Latest ArticlesThe observation of single-particle surface-enhanced Raman scattering (SERS) has generated considerable interest both in the nanomaterials filed and in the single-particle spectroscopy community. It is a challenge to realize rapid, facile, and high throughput SERS at single nanoparticle level. Here, without the complex experimental device and difficult experimental operations, a general single-particle SERS technique has been achieved by using dark-field-assisted surface-enhanced Raman spectroscopy (DFSERS). This advanced method provides in-situ characterization of the chemical reaction performance at single gold nanorod.
Nowadays, tremendous researches have been focused on the core-shell lipid-polymer nanoparticles (LPNs) due to the advantages of both liposomes and polymer nanoparticles. In this work, LPNs were applied to encapsulate brinzolamide (Brz-LPNs) for achieving sustained drug release, improving drug corneal permeation and enhancing drug topical therapeutic effect. The structure of Brz-LPNs was composed of poly(lactic-co-glycolic) acid (PLGA) nanocore which encapsulated Brz (Brz-NPs) and lipid shell around the core. Brz-LPNs were prepared by a modified thin-film dispersion method. With the parameters optimization of Brz-LPNs, optimal Brz-LPNs showed an average particle size of 151.23±1.64 nm with a high encapsulation efficiency (EE) of 86.7%±2.28%. The core-shell structure of Brz-LPNs were confirmed by transmission electronic microscopy (TEM). Fourier transformed infrared spectra (FTIR) analysis proved that Brz was successfully entrapped into Brz-LPNs. Brz-LPNs exhibited obvious sustained release of Brz, compared with AZOPT® and Brz-LPs. Furthermore, the corneal accumulative permeability of Brz-LPNs significantly increased compared to the commercial available formulation (AZOPT®) in vitro. Moreover, Brz-LPNs (1 mg/mL Brz) showed a more sustained and effective intraocular pressure (IOP) reduction than Brz-LPs (1 mg/mL) and AZOPT® (10 mg/mL Brz) in vivo. In conclusion, Brz-LPNs, as promising ocular drug delivery systems, are well worth developing in the future for glaucoma treatment.
A straightforward coassembly strategy was developed for the preparation of polymeric nanoparticles driving by the intermolecular hydrogen bond between neutral poly(2-methyl-2-oxaozline) (PMeOx), tannic acid (TA) and doxorubicin hydrochloride (Dox). The occurrence of the hydrogen-bonding amongst the different functionalities within the formed nanoparticles was verified by infrared (IR) spectroscopy. Scanning electron microscopy (SEM), dynamic light scattering (DLS), UV-vis absorption and photoluminescent measurements indicated the rapid formation of uniform and water dispersible/stable nanoparticles. The relative poor stability of PMeOx-TA-Dox in fetal bovine serum (FBS) solution enabled the rapid separation of Dox and PMeOx-TA, facilitating the release of Dox and its entrance into cellular nuclei as revealed by confocal laser scanning microscopy (CLSM). The presented strategy may provide an efficient alternative for the construction of multifunctional nanomedicines.
Callicarpa bodinieri is a Chinese traditional medicine herbwith anti-inflammatory activity in clinic. Herein, we report two new 9, 10-seco and etherified abietane diterpenoids bodinieric acids J and K(1 and 2)and one known compound (3) isolated from the leaves and twigs of this plant. Their chemical structures were elucidated by detailed spectrometry data analysis and DP4+ NMR calculation methods. Hypothetical biosynthetic pathways of 1-3 were preliminarily speculated. Compound 3 inhibited inflammasome activation and exhibited blockage of NLRP3 inflammasome activation at non-cytotoxic concentrations in vitro.
Developing low-cost and high performance catalysts to replace precious metal based catalysts for oxygen reduction reaction (ORR) is one of the most feasible ways to promote the commercial application of fuel cells. In this work, flower-like CoS and octahedral CoS2 are synthesized by a facile one-pot hydrothermal method without any adjunction of surfactants or follow-up thermolysis, their catalytic performance towards ORR in alkaline electrolyte are comparatively investigated. The results reveal that CoS2 outperforms CoS owing to the higher electron density around S-S bond of S22- in the crystal structure, which promotes the adsorption of oxygen on catalyst surface and facilitates the breakage of O-O bond in oxygen, leading to direct 4-electron transfer ORR. When CoS2 particles are dispersed on the surface of rGO with large surface area, their ORR performance could be further improved.
(C6H14N2)[NH4(ClO4)3] is a newly developed porous hybrid inorganic-organic framework material with easy access and excellent detonation performances, however, its thermal properties is still unclear and severely hampered further applications. In this study, thermal behaviors and non-isothermal decomposition reaction kinetics of (C6H14N2)[NH4(ClO4)3] were investigated systematically by the combination of differential scanning calorimetry (DSC) and simultaneous thermal analysis methods. In-situ FTIR spectroscopy technology was applied for investigation of the structure changes of (C6H14N2)[NH4(ClO4)3] and some selected referents for better understanding of interactions between different components during the heating process. Experiment results indicated that the novel molecular perovskite structure renders (C6H14N2)[NH4(ClO4)3] better thermal stability than most of currently used energetic materials. Under high temperatures, the stability of the cage skeleton constructed by NH4+ and ClO4- ionsdetermined the decomposition process rather than organic moiety confined in the skeleton. The simple synthetic method, good detonation performances and excellent thermal properties make (C6H14N2)[NH4(ClO4)3] an ideal candidate for the preparation of advanced explosives and propellants.
Ionophore can prominently improve the ion permeability of cell membrane and disrupt cellular ion homeostasis. Most studies regarding ionophore facilitating ion transmembrane transport focus on artificial liquid-liquid interfaces, which have large difference from the actual environment of cell membrane. Here, we construct a supported lipid bilayer on a gold nanoparticles film modified ZnSe prism as an appropriate model of cell membrane to investigate the dynamic of the ion transport facilitated by ionophore using surface enhanced infrared absorption spectroscopy (SEIRAS). We find that the ion transmembrane transport consists of two steps: The ion transmembrane transport starts with the association/disassociation between ion and ionophore at the edge of lipid bilayer; The second step is the transfer of ion-ionophore complex across lipid bilayer. Our results show that the complex transfer across the lipid bilayer is the rate determining step.
A range of bench-stable carbazole-containing hypervalent iodine(Ⅲ) reagents were synthesized by I-N bond formation in good yields. This kind of benziodoxolone reagents was used for a C-N coupling reaction to introduce a carbazole group to aromatic heterocycle compounds.
Lung cancer is the most malignant tumor disease with the highest diagnosis and mortality rate in China. The development of therapeutic drugs is the current research focus. Dai-Bai-Jie is a traditional medicine of the Dai nationality, which is commonly used in the treatment of decreasing swelling, alleviating pain and detoxification. Most of the current researches focused on the component analysis of Dai-Bai-Jie, but few researches studied on its antitumor and pharmacological effect. In this study, we incubated A549 cells with different concentrations of Dai-Bai-Jie. The cell proliferation experiment showed that the DaiBai-Jie solution inhibited the proliferation of A549 cells and caused cell apoptosis. In this work, we confirmed that Dai-Bai-Jie had an inhibitory effect on the proliferation and migration of non-small cell lung cancer A549, which may be used as a novel candidate of anti-tumor therapy for lung cancer patients.
ZnO-CeO2/SBA-15 catalysts were prepared by two kinds of solid-state grinding method and used for the production of 1, 3-butadiene (1, 3-BD) from ethanol. A mixture of SBA-15 (with or without organic template) and metal precursors were ground in solid-state. The obtained catalysts were characterized by TG, N2 adsorption-desorption, TEM, XRD, Py-FTIR and NH3-TPD techniques. Superior dispersion of metal oxides and more exposed acid sites were achieved on the catalyst 10Zn1Ce5-AS with the presence of organic template in SBA-15 during the solid-state grinding process. The catalytic performance was evaluated in a fixed-bed reactor and a 1, 3-butadiene selectivity of as high as 45% is achieved. This is attributed to the coupling effect of Zn and Ce species in the mesopores of SBA-15, in which Zn promotes ethanol dehydrogenation and Ce enhances aldol-condensation, respectively. Additionally, solvent-free method inspires new catalyst synthesis strategy for the production of 1, 3-butadiene from ethanol.