Easy One-step Method Research Articles

NaW2S4 and RbxWS2: Alternative Sources for 2M-WS2 and 1T'-WS2 Monolayers.

With the recent strive to develop novel quantum materials, including two-dimensional nanosheets, alkali-layered intercalated materials have found a new purpose as starting materials for such compounds. Enriching the library of alkali materials, we present a solid-state synthesis for preparing NaW2S4 (P1̅, No. 2) and RbxWS2 (C2/m, No. 12). Solving their crystal structure from their powder X-ray diffraction patterns, we show that both materials are layered, the former being a slightly distorted version of the latter. We compare the two structures and find that the main difference is the interlayer spacing in the a-direction. We further show that, like their cousin, KxWS2, both compounds can be deintercalated with dilute acid to form superconducting 2M-WS2, with structural and property characterization showing similar behavior, regardless of the starting material. Lastly, we find that both materials can be exfoliated in the same manner as KxWS2 to form superconducting 1T'-WS2 monolayers. We describe an easy one-step method for preparing two new layered materials and, thus, provide more opportunities to access valuable superconducting materials.

Easy preparation of a liposome-mediated protein delivery system by freeze-thawing a liposome-protein complex.

Homeostasis can be achieved by adding a protein supplement; however, an appropriate vector is required to deliver the protein into the cell because of the low stability of proteins in the blood and low cell membrane permeability. Here we report an easy one-step method of encapsulating proteins into liposomes for delivery. We used negatively charged superoxide dismutase (SOD) and a polycation liposome as protein and liposome models, respectively. Liposome-encapsulated SOD was prepared by freeze-thawing the SOD-liposome complex (lipoplexes). The amount of immobilized SOD within the lipoplex significantly increased on freeze-thawing. Surprisingly, subjecting the single-layered lipoplexes to freeze-thawing produced multilayered liposomes with SOD localized between the lipid layers. The amount of SOD delivered intracellularly significantly increased by freeze-thawing compared with that delivered by lipoplexes without freeze-thawing. SOD, liposomes, and endosomes were separately localized in the cells. The freeze-thawed lipoplex-encapsulated SOD samples were intravenously injected in mice. The SOD biodistribution was dramatically changed compared with the injection of free SOD or lipoplex. SOD was detached from the lipoplex in the bloodstream after the injection of non-freeze-thawed lipoplex, whereas the encapsulation of SOD in the liposomes upon freeze-thawing enabled the stable circulation of SOD with the liposomes in the bloodstream. This work paves the way for the application of the freeze-thawing technology for the easy one-step encapsulation of proteins into liposomes for protein delivery.

Umbilical Cord Mesenchymal Stem Cells Derived Neurospheres Promote Long-term functional recovery But Aggravate Acute Phase Inflammation in Experimental Stroke

Human umbilical cord mesenchymal stem cells (UC-MSCs) transplantation has been shown to ameliorate intracerebral hemorrhage (ICH) in animal and clinical studies. We previously reported an easy one-step method to induce UC-MSCs into neurospheres with much enhanced neurogenic and angiogenic potential. In the present study, we further evaluated the neuro-protective effects of these UC-MSCs derived neurospheres (UC-MSCs-NS) using a murine collagenase induced ICH model. We compared the effects of UC-MSCs or UC-MSCs-NS transplantation at two different time-points: 3 h after ICH induction (early transplantation) or three days after ICH induction (delayed transplantation). The results showed that UC-MSCs exhibited favorable effects at both time-points whereas UC-MSCs-NS early delivery led to increased cell apoptosis, exacerbated brain edema, enlarged ICH volume and deteriorated neurological function. In vivo inflammatory cytokine analysis indicated UC-MSCs transplantation was able to attenuate the acute phase secretion of inflammatory cytokines TNF-α and IL-1β whereas UC-MSCs-NS immediate transplantation led to increased levels of these cytokines. However, long-term follow-up experiment showed delayed UC-MSCs-NS transplantation was superior to UC-MSCs transplantation alone in terms of increased neurogenic reconstitution. Our results suggest both UC-MSCs and UC-MSCs-NS can exert favorable effects in ICH therapy but the infusion of UC-MSCs-NS should avoid the super-early phase of ICH. We believe UC-MSCs derived neurospheres should be further exploited for chronic refractory neurological disorders such as chronic phase of stroke and various neurodegenerative disorders such as Alzheimer’s disease.

One-step synthesis of easily-recoverable carboxylated biogas residues for efficient removal of heavy metal ions from synthetic wastewater

Abstract Simultaneous treatment of organic solid waste and heavy metal polluted water has drawn public attention, which can reuse solid waste resource and purify water body. However, regeneration efficiency and production cost limited the wide application of traditional biosorbents in practice. Herein, a recoverable and cost-efficient carboxymethylated biosorbent, named as CA-BR, was synthesized from biogas residues by an easy one-step method. The morphology properties of the CA-BR indicated that this novel biosorbent had a well-developed pore structure with abundant carboxyl functional groups, which contributed to the diffusion and chelation of heavy metal ions. Cu2+ uptake by CA-BR increased with the rising temperature, and the maximum adsorption capability was 76.92 mg/g. The preferential Cu2+ capture by CA-BR can also be achieved in the presence of co-existing cations (K+ and Na+, 200 mg/L), and adsorption capacity could still keep more than 67.69 mg/g. The CA-BR exhibited a good chemical stability and its adsorption capacity could still reach up to 92% after 8 continuous adsorption-desorption cycles, which indicated the feasibility of CA-BR in real applications. Furthermore, the treatment volumes of synthetic wastewater were 550 mL (275 BV) for Cu2+ (using 1 g of CA-BR), and several column adsorption-desorption cycles exhibited that there was no significant loss in Cu2+ capacity (

Greener assembling of MoO3 nanoparticles supported on gum arabic: cytotoxic effects and catalytic efficacy towards reduction of p-nitrophenol

An economical and easy one-step method for the biosynthesis of highly stable molybdenum trioxide (MoO3) nanoparticles was developed using gum arabic as a bio-template; ensuing nanoparticles (NP) were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, UV–visible spectroscopy, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The crystallinity and purity of MoO3 nanoparticles in the orthorhombic phase were confirmed by XRD analysis, and their rod-shaped identity (average sizes ranging from 7.5 to 42 nm) were observed by TEM. Cytotoxic effects of the NP were monitored using Hep G2 (human liver cancer) and HEK 293 (human embryonic kidney) cell lines via 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assays. The results of this study revealed that MoO3 nanoparticles are nontoxic towards Hep G2 cell lines and displayed negligible toxicity, even at very high concentrations (1000 ppm), although had moderate toxicity towards HEK 293 cells. Furthermore, their catalytic activity was evaluated for the reduction of p-nitrophenol to p-aminophenol. Synopsis: Green synthesis of MoO3 nanorods using gum arabic demonstrated as an eco-friendly catalyst for the conversion of p-nitrophenol with negligible toxicity towards Hep G2 cell lines.

Facile synthesis of folic acid-conjugated fluorapatite nanocrystals for targeted cancer cell fluorescence imaging

Bioluminescent calcium fluorapatite nanocrystals (TCaFAp:Eu) with controlled morphology were fabricated through an easy one-step method and found to have excellent water dispersibility and biocompatibility. Further modification of conjugation with both optical imaging and cell targeting capabilities provided useful nanoprobes for highly sensitive biorecognition applications, which was realized by grafting folic acid onto the surface of TCaFAp:Eu. The uptake of designed TCaFAp:Eu-FA by HepG2 cancer cells was verified by confocal laser scanning microscopy after 30min, whereas the uptake of TCaFAp:Eu-FA by MCF-7 cells did not work, indicating that the prepared nanoprobe effectively targeted the imaging of cancer cells with over-expression of folate receptor.

Temperature-Sensitive Gold Nanoparticle-Coated Pluronic-PLL Nanoparticles for Drug Delivery and Chemo-Photothermal Therapy.

Gold nanoparticle-coated Pluronic-b-poly(L-lysine) nanoparticles (Pluronic-PLL@Au NPs) were synthesized via an easy one-step method and employed as carriers for the delivery of paclitaxel (PTX) in chemo-photothermal therapy, in which Pluronic-PLL acts as the reductant for the formation of AuNPs without the need for an additional reducing agent. Methods: The deposition of AuNPs on the surface of Pluronic-PLL micelles and the thermal response of the system were followed via ultraviolet-visible spectroscopy and dynamic light scattering. Calcein-AM and MTT assays were used to study the cell viability of MDA-MB-231 cells treated with PTX-loaded Pluronic-PLL@Au NPs, and we then irradiated the cells with NIR light. Results: An obvious temperature response was observed for the Pluronic-PLL@Au NPs. Blood compatibility and in vitro cytotoxicity assays confirmed that the Pluronic-PLL@Au NPs have excellent biocompatibility. Compared to Taxol, the PTX-loaded Pluronic-PLL@Au NPs exhibited higher cytotoxicity in MDA-MB-231 cells. All of these results and confocal laser scanning microscopy analysis results suggest that Pluronic-PLL@Au NPs greatly enhance the cellular uptake efficiency of the drug. Conclusion: As confirmed by in vitro and in vivo studies, the combination of chemotherapy and photothermal therapy can cause more damage than chemo- or photothermal therapy did alone, demonstrating the synergistic effect of chemo-photothermal treatment. Thus, the as-prepared Pluronic-PLL@Au NPs are promising for chemo-photothermal therapy.

Preparation of gold nanostars and their study in selective catalytic reactions

Abstract In this work, gold nanostars (AuNSs) with size around 90 nm were prepared through an easy one-step method. They show excellent catalytic activity and large surface-enhanced Raman scattering (SERS) activity at the same time. Surprisingly, they exhibited different catalytic performance on the reduction of aromatic nitro compounds with different substituents on the para position. To understand such a difference, the SERS spectra were recorded, showing that the molecular orientation of reactants on the gold surface were different. We anticipate that this research will help to understand the relationship of the molecular orientation with the catalytic activity of gold nanoparticles.

Facile Photoimmobilization of Proteins onto Low-Binding PEG-Coated Polymer Surfaces

Immobilization of proteins onto polymer surfaces usually requires specific reactive functional groups. Here, we show an easy one-step method to conjugate protein covalently onto almost any polymer surface, including low protein-binding poly(ethylene glycol) (PEG), without the requirement for the presence of specific functional groups. Several types of proteins, including alkaline phosphatase, bovine serum albumin, and polyclonal antibodies, were photoimmobilized onto a PEG-coated polymer surface using a water-soluble benzophenone as photosensitizer. Protein functionality after immobilization was verified for both enzymes and antibodies, and their presence on the surface was confirmed by X-ray photoelectron spectroscopy (XPS) and confocal fluorescence microscopy. Conjugation of capture antibody onto the PEG coating was employed for a simplified ELISA protocol without the need for blocking uncoated surface areas, showing ng/mL sensitivity to a cytokine antigen target. Moreover, spatially patterned attachment of fluorescently labeled protein onto the low-binding PEG-coated surface was achieved with a projection lithography system that enabled the creation of micrometer-sized protein features.

Annealing Effect on Microstructure and Superconductivity of K $$_{x}$$ x Fe $$_{y}$$ y Se $$_{2}$$ 2 Synthesized by an Easy One-step Method

High-quality superconducting K $$_{x}$$ Fe $$_{y}$$ Se $$_{2}$$ single crystals were synthesized using an easy one-step method. Detailed annealing studies were performed to make clear the phase formation process in K $$_{x}$$ Fe $$_{y}$$ Se $$_{2}$$ . Compatible observations were found in temperature-dependent X-ray diffraction patterns, back-scattered electron images and corresponding electromagnetic properties, which proved that good superconductivity performance was closely related to the microstructure of superconducting component. Analysis based on the scaling behavior of flux pinning force indicated that the dominant pinning mechanism was $$\Delta T_\mathrm{c}$$ pinning and independent of connectivity. The annealing dynamics studies were also performed, which manifested that the humps in temperature-dependent resistance curves were induced by competition between the metallic/superconducting and the semiconducting/insulating phases.

One-step synthesis of linear and cyclic RGD conjugated gold nanoparticles for tumour targeting and imaging

We developed an easy one-step method for the synthesis of linear and cyclic arginine-glycine-aspartate (RGD) conjugated gold nanoparticles (GNPs). Compared with the previously reported multistep process, our method is simple, time-efficient, and cost-effective. Interestingly, the RGD peptides can function as reducing, protecting and tumour targeting agents and the prepared GNPs possess good stability and good biocompatibility. The uptake of RGD–GNPs by human tumour cells was assessed by dark-field light scattering imaging and transmission electron microscopy (TEM). Both types of RGD–GNPs can specifically target the melanoma A375 cells better than the breast cancer MCF-7 cells, which express the integrin αvβ3 at low level. We also compared the cellular uptake ability between the linear and cyclic RGD conjugated GNPs quantitatively. In order to validate the cellular uptake mechanism, the competitive inhibition assay was performed. Various important results indicated that the activity of the RGD peptides to specifically target tumour cells was not influenced noticeably after conjugation with GNPs.

Improvement of the hydrogen storage kinetics of NaAlH4 with nanocrystalline titanium dioxide loaded carbon spheres (Ti-CSs) by melt infiltration

Nanocrystalline titanium dioxide loaded carbon spheres (Ti-CSs) with 10wt% TiO2 were synthesized through an easy one-step method using phenolic resols, titania nanoparticles and Pluronic F127 as organic carbon sources, inorganic precursors and surfactant, respectively. The results show that the as-prepared Ti-CSs composite is spherical shape with a diameter ranging from 0.3 to 2 μm, and rutile TiO2 nanoparticles are distributed on the surface of the carbon spheres. Then the kinetics of NaAlH4 was improved through depositing it on the surface of as-prepared Ti-CSs by melt infiltration. The results show that NaAlH4 with Ti-CSs exhibits better hydrogen desorption kinetics than TiF3 or nanocrystalline TiO2 catalysted-NaAlH4, and it starts to release hydrogen at about 40 °C and releases about 25% of the hydrogen content during heating to 60 °C. The results from SEM and XPS show that hydrogen storage properties of NaAlH4 were considerably improved due to the formation of special structure during melt infiltration and the nanocrystalline TiO2 and/or amorphous phase Ti–Al clusters near the subsurface sites, which succeed in combining catalyst addition (TiO2 nanoparticles) and nanoconfinement to improve the kinetics of NaAlH4.

A simple method for producing mesoporous anatase TiO 2 nanocrystals with elevated photovoltaic performance

Mesoporous anatase TiO 2 nanocrystals with high crystallinity and large surface area were synthesized by an easy one-step method, combining hydrolysis and alcothermal processes, without the use of a templating agent. The photovoltaic performance of photoanodes for dye-sensitized solar cell under 1 sun (AM 1.5G) illumination gave a solar conversion efficiency as high as 6.06%, an enhancement of ∼20% with respect to that of a reference photoanode made of a commercial TiO 2 (Degussa, P25) powder.

One-step synthesis of iron-oxide-loaded functionalized carbon spheres

Size- and surface-tunable carbon spheres loaded with iron-oxide (α-Fe 2O 3 or Fe 3O 4) nanoparticles have been obtained from 4-ferrocenyl-butyric acid via an easy one-step method in a solvothermal system. The composites obtained have been fully characterized by X-ray powder diffraction, scanning and transmission electron microscopy, Fourier transform infrared spectrometry, Raman spectrometry and vibrating sample magnetometry. The results show that the diameters and morphologies of the spheres can be tuned by adjusting the experimental parameters including the reaction temperature, time, medium, and precursor concentration. Most of the iron-oxide nanoparticles are evenly distributed on the surface of the carbon spheres and also the surface of the iron-oxide-loaded carbon spheres has large numbers of functional groups. The α-Fe 2O 3-loaded carbon spheres show special magnetic properties with a coercivity of 101.5 Oe and a remanent magnetization of 0.203 emu/g at room temperature, while the coercivity and remanent magnetization for the Fe 3O 4-loaded carbon spheres are 58.4 Oe and 0.174 emu/g, respectively. A possible formation mechanism is proposed and discussed based on the features of the reaction system.

Efficiency of porous hydrophilic polymer-based packing materials in chromatographic analysis of drugs existing with polypeptide

A size monodispersed restricted-access polymeric packing material has been prepared through a simple and easy one-step method of co-polymerization of glycerol monomethacrylate and glycerol dimethacrylate with cyclohexanol as prorogen. A typical seeded polymerization (two step swelling and polymerization method) in an aqueous medium gave a 90 % yield of porous beads which could be utilized as a packing material in high performance liquid chromatography (HPLC) without any size classification due to the excellent size monodispersity. A BET measurement and size exclusion chromatography in either tetrahydrofuran or water revealed that the prepared material had only small pores (around 100 A in diameter). It showed ample hydrophobicity for the separation of hydrophilic drug molecules in 10% aqueous acetonitrile buffer, while polypeptides such as bovine serum albumin were excluded and eluted before the void volume of the column with quantitative recovery.