Physicochemical characterization and antioxidant activity of quercetin‐loaded chitosan nanoparticles

Quercetin is an abundant flavonoid in food plants with numerous biological activities and widely used as a potent antioxidant. Being sparingly soluble in water and subject to degradation in aqueous intestinal fluids, the absorption of quercetin is limited upon oral administration. In the present study, chitosan nanoparticles and quercetin‐loaded nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. The encapsulation of quercetin in the chitosan nanoparticles were confirmed by differential scanning calorimetry, X‐ray powder diffractometry, Fourier transformed infrared spectroscopy, ultraviolet‐visible spectrum, and fluorescence spectrum. The morphology of the nanoparticles was characterized by atomic force microscopy. The antioxidant activity of the quercetin‐nanoparticles was also evaluated in vitro by two different methods (free radical scavenging activity test and reducing power test), which indicates that inclusion of quercetin in chitosan nanopaticles may be useful in improving the bioavailabilty of quercetin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Fabrication and DOE Optimization of Electrospun Chitosan/Gelatin/PVA Nanofibers for Skin Tissue Engineering

Chitosan/gelatin-based nanofibers display excellent biological performance in tissue engineering because of their biocompatible composition and nanofibrous structure with a high surface-to-volume ratio mimicking the native extracellular matrix. In this study, to save time and cost of experiments, a response surface methodology based on Box–Behnken design (BBD) is developed to predict the mean diameter of (chitosan:gelatin)/poly(vinyl alcohol) (PVA) nanofibers in three volume ratios of chitosan:gelatin by considering PVA percentage, applied voltage, and flow rate as input variables. The morphology and chemical composition of nanofibers are investigated through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The optimum conditions to yield the minimum diameter of nanofibers with chitosan:gelatin ratios of 25:75, 50:50, and 75:25 are found and result in 165, 121, and 92 nm, respectively, which show good accordance with BBD estimated results. The tensile testing indicates that nanofibers containing higher ratio of chitosan:gelatin result in higher tensile stress and lower toughness and tensile strain. The water contact angle analysis (WCA) shows the appropriate hydrophilicity of crosslinked nanofibers. The MTT assay shows excellent cell viability and cell attachment of nanofibers for mouse fibroblast (L929) cells. The results indicate that optimum nanofibers are potent candidates for wound healing applications.     

Adsorption of basic red 9 on activated waste Gossypium hirsutum seeds: Process modeling,analysis and optimization using statistical design

Sulfuric acid activated immature Gossypium hirsutum seed was utilized as adsorbent for the batch adsorption of basic red 9. The main and interactive effects of five process factors like, adsorbent dose, initial dye concentration, contact time, pH and temperature were investigated to select the influencing key factors via 2⁵ two-level full factorial design. Box–Behnken statistical design with the selected key factors employed for process optimization. The simultaneous optimization by Derringer's desirability function indicated that 54.27% removal of BR9 could be possible at the optimal conditions. Isotherm and kinetic studies confirmed the chemisorption on homogeneous and heterogeneous patches.     

Fabrication and characterization of zinc oxide nanoparticle coated magnetic iron oxide: Effect of S-layers adsorption on surface of oxide

Mixed zinc oxide nanoparticle coated magnetic iron oxide has been prepared by a sol–gel and co-precipitation routes. Magnetic iron oxide nanoparticles were synthesized by co-precipitation of ferric and ferrous ions with ammonia, and then zinc oxide was coated onto the surface of magnetic iron oxide by hydrolysis of zinc precursors. As a result, zinc oxide coated magnetic iron oxide nanoparticles with an average size of 68 nm were obtained. The crystalline bacterial cell surface layer)S-layer (used in this study was isolated from Lactobacillus helveticus ATCC 12046. The S-layer was adsorbed onto the surface of zinc oxide nanoparticle coated magnetic iron oxide. The nanoparticles were analyzed by X-ray powder diffractometry (XRD), infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM) were used to characterize the structural and the chemical features of the nanocomposites. The infrared spectra indicate that the S-layer-nanoparticle interaction occurs. This novel nanoparticle showed admirable potential in adsorption of S-layers on the surface of oxides for drug delivery.     

体外消化对蓝莓提取物抗氧化、抗癌及组分的影响

以蓝莓为原料,考察了体外消化前、后蓝莓提取物(总酚和花色苷)含量、抗氧化性、抗癌作用及花色苷组成的变化,并推测了花色苷的降解途径。分别采用福林-酚法和pH示差法测定总酚和花色苷含量;以脂质体的抑制率、DPPH和ABTS+自由基清除能力评价体外消化前后提取物的抗氧化能力;利用高效液相色谱-电喷雾二级质谱联用技术分析花色苷组成。结果表明,与未经消化的提取物相比,经肠道消化后样品总酚含量增加47.21%,花色苷含量降低71.82%,脂质体的抑制率、DPPH和ABTS+自由基清除率分别提高38.45%、29.41%和29.12%;对Hep G2肝癌细胞、A549肺癌细胞和Hela人宫颈癌细胞的生长抑制作用显著增加,蓝莓花色苷组分由12种降为9种。对胃肠消化花色苷的降解过程推测发现,矢车菊素-3-葡萄糖苷降解形成槲皮素的过程与天竺葵素-3-葡萄糖苷降解成山柰酚的过程机制相同。     

High surface area and mesoporous activated carbon from KOH-activated dragon fruit peels for methylene blue dye adsorption:Optimization and mechanism study

In tnis study,an alternative precursor for production of activated carbon was introduced using dragon fruit(Hylocereus costaricensis) peel(DFP).Moreover,KOH was used as a chemical activator in the thermal carbonization process to convert DFP into activated carbon(DFPAC).In order to accomplish this research,several approaches were employed to examine the elemental composition,surface properties,amorphous and crystalline nature,essential active group,and surface morphology of the DFPAC.The Brunauer-Emmett-Teller test demonstrated a mesoporous structure of the DFPAC has a high surface area of 756.3 m~2·g~(-1).The cationic dye Methylene Blue(MB) was used as a probe to assess the efficiency of DFPAC towards the removal of MB dye from aqueous solution.The effects of adsorption input factors(e.g.DFPAC dose(A:0.04-0.12 g·L~(-1)), pH(B:3-10),and temperature(C:30-50℃)) were investigated and optimized using statistical analysis(i.e.Box-Behnken design(BBD)).The adsorption kinetic model can be best categorized as the pseudo-first order(PFO).Whereas,the adsorption isotherm model can be best described by Langmuir model,with maximum adsorption capacity of DFPAC for MB dye was 195.2 mg·g~(-1) at 50℃.The adsorption mechanism of MB by DFPAC surface was attributed to the electrostatic interaction,π-π interaction,and H-bonding.Finally,the results support the ability of DFP to be a promising precursor for production of highly porous activated carbon suitable for removal of cationic dyes(e.g.MB).     

Valproate‐Loaded hydrogel nanoparticles: Preparation and characterization

Developing a simple and efficient approach to formulate biodegradable nanoparticles for intravenous delivery of sodium valproate (a hydrophilic small molecule drug chronically used in epileptic patients), is the principal objective of the current study. To fabricate particles via ionotropic gelation approach, a polycation polymer (chitosan) along with a polyanion (tripolyphosphate) was utilized in the presence of sodium valproate, and the Taguchi experimental design method was drawn upon so as to determine the optimum conditions of nanoparticle generation. In the following step, the researchers investigated sodium valproate‐loaded nanoparticles to explore various features of the nanoparticles including drug loading parameters, particle size distribution, zeta‐potential, morphology, stability, yield, and in vitro drug release profile. Nanoparticles with sizes of 63 ± 1 nm (number‐based) and 79 ± 3.21 (volume‐based) were obtained with slightly negative zeta–potential, which was more positive in drug‐loaded nanoparticles than the unloaded ones. The TEM imaging of the hydrogel nanoparticles manifested spherical shapes and corroborated the size achieved via particle size analyzer. The loading efficiency, loading amount, and loading ratio were determined to be 21.81 ± 3.90%, 10.31 ± 1.82 (mg sodium valproate/g nanoparticle) and 23.70 ± 4.54%, respectively, in optimum conditions. Moreover, there was observed a gradual drug release for nearly a week consisting, in average, about 94.64 ± 2.71% of the nanoparticles' drug content. In a nutshell, the present study introduces a practical, simple, and effective ionotropic gelation approach to generate sodium valproate‐loaded nanoparticles, leaving open a window of promising prospects in the field of intravenous long‐term delivery of this chronically used drug. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polycarbonate/silica nanocomposite membranes: Fabrication,characterization, and performance evaluation

Polycarbonate/silica nanocomposite membranes at low silica loading were fabricated by solution blending and solvent evaporation technique. The functionalized silica nanoparticles used were synthesized by co‐condensing hydrolyzed tetraethylorthosilicate with 3‐aminopropyl trimethoxysilane in the sol–gel process. The membranes morphology, composition, surface, structure, thermal and mechanical properties were analyzed by the standard characterization techniques. The gas permeation tests were conducted in four‐channel permeation cells. Field emission scanning electron microscopy results reveal that membranes above 3 wt % silica content formed distinguishable voids and agglomerates. Fair distribution of silica nanoparticles and absence of residual solvents were observed by energy dispersive X‐ray and thermogravimetric analysis. Fourier transform infrared spectroscopy spectra confirmed the presence of new functional groups (N? H) and (O? H) bonds. The X‐ray diffraction pattern revealed the polymer‐particle interactions, the formation of rigidified polymer chain, and nanostructured silicon crystals. Further, the thermogravimetric analysis results revealed thermal stability enhancement while differential scanning calorimetry results of increased glass transition temperatures confirmed the presence of rigidified polymer chain. Furthermore, enhancements in mechanical strength of the membranes were observed. Moreover, at all feed pressures, increased CO₂, N₂, and CH₄ gas permeation was observed. At 6 bar feed pressure, the CO₂/N₂ and CO₂/CH₄ ideal selectivities of PC membranes with 3 wt % silica loading have increased from 19.2 to 38.0 and 29.2, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45310.     

Oxovanadium(IV) complexes based on S-alkyl-thiosemicarbazidato ligands. Synthesis,characterization, electrochemical,and antioxidant studies

Reaction of VOSO₄ with 2-hydroxy-napthaldeyde-S-R-thiosemicarbazones (R: methyl, ethyl, propyl or allyl) and salicyl aldehyde yielded five-coordinate oxovanadium(IV) complexes having a N¹,N⁴-diarylidene-S-R-thiosemicarbazidato structures. The compounds were characterized by elemental analysis, magnetic measurements, electronic, infrared, ¹H-NMR, and electron paramagnetic resonance (EPR) spectra. The X-band EPR signals were recorded from powder forms and also in solution. All the complexes have a single asymmetric line shape and theoretical fit studies prove the presence of axial symmetry around the paramagnetic vanadium ions. A computer simulation of the EPR spectrum of each complex was carried out to derive the related EPR parameters. Cyclic voltammograms of the complexes exhibited two metal-based reversible redox peaks around 500 and ?800?mV corresponding to one electron oxidation/reduction of V^IVO/V^VO and V^IVO/V^IIIO, respectively. The reductive response in the 50–350?mV region was assigned to ligand reduction. Antioxidant activities of the compounds were determined with CUPric Reducing Antioxidant Capacity, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid, and 1,1-diphenyl-2-picrylhydrazyl assays. The test results indicated that the antioxidant capacity of the compounds increases with the carbon number of saturated hydrocarbon chain on sulfur atom.     

Fabrication,characterization, and thermal property evaluation of silver nanofluids

Silver nanoparticles were successfully prepared in two different solvents using a microwave heating technique, with various irradiation times. The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP). The optical properties, thermal properties, and morphology of the synthesized silver particles were characterized using ultraviolet-visible spectroscopy, photopyroelectric technique, and transmission electron microscopy. It was found that for the both solvents, the effect of microwave irradiation was mainly on the particles distribution, rather than the size, which enabled to make stable and homogeneous silver nanofluids. The individual spherical nanostructure of self-assembled nanoparticles has been formed during microwave irradiation. Ethylene glycol solution, due to its special properties, such as high dielectric loss, high molecular weight, and high boiling point, can serve as a good solvent for microwave heating and is found to be a more suitable medium than the distilled water. A photopyroelectric technique was carried out to measure thermal diffusivity of the samples. The precision and accuracy of this technique was established by comparing the measured thermal diffusivity of the distilled water and ethylene glycol with values reported in the literature. The thermal diffusivity ratio of the silver nanofluids increased up to 1.15 and 1.25 for distilled water and ethylene glycol, respectively.     

Fabrication and characterization of graphene oxide modified polycarboxylic by in situ polymerization

Graphene oxide (GO) was modified by in situ esterification reaction with isopentenol polyoxyethylene ether (IPEG) to obtain GO precursor (GO-IPEG) with some polymerization activity. GO-modified polycarboxylic (GO-PCE) was prepared by GO-IPEG and acrylic acid (AA) using the method of in situ polymerization. The molecular structure of GO-IPEG and GO-PCE was characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectra, and nuclear magnetic resonance (NMR). The dispersion properties and dispersion stability of GO-IPEG and GO-PCE in water solution were studied by ultraviolet–visible (UV–vis) absorption spectra, zeta potential, and atomic force microscope. The results of FTIR, Raman, ¹H-NMR, and ¹³C-NMR indicate that IPEG was successfully grafted onto the surface of GO and then fabricated with AA by in situ free-radical polymerization. The results of UV–vis and zeta potential show that GO nanosheets have a better dispersion in GO-IPEG or GO-PCE system when the reaction time of GO and IPEG is 1 h, and the dispersion stability can reach up to 1 month. The better dispersion and application property are confirmed by atomic force microscopy image and cement fluidity, water reducing rate, and compression strength. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48316.     

Fabrication and characterization of new bulky layer mixed metal oxide ceramic nanofibers through two nozzle electrospinning method

New bulky layers of metal mixed ceramic nanofibers were fabricated through two-nozzle electrospinning method followed by calcination. Solutions of PAN in DMF with various concentrations were prepared as: 11, 12, 13, 14, and 15 wt% to which the constant amounts of 2.1 g of Aluminum acetate, 0.3 g of Copper acetate and 0.3 g of Boehmite nanoparticles were added. A stepwise calcination process was utilized to obtain the ceramic nanofibers. The nanofibers were characterized by FTIR spectroscopy, TG-DTA, XRD, SEM and EDS techniques. The formulation with 12 wt% of PAN in DMF was proved to be the optimum spinable sample. The average diameter of as spun nanofibers was detected as 568 nm, which decreased to 181 nm after calcination and thermal degradation. Ceramic nanofibers were composed of CuO, Al₂O₃ and Cu₂Al₄O₇ phases. The average density of the sample was about 0.090 (g/cm³) and the porosity of the mat was 94.5% and thus, production of a 3D structure may be claimed. The ceramic nanofibers performed well as catalyst in the C-C coupling reaction (Suzuki reaction) by facilitating the synthesis of biaryl compound from aryl iodide in 20 min with isolated yield of 89% only by using 15 mg of ceramic nanofibers as the nano catalyst.     

Fabrication,characterization, cytocompatibility,and biological activity of lemon fiber-filled polyester composites

The structure, cytocompatibility, and biological activity of composites prepared from polycaprolactone (PCL) and lemon fiber (LF) blends (PCL/LF) were evaluated. Acrylic acid-grafted PCL (PCL-g-AA) was used to enhance the desirable characteristics of these composites, which had better tensile properties than the corresponding PCL/LF composites. A cytocompatibility evaluation with normal human foreskin fibroblasts of the water released from the PCL/LF and PCL-g-AA/LF composites indicated that both materials were nontoxic. Moreover, LF enhanced the flavonoid and polyphenol contents and the anti-inflammatory and antioxidant properties of the PCL-g-AA/LF and PCL/LF composites. We analyzed the effects of these composites in mushroom tyrosinase activity and B16-F10 melanoma cells; the PCL/LF and PCL-g-AA/LF membranes demonstrated reduced tyrosinase activity. Composites of PCL-g-AA or PCL containing LF had better antibacterial activity.     

Magnetic Particle Imaging: Current and Future Applications,Magnetic Nanoparticle Synthesis Methods and Safety Measures

Magnetic nanoparticles (MNPs) have a wide range of applications; an area of particular interest is magnetic particle imaging (MPI). MPI is an imaging modality that utilizes superparamagnetic iron oxide particles (SPIONs) as tracer particles to produce highly sensitive and specific images in a broad range of applications, including cardiovascular, neuroimaging, tumor imaging, magnetic hyperthermia and cellular tracking. While there are hurdles to overcome, including accessibility of products, and an understanding of safety and toxicity profiles, MPI has the potential to revolutionize research and clinical biomedical imaging. This review will explore a brief history of MPI, MNP synthesis methods, current and future applications, and safety concerns associated with this newly emerging imaging modality.     

Adhesion of graphene oxide on a transparent PET substrate: a study focused on the optimization process

The procedure with the aim to optimize a process of transfer of GO layer, formed by filtration on a PET substrate, was run out in two stages. First, using a Plackett–Burman experimental design strategy was to investigate the most significant technological parameters. Seven types of different interlayer materials (composed either of polymers or smaller organic molecules) were used to improve the quality of the operation. Using a quantitative structure property relationship strategy, it was stated that the hydrogen bonds play a very important role in the quality assurance of the process of GO transfer. However, hydrogen bonds formed between GO sheets and interlayer molecules influence only in the case when these molecules are sufficiently large. SEM images have shown that the morphology of GO layer after transfer is dependent on the interlayer material. Raman spectra revealed typical changes in the structure of GO layer using different interlayer materials. Arrangement of GO sheets in the layer and the structure of the GO single layer can be controlled by using appropriate interlayer materials. It was found that the main parameters, operating the quality of the process of GO transfer are: the thickness of interlayer, the coating thickness, and the temperature. At the second stage, using a simplex optimization strategy, a specific set of optimal values to obtain the best quality during the transfer procedure, was determined.     

Preparation,optimization, and characterization of simvastatin nanoparticles by electrospraying: An artificial neural networks study

The purpose of this study was to determine major factors impacting the size of simvastatin (SIM)‐loaded poly(d , l ‐lactic‐co‐glycolide) (PLGA) nanoparticles (NPs) that was prepared using electrospraying. Three variables including concentration of polymer and salt as well as solvent flow rate were used as input variables. Size of NPs was considered as output variable. For the first time, our findings using a systematic and experimental approach, showed the importance of salt concentration as the dominant factor determining the size with a sharp and reverse effect. Optimum formulation (i.e., flow rate 0.08 mL h^?1, polymer concentration 0.7 w/v %, and salt concentration 0.8 mM) was then evaluated for aqueous solubility, encapsulation efficiency, particle size, in vitro drug release pattern and cytotoxicity. A very appreciable encapsulation efficiency (90.3%) as well as sustained release profile, considerable enhancement in aqueous solubility (～5.8 fold) and high IC₅₀ (>600 µM of SIM‐loaded PLGA NPs) indicated PLGA as a promising nanocarrier for SIM. The optimum formulation had particle size, zeta potential value, polydispersity index (PDI) and drug loading of 166 nm, +3 mV, 0.62 and 9%, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43602.     

Design,Synthesis and Biological Activity of New Amides Derived from 3-Benzhydryl and 3-sec-Butyl-2,5-dioxo-pyrrolidin-1-yl-acetic Acid

The aim of this study was to design and synthesize two new series of pyrrolidine-2,5-dione-acetamides with a benzhydryl or sec-butyl group at position 3 as potential anticonvulsants. Their anticonvulsant activity was evaluated in standard animal models of epilepsy: the maximal electroshock (MES), the 6 Hz, and the subcutaneous pentylenetetrazole (scPTZ) tests. The in vivo studies revealed the most potent anticonvulsant activity for 15 (3-(sec-butyl)-1-(2-(4-(3-trifluoromethylphenyl)piperazin-1-yl)-2-oxoethyl)pyrrolidine-2,5-dione), with ED₅₀ values of 80.38 mg/kg (MES) and 108.80 mg/kg (6 Hz). The plausible mechanism of action was assessed in in vitro binding assays, in which 15 interacted effectively with voltage-gated sodium (site 2) and L-type calcium channels at a concentration of 100 μM. Subsequently, the antinociceptive activity of compounds 7 and 15 was observed in the hot plate test of acute pain. Moreover, compounds 7 , 11 and 15 demonstrated an analgesic effect in the formalin test of tonic pain. The hepatotoxic properties of the most effective compounds ( 7 , 11 and 15 ) in HepG2 cells were also investigated.     

磁性纳米三苯基膦配体制备及其催化氢甲酰化反应研究

通过表面交换反应,以多巴胺为偶联剂,将三苯基膦担载到磁性纳米氧化铁表面制得磁性纳米三苯基膦配体,其结构通过红外光谱、元素分析以及热重分析进行了表征。初步考察了表面交换反应条件对三苯基膦在纳米粒子表面担载量的影响;提高多巴胺-三苯基膦衍生物与磁性纳米氧化铁粒子比例以及延长超声时间有助于提高三苯基膦的担载量。在优化后的反应条件下,即苯乙烯1.25 m L,30 mg磁性纳米三苯基膦,1.8 mg Rh(OAc)2,12 m L无水四氢呋喃,3 MPa合成气VCO∶VH2=1∶1,纳米三苯基膦配体中的三苯基膦含量为0.21μmol/mg,该配体能够与Rh(OAc)2一起催化苯乙烯的氢甲酰化反应并能重复使用4次,且仅有4.8%的三苯基膦配体从纳米粒子表面脱落。