Co-delivery of hydrophilic and hydrophobic drugs by micelles: a new approach using drug conjugated PEG–PCLNanoparticles

Co-delivery strategy has been proposed to minimize the amount of each drug and to achieve the synergistic effect for cancer therapies. A conjugate of the antitumor drug, doxorubicin, with diblock methoxy poly (ethylene glycol)-poly caprolactone (mPEG-PCL) copolymer was synthesized by the reaction of mPEG–PCL copolymer with doxorubicin in the presence of p-nitrophenylchloroformate. The conjugated copolymer was characterized in vitro by ¹H-NMR, FTIR, DSC and GPC techniques. Then, the doxorubicin conjugated mPEG–PCL(DOX–mPEG-PCL) was self-assembled into micelles in the presence of curcumin in aqueous solution. The resulting micelles were characterized further by various techniques such as dynamic light scattering (DLS) and atomic force microscopy (AFM).The encapsulation efficiency of doxorubicin and curcumin were 82.31?±?3.32 and 78.15?±?3.14%, respectively. The results revealed that the micelles formed by the DOX–mPEG-PCL with and without curcumin have spherical structure with average size of 116 and 134?nm respectively. The release behavior of curcumin and doxorubicin loaded to micelles were investigated in a different media. The release rate of micelles consisted of the conjugated copolymer was pH dependent as it was higher at lower pH than in neutral condition. Another feature of the conjugated micelles was a sustained release profile. The cytotoxicity of micelles were evaluated by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, atetrazole) assay on lung cancer A549 cell lines. In vitro cytotoxicity assay showed that the mPEG–PCL copolymer did not affect the growth of A549 cells. The cytotoxic activity of the micelles against A549 cells was greater than free doxorubicin and free curcumin.     

Enhancement of solubility and oral bioavailability of manidipine by formation of ternary solid dispersion with d-α-tocopherol polyethylene glycol 1000 succinate and copovidone

Context: Low bioavailability of oral manidipine (MDP) is due to its low water solubility.

Objective: The objective of this study was to increase the solubility and bioavailability of MDP by fabricating ternary solid dispersion (tSD) with d-α-tocopherol polyethyleneglycol-1000-succinate and copovidone.

Methods: In this study, solid ternary phase diagram was applied in order to check the homogeneity of tSD prepared by melting and solidifying with dry ice. The physicochemical properties of different formulations were determined by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and hot stage microscopy. Their solubility, dissolution, stability and bioavailability were also investigated.

Results and discussion: The results demonstrated that tSD obtained from ternary phase diagram divided into homogeneous and non-homogeneous regions. In the homogenous region, the transparent characteristics of tSD was observed and considered as a glass solution, which have a higher MDP solubility than that in non-homogenous region. The hot stage microscopy, DSC and PXRD confirmed that solid dispersion was formed in which MDP was molecularly dispersed in the carriers, especially in the homogenous region of phase diagram. FTIR analysis demonstrated strong hydrogen bonding between amine groups of MDP and carbonyl groups of copovidone, which supported a higher solubility and dissolution of tSD. The pharmacokinetic study in Wistar rats showed that the tSD had the greatest effect on oral bioavailability. Immediate hypotensive effect of tSD was also observed in vivo.

Conclusions: The improvement of stability, dissolution and oral bioavailability of MDP could be achieved by using tSD technique.     

Synthesis of novel counter electrode by combination of mesoporous–macroporous CZTS films for enhanced performance of quantum-dots sensitized solar cells

This present study aims to manifest the potential of CZTS films as a low-cost counter electrode (CE) in quantum-dots sensitized solar cells (QDSSCs). Hitherto, numerous researchers have reported the application of either CZTS nano particles or films as a counter electrode in dye sensitized solar cells. However, its use in QDSSCs is scarcely reported. Herein, CdS quantum-dots sensitized ZnO film is used as photoanode. In the beginning, as a counter electrode, two different CZTS films (mesoporous and macroporous) are prepared using two different deposition techniques (spray pyrolysis and spin coating, respectively). For the meso-CZTS film, high V_OC and FF are observed, whereas, for the macro-CZTS film, high J_SC is observed. Hence, to take the advantage of both, subsequently, a film (meso–macro-CZTS) comprising mesoporous film upon the macroporous film is prepared and applied as CE. For the meso–macro-CZTS, substantial enhancement in power conversion efficiency (PCE) is observed. Additionally, to compare the results with commonly reported CEs (SnS/FTO and Pt–FTO) are also applied in QDSSCs. Moreover, to improve the PCE combination of these CEs along with meso–macro-CZTS, for instance, CZTS/SnS/FTO and CZTS/Pt–FTO are also applied as CE. The highest efficiency of 4.34% is achieved with CZTS/Pt–FTO.     

A novel method for synthesis of α-Si3N4 nanowires by sol–gel route

Abstract

Silicon nitride (Si₃ N₄) nanowires have been prepared by carbothermal reduction followed by the nitridation (CTRN) of silica gel containing ultrafine excess carbon obtained by the decomposition of dextrose over the temperature range of 1200–1350 °C. This innovative process involves repeated evacuation followed by purging of nitrogen gas so that the interconnected nanopores of the gel are filled with nitrogen gas prior to heat treatment. During heat treatment at higher temperatures, the presence of nitrogen gas in the nanopores of the gel starts the CTRN reaction simultaneously throughout the bulk of the gel, leading to the formation of Si₃ N₄ nanowires. The in situ generated ultrafine carbon obtained by the decomposition of dextrose decreases the partial pressure of oxygen in the system to stabilize the nanowires. The nanowires synthesized by this process are of ～500 nm diameter and ～0.2 mm length. The product was characterized by scanning electron microscope (SEM), energy dispersive x-ray analysis (EDX), x-ray diffraction (XRD) and infrared (IR) spectra.     

Thermal stability of the αZn–Mg2Zn11 and αZn–βAl eutectics obtained by Bridgman growth

The thermal stability of rod-like Zn–Mg2Zn11 and lamellar Zn–Al eutectics obtained by Bridgman growth of Zn–3.1 wt% Mg and Zn–5 wt% Al has been studied for soaking times up to 10 h at 300 and 350°C, respectively. Two-dimensional coarsening resulted for Zn–Mg2Zn11 grown at 0.5 and 1 mm s-1 while fault migration was operative for lamellar Zn–Al grown at 0.1 and 1 mm s-1. Hardness decreased with increased soaking time according to a Hall–Petch relationship with mean interphase spacing and the values H0 and kY accord well with the values obtained from the Hall–Petch relationship for HV of as-solidified Zn–Mg2Zn11 and Zn–Al with eutectic interphase spacing, respectively. © 1998 Chapman & Hall     

Nanodispersions stabilized by β-cyclodextrin nanosponges: application for simultaneous enhancement of bioactivity and stability of sage essential oil

The aim of this work was to stabilize oil-in-water nanoemulsion containing sage (salvia officinalis) essential oil, for enhancing its physicochemical stability and enlarging its industrial applications. New β-cyclodextrin nanosponges were synthesized by polycondensation using naphthalene dicarboxylic acid as cross-linking agent, the latter system was characterized by FTIR spectroscopy, SEM, BET, and powder XRD. Nanoemulsions stabilized by free β-cyclodextrin or nanosponges were prepared, their physicochemical properties were determined (particles size, zeta potential, viscosity, turbidity, and essential oil content) and their stability was studied at different storage temperatures (4?°C, 20?°C, and 40?°C) during 3?months. Pharmaceutical application of prepared nanoemulsions was investigated in vitro by dissolution test study and in vivo by their antidiabetic activity evaluation in rats. Sage essential oil nanoemulsion stabilized by β-cyclodextrin-naphthalene dicarboxylic acid nanosponges presents very high stability and promising uses in pharmaceutical industry.     

Formulation design and optimization of novel soft glycerosomes for enhanced topical delivery of celecoxib and cupferron by Box–Behnken statistical design

Background: The present study describes glycerosomes (vesicles composed of phospholipids, glycerol and water) as a novel drug delivery system for topical application of celecoxib (CLX) and cupferron (CUP) compound.

Aim: The goal of this research was to design topical soft innovative vesicles loaded with CLX or CUP for enhancing the efficacy and avoiding systemic toxicity of CLX and CUP.

Methods: CLX and CUP loaded glycerosomes were prepared by hydrating phospholipid-cholesterol films with glycerol aqueous solutions (20–40%, v/v). Box–Behnken design, using Design-Expert® software, was the optimum choice to statistically optimize formulation variables. Three independent variables were evaluated: phospholipid concentration (X₁), glycerol percent (X₂) and tween 80 concentration (X₃). The glycerosomes particle size (Y₁), encapsulation efficiency percent (Y₂: EE %) and drug release (Y₃) were selected as dependent variables. The anti-inflammatory effect of CLX and CUP glycerosomal gel was evaluated by carrageenan-induced rat paw edema method followed by histopathological studies.

Results: The optimized formulations (CLX2* and CUP1*) showed spherical morphology under transmission electron microscopy, optimum particle size of 195.4?±?3.67?nm, 301.2?±?1.75?nm, high EE of 89.66?±?1.73%, 93.56?±?2.87%, high drug release of 47.08?±?3.37%, 37.60?±?1.89% and high cumulative amount of drug permeated in 8?h of 900.18?±?50.24, 527.99?±?34.90?µg.cm^?2 through hairless rat skin, respectively. They also achieved significant remarkable paw edema inhibition in comparison with the control group (p? Conclusion: Finally, the administration of CLX2* and CUP1* loaded glycerosomal gel onto the skin resulted in marked reduction of edema, congestive capillary and inflammatory cells and this approach may be of value in the treatment of different inflammatory disorders.     

A novel strategy for improving upconversion luminescence of NaYF4：Yb, Er nanocrystals by coupling with hybrids of silver plasmon nanostructures and poly（methyl methacrylate） photonic crystals

The coupling of upconversion nanophosphors （UCNPs） with the surface plasmonic resonance （SPR） of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achieve stable, reproducible and effective upconversion luminescence （UCL） enhancement through such coupling. In this work, we present a novel strategy to improve UCL of NaYF4：ybB,Er3. UCNPs, by combining the near-field coupling of SPR of silver and the far-field coupling of poly（methyl methacrylate） （PMMA） opal photonic crystals （OPCs） with the UCNPs. In order to control the effective interaction distance between the UCNPs and the SPR, a porous silver film consisting of randomly distributed silver nanoparticles （NPs） （〉 100 nm） was prepared which demonstrated strong SPR over a broad wavelength range, and its coupling to the UCNPs was found to be much stronger than that of a dense film. In the far-field coupling of OPCs, the photonic stop band （PSB） of the PMMA OPCs was tuned to 980 nm, matching exactly the excitation light. By modulating the particle size of the UCNPs, and the direction and excitation power of the incident light, a maximum enhancement of 60-fold was observed, which is an important advance for metaMnduced UCL enhancement systems.     

Synthesis of α-Mo_2C by Carburization of α-MoO_3 Nanowires and Its Electrocatalytic Activity towards Tri-iodide Reduction for Dye-Sensitized Solar Cells

Nanowire-shaped α-Mo O3 was synthesized on a large scale by hydrothermal route.Nanocrystalline α-Mo2 C phase was obtained by the carburization of α-Mo O3 nanowires with urea as a carbon source precursor.The phase purity and crystalline size of the synthesized materials were ascertained by using powder X-ray diffraction.The shape and morphology of synthesized materials were characterized by field-emission scanning electron microscopy(FE-SEM) and high resolution transmission electron microscopy(HR-TEM).The electrocatalytic activity of α-Mo2 C for I-/I3-redox couple was investigated by the cyclic voltammetry.The synthesized α-Mo2 C was subsequently applied as counter electrode in dye-sensitized solar cells to replace the expensive platinum.     

Synthesis of LiNi1−xCoxPO4/C nanocomposite cathode for lithium ion batteries by a combination of aerosol and powder technologies

Pure LiNi_1?xCo_xPO₄ (x?=?0, 0.2, 0.5, 0.8, 1) was synthesized by spray pyrolysis followed by heat treatment. The X-ray diffraction (XRD) patterns of LiNi_1?xCo_xPO₄ were indexed to olivine structure with a Pnma space group. The peak shift and variation of lattice parameters suggested that LiNi_1?xCo_xPO₄ solid solution was formed. Moreover, LiNi_1?xCo_xPO₄/C (x?=?0, 0.2, 0.5, 0.8, 1) nanocomposites were successfully synthesized by a combination of spray pyrolysis and wet ball milling followed by heat treatment. The XRD patterns of all samples were indexed to olivine structure with a Pnma space group. From scanning electron microscopy images, the primary particle sizes of LiNi_1?xCo_xPO₄/C nanocomposites were reduced to the range of approximately 50–100?nm. LiNi_0.5Co_0.5PO₄/C cathode exhibited a higher first discharge capacity and cyclability than those of pure LiNi_0.5Co_0.5PO₄. Cyclic voltammetry data demonstrated that reduction peaks of LiNi_0.5Co_0.5PO₄/C cathode occur at 4.44?V and 4.71?V, which were ascribed to Co³⁺/Co²⁺ and Ni³⁺/Ni²⁺ reduction couples, respectively. Electrochemical impedance spectroscopy data revealed that the LiNi_0.5Co_0.5PO₄/C cathode had a smaller charge transfer resistance, resulting in a faster redox reaction kinetics for the lithium insertion and extraction, due to reduced particle size and introduced conductive carbon.     

Growth of Carbon Nanocoils by Porous α-Fe2O3/SnO2 Catalyst and Its Buckypaper for High Efficient Adsorption

High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicating that this method is promising to synthesize high-purity CNCs on a large scale.It is considered that an appropriate proportion of Fe and Sn,proper particle size distribution,and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs.Benefiting from the high-purity preparation,a CNC Buckypaper was successfully prepared and the electrical,mechanical,and electrochemical properties were investigated comprehensively.Furthermore,as one of the practical applications,the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%.This study provides a facile and economical route for preparing high-purity CNCs,which is suitable for large-quantity production.Furthermore,the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.     

Size Dependent Physical Properties of Nanostructured α-Fe_2O_3 Thin Films Grown by Successive Ionic Layer Adsorption and Reaction Method for Antibacterial Application

Thin films of nanostructured α-Fe_2O_3 with thickness of 1 56,203 and 251 nm were deposited by successive ionic layer adsorption and reaction(SILAR) method onto glass substrates using FeCl_3-6H_2O and NaOH as cationic and anionic precursors.The X-ray diffraction studies revealed that,α-Fe_2O_3 thin films are nanocrystalline in nature with rhombohedral structure.The morphological properties were investigated by field emission scanning electron and atomic force microscopy.The optical studies showed that α-Fe_2O_3 exhibits direct as well as indirect optical band gap energy.The electrical resistivity of α-Fe_2O_3 at 305 K decreases from 11.76×102 to9.46 × 10~2 Ω cm as film thickness increases from 156 to 251 nm.The thermo-emf measurements confirmed that α-Fe_2O_3 exhibits n-type conductivity.The nanocrystalline α-Fe_2O_3 exhibits antibacterial character against Staphylococcus aureus and its efficiency increases from 37.50%to 87.50%depending on crystallite size.     

Evaluation of ship’s green degree using a novel hybrid approach combining group fuzzy entropy and cloud technique for the order of preference by similarity to the ideal solution theory

Clean Technologies and Environmental Policy - The pollution and emission caused by the manufacturing, operation, and scrapping of marine ships have considerable impact on the environment....     

Prolonged lifetime and enhanced separation of photogenerated charges of nanosized α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> by coupling SnO<Subscript>2</Subscript> for efficient visible-light photocatalysis to convert CO<Subscript>2</Subscript> and degrade acetaldehyde

To develop efficient visible-light photocatalysis on α-Fe2O3,it is highly desirable to promote visible-light-excited high-energy-level electron transfer to a proper energy platform thermodynamically.Herein,based on the transient-state surface photovoltage responses and the atmosphere-controlled steady-state surface photovoltage spectra,it is demonstrated that the lifetime and separation of photogenerated charges of nanosized α-Fe2O3 are increased after coupling a proper amount of nanocrystalline SnO2.This naturally leads to greatly improved photocatalytic activities for CO2 reduction and acetaldehyde degradation.It is suggested that the enhanced charge separation results from the electron transfer from α-Fe2O3 to SnO2,which acts as a proper energy platform.Based on the photocurrent action spectra,it is confirmed that the coupled SnO2 exhibits longer visible-light threshold wavelength (～590 nm) compared with the coupled TiO2 (～550 nm),indicating that the energy platform introduced by SnO2 would accept more photogenerated electrons from α-Fe2O3.Moreover,electrochemical reduction experiments proved that the coupled SnO2 possesses better catalytic ability for reducing CO2 and O2.These are well responsible for the much efficient photocatalysis on SnO2-coupled α-Fe2O3.