原料、α-噻吩甲酰三氟丙酮和邻菲啰啉为配体制备了稀土铕的三元配合物,并将其成功包覆在SiO2微球表面,形成核-壳复合粒子。采用红外光谱和元素分析表征配合物的结构。透射电镜照片表明,稀土有机配合物在SiO2微球表面形成了致密的纳米级包覆层,包覆层厚度随配合物用量的增加而增加。复合粒子呈现出很强的Eu配合物发光,纳米SiO2核对配合物有荧光增强作用,但配合物浓度较高时荧光增强效应有所减弱。     

自蔓延低温合成SrAl2O4∶Eu2+,Dy3+及其粒径控制与发光性能

本文采用自蔓延低温(600℃)方法合成了铝酸盐长余辉材料SrAl2O4∶Eu2+,Dy3+;通过添加聚乙二醇(PEG)有效控制材料的粒径,并采用XRD,SEM,PL等测试方法对粒径、形貌、发光性能等进行了研究。随着PEG量的增加,材料粒径呈减小趋势;未添加PEG时,材料粒径范围在0.2～1.2μm;当PEG的量为0.4%时,材料初始亮度最高,为19110mcd/m2,余辉衰减最慢,材料粒径分布在0.1～0.8μm;当PEG量为0.6%时,粒径最小,粒径范围在0.1～0.5μm。添加PEG后材料的发光亮度有所提高,而余辉衰减变化不明显。实验结果表明:自蔓延低温合成SrAl2O4∶Eu2+,Dy3+时,通过添加PEG能有效控制合成材料的粒径,借助于PL测试手段以及余辉衰减实验,激发、发射光谱测定所得的检测波长分别为516nm、363nm,合成了粒径细小且发光性能优良的发光材料。     

One-Step Assembly of Versatile Multifunctional Coatings Based on Host-Guest and Polyphenol Chemistry

Developing a facile, efficient, and versatile polyphenol coating strategy and exploring its novel applications are of great significance in the fields of material surfaces and interfaces. Herein, a one-step assembly strategy for constructing novel tannic acid (TA) coatings via a solvent evaporation method is reported using TA and polycyclodextrin (PCD) particles (TPP). TPP with a high phenolic group activity of 88% integrates the advantages of host-guest and polyphenol chemistry. The former can drive TPP dynamically assemble into a large and collective aggregation activated by high temperature or density, and the latter provides excellent adhesion properties to substrates (0.9 mg cm⁻²). TPP can assemble into a coating (TPC) rapidly on various substrates within 1 h at 37 °C while with a high availability of feed TPP (≈90%). The resulting TPC is not only high-temperature steam-sensitive for use as an anti-fake mask but also pH-sensitive for transforming into a free-standing film under physiological conditions. Moreover, various metal ions and functional particles can incorporate into TPC to extend its versatile properties including antibacterial activity, enhanced stability, and conductivity. This work expands the polyphenol coating strategy and builds up a one-step and efficient preparation platform of polyphenol coating for multiapplication prospects in various fields.     

Anti‐Biofouling Polymer‐Decorated Lutetium‐Based Nanoparticulate Contrast Agents for In Vivo High‐Resolution Trimodal Imaging

Nanomaterials have gained considerable attention and interest in the development of novel and high‐resolution contrast agents for medical diagnosis and prognosis in clinic. A classical urea‐based homogeneous precipitation route that combines the merits of in situ thermal decomposition and surface modification is introduced to construct polyethylene glycol molecule (PEG)‐decorated hybrid lutetium oxide nanoparticles (PEG–UCNPs). By utilizing the admirable optical and magnetic properties of the yielded PEG–UCNPs, in vivo up‐conversion luminescence and T₁‐enhanced magnetic resonance imaging of small animals are conducted, revealing obvious signals after subcutaneous and intravenous injection, respectively. Due to the strong X‐ray absorption and high atomic number of lanthanide elements, X‐ray computed‐tomography imaging based on PEG–UCNPs is then designed and carried out, achieving excellent imaging outcome in animal experiments. This is the first example of the usage of hybrid lutetium oxide nanoparticles as effective nanoprobes. Furthermore, biodistribution, clearance route, as well as long‐term toxicity are investigated in detail after intravenous injection in a murine model, indicating the overall safety of PEG–UCNPs. Compared with previous lanthanide fluorides, our nanoprobes exhibit more advantages, such as facile construction process and nearly total excretion from the animal body within a month. Taken together, these results promise the use of PEG–UCNPs as a safe and efficient nanoparticulate contrast agent for potential application in multimodal imaging.     

Combined Positron Emission Tomography and Cerenkov Luminescence Imaging of Sentinel Lymph Nodes Using PEGylated Radionuclide‐Embedded Gold Nanoparticles

New imaging probes with high sensitivity and stability are urgently needed to accurately detect sentinel lymph nodes (SLNs) for successful cancer diagnosis. Herein, the use of highly sensitive and stable PEGylated radionuclide‐embedded gold nanoparticles (PEG‐RIe‐AuNPs) is reported for the detection of SLNs by combined positron emission tomography and Cerenkov luminescence imaging (PET/CLI). PEG‐RIe‐AuNPs show high sensitivity and stability both in vitro and in vivo, and are not toxic to normal ovarian and immune cells. In vivo PET/CLI imaging clearly reveals SLNs as early as 1 h post PEG‐RIe‐AuNP‐injection, with peak signals achieved at 6 h postinjection, which is consistent with the biodistribution results. Taken together, the data provide strong evidence that PEG‐RIe‐AuNPs are promising as potential lymphatic tracers in biomedical imaging for pre and intraoperative surgical guidance.     

Matrix-assisted pulsed laser deposition of polymer and nanoparticle films

Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique was used to deposit films of Poly(9,9-dioctylfluorene) - PFO and Methoxy Ge Triphenylcorrole [Ge(TPC)OCH3]. The PFO was dissolved in different matrices, like chloroform-CHCl3, tetrahydrofuran - THF and toluene with a 0.5 wt % concentration, while Ge(TPC)OCH3 was diluted in THF with a concentration of 0.01 wt %. The frozen targets were irradiated with a KrF excimer laser. The, films presented good emission properties to be exploited in light emitting devices and gas sensors based on luminescence quenching. The working principle of the MAPLE technique was used for the deposition of colloidal nanoparticles and nanorods, too. TiO2 colloidal nanoparticles (diameter: ∼10 nm) and nanorods (diameter: 5 nm; length: 50 nm) were diluted in deionised water (0.02 wt %) and toluene (0.016 wt %) respectively. The deposited nanostructures preserved dimensions and structural properties of the starting particles and the films showed very interesting electrical responses when exposed to oxidizing gases for sensing applications.     

Effects of Puerarin-Loaded Tetrahedral Framework Nucleic Acids on Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is recognized as a common refractory orthopedic disease that causes severe pain and poor quality of life in patients. Puerarin (Pue), a natural isoflavone glycoside, can promote osteogenesis and inhibit apoptosis of bone mesenchymal stem cells (BMSCs), demonstrating its great potential in the treatment of osteonecrosis. However, its low aqueous solubility, fast degradation in vivo, and inadequate bioavailability, limit its clinical application and therapeutic efficacy. Tetrahedral framework nucleic acids (tFNAs) are promising novel DNA nanomaterials in drug delivery. In this study, tFNAs as Pue carriers is used and synthesized a tFNA/Pue complex (TPC) that exhibited better stability, biocompatibility, and tissue utilization than free Pue. A dexamethasone (DEX)-treated BMSC model in vitro and a methylprednisolone (MPS)-induced ONFH model in vivo is also established, to explore the regulatory effects of TPC on osteogenesis and apoptosis of BMSCs. This findings showed that TPC can restore osteogenesis dysfunction and attenuated BMSC apoptosis induced by high-dose glucocorticoids (GCs) through the hedgehog and Akt/Bcl-2 pathways, contributing to the prevention of GC-induced ONFH in rats. Thus, TPC is a promising drug for the treatment of ONFH and other osteogenesis-related diseases.     

Induced synthesis of ZnO:Tb3+ green hybrid phosphors by the assembly of polyethylene glycol matrices

The Tb³⁺, Li⁺ ion co-doped ZnO/PEG particles were prepared by a co-precipitation approach derived from Zn(CH₃COO)₂, NaOH, CH₃COOLi and PEG in ethanol solution at room temperature. The characteristic green luminescence spectra which corresponded to f–f transitions of Tb³⁺ were observed. The microstructure and luminescent properties were investigated by XRD, SEM and luminescent spectra. The strong emissions at 484 and 545 nm were noticed from the Tb³⁺ doped ZnO/PEG composites. With regard to the comparison between the emission spectra of pure and PEG directed ZnO:Tb hybrids, it is worthy of pointing out that the PEG matrix largely improves the emission intensity of Tb³⁺.     

A reactive poly(ethylene glycol) layer to achieve specific surface plasmon resonance sensing with a high S/N ratio: the substantial role of a short underbrushed PEG layer in minimizing nonspecific adsorption

A reactive poly(ethylene glycol) (PEG)-brushed layer was constructed on a surface plasmon resonance (SPR) sensor chip using a heterobifunctional PEG possessing an acetal group at one end and a mercapto group at the other end (alpha-acetal-omega-mercapto-PEG). The density of the PEG brushed layer substantially increased with repetitive adsorption/rinse cycles of the PEG on the sensor chip, allowing dramatic reduction of nonspecific protein adsorption. Notably, formation of a short, filler layer of PEG (2 kDa) in the preconstructed longer PEG brushed layer (5 kDa) achieved almost complete prevention of nonspecific protein adsorption. The acetal group located at the distal end of the tethered PEG was converted to an aldehyde group by the acid treatment, followed by the installation of biocytin hydrazide through Schiff base formation. SPR sensing of streptavidin was done with a very high S/N ratio even in a proteinous medium using the biotinylated PEG (5 kDa) tethered chip with an inert filler layer of short PEG (2 kDa). Furthermore, the specific affinity of streptavidin for the biotinylated PEG was highly influenced by the length of the filler PEG and was significantly reduced when the length of the filler PEG was longer than that of the biotinylated PEG. This result clearly revealed the substantial importance of the steric factor on biospecific interaction at the distal end of tethered PEG on the sensor surface.     

Morphology control and luminescence properties of YAG:Eu phosphors prepared by spray pyrolysis

Starting from nitrate aqueous solutions with citric acid and polyethylene glycol (PEG) as additives, Y₃Al₅O₁₂:Eu (YAG:Eu) phosphors were prepared by a two-step spray pyrolysis (SP) method. The obtained YAG:Eu phosphor particles have spherical shape, submicron size and smooth surface. The effects of process conditions of the spray pyrolysis on the crystallinity, morphology and luminescence properties of phosphor particles were investigated. The emission intensity of the phosphors increased with increasing of sintering temperature and solution concentration due to the increase of the crystallinity and particles size, respectively. Adequate amount of PEG was necessary for obtaining spherical particles, and the optimum emission intensity could be obtained when the concentration of PEG was 0.10 g/ml in the precursor solution. Compared with the YAG:Eu phosphor prepared by citrate-gel (CG) method with non-spherical morphology, spherical YAG:Eu phosphor particles showed a higher emission intensity.     

Multifunctional Upconversion Mesoporous Silica Nanostructures for Dual Modal Imaging and In Vivo Drug Delivery

Incorporating the agents for magnetic resonance imaging (MRI), optical imaging, and therapy in one nanostructured matrix to construct multifunctional nanomedical platform has attracted great attention for simultaneous diagnostic and therapeutic applications. In this work, a facile methodology is developed to construct a multifunctional anticancer drug nanocarrier by combining the special advantages of upconversion nanoparticles and mesoporous silica. β‐NaYF₄:Yb³⁺, Er³⁺@β‐NaGdF₄:Yb³⁺ is chosen as it can provide the dual modality of upconversion luminescence and MRI. Then mesoporous silica is directly coated onto the upconversion nanoparticles to form discrete, monodisperse, highly uniform, and core–shell structured nanospheres (labeled as UCNPs@mSiO₂), which are subsequently functionalized with hydrophilic polymer poly(ethylene glycol) (PEG) to improve the colloidal stability and biocompatibility. The obtained multifunctional nanocomposites can be used as an anticancer drug delivery carrier and applied for imaging. The anticancer drug doxorubicin (DOX) is absorbed into UCNPs@mSiO₂‐PEG nanospheres and released in a pH‐sensitive pattern. In vitro cell cytotoxicity tests on cancer cells verify that the DOX‐loaded UCNPs@mSiO₂‐PEG has comparable cytotoxicity with free DOX at the same concentration of DOX. In addition, the T₁‐weighted MRI that measures in aqueous solutions reveals that the contrast brightening increases with the concentration of Gd³⁺ component. Upconversion luminescence images of UCNPs@mSiO₂‐PEG uptaken by cells show green emission under 980 nm infrared laser excitation. Finally, the nanocomposites show low systematic toxicity and high in vivo antitumor therapy efficacy. These findings highlight the fascinating features of upconversion‐mesoporous nanocomposites as multimodality imaging contrast agents and nanocarrier for drug molecules.