Journal of nanoscience and nanotechnology最新文献

Various Eu²⁺-based Ca₉Nd(PO₄)₇ (CNP:xEu²⁺, with different x values) materials are prepared via facile solid-state reaction. Their crystal structures are investigated in detail by means of the Rietveld refinement. The structure of CNP:Eu²⁺ with a trigonal lattice is analogous to that of β-Ca₃(PO₄)₂. Therefore, Eu2+ ions tend to incorporate calcium sites in the host. All the obtained samples can be excited using near ultraviolet (nUV) light to present blue-green emission. An optimal dopant concentration is verified at x = 0.8 with a large critical interaction radius (11.21 Å). The mechanism of the concentration quenching effect is assigned to the multipole-multipole interaction. CNP:xEu²⁺ possesses a short decay lifetime of ∼60 μs and can endure severe working conditions thanks to its great thermal stability. The relative photoluminescence (PL) intensity of CNP:0.8Eu²⁺ can retain 84.75% of the pristine intensity measured at room temperature, and the relative intensity remains as high as 69.97% at 423 K. The CNP:Eu²⁺ phosphors also show great performance in the WLED demonstration. The correlated color temperature (CCT) of the prototype device is 3404 K, with an extremely high Ra (97.6). Therefore, CNP:xEu²⁺ could be regarded as a promising alternative to blue green phosphors in nUV chip-based WLED applications.

The usefulness of carboxymethyl cellulose (CMC) as a matrix material in enhancing the controlled release formulations of bispyribac (BP) herbicide from the interlayer gallery of zinc hydroxide nitratesodium dodecylsulphate-bispyribac (ZHN-SDS-BP) nanocomposite was investigated. The CMC coated nanocomposite, ZHN-SDS-BP-CMC was characterised using several instruments for the determination of its physicochemical properties. The release rates of the BP were measured using a UV spectrophotometer, and the aqueous solutions containing PO^3-₄ , SO^2-₄ and Cl^- were selected as release media in the release studies so as to mimic the real conditions of environmental soil. Significant release time delays, triggered by the gelation forming ability and hygroscopic nature of CMC, were observed in all release media, and the release processes were found to behave in a concentration-dependent manner in all release media. Fitting the release data into several kinetic models demonstrated that release in aqueous solutions of Na₃PO₄ and Na₂SO₄ was governed by pseudo second order processes, whereas the release in an aqueous NaCl solution was governed by the parabolic diffusion kinetic model. The potential of CMC in prolonging the release of BP from ZHN-SDS-BP-CMC can potentially help in reducing the pollution resulting from the overuse of pesticides.

Supercapacitor and hydrogen-based fuel cells are cheap and environmental-friendly next-generation energy storage devices that are intended to replace Lithium-ion batteries. Metal oxide nanostructures having perovskite crystal structure have been found to exhibit unique electrochemical properties owing to its unique electronic band structure and multiple redox-active ions. Herein, MgTiO₃ nanoparticles (MTO-1) were synthesized by wet-chemical sol-gel technique with an average particle size of 50-55 nm, which exhibited superior supercapacitor performance of capacitance (C) = 25 F/g (at 0.25 A/g), energy density (E_D) = 17 Wh/kg, power density (P_D) = 275 W/kg and 82.41% capacitance retention (after 1000 cycles). Aqueous 1 M Mg(ClO₄)₂ solution was used as the electrolyte. MTO-1 revealed an overpotential () = 1.329 V and Tafel slope (b) = 374 mV/dec towards Oxygen Evolution Reaction (OER) electrocatalyst and exhibited = 0.914 V and b = 301.4 mV/dec towards Hydrogen Evolution Reaction (HER) electrocatalyst, both in presence of alkaline 1 M KOH solution, making these MgTiO₃ nanoparticles very promising for potential use in various technologically important electrochemical applications.

Ionic liquids are an interesting class of materials that have recently been utilized as chemotherapeutic agents in cancer therapy. Aniline blue, a commonly used biological staining agent, was used as a counter ion to trihexyltetradecylphosphonium, a known cytotoxic cation. A facile, single step ion exchange reaction was performed to synthesize a fluorescent ionic liquid, trihexyltetradecylphosphonium aniline blue. Aqueous nanoparticles of this hydrophobic ionic liquid were prepared using reprecipitationmethod. The newly synthesized ionic liquid and subsequent nanoparticles were characterized using various spectroscopic techniques. Transmission electron microscopy and zeta potential measurements were performed to characterize the nanoparticles' morphology and surface charge. The photophysical properties of the nanoparticles and the parent aniline blue compound were studied using absorption and fluorescence spectroscopy. Cell viability studies were conducted to investigate the cytotoxicity of the newly developed trihexyltetradecylphosphonium aniline blue nanoparticles in human breast epithelial cancer cell line (MCF-7) and its corresponding normal epithelial cell line (MCF-10A) in vitro. The results revealed that the synthesized ionic nanomedicines were more cytotoxic (lower IC₅₀) than the parent chemotherapeutic compound in MCF-7 cells. Nanoparticles of the synthesized ionic liquid were also shown to be more stable in both aqueous and cellular media and more selective than parent compounds towards cancer cells.

Zinc oxide nanoparticles were synthesized using different surfactants such as SDS, CTAB, Triton X-100, PVP K-30 and ethylene glycol. ZnO NPs were tested for antibacterial activity before and after calcination against different micro-organisms like E. coli and P. aeruginosa (Gram negative) as well as S. aureus and B. subtilis (Gram positive). Antibacterial activity was observed in SDScapped ZnO NPs only against B. subtilis. Antibacterial activity of ZnO-capped SDS was tested in a concentration range 0.625-10 mg/mL. Increased antibacterial activity was observed before calcination as compared to after calcination. Minimum concentration at which uncalcinated as well as calcinated SDS-capped ZnO NPs show antibacterial activity is 2.5 mg/mL and 5 mg/mL respectively. Non-antibacterial nature of ZnO NPs highlights its further use in drug delivery due to its inert nature, enhanced efficacy in association with therapeutic drugs as well as easy disposal.

Zinc oxide nanoparticles have been biosynthesized with the help of Neolamarckia cadamba leaf and fruit extracts. ZnO nanoparticles were tested for antibacterial activity before and after calcination against Gram positive (Staphylococcus aureus, Bacillus subtilis) as well as Gram negative micro-organisms (Escherichia coli, Pseudomonas aeruginosa) within the concentration range 0.625-10 mg/mL with the help of well diffusion technique. Higher antibacterial potential has been observed in ZnO nanoparticles synthesized using leaf extract in comparison with those synthesized using fruit extract. Increased antibacterial activity was observed before calcination as compared to after calcination. ZnO synthesized using leaf extract were observed to show significant antibacterial potential against E. coli, S. aureus along with P. aeruginosa before calcination as well as against E. coli after calcination. Similarly, ZnO nanoparticles synthesized using fruit extract exhibited antibacterial activity against E. coli and P. aeruginosa before calcination and against E. coli after calcination. Both the ZnO nanoparticles before and after calcination did not show any antibacterial activity against B. subtilis. Thus, ZnO nanoparticles can serve a dual purpose by its application as an antibacterial agent against susceptible micro-organisms as well as biocompatible carrier system for drug delivery applications in case of non-antibacterial properties by virtue of its inertness as well as easy disposal.

The Zn₃V₃O₈ was synthesized by solvothermal method combined with heat treatment using Zn(NO₃)₃ · 6H₂O and NH₄VO₃ as raw materials. The Zn₃V₃O₈ was doped by Co²⁺ to form Zn_2.88Co_0.12V₃O₈. The samples were characterized by X-ray diffraction and scanning electron microscopy techniques. Electrochemical tests showed that the initial discharge specific capacity for Zn_2.88Co_0.12V₃O₈ was 640.4 mAh·g^-1 when the current density was 100 mA·g^-1, which was higher than that of pure Zn₃V₃O₈ (563.5 mAh · g^-1). After 80 cycles, the discharge specific capacity of Zn_2.88Co_0.12V₃O₈ could maintain at 652.2 mAh · g^-1, which was higher than that of pure Zn₃V₃O₈ (566.8 mAh·g^-1) under same condition. The Zn_2.88Co_0.12V₃O₈ owned better rate performances than those of pure Zn₃V₃O₈ also. The related modification mechanisms were discussed in this paper.

Supported catalysts, consisting of PMo₁₂ immobilized on silver nanomaterials at different recombination time and the silver nanomaterials with different template sodium citrate amount characterized by FT-IR, XRD, SEM, UV-vis and other test methods. The results show that the AgNPs are relatively uniformed with sizes between 100-300 nm when the sodium citrate addition amount is 9.0 mL. As the reaction time of PMo₁₂/AgNPs increases, the adhesion of AgNPs on the surface of PMo₁₂ becomes more complete. Using PMo₁₂ and PMo₁₂/AgNPs composite materials as catalysts, methylene blue (MB) is photocatalytically degraded under simulated visible light conditions. The results show that PMo₁₂ can catalyze MB effectively, and the decolorization rate reached 98.6% when the catalyst content is 2 g/L, the solution pH is 3 and the MB concentration is 5 mg/L. Under the same experimental conditions, photocatalytic performance of the PMo₁₂/AgNPs system is better than that of the PMo₁₂ further improved the photocatalytic degradation effect of the MB solution with a decolorization rate of 100%. The composite still keeps good photocatalytic activity and stability after three cycles of use. Finally, the catalytic mechanism of the POMs composite material is preliminarily discussed.

Metastatic lung cancer is the leading cause of death for cancer patients. Although many chemical drugs were developed for cancer treatment, metastatic cancer mortality did not decrease significantly. In this article, we designed an Au clusters (AuCs) modified by cyclic RGD peptides which well target the integrin of human lung carcinoma cells (A549). The RGD-AuCs could well induce A549 cells apoptosis, but have no cytotoxicity on the human bronchial epithelial cells (16HBE), which are normal cells support respiratory system. The AuCs could be internalized and localized in the lysosomes of A549 tumor cells and further release into cytoplasma. We found the ROS level was increased by AuCs, and such high ROS level finally leads to depolarization of mitochondria. Eventually, the AuCs stimulating mitochondria related apoptosis pathway to induce A549 tumor cells apoptosis. We deduce the gold clusters would be an effective therapeutic candidate to against metastatic lung tumor in the future studies.

Recently, flexible electronic device technology has evolved beyond curved devices with the development of flexible/stretchable devices that can be crumpled or stretched. Both elasticity and durability are essential for these devices, which should have high-conductivity for antennas and repeatability for sensors. In addition, electronic-skins, which can have a direct impact on the human-body, should be harmless to the human-body and should not be deformed by contact with sweat or organic matter. In this study, PDMS substrates were used to satisfy the above conditions. PDMS is used to fabricate human-friendly, flexible/stretchable substrates, and it has excellent repeat durability characteristics. To improve the adhesion of these PDMS films and electrodes, conductive paste was produced based on PDMS resins of the same properties. In addition, two types of Ag particles were selected as conductive fillers because the electrode characteristics of the antenna application requires excellent conductivity, and conductive paste were produced using flake Ag, which could affect conductivity, and Ag nanoparticles that affect stretchability and repeatability. The paste was applied using a high-efficiency printing technique. The printed electrodes were cured in a thermal oven. For higher conductivity, photonic-sintering was carried out during post-processing. As a result, 1.1117×106 (S/m) had excellent conductivity, performed well in repeated tensile-durability experiments of 30% to 100 times, and produced a bow-tie antenna for the above electrodes. As a result of tensing up to 35% through a Network-Analyzer, there was no performance change in the resonance-frequency or return-loss values, and excellent electrodes were developed that would achieve excellent performance even if they are applied in the sub-frequency area of 5G-antennas in the future.