Mechanically reinforced biodegradable nanocomposites. A facile synthesis based on PEGylated silica nanoparticles

Biodegradable nanocomposites consisting of poly(?-caprolactone) (PCL) reinforced by PEGylated silica (polyethylene-glycol/SiO₂) nanoparticles were prepared by a melt-extrusion process. The PEGylated silica nanoparticles were prepared in a facile, one-pot synthesis process. Transmission electron microscopy (TEM) observations of the PEGylated silica nanoparticles inside the PCL matrix indicated that a homogeneous dispersion had been achieved. As a result, the storage modulus (E′) in the rubbery plateau increased significantly with the filler contents at all temperatures studied, at values approximately 45% higher than the neat PCL, at a loading level of only 4 wt.%. In comparison, in the absence of polyethylene-glycol (PEG) the silica nanoparticles formed aggregates inside the PCL matrix, and the reinforcement was negligible. The results from X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR) analyses identified the location of the PEG at the PCL/silica interface.     

Synthesis and characterization of polyethylene glycols conjugated to polybutylcyanoacrylate nanoparticles

This study aimed to evaluate the cytotoxicity effects of various polyethylene glycols (PEGs), and construction and characterization of polybutylcyanoacrylate (PBCA) nanoparticles. Cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on rat glioma C6 cell line, and PBCA nanoparticles were prepared by emulsion polymerization method. Also, the nanoparticles were characterized by dynamic light scattering and scanning electron microscopy. The findings showed that PEGs were approximately safe and cytotoxicity was inversely proportional with their molecular weights. In addition, the size of nanoparticles were increased with reducing molecular weights of PEGs. PEGs with negligible cytotoxicity and stabilizing functionality were demonstrated in this study.     

载银介孔氧化硅防污剂的制备及其防污机理研究

采用化学法制备出载银介孔氧化硅(Ag-MSN)粉体,通过扫描电镜(SEM)和透射电镜(TEM)表征纳米材料的微观形貌和尺寸,利用X射线衍射(XRD)确定纳米材料的成分并结合公式确定纳米银的粒径;通过平板培养法和分光光度计法揭示载银介孔氧化硅对于海洋微生物(需钠弧菌)的抗菌效果和机理。将载银介孔氧化硅粉体作为主要颜料与有机硅树脂复合,得到具有一定抑菌性能的涂层。该研究成果将有助于揭示纳米银防污机理,并对绿色海洋防污剂的制备与应用起到重要的促进作用。     

Enhanced Anti-Tumoral Activity of Methotrexate-Human Serum Albumin Conjugated Nanoparticles by Targeting with Luteinizing Hormone-Releasing Hormone (LHRH) Peptide

Active targeting could increase the efficacy of anticancer drugs. Methotrexate-human serum albumin (MTX-HSA) conjugates, functionalized by luteinizing hormone-releasing hormone (LHRH) as targeting moieties, with the aim of specifically targeting the cancer cells, were prepared. Owing to the high expression of LHRH receptors in many cancer cells as compared to normal cells, LHRH was used as the targeting ligand in this study. LHRH was conjugated to MTX-HSA nanoparticles via a cross-linker. Three types of LHRH targeted nanoparticles with a mean particle size between 120-138 nm were prepared. The cytotoxicity of LHRH targeted and non-targeted nanoparticles were determined on the LHRH positive and negative cell lines. The internalization of the targeted and non-targeted nanoparticles in LHRH receptor positive and negative cells was investigated using flow cytometry analysis and fluorescence microscopy. The cytotoxicity of the LHRH targeted nanoparticles on the LHRH receptor positive cells were significantly more than non-targeted nanoparticles. LHRH targeted nanoparticles were also internalized by LHRH receptor positive cells significantly more than non-targeted nanoparticles. There were no significant differences between the uptake of targeted and non-targeted nanoparticles to the LHRH receptor negative cells. The active targeting procedure using LHRH targeted MTX-HSA nanoparticles could increase the anti-tumoral activity of MTX.     

Carboplatin liposomal nanoparticles: Preparation,characterization, and cytotoxicity effects on lung cancer in vitro environment

The study aimed to encapsulate anticancer drug carboplatin into liposomal nanoparticles by reverse-phase evaporation technique and evaluate its efficacy on lung cancer in vitro environment. Nanoparticles were characterized in terms of size, drug loading efficiency, drug retention capability, and cytotoxicity effects. Nanoscale particles with 67% drug encapsulation efficiency were prepared. Also, high retention capability (drug release equal to 25% after 72?h) of the nanodrug was confirmed. In addition, results of the nanodrug cytotoxicity indicated nanoparticles increased potency of the drug by approximately 90%. Findings of the study indicated liposome can be used for carboplatin delivery to lung cancer.     

Fabrication of microcellular polylactide/modified silica nanocomposite foams

Microcellular polylactide (PLA)/modified-silica (m-silica) nanocomposite foams were prepared in a batch process using supercritical carbon dioxide as physical blowing agent. To enhance the dispersion in the PLA matrix, silica nanoparticles were modified by dodecyltrichlorosilane) and were melt compounded with PLA using a twin-screw extruder. PLA/m-silica nanocomposites with m-silica contents of 0.5, 1, 2, 3, and 5 wt % were obtained. The incorporation of m-silica nanoparticles in PLA enhanced the thermal and mechanical properties of PLA. The resultant foams were observed by scanning electron microscopy (SEM) and average cell diameter and cell density were calculated using SEM micrographs. The incorporation of m-silica nanoparticles into the PLA matrix had the effect of decreasing the cell diameter and increasing the cell uniformity and cell density. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48616.     

掺杂无机纳米粒子PVA复合改性香精微胶囊壁性能研究

采用原位聚合法, 以掺杂了金属Fe3+、Zr4+、Ce4+的二氧化钛（TiO2）纳米粒子及TiO2纳米粒子填充聚乙烯醇（PVA）改性三聚氰胺甲醛树脂（MF）为微胶囊复合壁材,橙花精油为芯材,制备了掺杂TiO2纳米粒子填充PVA改性囊壁的相变微胶囊。采用傅里叶变换红外光谱仪、热失重分析仪、扫描电子显微镜和透射电子显微镜研究了掺杂TiO2纳米粒子对微胶囊力学性能、热性能及表面形态的影响。结果表明,当囊壁中均匀地加入掺杂纳米TiO2后,芯材释放速率减小;当壁材中Fe3+掺杂纳米TiO2含量为0.5 %（质量分数,下同）时,微胶囊的破损率为18.1 %,芯材的10 d释放速率为4.5 %。     

Fabrication of superhydrophobic and antibacterial surface on cotton fabric by doped silica-based sols with nanoparticles of copper

The study discussed the synthesis of silica sol using the sol-gel method, doped with two different amounts of Cu nanoparticles. Cotton fabric samples were impregnated by the prepared sols and then dried and cured. To block hydroxyl groups, some samples were also treated with hexadecyltrimethoxysilane. The average particle size of colloidal silica nanoparticles were measured by the particle size analyzer. The morphology, roughness, and hydrophobic properties of the surface fabricated on cotton samples were analyzed and compared via the scanning electron microscopy, the transmission electron microscopy, the scanning probe microscopy, with static water contact angle (SWC), and water shedding angle measurements. Furthermore, the antibacterial efficiency of samples was quantitatively evaluated using AATCC 100 method. The addition of 0.5% (wt/wt) Cu into silica sol caused the silica nanoparticles to agglomerate in more grape-like clusters on cotton fabrics. Such fabricated surface revealed the highest value of SWC (155° for a 10-μl droplet) due to air trapping capability of its inclined structure. However, the presence of higher amounts of Cu nanoparticles (2% wt/wt) in silica sol resulted in the most slippery smooth surface on cotton fabrics. All fabricated surfaces containing Cu nanoparticles showed the perfect antibacterial activity against both of gram-negative and gram-positive bacteria.     

pH sensitive functionalized hyperbranched polyester based nanoparticulate system for the receptor-mediated targeted cancer therapy

The aim of this study is to develop a novel folic acid conjugated, DL-lysine modified, PEGylated, the 3rd generation hyperbranched polymer (HBP-PEG-Lys-FA) for use in receptor-mediated therapy. 5-fluorouracil, model anti-cancer drug, loaded nanoparticles were found an average size of 177?nm with loading efficiency of 23.18%. In vitro drug release studies demonstrated that nanoparticles showed pH-dependent release. HBP-PEG-Lys-FA were efficiently taken up by HeLa cells and specificity of targeted nanoparticles to folate receptors of cells was proved. It was concluded that the HBP-PEG-Lys-FA nanoparticles can provide an advantage on delivering of the drug efficiently into the cytosol for cancer therapy.     

载三氧化二砷的PEG—PLGA隐性纳米粒的制备及体外研究

The aim of this study was to prepare arsenic trioxide （ATO）-loaded stealth PEGylated PLGA nanoparticles （PEG-PLGA-NPs） and to assess the merits of PEG-PLGA-NPs as drug carriers for ATO delivery. PEG-PLGA copolymer was synthesized with methoxypolyethyleneglycol （Mw=5000）, D, L-lactide, and glycolide by the ring-opening polymerization method. Amorphous ATO was transformed into cubic crystal form to increase its solu-bility in the organic solvent. ATO-loaded PEG-PLGA-NPs were prepared by the modified spontaneous emulsification solvent diffusion （SESD） method, and the main experimental factors influencing the characteristics of nanopar- ticles were investigated, to optimize the preparation. To confirm the escape of PEG-PLGA-NPs from phagocytosis by phagocytes, PEG-PLGA-NPs labeled rhodamine B uptake by murine peritoneal macrophages （MPM） were analyzed by flow cytometry. The results showed that the physicochemical characteristics of PEG-PLGA-NPs were affected by the type and concentration of the emulsifiers, polymer concentration, and drug concentration. ATO-loaded PEG-PLGA-NPs, with particle size of 120.8nm, zeta potential of-10.73mV, encapsulation efficiency of 73.6%, and drug loading of 1.36%, were prepared under optimal conditions. The images of transmission electron micros-copy （TEM） indicated that the optimized nanoparticles were near spherical and without aggregation or adhesion. The release experiments in vitro showed the ATO release from PEG-PLGA-NPs exhibited consequently sustained release for more than 26d, which was in accordance with Higuchi equation. The uptake of PEG-PLGA-NPs by MPM was found to decrease markedly compared to PLGA-NPs. The experimental results showed that PEG-PLGA-NPs were potential nano drug delivery carriers for ATO.     

银纳米颗粒及其负载TiO2的制备与应用研究

采用液相化学还原法和溶胶-凝胶法,制备得到形貌各异的银颗粒及其负载的TiO2复合材料。透射电镜（TEM）结果显示,可以制备得到表面光滑,形状均匀一致的球形、三角形和四方形银纳米颗粒;X射线衍射（XRD）结果表明,银纳米颗粒晶体结构属于立方品系;利用傅立叶变换红外光谱仪（FT—IR）研究了聚乙烯吡咯啉酮（PVP）在生成不同形貌银纳米颗粒的化学反应中的作用机理;Ag／TiO2复合材料的X射线衍射能谱（XPS）结果表明,负载的银主要以零价态形式存在于TiO2的表面;研究了不同形貌银纳米颗粒的抗菌性能以及Ag／TiO2复合材料的光催化脱色亚甲基蓝的活性,结果表明,所制备的银纳米颗粒杀菌率均在99％以上;银负载到TiO2后,Ag／TiO2复合材料的光催化活性得到明显提高。其中,球形银负载的Ag／TiO2复合光催化剂活性最好。     

Stability and cytotoxicity study of NiFe2O4 nanocomposites synthesized by co-precipitation and subsequent thermal annealing

In this article, NiFe₂O₄ nanoparticles (NPs) were prepared by co-precipitation method with subsequent thermal annealing leading to obtainment NPs with average sizes of 78 nm. Structure and magnetic analysis were performed by X-ray diffraction, transmission electron microscopy, Mössbauer spectroscopy and vibrating sample magnetometry techniques. Stability of NiFe₂O₄ NPs was evaluated in PBS solution during 20 days. The toxicity of prepared NPs was evaluated in vitro using different cancer cell lines: HeLa (cervical cancer cell), PC-3 (prostate cancer cell). Fibroblasts like cells of L929 obtained from subcutaneous adipose tissue of mouse were used as normal cells. Results indicate successful synthesis of NiFe₂O₄ NPs that exhibit low cytotoxicity in concentration range from 1 to 100 μg/ml. Presented physical and biological results indicate the possibility of application investigated magnetic nanoparticles in hyperthermia, targeted drug delivery, magnetic resonance imaging or cell separation.     

Preparation and characterizations of superparamagnetic iron oxide‐embedded poly(2‐hydroxyethyl methacrylate) nanocarriers

The present study aims at formulating a novel multifunctional biocompatible superparamagnetic nanoparticles carrier system with homogeneously dispersed magnetic material in solid polymer matrix of poly(2‐hydroxyethyl methacrylate) (PHEMA). The nanocomposites were designed by modified suspension polymerization of 2‐hydroxyethyl methacrylate followed by in situ coprecipitation of iron oxide inside the nanoparticle matrix yielding magnetic PHEMA (mPHEMA) nanocomposites. The so prepared nanocomposites were characterized by Fourier transform Infrared spectroscopy, X‐ray diffraction technique, Raman spectroscopy, electron diffraction, and energy‐dispersive X‐ray spectroscopy confirming the presence of Fe₃O₄ inside the PHEMA nanoparticles. The magnetization studies of nanocomposites conducted at room temperature using vibrating sample magnetometer suggested for their superparamagnetic nature having saturation magnetization (Ms) of 20 emu/g at applied magnetic field of 5 kOe. Transmission electron microscopy, field‐emission scanning electron microscopy, and dynamic light scattering/zeta potential measurements were also performed which revealed that size of mPHEMA nanocomposites was lying in the range of 60–300 nm having zeta potential of ?93 mV. The nanocomposites showed no toxicity as revealed by cytotoxicity test performed on L‐929 fibroblast by extract method. The results indicated that the prepared superparamagnetic mPHEMA nanocomposites have enormous potential to provide a possible option for magnetically assisted targeted delivery of anticancer drugs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40791.     

Preparation and characterization of poly{[α‐maleic anhydride‐ω‐methoxy‐poly(ethylene glycol)]‐co‐(ethyl cyanoacrylate)} copolymer nanoparticles

Poly{[α‐maleic anhydride‐ω‐methoxy‐poly(ethylene glycol)]‐co‐(ethyl cyanoacrylate)} (PEGECA) copolymers were prepared by radical polymerization of macromolecular poly(ethylene glycol) monomers (PEGylated) and ethyl 2‐cyanoacrylate in solvent. The structures of the copolymer were characterized by Fourier‐transform infrared (FTIR) and proton nuclear magnetic resonance (¹H‐NMR). The morphology and size of the PEGECA nanoparticles prepared by nanoprecipitation techniques were investigated by transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS) methods. The results show that the PEGECA can self‐assemble into highly stable nanoparticles in aqueous media, and inner core and outer shell morphology. The size of the nanoparticles was strongly influenced by the solvent character and the copolymer concentration in the organic solvents. A hydrophobic drug, ibuprofen, was effectively incorporated into the nanoparticles, which provides a delivery system for ibuprofen and other hydrophobic compounds. Copyright © 2005 Society of Chemical Industry     

Nanodiamonds for surface engineering of orthopedic implants: Enhanced biocompatibility in human osteosarcoma cell culture

Recently, nanodiamonds have attracted interest in biomedical applications such as drug delivery, targeted cancer therapies, fabrication of tissue scaffolds, and biosensors. We incorporated diamond nanoparticles in alginate–bioactive glass films by electrophoretic process to prepare functional coatings for biomedical implants. Turbidity examination by time-resolved laser transmittance measurement revealed that a stable multi-component aqueous suspension of alginate, bioactive glass and diamond particles could be obtained at concentrations of 0.6, 1.3, and 0.65 g/l, respectively. Uniform films with ~ 5 μm thickness were deposited on 316 stainless steel foils by employing constant field strength of 15 V/cm for 45 s. Scanning electron microscopy and simultaneous thermal analysis showed that the composite films were homogeneous and contained ~ 39 wt.% inorganic particles. In vitro bioactivity assessment in simulated body fluid for 4 weeks and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using human osteoblast-like cell line (MG-63) and mouse fibroblast cell line (L929) exhibited enhanced biocompatibility and bioactivity of the composite films. Results show advantages of alginate-nanodiamonds in cell culture, tissue engineering, and pharmaceutical applications.     

Preparation and Performance of Highly Efficient Au Nanoparticles Electrocatalyst for the Direct Borohydride Fuel Cell

Au nanoparticles supported on Vulcan XC‐72R carbon were prepared by a modified NaBH₄ method in aqueous solution and employed as electrocatalyst of oxidation for the direct borohydride fuel cell (DBFC). The morphology and structure of as‐prepared particles were examined by transmission electron microscopy (TEM) and X‐ray diffraction (XRD). It was found that Au nanoparticles were mainly about 3.0 ± 0.5 nm in size and uniformly distributed on the surface of Vulcan XC‐72R carbon. The electrooxidation behaviors of and fuel cell performances using carbon‐supported Au nanoparticles as catalysts were investigated. Compared with Au/C prepared by conventional reduction method, the kinetics of oxidation on as‐prepared carbon supported 3.0 ± 0.5 nm Au nanoparticles were significantly improved. The DBFC employing carbon supported 3.0 ± 0.5 nm Au nanoparticles showed a maximum power density of 85.3 mW cm^–2 at 60 °C.     

微乳液法制备CdTe纳米颗粒的表征

CdTe纳米晶作为一种重要的Ⅱ-Ⅵ族半导体材料,在LEDs、光子学材料和生物标记等方面已被应用。本实验利用CTAB／环己烷／异丁醇／水作为反应介质,氮气保护下在微乳液体系中制备了CdTe纳米颗粒。利用X射线衍射（XRD）、透射电子显微镜（TEM）、扫描电子电镜（SEM）表征了CdTe纳米颗粒的形貌和粒径尺寸,研究水与表面活性剂摩尔比以及陈化时间对CdTe纳米颗粒的影响,结果表明当水与表面活性剂摩尔比为40,陈化时间为24h时制备出了产量高,稳定性好的直径为40-50nm的CdTe纳米颗粒。     

碳纳米管负载二氧化铈纳米粒子的研究

通过在液相沉淀反应中直接加入碳纳米管作为沉淀承载基体制备了碳纳米管负载的二氧化铈纳米颗粒。电镜分析证实了在碳管的表面高密度地均匀沉积了多层粒径为4～6nm的二氧化铈粒子,也有部分二氧化铈粒子填充进入碳管的内腔,形成了二氧化铈,多壁碳管复合材料,所获得的纳米复合材料可望成为一种新型的高效催化剂,在催化领域特别是车辆尾气处理上有潜在应用。     

The preparation of graphene hybrid films decorated with poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] particles prepared by non-solvent induced precipitation

A hybrid film of graphene decorated with poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) nanoparticles is fabricated by a simple non-solvent induced precipitation method. The structure of the graphene film and graphene/MEH-PPV hybrid film are investigated by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The large specific surface area of graphene sheets makes it an ideal support for depositing MEH-PPV nanoparticles as well as preventing aggregation of the nanoparticles. The graphene/MEH-PPV hybrid film is superhydrophobic, which is attributed to the increase in surface roughness as a result of random decoration of MEH-PPV nanoparticles on the graphene sheets. The MEH-PPV nanoparticles endow the graphene hybrid film with strong photoluminescence. The hybrid film also shows excellent conductivity and high thermal stability. The graphene/MEH-PPV hybrid film thus prepared may find potential applications in various devices where integrated properties of superhydrophobicity, conductivity and luminescence are required.     

Preparation of Mesoporous Carbons from Acrylonitrile-methyl Methacrylate Copolymer/Silica Nanocomposites Synthesized by in-situ Emulsion Polymerization

Acrylonitrile-methyl methacrylate (AN-MMA) copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2'-azobis(2-amidinopropane) dihydrochloride absorbed onto colloidal silica particles, and the mesoporous carbon materials were prepared through carbonization of the obtained AN-MMA copolymer/silica nanocomposites, followed by HF etching. Thermogravimetric analysis of AN-MMA copolymer/silica nanocomposites showed that the carbon yield of copolymer was slightly decreased as silica particle incorporated. N₂ adsorption-desorption, scan electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and morphology of the mesoporous carbon materials. Both SEM and TEM results showed that disordered mesopores were formed in the obtained carbon material mainly through templating effect of silica nanoparticles. The diameter of mesopores was mainly distributed in the range from 5 nm to 15 nm. The mean pore diameter and total pore volume of the material increased as the mass fraction of silica in the nanocomposites increased from 0 to 24.93%. The significant increase of the mean pore diameter and the decrease of surface area for the carbon material prepared from the nanocomposite with 24.93% silica were caused by partial aggregation of silica nanoparticles in the polymer matrix.