A fluorescent and chemiluminescent difunctional mesoporous silica nanoparticle as a label for the ultrasensitive detection of cancer cells

A new kind of ultrabright fluorescent and chemiluminescent difunctional mesoporous silica nanoparticle (FCMSN) is reported. A luminescent dye, Rhodamine 6G or tris(2,2′-bipyridyl)dichlororuthenium(II) hexahydrate (Rubpy), is doped inside nanochannels of a silica matrix. The hydrophobic groups in the silica matrix avoid the leakage of dye from open channels. The amines groups on the surface of the FCMSN improve the modification performance of the nanoparticle. Because the nanochannels are isolated by a network skeleton of silica, fluorescence quenching based on the inner filter effect of the fluorescent dyes immobilized in nanochannels is weakened effectively. The Quantum Yield of obtained 90 nm silica particles was about 61%. Compared with the fluorescent core–shell nanoparticle, the chemiluminescence reagents can freely enter the nanoparticles to react with fluorescent dyes to create chemiluminescence. The results show that the FCMSN are both fluorescent labels and chemiluminescent labels. In biological applications, the NaIO₄ oxidation method was proven to be superior to the glutaraldehyde method. The amount of amino could affect the specificity of the FCMSN. The fluorescence microscopy imaging demonstrated that the FCMSN is viable for biological applications.     

Preparation,Characterization, Luminescent and Electrochemical Properties of Ru(bpy)2-functionalized Silica Nanoparticles

Ru(II)-complex functionalized silica nanoparticles(nano-SiO₂) were prepared via a coordination reaction of cis-dichlorobis(2,2'-bipyridine)ruthenium[Ru(bpy)₂Cl₂] complex with poly(4-vinylpyridine)(P4VP)-modified nano-SiO₂ particles. Both the Ru-complex and the functionalized nano-SiO₂P4VP-Ru(bpy) hybrids were doped in poly(methyl methacrylate)(PMMA) to form optically transparent thin films. The composition and spectroscopic properties of the nano-SiO₂P4VP-Ru(bpy) hybrids were evaluated with the help of thermogravimetric and elemental analysis, and UV-Vis absorption spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and fluorescence spectroscopy. Microscopy images revealed that the nanohybrids were approximately 12 nm in diameter and readily formed aggregates following the functionalization with P4VP and Ru(bpy)₂Cl₂. The as-prepared nano-SiO₂P4VP-Ru(bpy) hybrids produced emissions at approximately 604 and 654 nm under radiation both in solution and in doped thin films. Finally, cyclic voltammetry studies on the nanohybrid-modified electrode revealed a redox couple with the cathodic and anodic potentials at approximately 0.28 and 0.73 V(vs. Ag/AgCl), attributed to the one electron transfer of Ru(bpy)₂^2+/3+ immobilized on the nano-SiO₂ particles.     

ZnS:Mn nanoparticles conjugated to sol–gel-derived silica matrices

Composites from ZnS:Mn nanoparticles and modified silicas are of interest for a broad range of potential applications in the form of films, structured particles, and self-assembled structures (e.g., colloidal crystals). They combine the versatility of silica sol gel chemistry with the wealth of functionalities available from doped nanoparticulate semiconductors (e.g., optical, electrical, and magnetic). In this work, ZnS:Mn nanoparticles have been prepared and modified in such a way that they can be incorporated seamlessly, either by inclusion or by covalent bonding into silicas. Functionalization was achieved through the use of silanes or thioles. Further processing by standard sol gel chemistry then either led directly to covalent conjugation with the silica network formed after condensation, or to isolated particles encapsulated in a silica shell. The results are heavily loaded (up to 30 wt%), transparent (including semiconductor particles that are smaller than 15 nm) and luminescent films, and massive bodies. In this work, the progress of nanocomposite formation was followed mainly by luminescence spectroscopy. Further work will have to address the electrical and magnetic properties of these nanocomposites as well.     

Bright luminescent, colloidal stable silica coated CdSe/ZnS nanocomposite by an in situ, one-pot surface functionalization

In this article, a systematic study of the design and development of surface-modification schemes for silica coated nanocomposite via an in situ, one-pot way is presented. Silica coated CdSe/ZnS nanoparticles were prepared in a water-in-oil microemulsion and subsequently surface modified via addition of various organosilane reagents to the microemulsion system. The resulting functionalized composite nanoparticles were characterized by different techniques like Transmission Electron Microscopy (TEM), photoluminescence spectroscopy and zeta-potential measurements. The results demonstrate that depending on the sequence of addition of silica precursors and organosilanes the product can show bright luminescence or considerable colloidal stability. The organosilanes molecules which are used here, act both as a stabilizer of the microemulsion system (regarding the charge compensation) and as a functional group the final product on top of silica shell. Using these surface-modification process, silica coated nanoparticles can be more readily conjugated with biomolecules and used as highly luminescent, sensitive, and reproducible labels in bioanalytical applications. Most importantly such surface functionalization could pave the way for controlled multi-mixed nanoparticles encapsulation (for example magnetic and QD nanoparticles).     

纳米Ag@SiO_2核壳结构的表面等离子体共振效应对铕配合物的荧光增强作用(英文)

分别制备了二氧化硅壳层厚度为10、25和80 nm的三种Ag@S O2纳米粒子,合成了铕与不同比例苯甲酸根(BA)的配合物、铕与1,10-邻菲罗啉(phen)及2,2′-联吡啶(bpy)的配合物,并对其进行表征.表征结果推测配合物的组成为Eu(BA)nCl3-n·2H2O(n=1,2,3)、Eu(phen)Cl3·2H2O和Eu(bpy)Cl3·2H2O.配合物的荧光光谱显示,在加入Ag@Si O2纳米粒子后,复合物的荧光强度有不同程度的增加,这可能是由于表面等离子体共振造成的.不同硅壳厚度的Ag@Si O2纳米粒子的荧光增强顺序是25 nm80 nm10 nm,这表明二氧化硅核壳厚度约25 nm时有较强的表面等离子体共振效应.此外,在这些复合物中,Eu(phen)Cl3·2H2O复合物的增强效果是最强的,而Eu(BA)nCl3-n·2H2O的增强效果是最弱的.在三个苯甲酸铕配合物中,Eu(BA)3·2H2O的增强效果最弱,其他两个苯甲酸铕复合物增强效果相对较好.原因可能是含氮配合物(Eu(phen)Cl3·2H2O和Eu(bpy)Cl3·2H2O)可以和Ag@SiO2更好地成键,而苯甲酸铕配合物和Ag@Si O2纳米粒子的作用相对较弱.Ag@SiO2纳米粒子有望应用于增强稀土材料的发光.     

HEDP-capped Terbium Orthophosphate Nanoparticles as Sensitive Luminescent Probes for the Detection of Pb2+ Ions

Terbium orthophosphate nanoparticles were synthesized using 1-hydroxy ethylidene-1,1-diphosphonic acid(HEDP) as a capping ligand under hydrothermal conditions at 80℃. These HEDP-capped TbPO₄ nanoparticles owned a hexagonal phase structure according to the powder X-ray diffraction(XRD) results and were spherical monodispersed particles with a diameter of about 10 nm confirmed by transimission electron microscope(TEM) images. Interestingly, the luminescent intensities of the HEDP-capped TbPO₄ nanoparticles decreased obviously in the presence of Pb²⁺ ions and such a quenching behavior of luminescence was well fitted by the Stern-Volmer equation.     

Stable Near-infrared-emitting Radical Nanoparticles for Fluorescence Imaging

Stable neutral luminescent radicals with unpaired electrons exhibit unique spin-allowed doublet-doublet transitions, which has attracted significant attention. Although they are pure organic molecules without metal ions thus thought to have low biological toxicity, the application of luminescent radicals to bioimaging has rarely been reported. Here, a stable radical with efficient near-infrared(NIR) emission and good photostability was designed and synthesized. After being wrapped into nanoparticles, it was applied to cell fluorescence imaging. The cytotoxicity experiments suggested that the nanoparticles have remarkable biocompatibility and excellent stability. An NIR fluorescent signal was successfully observed in the cytoplasm of HCT116 cells. The experimental results gave the first example of NIR emitting radical nanoparticles for cell fluorescence imaging and proved the feasibility of the application of luminescent radicals to fluorescence imaging.     

固定化金属离子亲和发光二氧化硅纳米粒子的制备及其用于磷酸化蛋白免疫印迹标记

发展了一种能够识别磷酸化蛋白的固定化金属离子亲和发光二氧化硅纳米粒子用于免疫印迹(Western Blot)磷酸化蛋白的标记.首先通过反相微乳液St?ber方法合成了掺杂异硫氰酸荧光素硅烷化衍生物的发光二氧化硅(FITC@SiO2)球形纳米粒子,粒子平均粒径为60 nm.然后通过共聚反应在FITC@SiO2纳米粒子表面...     

CO2/NIR light dual-controlled nanoparticles for dsDNA unzipping

Both of carbon dioxide(CO2)and near-infrared(NIR)light as triggers for non-invasive remotely control are attracting wide attentions due to their good biocompatibility and easy operation.Here,CO2/NIR light dual controlled nanoparticles are proposed to remotely regulate the unzipping of dsDNA by using imidazole functionalized conjugated polymer nanoparticles(imidazole-CPNs).The dsDNA successfully coats on the shell of imidazole-CPNs to form imidazole-CPNs/dsDNA assembly due to intensively electrostatic interaction triggered by CO2.Furthermore,the unzipping process of dsDNA is remotely controlled by NIR light based on the photothermal effect,and it can be readily monitored by the fluorescence intensity of ethidium bromide(EB)and CD spectra of dsDNA.Thus,dual stimulation responsive imidazole-CPNs effectively control dsDNA unzipping under CO2 stimulus and NIR light,promising a new direction in the biological applications of DNA,such as the treatments of diseases caused by gene duplication abnormality.     

Preparation of mesophase pitch doped with TiO2 or TiC particles

The co-pyrolysis of a petroleum residue with two different sources of titanium (tetrabutyl-ortotitanate (TBO) or titanium carbide nano-powder) was carried out to obtain mesophase pitches containing TiO₂ or TiC nanoparticles. Co-pyrolysis is an appropriate technique to achieve a good dispersion and low particle size. In the case of TBO, TiO₂ nanoparticles (5–20 nm) are observed, which are forming aggregates, the largest of them being 1–2 μm. In the case of TiC nano-particles, they are more difficult to disperse and larger aggregates are formed, although the final material is rather homogenous. The chemistry of pyrolysis for the production of doped and undoped mesophase pitches has been followed by means of solvent insolubility, XRD, XPS, FTIR and elemental analysis. They show evidences of promotion of the formation of mesophase in the presence of the titanium-containing particles, especially in the presence of TiO₂. The final materials can be of great value as precursors to produce high density titanium doped graphites for nuclear and space applications.     

多色高发光效率CsPbX3(X=Cl,Br,I)钙钛矿量子点的制备及其在发光二极管中的应用

采用室温合成法制备出一系列具有高发光效率和多色发光的CsPbX₃钙钛矿量子点(PQDs),反应全过程快速简便,且通过调节不同的卤素组成(Cl,Br,I)可以实现CsPbX₃ PQD的多色发光。 通过表征证明,CsPbX₃ PQDs呈立方晶型,平均粒径约为10 nm,发射光谱覆盖可见光波长范围为410~630 nm,半峰宽14~38 nm,荧光量子产率10%~90%。 最后将CsPbX₃ PQDs应用于发光二极管(LED)器件的制备中,在恒定电压下工作时,能保持LED器件的发光颜色、强度和颜色坐标不变。     

In-vitro cytotoxicity evaluation of surface design luminescent lanthanide core/shell nanocrystals

Lanthanide nanocrystals (NCs) are the most promising luminescent materials for bioapplications, but their use is hindered by difficulties in obtaining biocompatible and photoluminescence lanthanide NCs. To solve this problem, a simple and versatile strategy was developed for improving the luminescence efficiency with the hydrophilicity of the lanthanide NCs. In this study, the effects of shell formation on structural, morphological, and optical properties (optical absorption, band-gap energy, excitation, emission, and luminescent decay time) were evaluated. To improve the luminescence efficiency and aqueous dispersion, luminescent core-NCs were encapsulated with inert NaGdF₄ and amorphous silica layers. These surface coating layers significantly improved the luminescence efficiency and dispersion of the core/shell NCs in which the silica surface provides a negatively charged surface to the NCs at physiological pH. Optical properties of these NCs strongly depend on the external change of NCs, demonstrating the impact of coating in improving the luminescence efficiency. The outcomes can be ascribed to the development of surface chemical bonds between core/shell and noncrystalline SiO₂ shell via GdOSi bridges, activating the ‘dormant’ Ce³⁺ and Tb³⁺ ions on the surface of NCs. An intensive emission and good hydrophilic property from the active functional groups in solutions show a great potential for applications such as multi-analyte fluorescent biolabeling, optical biosensing, staining, display, and other optical technologies. The core/shell/SiO₂ NCs showed higher nontoxicity and biocompatibility with respect to the core NCs because of biocompatible silica surface modification, facilitating entry into the living cells. Therefore, this developed synthesis approach might advance the field of biomolecule-based nanotechnology in near future.     

Controllable Multicolor Upconversion Luminescence by Tuning the NaF Dosage

Multicolor upconversion (UC) luminescence of NaYF₄:Yb³⁺/Er³⁺ nanoparticles (NPs) was successfully tuned by simply controlling the NaF dosage. Unlike UC nanocrystals previously reported in the literature with multicolor emission obtained by varying the rare‐earth dopants, the current work developed a new approach to tune the UC emission color by controlling the NaF concentration without changing the ratio and dosage of rare‐earth ions. TEM and powder XRD were used to characterize the shape, size, and composition of the UC luminescent nanocrystals. The luminescence images, emission spectra, and multicolor emission mechanism of the NPs have also been demonstrated. As a result of the excellent ability of this new method to manipulate color emission, this will open up new avenues in the areas of bioprobes, light‐emitting devices, color displays, lasers, and so forth. To demonstrate their biological applications, the water‐stable, biocompatible, and bioconjugatable NaYF₄:Yb³⁺/Er³⁺@poly(acrylic acid) NPs were synthesized by this developed strategy and applied in targeted‐cell UC luminescence imaging.     

上转换纳米粒子的Y(OH)CO3壳层包覆及壳层转化

Along with the promising applications of lanthanide doped upconversion nanomaterials in diverse fields such as biology, anti-counterfeiting, and lasering, the demand for multifunctional upconversion nanomaterials is increasing. One effective means of obtaining these nanomaterials is to fabricate upconversion nanomaterial-based heterostructures, which may provide superior properties as compared to the sum of the parts. However, obtaining heterostructured upconversion nanomaterials remains challenging mainly because of the crystal lattice mismatch between upconversion nanomaterials and other materials. Typically used strategies for synthesizing upconversion nanomaterial-based heterostructures are applicable only to limited types of materials. Alternatively, transformation of the intermediate layer is a promising strategy used to obtain these heterostructures. Nevertheless, this method remains in its infancy and, to date, only a few intermediate layers have been developed. New types of intermediate layers are therefore highly desirable. In this study, we show that amorphous Y(OH)CO₃ can be a promising candidate as an intermediate layer for fabricating upconversion nanoparticle-based heterostructures. As a proof-of-concept experiment, ligand-free NaGdF₄:Yb/Tm upconversion nanoparticles were first prepared as core nanoparticles. The Y(OH)CO₃ shell was then directly coated on the NaGdF₄:Yb/Tm upconversion nanoparticles in an aqueous solution using urea and Y(NO₃)₃, by a homogeneous precipitation approach. The thickness of the resulting Y(OH)CO₃ shell could be tuned by adjusting the amounts of either urea or Y(NO₃)₃. The as-coated Y(OH)CO₃ shell could be easily converted to YOF by heating at 300 ℃, yielding NaGdF₄:Yb/Tm@YOF core-shell heterostructured nanoparticles. In addition, we found that the NaGdF₄ core could be transformed to lanthanide oxide fluoride if the NaGdF₄:Yb/Tm@Y(OH)CO₃ core-shell nanoparticles were heated at 350 ℃. We also observed that treating the NaGdF₄:Yb/Tm@Y(OH)CO₃ core-shell nanoparticles at even higher temperatures (e.g., 400 ℃) produced aggregations of nanoparticles without regular morphologies. The transformation of the shell can be attributed to the decomposition of Y(OH)CO₃ and reactions between the Y(OH)CO₃ shell and NaGdF₄ core. Meanwhile, the transformation of the NaGdF₄ core at relatively high temperatures could be primarily due to the reactions between Y(OH)CO₃ and NaGdF₄. Notably, in this study, the core-shell structured nanoparticles, with either a Y(OH)CO₃ or YOF shell, maintained the photon upconversion properties of NaGdF₄:Yb/Tm upconversion nanoparticles. In addition, the method used here could be extended to the coating of other shells such as Tb(OH)CO₃ and Yb(OH)CO₃ on upconversion nanoparticles. Moreover, the NaGdF₄:Yb/Tm@Y(OH)CO₃ core-shell nanoparticles could be transformed to other nanoparticles with novel structures such as yolk-shell nanoparticles. These results can pave the way for preparing upconversion nanoparticle-based heterostructures and multifunctional composites, thus promoting new applications of upconversion nanoparticles.     

Hue‐ and Chromaticity‐Based Exploration of Surface Complexation‐Induced Tunable Emission from Non‐Luminescent Quantum Dots

Herein we report the use of a hue parameter of HSV (Hue, Saturation and Value) color space—in combination with chromaticity color coordinates—for exploring the complexation‐induced luminescence color changes, ranging from blue to green to yellow to white, from a non‐luminescent Fe‐doped ZnS quantum dot (QD). Importantly, the surface complexation reaction helped a presynthesized non‐luminescent Fe‐doped ZnS QD to glow with different luminescence colors (such as blue, cyan, green, greenish‐yellow, yellow) by virtue of the formation of various luminescent inorganic complexes (using different external organic ligands), while the simultaneous blue‐ and yellow‐emitting complex formation on the surface of non‐luminescent Fe‐doped ZnS QD led to the generation of white light emission, with a hue mean value of 85 and a chromaticity of (0.28,0.33). Furthermore, the surface complexation‐assisted incorporation of luminescence properties to a non‐luminescent QD not only overcomes their restricted luminescence‐based applications such as light‐emitting, biological and sensing applications but also bring newer avenues towards unravelling the surface chemistry between QDs and inorganic complexes and the advantage of having an inorganic complex with QD for their aforementioned useful applications.     

Synthesis and sol–gel assembly of nanophosphors

Some recent works made in our group on inorganic nanophosphors are briefly reviewed in this paper. We first present the synthesis of highly concentrated semiconductor quantum dot colloids allowing the extension of the well-known oxide sol–gel process to chalcogenide compounds. Secondly, we show the synthesis and the chemical functionalization of lanthanide-doped insulator nanoparticles. In particular, the annealing process of these particles at high temperature leads to highly bright nanocrystals, which can be used as biological luminescent labels or for integration in transparent luminescent coatings. Finally, we consider luminescent transition metal clusters, which combine the inorganic structure of nanoparticles with the monodispersity and the easy functionalization of the organic molecules. Emphasis is put on the original thermochromic luminescence properties of copper iodide clusters trapped in siloxane-based films.     

Establishing the Structural Integrity of Core–Shell Nanoparticles against Elemental Migration using Luminescent Lanthanide Probes

Core–shell structured nanoparticles are increasingly used to host luminescent lanthanide ions but the structural integrity of these nanoparticles still lacks sufficient understanding. Herein, we present a new approach to detect the diffusion of dopant ions in core–shell nanostructures using luminescent lanthanide probes whose emission profile and luminescence lifetime are sensitive to the chemical environment. We show that dopant ions in solution‐synthesized core–shell nanoparticles are firmly confined in the designed locations. However, annealing at certain temperatures (greater than circa 350 °C) promotes diffusion of the dopant ions and leads to degradation of the integrity of the nanoparticles. These insights into core–shell nanostructures should enhance our ability to understand and use lanthanide‐doped luminescent nanoparticles.     

Rapid one-step synthesis, characterization and functionalization of silica coated gold nanoparticles

This paper describes a rapid, simple and one-step method for preparing silica coated gold (Au@SiO₂) nanoparticles with fine tunable silica shell thickness and surface functionalization of the prepared particles with different groups. Monodispersed Au nanoparticles with a mean particle size of 16 nm were prepared by citrate reduction method. Silica coating was carried out by mixing the as prepared Au solution, tetraethoxysilane (TEOS) and ammonia followed by microwave (MW) irradiation. Although there are several ways of coating Au nanoparticles with silica in the literature, each of these needs pre-coating step as well as long reaction duration. The present method is especially useful for giving the opportunity to cover the colloidal Au particles with uniform silica shell within very short time and forgoes the use of a silane coupling agent or pre-coating step before silica coating. Au@SiO₂ nanoparticles with wide range of silica shell thickness (5-105 nm) were prepared within 5 min of MW irradiation by changing the concentration of TEOS only. The size uniformity and monodispersity were found to be better compared to the particles prepared by conventional methods, which were confirmed by dynamic light scattering and transmission electron microscopic techniques. The prepared Au@SiO₂ nanoparticles were further functionalized with amino, carboxylate, alkyl groups to facilitate the rapid translation of the nanoparticles to a wide range of end applications. The functional groups were identified by XPS, and zeta potential measurements.     

Luminescent nanoparticles prepared by encapsulating lanthanide chelates to silica sphere

The luminescent nanoparticles were prepared by encapsulating the [LnL₄]^? (Ln = Eu, Tb; L = BTFA, HFAA, TTFA, TFAA) complexes anion into the silicon framework. We firstly synthesized a series of novel siloxy-bearing lanthanide complex precursor, and then encapsulated them into the silica sphere by a modified Stöber process. As a result, four europium and two terbium tetrakis β-diketonate complexes functionalized silica sphere nanoparticles were obtained and characterized in detail using Fourier transform infrared spectra, X-ray diffraction, scanning electronic microscope, thermogravimetric analysis, luminescence excitation and emission spectroscopy, luminescence lifetime measurements, and diffuse reflectance UV–Vis spectroscopy. The result shows that these luminescent nanoparticles maintain the distinctive luminescence character of lanthanide chelate including broad excitation spectra, line-like emission spectra, high quantum efficiency, and long luminescent lifetime, which makes them great potential application in the synthesis of luminescent nanoparticle.     

Study on the Dye-Doped Funcionalized Silica Nanoparticles for The Recognition of SmIgG+B Lymphocytes

The development of sensitive non-isotopic detection sys tem for biological and medicinal applications, such as single cell analyse, DNA sequence, clinical diagnose etc., has driven nanomaterials more towards cell biology and ultrasensitive immunoassay^[1]. Semiconductor nanoparticles have been used for coupling biomolecules but suffer from some disadvantages including poor solubility in water, blinking properties or low quantum yields^[1,3,4]. In this paper, we developed a novel dye-doped functionalized silica nanoparticles and used for detection of SmIgG⁺ B lymphocytes.