Quantification of Phosphatidylserine Molecules on the Surface of Individual Cells Using Single-Molecule Force Spectroscopy.

Identification of the phosphatidylserine (PS) discrepancies occurring on the cellular membrane during apoptotic processes is of the utmost importance. However, monitoring the quantity of PS molecules in real-time at a single-cell level currently remains a challenging task. Here, we demonstrate this objective by leveraging the specific binding and reversible interaction exhibited by the zinc(II) dipyridinamine complex (ZnDPA) with PS. Lipoic acid-functionalized ZnDPA (LP-ZnDPA) was subsequently immobilized onto the surface of an atomic force microscopy cantilever to form a force probe, ALP-ZnDPA, enabling a PS-specific dynamic imaging and detection mode. By utilizing this technique, we can not only create a heat map of the expression level of PS with submicron resolution but also quantify the number of molecules present on a single cell's surface with a detection limit of 1.86 × 104 molecules. The feasibility of the proposed method is demonstrated through the analysis of PS expression levels in different cancer cell lines and at various stages of paclitaxel-induced apoptosis. This study represents the first application of a force probe to quantify PS molecules on the surface of individual cells, providing insight into dynamic changes in PS content during apoptosis at the molecular level and introducing a novel dimension to current detection methodologies.

Frenkel Defect-modulated Anti-thermal Quenching Luminescence in Lanthanide-doped Sc2 (WO4 )3.

Although large amount of effort has been invested in combating thermal quenching that severely degrades the performance of luminescent materials particularly at high temperatures, not much affirmative progress has been realized. Herein, we demonstrate that the Frenkel defect formed via controlled annealing of Sc2 (WO4 )3 :Ln (Ln=Yb, Er, Eu, Tb, Sm), can work as energy reservoir and back-transfer the stored excitation energy to Ln3+ upon heating. Therefore, except routine anti-thermal quenching, thermally enhanced 415-fold downshifting and 405-fold upconversion luminescence are even obtained in Sc2 (WO4 )3 :Yb/Er, which has set a record of both the Yb3+ -Er3+ energy transfer efficiency (>85 %) and the working temperature at 500 and 1073 K, respectively. Moreover, this design strategy is extendable to other hosts possessing Frenkel defect, and modulation of which directly determines whether enhanced or decreased luminescence can be obtained. This discovery has paved new avenues to reliable generation of high-temperature luminescence.

A luminescent view of the clickable assembly of LnF3 nanoclusters.

Nanoclusters (NCs) bridge the gap between atoms and nanomaterials in not only dimension but also physicochemical properties. Precise chemical and structural control, as well as clear understanding of formation mechanisms, have been important to fabricate NCs with high performance in optoelectronics, catalysis, nanoalloys, and energy conversion and harvesting. Herein, taking advantage of the close chemical properties of Ln3+ (Ln = Eu, Nd, Sm, Gd, etc.) and Gd3+-Eu3+ energy transfer ion-pair, we report a clickable LnF3 nanoparticle assembly strategy allowing reliable fabrication of diversely structured NCs, including single-component, dimeric, core-shelled/core-shell-shelled, and reversely core-shelled/core-shell-shelled, particularly with synergized optical functionalities. Moreover, the purposely-embedded dual luminescent probes offer great superiority for in situ and precise tracking of tiny structural variations and energy transfer pathways within complex nanoarchitectures.

Photocatalytic partial oxidation of methanol to methyl formate under visible light irradiation on Bi-doped TiO2 via tuning band structure and surface hydroxyls.

Preparing visible light responsive catalysts for partial oxidation of methanol to methyl formate is a challenging issue. This work addresses the synthesis, characterization and theoretical calculation of Bi doped TiO2 catalysts as well as their photocatalytic performance and reaction mechanism for MF synthesis from methanol. The catalysts were prepared by a simple wet chemical method. The results of the characterization and theoretical calculation evidenced that bismuth was intercalated in the lattice of anatase by the substitution of titanium. Impurity levels were formed in the valence band, conduction band and between the two bands. The Bi 6s and 5p orbitals contributed to the formation of the impurity levels. The photo-excited electrons transited from the valence band via impurity levels, formed by Bi 6s orbitals, to the conduction band. The doping of Bi enhanced surface hydroxyls, reduced the band gaps and raised the valence band edges (VBE) of the Bi doped catalyst. The Bi doped catalysts were visible light responsive due to the reduced band gap. The surface hydroxyls were beneficial to the methanol conversion, and the rise of the VBE enhanced the redox potential of the photogenerated holes. Only moderate redox potentials and sufficient surface hydroxyls could lead to high methanol conversion and MF selectivity. This study is of great significance to the development of the photocatalytic synthesis theory and provides a green route for MF synthesis from methanol.

Efficient preparation of kaolinite/methanol intercalation composite by using a Soxhlet extractor.

Kaolinite/methanol intercalation composite (KMe) is a key precursor for preparing clay-based inorganic/organic hybrid materials and kaolinite nanoscrolls. However, synthesis of KMe is a time and methanol dissipative process and the complexity of this process also limits its further applications. In this study, Soxhlet extractor was introduced to synthesize an intercalation composite and KMe was efficiently synthesized in a Soxhlet extractor through a continuous displacement process by using kaolinite/DMSO intercalation composite (KD) as a precursor. The formation process of kaolinite/methanol intercalation composite was studied by X-ray diffraction (XRD) and infrared spectroscopy (IR). The results showed that the DMSO in kaolinite could be completely displaced by methanol in this process and the preparation of KMe could be completed in 8 hours, which was far faster than the reported methods. Moreover, methanol used in this process could be recycled. Furthermore, the resulting material could be successfully used to prepare kaolinite nanoscrolls in high yield.

A stable mixed lanthanide metal-organic framework for highly sensitive thermometry.

A family of lanthanide-based MOFs (Ln-MOFs) with high thermal and chemical stability have been successfully synthesized by a solvothermal method. Owing to the intrinsic robustness of the framework and temperature-dependent luminescence behaviour of lanthanides, Eu3+/Tb3+-mixed MOFs ([(CH3)2NH2]Eu0.036Tb0.964BPTC) have also been successfully synthesized and targeted for developing excellent luminescent thermometers. The obtained mixed Ln-MOF exhibits ratiometric temperature sensing based on the distinguished characteristic emission of lanthanides with a wide temperature range from 77 K to 377 K. Particularly, the temperature sensor shows good linear responses from 220 K to 310 K with the maximum relative sensitivities (Sm) of 9.42% per K at 310 K. This value is comparable to those of the most excellent Ln-MOF thermometers reported. Besides, the temperature-dependent luminescent colours could also be systematically tuned from green, through yellow to red with increasing temperature, which can be clearly and directly observed even by the naked eye or a camera, thus also allowing colorimetric luminescence thermometry.

A Novel Nitrogen Enriched Hydrochar Adsorbents Derived from Salix Biomass for Cr (VI) Adsorption.

Hydrochars were prepared from Salix by hydrothermal carbonization, and characterized by FT-IR, 13C NMR, XPS, UV-vis, TG, SEM and BET techniques. The results showed that the hydrochars with molecular sieve-type open pore structure contained numbers of oxygen and nitrogen functional groups, which benefited the adsorption and diffusion of adsorbent Cr (VI). The hydrochar obtained from 26 h reaction (HC-26) was indicated an excellent adsorbent compared to the commercial activated carbon, and its maximum removal efficiency for Cr (VI) reaches up to 99.84% at pH 1. Langmuir´s model is well fitted the experimental equilibrium adsorption data of total Cr. The bath experiment results showed that Cr (VI) could be removed rapidly in the first 300 min. Furthermore, the adsorption kinetics process of HC-26 could be described by pseudo-second-order model. Based on the above results, HC-26 could be acted as a potential efficient adsorbent for removal of Cr (VI) from aqueous solution.

Inherently Eu2+ /Eu3+ Codoped Sc2 O3 Nanoparticles as High-Performance Nanothermometers.

Luminescent nanothermometers have shown competitive superiority for contactless and noninvasive temperature probing especially at the nanoscale. Herein, we report the inherently Eu2+ /Eu3+ codoped Sc2 O3 nanoparticles synthesized via a one-step and controllable thermolysis reaction where Eu3+ is in-situ reduced to Eu2+ by oleylamine. The stable luminescence emission of Eu3+ as internal standard and the sensitive response of Eu2+ emission to temperature as probe comprise a perfect ratiometric nanothermometer with wide-range temperature probing (77-267 K), high repeatability (>99.94%), and high relative sensitivity (3.06% K-1 at 267 K). The in situ reduction of Eu3+ to Eu2+ ensures both uniform distribution in the crystal lattice and simultaneous response upon light excitation of Eu2+ /Eu3+ . To widen this concept, Tb3+ is codoped as additional internal reference for tunable temperature probing range.

Non-Noble Metal Nanoparticles Supported by Postmodified Porous Organic Semiconductors: Highly Efficient Catalysts for Visible-Light-Driven On-Demand H2 Evolution from Ammonia Borane.

From the viewpoint of controlling the visible-light-driven activities of catalysts containing metal nanoparticles (NPs) by tuning the microstructures of semiconducting supports, we employed a postsynthetic thermal modification approach to prepare carbon nitride (C3N4) species featuring different microstructures and then we synthesized Co and Ni NPs supported by these C3N4 species, which were used to catalyze the room-temperature H2 evolution from ammonia borane (NH3BH3). The systematic investigation showed that the catalysts had different activities under light irradiation. Compared with the pristine C3N4-based catalyst, all the modified C3N4-based catalysts had enhanced activities. The highest active Co catalyst with a total turnover frequency of 93.8 min-1 was successfully obtained, which exceeded the values of all the reported heterogeneous noble metal-free catalysts. The structure characterizations indicated that the postmodified porous C3N4 species had the different band structures, photoluminescence lifetime, and photocurrent density under visible light irradiation, leading to the different separation efficiency of photogenerated charge carriers. These characteristics helped us regulate the electronic characteristics of Co and Ni NPs in the supported catalysts and then led to the significantly different and enhanced activity in the visible-light-driven H2 evolution.

Highly Water-Stable Lanthanide-Oxalate MOFs with Remarkable Proton Conductivity and Tunable Luminescence.

Although proton conductors derived from metal-organic frameworks (MOFs) are highly anticipated for various applications including solid-state electrolytes, H2 sensors, and ammonia synthesis, they are facing serious challenges such as poor water stability, fastidious working conditions, and low proton conductivity. Herein, we report two lanthanide-oxalate MOFs that are highly water stable, with so far the highest room-temperature proton conductivity (3.42 × 10-3 S cm-1 ) under 100% relative humidity (RH) among lanthanide-based MOFs and, most importantly, luminescent. Moreover, the simultaneous response of both the proton conductivity and luminescence intensity to RH allows the linkage of proton conductivity with luminescence intensity. This way, the electric signal of proton conductivity variation versus RH will be readily translated to optical signal of luminescence intensity, which can be directly visualized by the naked eye. If proper lanthanide ions or even transition-metal ions are used, the working wavelengths of luminescence emissions can be further extended from visible to near infrared light for even wider-range applications.

Highly Efficient Catalytic Hydrogen Evolution from Ammonia Borane Using the Synergistic Effect of Crystallinity and Size of Noble-Metal-Free Nanoparticles Supported by Porous Metal-Organic Frameworks.

A series of nonprecious metal nanoparticles (NPs) supported by metal-organic framework MIL-101 were synthesized using four methods and their catalytic performance on hydrogen evolution from ammonia borane (NH3BH3) was studied. The results showed that the crystalline Co NPs with size of 4.5-8.5 and 14.5-24.5 nm had low activities featuring the total turnover frequency (TOF) values of 9.9 and 4.5 molH2 molcat-1 min-1, respectively. In contrast, the amorphous Co NPs with size of 1.6-2.6 and 13.5-24.5 nm exhibited high activities featuring the total TOF values of 51.4 and 22.3 molH2 molcat-1 min-1, respectively. The remarkably different activities could be ascribed to the different crystallinity and size of Co NPs in the catalysts. Moreover, the ultrasound-assisted in situ method was also successfully applied to bimetallic systems, and MIL-101-supported amorphous CuCo, FeCo and NiCo NPs had the catalytic activities with total TOF values of 51.7, 50.8, and 44.3 molH2 molcat-1 min-1, respectively, which were the highest in the values of the reported non-noble metal Co-based catalysts. The present approach, namely, using the synergistic effect of crystallinity and size of metal NPs, may offer a new prospect for high-performance and low-cost nanocatalysts.

From Graphite to Graphene Oxide and Graphene Oxide Quantum Dots.

Many methods have been reported for synthesizing graphene oxide (GO) and graphene oxide quantum dots (GOQDs) where a tedious operational procedure and long reaction time are generally required. Herein, a facile one-pot solvothermal method that allows selective synthesis of pure GO and pure GOQDs, respectively is demonstrated. What is more, the final product of either GO or differently sized GOQDs can be easily controlled by adjusting the reaction temperatures or reactant ratios, which is also feasible when enlarged to gram scale. The 2.5 nm GOQDs show excellent photoluminescence that can be utilized for bioimaging or distinctive detection of Eu3+ and Tb3+ from their respective mixtures with other rare earth and/or transition metal ions, at sub-ppm level.

Synthesis and Characterization of α-ZrP@CHI Drug Deliver System.

This paper described the controlled synthesis and release properties of a new kind of multifunctional drug-release system which was prepared by encapsulation of zirconium bis-(monohydrogen orthophosphate) monohydrate (α-ZrP) with chitosan (CHI). As obtained the α-ZrP@CHI nanocomposites were found to possess the structural features of both α-ZrP and CHI. The release properties of the α-ZrP@CHI nanocomposites were evaluated using Gentamicin sulfate as the model drug. And α-ZrP@CHI composites showed a prolonged drug release time compared with α-ZrP, which can be attributed to the unique lamellar structure and the encapsulation with CHI. The controlled synthesis of α-ZrP@CHI nanocomposite thus provided a new opportunity for future development of delivery vehicles.

Synthesis and Characteristic of the NaYF4/Fe3O4@SiO2@Tb(DBM)3 . 2H2O/SiO2 Luminomagnetic Microspheres with Core-Shell Structure.

The structure and properties of the multifunctional nanoparticles were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Photoluminescence spectra and Vibrating sample magnetometer (VSM). The experimental results show that the microsphere has the magnetic core and silica shell bonded with terbium complex. These multifunctional nanoparticles exhibit strong visible emission and up-conversion emission, which is based on the use of up-converting nanoparticles (UCNPs) of the NaYF4:Yb3+, Er3+/Tm3+ type that can be excited with 980 nm laser light to give a green and red luminescence, moreover, nanoparticles possess magnetism with a saturation magnetization of 18.48 emu/g and paramagnetism at room temperature.

From ScOOH to Sc2 O3 : Phase Control, Luminescent Properties, and Applications.

In the controlled synthesis of ScOOH nanomaterials, the surfactant molecule Na3 Cit not only helps to manipulate the crystallographic structures, but also to initiate the transfer from α-ScOOH to γ-ScOOH. Further annealing of ScOOH generates cubic Sc2 O3 with morphologies inherited from respective origins. When doped with lanthanide ions, both ScOOH and Sc2 O3 can be utilized for high-temperature probing and light-emitting-diode lighting.

Inorganic nanovehicle for potential targeted drug delivery to tumor cells, tumor optical imaging.

In this work, an inorganic multifunctional nanovehicle was tailored as a carrier to deliver anticancer drug for tumor optical imaging and therapy. The nanovehicle could be used as a dually targeted drug nanovehicle by bonded magnetical (passive) and folic acid (active) targeting capabilities. In addition, it was developed using rhodamine 6G (R6G) as a fluorescence reagent, and an α-zirconium phosphate nanoplatform (Zr(HPO4)2·H2O, abbreviated as α-ZrP) as the anticancer drug nanovehicle. The novel drug-release system was designed and fabricated by intercalation of α-ZrP with magnetic Fe3O4 nanoparticles and anticancer drug 5-fluorouracil (5-FU), followed by reacting with a folate acid-chitosan-rhodamine6G (FA-CHI-R6G) complex, and then α-ZrP intercalated with Fe3O4 nanoparticles and 5-fluorouracil (5-FU) was successfully encapsulated into chitosan (CHI). The resultant multifunctional drug delivery system was characterized by scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, photoluminescence spectra, magnetometry, fluorescence microscopy imaging studies and other characterization methods. Simultaneously, the drug release in vitro on the obtained nanocomposites that exhibited a sustained release behavior was carried out in buffer solution at 37 °C, which demonstrated clearly that the nanocomposites shown a sustained release behavior. Meanwhile, cell culture experiments also indicated that the drug-release system had the potential to be used as an dually targeted drug nanovehicle into the tumor cells.

N-Doped carbon coated hollow Ni(x)Co(9-x)S8 urchins for a high performance supercapacitor.

N-doped carbon coated NixCo9-xS8 (NixCo9-xS8@C) hollow urchins have been synthesized via a two-step solvothermal synthesis and an in situ polymerization in dopamine together with a post-annealing process. The characterization indicated that NixCo9-xS8@C hollow urchins have urchin-like morphology and a uniform size distribution. Furthermore, there is a complete phrase transformation from the as obtained NiCo2S4/NixCo9-xS8 hybrid to NixCo9-xS8 during the thermal annealing process. More importantly, as electrochemical materials, NixCo9-xS8@C has a high specific capacitance (1404.0 F g(-1) at 2.0 A g(-1)) and excellent cycling performance (95.8% capacitance retention of the highest value after 2000 cycles). These results can be attributed to the coating of N-doped carbon, which gives the composite good conductivity. Additionally, the phase transformation from NiCo2S4/NixCo9-xS8 to NixCo9-xS8 during the thermal annealing greatly enhanced the redox reaction of the Co and Ni species.

Synthesis of star poly(N-isopropylacrylamide) with a core of cucurbit[6]uril via ATRP and controlled thermoresponsivity.

A series of CB[6]-based macroinitiators with "n" bromo-initiation sites on the "equator" of CB[6] is developed for the synthesis of CB[6]-star poly(N-isopropylacrylamide) (CB[6]-star PNIPAM) by atom transfer radical polymerization. By taking advantage of the exceptional binding affinity of the CB[6] core, CB[6]-star PNIPAM is used as a host macromolecule to construct large compound vesicles in the presence of protonated n-butylamine at pH 5.63. The deprotonated n-butylamine is detached from the CB[6] core at pH 11.1, which destructs the vesicular structures. For CB[6]-star PNIPAM, the thermoresponsive properties can be adjusted by simply changing the formation and destruction of the inclusion complexes of the CB[6] core with n-butylamine. These results suggest that the prepared CB[6]-star PNIPAM shows pH and temperature responsiveness, which has great potential for the design of a dual response smart material.

Shape-controlled synthesis of NiCo2S4 and their charge storage characteristics in supercapacitors.

In this work, a facile hydrothermal approach for the shape-controlled synthesis of NiCo2S4 architectures is reported. Four different morphologies, urchin-, tube-, flower-, and cubic-like NiCo2S4 microstructures, have been successfully synthesized by employing various solvents. The obtained precursors and products have been characterized by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. It is revealed that the supersaturation of nucleation and crystal growth is determined by the solvent polarity and solubility, which can precisely control the morphology of NiCo2S4 microstructures. The detailed electrochemical performances of the various NiCo2S4 microstructures are investigated by cyclic voltammetry and galvanostatic charge-discharge measurements. The results indicate that the tube-like NiCo2S4 exhibits promising capacitive properties with high capacitance and excellent retention. Its specific capacitance can reach 1048 F g(-1) at the current density of 3.0 A g(-1) and 75.9% of its initial capacitance is maintained at the current density of 10.0 A g(-1) after 5000 charge-discharge cycles.

Hydrothermal synthesis and upconversion properties of CaF2:Er3+/Yb3+ nanocrystals.

A series of rare-earth ions (Er3+ and Yb3+) Co-doped CaF2 upconversion luminescent nanomaterials have been successfully prepared via a facile hydrothermal method using pluronic p123 (p123), pluronic F127 (F127) and sodium citrate as surfactants at 180 degrees C with different reaction time. The crystallographic phase, size and morphology can be controlled by simply tuning the reaction parameters such as the types of surfactants and the reaction time. It is found that reaction time and surfactant play a key role in forming the nanocrystals with different morphologies. X-ray diffraction, field-emission scanning electron microscopy FE-SEM, and photoluminescence spectra were used to characterize the structure, morphology and upconversion luminescence properties of CaF2:Er3+/Yb3+ upconversion nanomaterials, respectively. The experimental results indicate that three monodispersive and highly uniform CaF2:Er3+/Yb3+ nanocrystals with mean size of 200 nm, 3 um, and 700 nm have cubic and sphere shapes, respectively. While the possible mechanisms of upconversion luminescence are analyzed by the diagram of proposed energy transfer mechanisms, the schematic energy level diagrams showing typical upconversion processes for Er3+ also reveals that the as-synthesized CaF2:Er3+/Yb3 nanomaterials may be in the cubic structure with space group Fm-3m, in which Ln3+ cations occupy crystal lattice positions with lower point symmetry, leading to a high upconversion efficiency under the excitation of a 980 nm diode laser.