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Sample records for solid supported lipid

  1. Polymer-Induced Swelling of Solid-Supported Lipid Membranes

    Directory of Open Access Journals (Sweden)

    Martin Kreuzer

    2015-12-01

    Full Text Available In this paper, we study the interaction of charged polymers with solid-supported 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC membranes by in-situ neutron reflectivity. We observe an enormous swelling of the oligolamellar lipid bilayer stacks after incubation in solutions of poly(allylamine hydrochloride (PAH in D2O. The positively charged polyelectrolyte molecules interact with the lipid bilayers and induce a drastic increase in their d-spacing by a factor of ~4. Temperature, time, and pH influence the swollen interfacial lipid linings. From our study, we conclude that electrostatic interactions introduced by the adsorbed PAH are the main cause for the drastic swelling of the lipid coatings. The DMPC membrane stacks do not detach from their solid support at T > Tm. Steric interactions, also introduced by the PAH molecules, are held responsible for the stabilizing effect. We believe that this novel system offers great potential for fundamental studies of biomembrane properties, keeping the membrane’s natural fluidity and freedom, decoupled from a solid support at physiological conditions.

  2. Anionic solid lipid nanoparticles supported on protamine/DNA complexes

    International Nuclear Information System (INIS)

    Ye Jiesheng; Liu Chunxi; Chen Zhijin; Zhang Na; Wang Aihua

    2008-01-01

    The objective of this study was to design novel anionic ternary nanoparticles for gene delivery. These ternary nanoparticles were equipped with protamine/DNA binary complexes (150-200 nm) as the support, and the anionic formation was achieved by absorption of anionic solid lipid nanoparticles (≤20 nm) onto the surface of the binary complexes. The small solid lipid nanoparticles (SLNs) were prepared by a modified film dispersion-ultrasonication method, and adsorption of the anionic SLNs onto the binary complexes was typically carried out in water via electrostatic interaction. The formulated ternary nanoparticles were found to be relatively uniform in size (257.7 ± 10.6 nm) with a 'bumpy' surface, and the surface charge inversion from 19.28 ± 1.14 mV to -17.16 ± 1.92 mV could be considered as evidence of the formation of the ternary nanoparticles. The fluorescence intensity measurements from three batches of the ternary nanoparticles gave a mean adsorption efficiency of 96.75 ± 1.13%. Circular dichroism spectra analysis showed that the protamine/DNA complexes had been coated by small SLNs, and that the anionic ternary nanoparticles formed did not disturb the construction of the binary complexes. SYBR Green I analysis suggested that the ternary nanoparticles could protect the DNA from nuclease degradation, and cell viability assay results showed that they exhibit lower cytotoxicity to A549 cells compared with the binary complexes and lipofectamine. The transfection efficiency of the ternary nanoparticles was better than that of naked DNA and the binary complexes, and almost equal to that of lipofectamine/DNA complexes, as revealed by inversion fluorescence microscope observation. These results indicated that the anionic ternary nanoparticles could facilitate gene transfer in cultured cells, and might alleviate the drawbacks of the conventional cationic vector/DNA complexes for gene delivery in vivo

  3. Solid lipid nanoparticles for parenteral drug delivery

    NARCIS (Netherlands)

    Wissing, S.A.; Kayser, Oliver; Muller, R.H.

    2004-01-01

    This review describes the use of nanoparticles based on solid lipids for the parenteral application of drugs. Firstly, different types of nanoparticles based on solid lipids such as "solid lipid nanoparticles" (SLN), "nanostructured lipid carriers" (NLC) and "lipid drug conjugate" (LDC)

  4. Characterization of Carbamazepine-Loaded Solid Lipid ...

    African Journals Online (AJOL)

    loaded solid lipid nanoparticles by RESS as well as their characterization has been achieved in this study. Keywords: Rapid expansion of supercritical fluid, Stearic acid, Solid lipid nanoparticles, Carbamazepine, Co-precipitation ...

  5. Reconciling Differences between Lipid Transfer in Free-Standing and Solid Supported Membranes: A Time-Resolved Small-Angle Neutron Scattering Study.

    Science.gov (United States)

    Wah, Benny; Breidigan, Jeffrey M; Adams, Joseph; Horbal, Piotr; Garg, Sumit; Porcar, Lionel; Perez-Salas, Ursula

    2017-04-11

    Maintaining compositional lipid gradients across membranes in animal cells is essential to biological function, but what is the energetic cost to maintain these differences? It has long been recognized that studying the passive movement of lipids in membranes can provide insight into this toll. Confusingly the reported values of inter- and, particularly, intra-lipid transport rates of lipids in membranes show significant differences. To overcome this difficulty, biases introduced by experimental approaches have to be identified. The present study addresses the difference in the reported intramembrane transport rates of dimyristoylphosphatidylcholine (DMPC) on flat solid supports (fast flipping) and in curved free-standing membranes (slow flipping). Two possible scenarios are potentially at play: one is the difference in curvature of the membranes studied and the other the presence (or not) of the support. Using DMPC vesicles and DMPC supported membranes on silica nanoparticles of different radii, we found that an increase in curvature (from a diameter of 30 nm to a diameter of 100 nm) does not change the rates significantly, differing only by factors of order ∼1. Additionally, we found that the exchange rates of DMPC in supported membranes are similar to the ones in vesicles. And as previously reported, we found that the activation energies for exchange on free-standing and supported membranes are similar (84 and 78 kJ/mol, respectively). However, DMPC's flip-flop rates increase significantly when in a supported membrane, surpassing the exchange rates and no longer limiting the exchange process. Although the presence of holes or cracks in supported membranes explains the occurrence of fast lipid flip-flop in many studies, in defect-free supported membranes we find that fast flip-flop is driven by the surface's induced disorder of the bilayer's acyl chain packing as evidenced from their broad melting temperature behavior.

  6. Interaction analysis of chimeric metal-binding green fluorescent protein and artificial solid-supported lipid membrane by quartz crystal microbalance and atomic force microscopy

    International Nuclear Information System (INIS)

    Prachayasittikul, Virapong; Na Ayudhya, Chartchalerm Isarankura; Hilterhaus, Lutz; Hinz, Andreas; Tantimongcolwat, Tanawut; Galla, Hans-Joachim

    2005-01-01

    Non-specific adsorption and specific interaction between a chimeric green fluorescent protein (GFP) carrying metal-binding region and the immobilized zinc ions on artificial solid-supported lipid membranes was investigated using the quartz crystal microbalance technique and the atomic force microscopy (AFM). Supported lipid bilayer, composed of octanethiol and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-[N- (5-amino-1-carboxypentyl iminodiacetic acid)succinyl] (NTA-DOGS)-Zn 2+ , was formed on the gold electrode of quartz resonator (5 MHz). Binding of the chimeric GFP to zinc ions resulted in a rapid decrease of resonance frequency. Reversibility of the process was demonstrated via the removal of metal ions by EDTA. Nanoscale structural orientation of the chimeric GFP on the membrane was imaged by AFM. Association constant of the specific binding to metal ions was 2- to 3-fold higher than that of the non-specific adsorption, which was caused by the fluidization effect of the metal-chelating lipid molecules as well as the steric hindrance effect. This infers a possibility for a further development of biofunctionalized membrane. However, maximization is needed in order to attain closer advancement to a membrane-based sensor device

  7. Solid lipid nanoparticles: A drug carrier system

    Directory of Open Access Journals (Sweden)

    Rashmi R Kokardekar

    2011-01-01

    Full Text Available Solid lipid nanoparticles (SLN are a type of nanoparticles. They are submicron colloidal carriers which are composed of physiological lipids, dispersed in water or in aqueous surfactant solutions. SLN have wide range of advantages over other types of nanoparticles. These include availability of large-scale production methods and no signs of cytotoxicity, which are main hindrances in the application of other types of nanoparticles. Hot and cold homogenization techniques are mainly employed for its production. They are mainly evaluated on the basis of their drug release profile and particle internal structure. The products based on SLN are under development. They have a very wide range of applications in cosmetics and pharmaceuticals. They can be applied for any purpose, for which nanoparticles have a distinct advantage. Thus, SLN can be used extensively as an alternative to the existing drug carrier systems, providing more flexibility with respect to the area of applications and also aspects for commercialization.

  8. Preparation and evaluation of carvedilol-loaded solid lipid ...

    African Journals Online (AJOL)

    Keywords: Carvedilol, Solid lipid nanoparticles, Antihypertensive, Sustained release. Tropical Journal of ... Lipid particles are of great importance to drug researchers and ... toxic for human use and officially recognized as a pharmaceutical ...

  9. Inclusion of the helper lipid dioleoyl-phosphatidylethanolamine in solid lipid nanoparticles inhibits their transfection efficiency

    NARCIS (Netherlands)

    de Jesus, Marcelo B.; Radaic, Allan; Hinrichs, Wouter L J; Ferreira, Carmen V; de Paula, Eneida; Hoekstra, Dirk; Zuhorn, Inge S

    Solid lipid nanoparticles (SLNs) are a promising system for the delivery of lipophilic and hydrophilic drugs. They consist of a solid lipid core that is stabilized by a layer of surfactants. By the incorporation of cationic lipids in the formulation, positively charged SLNs can be generated, that

  10. Imaging of blood plasma coagulation at supported lipid membranes.

    Science.gov (United States)

    Faxälv, Lars; Hume, Jasmin; Kasemo, Bengt; Svedhem, Sofia

    2011-12-15

    The blood coagulation system relies on lipid membrane constituents to act as regulators of the coagulation process upon vascular trauma, and in particular the 2D configuration of the lipid membranes is known to efficiently catalyze enzymatic activity of blood coagulation factors. This work demonstrates a new application of a recently developed methodology to study blood coagulation at lipid membrane interfaces with the use of imaging technology. Lipid membranes with varied net charges were formed on silica supports by systematically using different combinations of lipids where neutral phosphocholine (PC) lipids were mixed with phospholipids having either positively charged ethylphosphocholine (EPC), or negatively charged phosphatidylserine (PS) headgroups. Coagulation imaging demonstrated that negatively charged SiO(2) and membrane surfaces exposing PS (obtained from liposomes containing 30% of PS) had coagulation times which were significantly shorter than those for plain PC membranes and EPC exposing membrane surfaces (obtained from liposomes containing 30% of EPC). Coagulation times decreased non-linearly with increasing negative surface charge for lipid membranes. A threshold value for shorter coagulation times was observed below a PS content of ∼6%. We conclude that the lipid membranes on solid support studied with the imaging setup as presented in this study offers a flexible and non-expensive solution for coagulation studies at biological membranes. It will be interesting to extend the present study towards examining coagulation on more complex lipid-based model systems. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Tethered and Polymer Supported Bilayer Lipid Membranes: Structure and Function

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    Jakob Andersson

    2016-05-01

    Full Text Available Solid supported bilayer lipid membranes are model systems to mimic natural cell membranes in order to understand structural and functional properties of such systems. The use of a model system allows for the use of a wide variety of analytical tools including atomic force microscopy, impedance spectroscopy, neutron reflectometry, and surface plasmon resonance spectroscopy. Among the large number of different types of model membranes polymer-supported and tethered lipid bilayers have been shown to be versatile and useful systems. Both systems consist of a lipid bilayer, which is de-coupled from an underlying support by a spacer cushion. Both systems will be reviewed, with an emphasis on the effect that the spacer moiety has on the bilayer properties.

  12. Applications of lipid nanocarriers for solid tumors therapy: literature review

    International Nuclear Information System (INIS)

    Oliveira, Lidiane Correia de; Souza, Leonardo Gomes; Marreto, Ricardo Neves; Lima, Eliana Martins; Taveira, Stephania Fleury; Taveira, Eliseu Jose Fleury

    2012-01-01

    Introduction: Lipid nanocarriers are systems used to target drugs to its site of action and have attracted attention of the scientific community because they are biocompatible and biodegradable. These systems can target drugs to solid tumors, providing sustained drug release in the site of action, thus increasing the utility of the antineoplastic chemotherapy. Objective: To review the available literature on in vivo experiments with lipid nanocarriers containing cytotoxic drugs for solid tumors treatment. Method: A search study was carried out in Pubmed R database from 2007 to 2011, with subject descriptors: liposomes, lipid nanoparticles, cancer and in vivo, with the boolean operator 'and' among them, in English. Results: 1,595 papers related to the use of liposomes and 77 related to lipid nanoparticles were found. Few studies reported in vivo experiments with lipid nanoparticles (28 papers) compared to liposomes (472 papers), since liposomes were developed two decades before lipid nanoparticles. Four liposomal medicines have already been approved and are used in the clinic while only one medicine containing lipid nanoparticles is in phase I of clinical studies. Conclusion: The number of papers related to the use of nanotechnology for cancer treatment is increasing rapidly, making important to know the different kinds of nanocarriers and, especially, those which are already used in the clinic. There are only few clinical studies on lipid nanocarriers; however, these systems present an enormous potential to improve the clinical practice in oncology. (author)

  13. Preparation and characterization of solid lipid nanoparticles-a review.

    Science.gov (United States)

    Parhi, Rabinarayan; Suresh, Padilama

    2012-03-01

    In the present scenario, most of the developed and new discovered drugs are posing real challenge to the formulation scientists due to their poor aqueous solubility which in turn is responsible for poor bioavailability. One of the approach to overcome above problem is the packaging of the drug in to particulate carrier system. Among various carriers, lipid emerged as very attractive candidate because of its unique property of enhancing the bioavailability of poorly water soluble drugs. Solid lipid, one of the physical forms of lipid, is used to formulate nanoparticles, popularly known as Solid lipid nanoparticles (SLNs), as an alternative carrier system to emulsions, liposomes and polymeric micro- and nano-particles. SLNs combine advantages of the traditional systems but avoid some of their major disadvantages. This paper reviews numerous production techniques for SLNs along with their advantages and disadvantages. Special attention is paid to the characterization of the SLNs by using various analytical tools. It also emphasizes on physical state of lipid (supercooled melts, different lipid modifications).

  14. Single-component solid lipid nanocarriers prepared with ultra-long chain amphiphilic lipids

    DEFF Research Database (Denmark)

    Wei, Wei; Lu, Xiaonan; Wang, Zegao

    2017-01-01

    HYPOTHESIS: Synthetic sugar alcohol mono-behenates with high melting points, surface activity and resistance to enzymatic lipolysis, are expected to form stable single-component solid lipid nanocarriers (SC-SLNs). The preparation methods and the polar head group of the molecules should affect the......-probe sonication method had a micelle structure with fenofibrate incorporated into a lipid monolayer. This study provides an insight into the systematic development of novel amphiphilic lipids for solid lipid-based drug delivery system.......HYPOTHESIS: Synthetic sugar alcohol mono-behenates with high melting points, surface activity and resistance to enzymatic lipolysis, are expected to form stable single-component solid lipid nanocarriers (SC-SLNs). The preparation methods and the polar head group of the molecules should affect...... using the lipolysis model. The structure and drug distribution of the nanocarriers were studied using AFM and TEM. FINDINGS: Both the polar head group of the molecules and the preparation methods affect the particle size and size distribution. Nanocarriers prepared with sorbitol mono-behenates showed...

  15. Production and characterization of nanostructured lipid carriers and solid lipid nanoparticles containing lycopene for food fortification.

    Science.gov (United States)

    Akhoond Zardini, Ali; Mohebbi, Mohebbat; Farhoosh, Reza; Bolurian, Shadi

    2018-01-01

    In this study, lycopene, was loaded on nanostructured lipid carrier and solid lipid nanoparticles using combination of high shear homogenization and ultrasonication method. Effect of applied lipids types, nanocarrier's type and lycopene loading on physicochemical properties of developed nanocarriers were studied. Particle sizes of developed nanocarriers were between 74.93 and 183.40 nm. Encapsulation efficiency of nanostructured lipid carrier was significantly higher than solid lipid nanoparticles. Morphological study of developed nanocarriers using scanning electron microscopy showed spherical nanoparticles with smooth surface. Lycopene was entrapped in nanocarriers without any chemical interaction with coating material according to Fourier transform infrared spectroscopy spectrum and differential scanning calorimetry thermogram. Glycerol monostearate containing nanoparticles showed phase separation after 30 days in 6 and 25 °C, whereas this event was not observed in nanosuspensions that produced by glycerol distearate. Lycopene release in gastrointestinal condition was studied by the dialysis bag method. To evaluate nanocarrier's potential for food fortification, developed lycopene-loaded nanocarriers were added to orange drink. Results of sensory analysis indicated that nanoencapsulation could obviate the poor solubility and tomato after taste of lycopene. Fortified sample with lycopene nanocarriers didn't show significant difference with blank orange drink sample except in orange odor.

  16. Nanostructured lipid carriers (NLCs) versus solid lipid nanoparticles (SLNs) for topical delivery of meloxicam.

    Science.gov (United States)

    Khalil, Rawia M; Abd-Elbary, A; Kassem, Mahfoz A; Ghorab, Mamdouh M; Basha, Mona

    2014-05-01

    The aim of this study was to develop nanostructured lipid carriers (NLCs) as well as solid lipid nanoparticles (SLNs) and evaluate their potential in the topical delivery of meloxicam (MLX). The effect of various compositional variations on their physicochemical properties was investigated. Furthermore, MLX-loaded lipid nanoparticles-based hydrogels were formulated and the gels were evaluated as vehicles for topical application. The results showed that NLC and SLN dispersions had spherical shapes with an average size between 215 and 430 nm. High entrapment efficiency was obtained ranging from 61.94 to 90.38% with negatively charged zeta potential in the range of -19.1 to -25.7 mV. The release profiles of all formulations exhibited sustained release characteristics over 48 h and the release rates increased as the amount of liquid lipid in lipid core increased. Finally, Precirol NLC with 50% Miglyol® 812 and its corresponding SLN were incorporated in hydrogels. The gels showed adequate pH, non-Newtonian flow with shear-thinning behavior and controlled release profiles. The biological evaluation revealed that MLX-loaded NLC gel showed more pronounced effect compared to MLX-loaded SLN gel. It can be concluded that lipid nanoparticles represent promising particulate carriers for topical application.

  17. Solid Lipid Nanoparticles of Guggul Lipid as Drug Carrier for Transdermal Drug Delivery

    Directory of Open Access Journals (Sweden)

    Praveen Kumar Gaur

    2013-01-01

    Full Text Available Diclofenac sodium loaded solid lipid nanoparticles (SLNs were formulated using guggul lipid as major lipid component and analyzed for physical parameters, permeation profile, and anti-inflammatory activity. The SLNs were prepared using melt-emulsion sonication/low temperature-solidification method and characterized for physical parameters, in vitro drug release, and accelerated stability studies, and formulated into gel. Respective gels were compared with a commercial emulgel (CEG and plain carbopol gel containing drug (CG for ex vivo and in vivo drug permeation and anti-inflammatory activity. The SLNs were stable with optimum physical parameters. GMS nanoparticle 1 (GMN-1 and stearic acid nanoparticle 1 (SAN-1 gave the highest in vitro drug release. Guggul lipid nanoparticle gel 3 (GLNG-3 showed 104.68 times higher drug content than CEG in receptor fluid. The enhancement ratio of GLNG-3 was 39.43 with respect to CG. GLNG-3 showed almost 8.12 times higher Cmax than CEG at 4 hours. The AUC value of GLNG-3 was 15.28 times higher than the AUC of CEG. GLNG-3 showed edema inhibition up to 69.47% in the first hour. Physicochemical properties of major lipid component govern the properties of SLN. SLN made up of guggul lipid showed good physical properties with acceptable stability. Furthermore, it showed a controlled drug release profile along with a promising permeation profile.

  18. Lipid bilayers suspended on microfabricated supports

    Science.gov (United States)

    Ogier, Simon D.; Bushby, Richard J.; Cheng, Yaling; Cox, Tim I.; Evans, Stephen D.; Knowles, Peter F.; Miles, Robert E.; Pattison, Ian

    2001-03-01

    The plasma membrane, that exists as part of many animal and plant cells, is a regulator for the transport of ions and small molecules across cell boundaries. Two main components involved are the phospholipid bilayer and the transport proteins. This paper details the construction of a micromachined support for bilayers (MSB) as a first step towards the development of highly selective and highly sensitive ion-channel based biosensors. The device consists of a ~100 micrometer hole in a polymeric support above a cavity that can hold ~25 nL of electrolyte. Electrodes attached to the structure allow the resistance of the membranes to be measured using d.c. conductivity. The MSB is made in two halves, using SU8 ultra-thick resist, which are subsequently bonded together to make the final structure. A layer of gold, surrounding the aperture, enables self-assembled monolayers of alkanethiols to be used to make the polymeric structure biocompatible. Lipid membranes have been formed over these holes with resistances comparable with those of natural membranes >10 MOhmcm^2. The ion-channel gramicidin has successfully been incorporated into the bilayer and its activity monitored. It is proposed that this type of device could be used not only for studying membrane transport phenomena but also as part of an ion-channel based biosensor.

  19. Sustained Cytotoxicity of Wogonin on Breast Cancer Cells by Encapsulation in Solid Lipid Nanoparticles

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    Jong-Suep Baek

    2018-03-01

    Full Text Available While wogonin has been known to have cytotoxicity against various cancer cells, its bioavailability and cytotoxicity are low due to its low water solubility. Therefore, wogonin-loaded solid lipid nanoparticles were fabricated using a hot-melted evaporation technique. The highest solubility of wogonin was observed in stearic acid. Hence, wogonin-loaded solid lipid nanoparticles were composed of stearic acid as the lipid matrix. The physicochemical properties of the wogonin-loaded solid lipid nanoparticles were evaluated by dynamic laser scattering and scanning electron microscopy. The wogonin-loaded solid lipid nanoparticles exhibited sustained and controlled release up to 72 h. In addition, it was observed that the wogonin-loaded solid lipid nanoparticles exhibited enhanced cytotoxicity and inhibited poly (ADP-ribose polymerase in MCF-7 breast cancer cells. Overall, the results indicate that wogonin-loaded solid lipid nanoparticles could be an efficient delivery system for the treatment of breast cancer.

  20. Solid lipid nanoparticles suspension versus commercial solutions for dermal delivery of minoxidil.

    Science.gov (United States)

    Padois, Karine; Cantiéni, Céline; Bertholle, Valérie; Bardel, Claire; Pirot, Fabrice; Falson, Françoise

    2011-09-15

    Solid lipid nanoparticles have been reported as possible carrier for skin drug delivery. Solid lipid nanoparticles are produced from biocompatible and biodegradable lipids. Solid lipid nanoparticles made of semi-synthetic triglycerides stabilized with a mixture of polysorbate and sorbitan oleate were loaded with 5% of minoxidil. The prepared systems were characterized for particle size, pH and drug content. Ex vivo skin penetration studies were performed using Franz-type glass diffusion cells and pig ear skin. Ex vivo skin corrosion studies were realized with a method derived from the Corrositex(®) test. Solid lipid nanoparticles suspensions were compared to commercial solutions in terms of skin penetration and skin corrosion. Solid lipid nanoparticles suspensions have been shown as efficient as commercial solutions for skin penetration; and were non-corrosive while commercial solutions presented a corrosive potential. Solid lipid nanoparticles suspensions would constitute a promising formulation for hair loss treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Peptide-Loaded Solid Lipid Nanoparticles Prepared through Coacervation Technique

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    Marina Gallarate

    2011-01-01

    Full Text Available Stearic acid solid lipid nanoparticles were prepared according to a new technique, called coacervation. The main goal of this experimental work was the entrapment of peptide drugs into SLN, which is a difficult task, since their chemical characteristics (molecular weight, hydrophilicity, and stability hamper peptide-containing formulations. Insulin and leuprolide, chosen as model peptide drugs, were encapsulated within nanoparticles after hydrophobic ion pairing with anionic surfactants. Peptide integrity was maintained after encapsulation, and nanoparticles can act in vitro as a sustained release system for peptide.

  2. Molecular phospholipid films on solid supports

    DEFF Research Database (Denmark)

    Czolkos, Ilja; Jesorka, Aldo; Orwar, Owe

    2011-01-01

    Phospholipid membranes are versatile structures for mimicking biological surfaces. Bilayer and monolayer membranes can be formed on solid supports, leading to enhanced stability and accessibility of the biomimetic molecular film. This has facilitated functional studies of membrane proteins and ai...

  3. Phase behavior of supported lipid bilayers: A systematic study by coarse-grained molecular dynamics simulations

    DEFF Research Database (Denmark)

    Poursoroush, Asma; Sperotto, Maria Maddalena; Laradji, Mohamed

    2017-01-01

    Solid-supported lipid bilayers are utilized by experimental scientists as models for biological membranes because of their stability. However, compared to free standing bilayers, their close proximity to the substrate may affect their phase behavior. As this is still poorly understood, and few co...

  4. Supported lipid bilayer on nanocrystalline diamond: dual optical and field-effect sensor for membrane disruption

    Czech Academy of Sciences Publication Activity Database

    Ang, P.K.; Loh, K.P.; Wohland, T.; Nesládek, Miloš; Van Hove, E.

    2009-01-01

    Roč. 19, č. 1 (2009), s. 109-116 ISSN 1616-301X Institutional research plan: CEZ:AV0Z10100520 Keywords : nanocrystalline diamond * biocompatibility * supported lipid bilayers * biosensors * solution gate field effect transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.990, year: 2009

  5. Enhanced rifampicin delivery to alveolar macrophages by solid lipid nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chuan Junlan [West China School of Pharmacy, Sichuan University, Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education (China); Li Yanzhen [Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technology and Pharmacokinetics (China); Yang Likai; Sun Xun [West China School of Pharmacy, Sichuan University, Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education (China); Zhang Qiang [Peking University, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences (China); Gong Tao, E-mail: gongtaoy@126.com; Zhang Zhirong, E-mail: zrzzl@vip.sina.com [West China School of Pharmacy, Sichuan University, Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education (China)

    2013-05-15

    The present study aimed at developing a drug delivery system targeting the densest site of tuberculosis infection, the alveolar macrophages (AMs). Rifampicin (RFP)-loaded solid lipid nanoparticles (RFP-SLNs) with an average size of 829.6 {+-} 16.1 nm were prepared by a modified lipid film hydration method. The cytotoxicity of RFP-SLNs to AMs and alveolar epithelial type II cells (AECs) was examined using MTT assays. The viability of AMs and AECs was above 80 % after treatment with RFP-SLNs, which showed low toxicity to both AMs and AECs. Confocal Laser Scanning Microscopy was employed to observe the interaction between RFP-SLNs and both AMs and AECs. After incubating the cells with RFP-SLNs for 2 h, the fluorescent intensity in AMs was more and remained longer (from 0.5 to 12 h) when compared with that in AECs (from 0.5 to 8 h). In vitro uptake characteristics of RFP-SLNs in AMs and AECs were also investigated by detection of intracellular RFP by High performance liquid chromatography. Results showed that RFP-SLNs delivered markedly higher RFP into AMs (691.7 ng/mg in cultured AMs, 662.6 ng/mg in primary AMs) than that into AECs (319.2 ng/mg in cultured AECs, 287.2 ng/mg in primary AECs). Subsequently, in vivo delivery efficiency and the selectivity of RFP-SLNs were further verified in Sprague-Dawley rats. Under pulmonary administration of RFP-SLNs, the amount of RFP in AMs was significantly higher than that in AECs at each time point. Our results demonstrated that solid lipid nanoparticles are a promising strategy for the delivery of rifampicin to alveolar macrophages selectively.

  6. Supported lipid bilayers with controlled curvature via colloidal lithography

    DEFF Research Database (Denmark)

    Sundh, Maria; Manandhar, Michal; Svedhem, Sofia

    2011-01-01

    Supported lipid bilayers (SLBs) at surfaces provide a route to quantitatively study molecular interactions with and at lipid membranes via different surface-based analytical techniques. Here, a method to fabricate SLBs with controlled curvatures, in the nanometer regime over large areas, is prese...

  7. Chitosan-coupled solid lipid nanoparticles: Tuning nanostructure and mucoadhesion.

    Science.gov (United States)

    Sandri, Giuseppina; Motta, Simona; Bonferoni, Maria Cristina; Brocca, Paola; Rossi, Silvia; Ferrari, Franca; Rondelli, Valeria; Cantù, Laura; Caramella, Carla; Del Favero, Elena

    2017-01-01

    Solid Lipid Nanoparticles (SLNs) composed of biodegradable physiological lipids have been widely proposed as efficient drug delivery systems, also for ophthalmic administration. Recently, chitosan-associated-SLNs have been developed to further improve the residence time of these colloidal systems in the precorneal area by means of mucoadhesive interaction. In the present study, a one-step preparation protocol was used aiming both at scale-up ease and at stronger coupling between chitosan and SLNs. The resulting particles were chitosan associated-SLNs (CS-SLNs). These nanoparticles were characterized, as compared to both the chitosan-free and the usual chitosan-coated ones, by applying a multi-technique approach: light, neutron and X-ray scattering, Zeta-potential, AFM, calorimetry. It was assessed that, while keeping the features of nano-size and surface-charge required for an efficient vector, these new nanoparticles display a strong and intimate interaction between chitosan and SLNs, far more settled than the usual simple coverage. Moreover, this one-step preparation method allows to obtain a strong and intimate interaction between chitosan and SLNs, firmer than the usual simple coating. This confers to the CS-SLNs an improved mucoadhesion, opening the way for a high-performing ophthalmic formulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Cholesterylbutyrate Solid Lipid Nanoparticles as a Butyric Acid Prodrug

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    Alessandro Mauro

    2008-02-01

    Full Text Available Cholesterylbutyrate (Chol-but was chosen as a prodrug of butyric acid.Butyrate is not often used in vivo because its half-life is very short and therefore too largeamounts of the drug would be necessary for its efficacy. In the last few years butyric acid'santi-inflammatory properties and its inhibitory activity towards histone deacetylases havebeen widely studied, mainly in vitro. Solid Lipid Nanoparticles (SLNs, whose lipid matrixis Chol-but, were prepared to evaluate the delivery system of Chol-but as a prodrug and totest its efficacy in vitro and in vivo. Chol-but SLNs were prepared using the microemulsionmethod; their average diameter is on the order of 100-150 nm and their shape is spherical.The antineoplastic effects of Chol-but SLNs were assessed in vitro on different cancer celllines and in vivo on a rat intracerebral glioma model. The anti-inflammatory activity wasevaluated on adhesion of polymorphonuclear cells to vascular endothelial cells. In thereview we will present data on Chol-but SLNs in vitro and in vivo experiments, discussingthe possible utilisation of nanoparticles for the delivery of prodrugs for neoplastic andchronic inflammatory diseases.

  9. Enhanced photocytotoxicity of curcumin delivered by solid lipid nanoparticles

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    Jiang S

    2016-12-01

    Full Text Available Shan Jiang,1 Rongrong Zhu,1 Xiaolie He,1 Jiao Wang,1 Mei Wang,1 Yechang Qian,2 Shilong Wang1 1Tenth People’s Hospital, School of Life Science and Technology, Tongji University, 2Department of Respiratory Disease, Baoshan District Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai, People’s Republic of China Abstract: Curcumin (Cur is a promising photosensitizer that could be used in photodynamic therapy. However, its poor solubility and hydrolytic instability limit its clinical use. The aim of the present study was to encapsulate Cur into solid lipid nanoparticles (SLNs in order to improve its therapeutic activity. The Cur-loaded SLNs (Cur-SLNs were prepared using an emulsification and low-temperature solidification method. The functions of Cur and Cur-SLNs were studied on the non-small cell lung cancer A549 cells for photodynamic therapy. The results revealed that Cur-SLNs induced ~2.27-fold toxicity higher than free Cur at a low concentration of 15 µM under light excitation, stocking more cell cycle at G2/M phase. Cur-SLNs could act as an efficient drug delivery system to increase the intracellular concentration of Cur and its accumulation in mitochondria; meanwhile, the hydrolytic stability of free Cur could be improved. Furthermore, Cur-SLNs exposed to 430 nm light could produce more reactive oxygen species to induce the disruption of mitochondrial membrane potential. Western blot analysis revealed that Cur-SLNs increased the expression of caspase-3, caspase-9 proteins and promoted the ratio of Bax/Bcl-2. Overall, the results from these studies demonstrated that the SLNs could enhance the phototoxic effects of Cur. Keywords: photodynamic therapy, curcumin, solid lipid nanoparticles, drug delivery, reactive oxygen species

  10. Development of solid lipid nanoparticles for enhanced solubility of poorly soluble drugs

    DEFF Research Database (Denmark)

    Potta, Sriharsha Gupta; Minemi, Sriharsha; Nukala, Ravi Kumar

    2010-01-01

    Cyclosporine (CyA) solid lipid nanoparticles were prepared by using a solvent free high pressure homogenization process. CyA was incorporated into SLNs that consisted of stearic acid, trilaurin or tripalmitin lipid solid cores in order to enhance drug solubility. The process was conducted...

  11. Solid-state nuclear magnetic resonance measurements of HIV fusion peptide 13CO to lipid 31P proximities support similar partially inserted membrane locations of the α helical and β sheet peptide structures.

    Science.gov (United States)

    Gabrys, Charles M; Qiang, Wei; Sun, Yan; Xie, Li; Schmick, Scott D; Weliky, David P

    2013-10-03

    infection. The present study shows that HFPmn_V2E induces much less vesicle fusion than HFPmn. "HFPtr" contained three strands with HFPmn sequence that were chemically cross-linked near their C-termini. HFPtr mimics the trimeric topology of gp41 and induces much more rapid and extensive vesicle fusion than HFPmn. For HFPmn and HFPtr, well-resolved α and β peaks were observed for A6-, L9-, and L12-labeled samples. For each of these samples, there were similar HFP (13)CO to lipid (31)P proximities in the α and β structures, which evidenced comparable membrane locations of the HFP in either structure including insertion into a single membrane leaflet. The data were also consistent with deeper insertion of HFPtr relative to HFPmn in both the α and β structures. The results supported a strong correlation between the membrane insertion depth of the HFP and its fusogenicity. More generally, the results supported membrane location of the HFP as an important determinant of its fusogenicity. The deep insertion of HFPtr in both the α and β structures provides the most relevant membrane location of the FP for HIV gp41-catalyzed membrane fusion because HIV gp41 is natively trimeric. Well-resolved α and β signals were observed in the HFPmn_V2E samples with L9- and L12- but not A6-labeling. The α signals were much more dominant for L9- and L12-labeled HFPmn_V2E than the corresponding HFPmn or HFPtr. The structural model for the less fusogenic HFPmn_V2E includes a shorter helix and less membrane insertion than either HFPmn or HFPtr. This greater helical population and different helical structure and membrane location could result in less membrane perturbation and lower fusogenicity of HFPmn_V2E and suggest that the β sheet fusion peptide is the most functionally relevant structure of HFPmn, HFPtr, and gp41.

  12. Multinuclear NMR studies of single lipid bilayers supported in cylindrical aluminum oxide nanopores.

    Science.gov (United States)

    Gaede, Holly C; Luckett, Keith M; Polozov, Ivan V; Gawrisch, Klaus

    2004-08-31

    Lipid bilayers were deposited inside the 0.2 microm pores of anodic aluminum oxide (AAO) filters by extrusion of multilamellar liposomes and their properties studied by 2H, 31P, and 1H solid-state NMR. Only the first bilayer adhered strongly to the inner surface of the pores. Additional layers were washed out easily by a flow of water as demonstrated by 1H magic angle spinning NMR experiments with addition of Pr3+ ions to shift accessible lipid headgroup resonances. A 13 mm diameter Anopore filter of 60 microm thickness oriented approximately 2.5 x 10(-7) mol of lipid as a single bilayer, corresponding to a total membrane area of about 500 cm2. The 2H NMR spectra of chain deuterated POPC are consistent with adsorption of wavy, tubular bilayers to the inner pore surface. By NMR diffusion experiments, we determined the average length of those lipid tubules to be approximately 0.4 microm. There is evidence for a thick water layer between lipid tubules and the pore surface. The ends of tubules are well sealed against the pore such that Pr3+ ions cannot penetrate into the water underneath the bilayers. We successfully trapped poly(ethylene glycol) (PEG) with a molecular weight of 8000 in this water layer. From the quantity of trapped PEG, we calculated an average water layer thickness of 3 nm. Lipid order parameters and motional properties are unperturbed by the solid support, in agreement with existence of a water layer. Such unperturbed, solid supported membranes are ideal for incorporation of membrane-spanning proteins with large intra- and extracellular domains. The experiments suggest the promise of such porous filters as membrane support in biosensors.

  13. Buparvaquone loaded solid lipid nanoparticles for targeted delivery in theleriosis

    Directory of Open Access Journals (Sweden)

    Maheshkumar P Soni

    2014-01-01

    Full Text Available Background: Buparvaquone (BPQ, a hydroxynaphthoquinone derivative, has been investigated for the treatment of many infections and is recommended as the gold standard for the treatment of theileriosis. Theileriosis, an intramacrophage infection is localized mainly in reticuloendotheileial system (RES organs. The present study investigates development of solid lipid nanoparticles (SLN of BPQ for targeted delivery to the RES. Materials and Methods: BPQ SLN was prepared using melt method by adding a molten mixture into aqueous Lutrol F68 solution (80°C. Larger batches were prepared up to 6 g of BPQ with GMS: BPQ, 2:1. SLN of designed size were obtained using ultraturrax and high pressure homogenizer. A freeze and thaw study was used to optimize type and concentration of cryoprotectant with Sf: Mean particle size, Si: Initial particle size <1.3. Differential scanning calorimetry (DSC, powder X-ray diffraction (XRD and scanning electron microscope (SEM study was performed on optimized formulation. Formulation was investigated for in vitro serum stability, hemolysis and cell uptake study. Pharmacokinetic and biodistribution study was performed in Holtzman rat. Results: Based on solubility in lipid; glyceryl monostearate (GMS was selected for preparation of BPQ SLN. Batches of BPQ SLN were optimized for average particle size and entrapment efficiency at <100 mg solid content. A combination of Solutol HS-15 and Lutrol F68 at 2% w/v and greater enabled the desired Sf/Si < 1.3. Differential scanning calorimetry and powder X-ray diffraction revealed decrease in crystallinity of BPQ in BPQ SLN while, scanning electron microscope revealed spherical morphology. BPQ SLN revealed good stability at 4°C and 25°C. Low hemolytic potential (<8% and in vitro serum stability up to 5 h was observed. Cytotoxicity of SLN to the U937 cell was low. The macrophage cell line revealed high (52% uptake of BPQ SLN in 1 h suggesting the potential to RES uptake. SLN revealed

  14. Effect of liquid-to-solid lipid ratio on characterizations of flurbiprofen-loaded solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) for transdermal administration.

    Science.gov (United States)

    Song, Aihua; Zhang, Xiaoshu; Li, Yanting; Mao, Xinjuan; Han, Fei

    2016-08-01

    The aim of this study is to evaluate the effect of liquid-to-solid lipid ratio on properties of flurbiprofen-loaded solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), and to clarify the superiority of NLCs over SLNs for transdermal administration. Particle size, zeta potential, drug encapsulation efficiency, in vitro occlusion factor, differential scanning calorimetry, X-ray diffractometry, in vitro percutaneous permeation profile, and stability of SLNs and NLCs were compared. Particle size, zeta potential, drug encapsulation efficiency, in vitro occlusion factor, and in vitro percutaneous permeation amount of the developed NLCs were all 78%, >35, and >240 μg/cm(2), respectively, however, for SLNs were 280 nm, -29.11 mV, 63.2%, 32.54, and 225.9 μg/cm(2), respectively. After 3 months storage at 4 °C and 25 °C, almost no significant differences between the evaluated parameters of NLCs were observed. However, for SLNs, particle size was increased to higher than 300 nm (4 °C and 25 °C), drug encapsulation efficiency was decreased to 51.2 (25 °C), in vitro occlusion factor was also decreased to lower than 25 (4 °C and 25 °C), and the cumulative amount was decreased to 148.9 μg/cm(2) (25 °C) and 184.4 μg/cm(2) (4 °C), respectively. And DSC and XRD studies indicated that not only the crystalline peaks of the encapsulated flurbiprofen disappeared but also obvious difference between samples and bulk Compritol® ATO 888 was seen. It could be concluded that liquid-to-solid lipid ratio has significant impact on the properties of SLNs and NLCs, and NLCs showed better stability than SLNs. Therefore, NLCs might be a better option than SLNs for transdermal administration.

  15. Solid lipid nanoparticles for pulmonary delivery of insulin.

    Science.gov (United States)

    Liu, Jie; Gong, Tao; Fu, Hualin; Wang, Changguang; Wang, Xiuli; Chen, Qian; Zhang, Qin; He, Qin; Zhang, Zhirong

    2008-05-22

    Growing attention has been given to the potential of pulmonary route as an alternative for non-invasive systemic delivery of therapeutic agents. In this study, novel nebulizer-compatible solid lipid nanoparticles (SLNs) for pulmonary drug delivery of insulin were developed by reverse micelle-double emulsion method. The influences of the amount of sodium cholate (SC) and soybean phosphatidylcholine (SPC) on the deposition properties of the nanoparticles were investigated. Under optimal conditions, the entrapment delivery (ED), respirable fraction (RF) and nebulization efficiency (NE) of SLNs could reach 96.53, 82.11 and 63.28%, respectively, and Ins-SLNs remained stable during nebulization. Fasting plasma glucose level was reduced to 39.41% and insulin level was increased to approximately 170 microIU/ml 4h after pulmonary administration of 20 IU/kg Ins-SLNs. A pharmacological bioavailability of 24.33% and a relative bioavailability of 22.33% were obtained using subcutaneous injection as a reference. Incorporating fluorescent-labelled insulin into SLNs, we found that the SLNs were effectively and homogeneously distributed in the lung alveoli. These findings suggested that SLNs could be used as a potential carrier for pulmonary delivery of insulin by improving both in vitro and in vivo stability as well as prolonging hypoglycemic effect, which inevitably resulted in enhanced bioavailability.

  16. Hypericin encapsulated in solid lipid nanoparticles: phototoxicity and photodynamic efficiency.

    Science.gov (United States)

    Lima, Adriel M; Pizzol, Carine Dal; Monteiro, Fabíola B F; Creczynski-Pasa, Tânia B; Andrade, Gislaine P; Ribeiro, Anderson O; Perussi, Janice R

    2013-08-05

    The hydrophobicity of some photosensitizers can induce aggregation in biological systems, which consequently reduces photodynamic activity. The conjugation of photosensitizers with nanocarrier systems can potentially be used to overcome this problem. The objective of this study was to prepare and characterise hypericin-loaded solid lipid nanoparticles (Hy-SLN) for use in photodynamic therapy (PDT). SLN were prepared using the ultrasonication technique, and their physicochemical properties were characterised. The mean particle size was found to be 153 nm, with a low polydispersity index of 0.28. One of the major advantages of the SLN formulation is its high entrapment efficiency (EE%). Hy-SLN showed greater than 80% EE and a drug loading capacity of 5.22% (w/w). To determine the photodynamic efficiency of Hy before and after encapsulation in SLN, the rate constants for the photodecomposition of two (1)O2 trapping reagents, DPBF and AU, were determined. These rate constants exhibited an increase of 60% and 50% for each method, respectively, which is most likely due to an increase in the lifetime of the triplet state caused by the increase in solubility. Hy-SLN presented a 30% increase in cell uptake and a correlated improvement of 26% in cytotoxicity. Thus, all these advantages suggest that Hy-loaded SLN has potential for use in PDT. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Phenylalanine-coupled solid lipid nanoparticles for brain tumor targeting

    Energy Technology Data Exchange (ETDEWEB)

    Kharya, Parul; Jain, Ashish; Gulbake, Arvind; Shilpi, Satish; Jain, Ankit; Hurkat, Pooja [Dr. Hari Singh Gour University, Pharmaceutical Research Projects Laboratory, Department of Pharmaceutical Sciences (India); Majumdar, Subrata [Bose Institute, Division of Molecular Medicine (India); Jain, Sanjay K., E-mail: drskjainin@yahoo.com [Dr. Hari Singh Gour University, Pharmaceutical Research Projects Laboratory, Department of Pharmaceutical Sciences (India)

    2013-11-15

    The purpose of this study is to investigate the targeting potential of amino acid (phenylalanine)-coupled solid lipid nanoparticles (SLN) loaded with ionically complexed doxorubicin HCl (Dox). Ionic complexation was used to enhance the loading efficiency and release characteristics of water soluble form of Dox. l-Type amino acid transporters (LAT1) are highly expressed on blood brain barrier as well as on many brain cancer cells, thus targeting LAT1 using phenylalanine improved anticancer activity of prepared nanocarrier. The phenylalanine-coupled SLN were characterized by fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, particle size, zeta potential, entrapment efficiency and in vitro release. The particle size of the resulting SLN was found to be in the range of 163.3 ± 5.2 to 113.0 ± 2.6 nm, with a slightly negative surface charge. In ex vivo study on C6 glioma cell lines, the cellular cytotoxicity of the SLN was highly increased when coupled with phenylalanine. In addition, stealthing sheath of PEG present on the surface of the SLN enhanced the cellular uptake of the SLN on C6 glioma cell line. Results of biodistribution and fluorescence studies clearly revealed that phenylalanine-coupled SLN could deliver high amount of drug into the brain tumor cells and showed the brain-targeting potential.

  18. Single Lipid Molecule Dynamics on Supported Lipid Bilayers with Membrane Curvature

    Directory of Open Access Journals (Sweden)

    Philip P. Cheney

    2017-03-01

    Full Text Available The plasma membrane is a highly compartmentalized, dynamic material and this organization is essential for a wide variety of cellular processes. Nanoscale domains allow proteins to organize for cell signaling, endo- and exocytosis, and other essential processes. Even in the absence of proteins, lipids have the ability to organize into domains as a result of a variety of chemical and physical interactions. One feature of membranes that affects lipid domain formation is membrane curvature. To directly test the role of curvature in lipid sorting, we measured the accumulation of two similar lipids, 1,2-Dihexadecanoyl-sn-glycero-3-phosphoethanolamine (DHPE and hexadecanoic acid (HDA, using a supported lipid bilayer that was assembled over a nanopatterned surface to obtain regions of membrane curvature. Both lipids studied contain 16 carbon, saturated tails and a head group tag for fluorescence microscopy measurements. The accumulation of lipids at curvatures ranging from 28 nm to 55 nm radii was measured and fluorescein labeled DHPE accumulated more than fluorescein labeled HDA at regions of membrane curvature. We then tested whether single biotinylated DHPE molecules sense curvature using single particle tracking methods. Similar to groups of fluorescein labeled DHPE accumulating at curvature, the dynamics of single molecules of biotinylated DHPE was also affected by membrane curvature and highly confined motion was observed.

  19. Formation of supported lipid bilayers of charged E. coli lipids on modified gold by vesicle fusion

    Directory of Open Access Journals (Sweden)

    Ileana F. Márquez

    2017-01-01

    Full Text Available We describe a simple way of fusing E. coli lipid vesicles onto a gold surface. Supported lipid bilayers on metal surfaces are interesting for several reasons: transducing a biological signal to an electric readout, using surface analytical tools such as Surface Plasmon Resonance (SPR, Infrared Reflection Absorption Spectroscopy, Neutron Reflectivity or Electrochemistry. The most widely used method to prepare supported lipid membranes is fusion of preexisting liposomes. It is quite efficient on hydrophilic surfaces such as glass, mica or SiO2, but vesicle fusion on metals and metal oxide surfaces (as gold, titanium oxide or indium tin oxide, remains a challenge, particularly for vesicles containing charged lipids, as is the case of bacterial lipids. We describe a simple method based on modifying the gold surface with a charged mercaptopropionic acid self-assembled monolayer and liposomes partially solubilized with detergent. The formed bilayers were characterized using a Quartz Crystal Microbalance with dissipation (QCM-D and Atomic Force Microscopy (AFM. Some advantages of this protocol are that the stability of the self-assembled monolayer allows for repeated use of the substrate after detergent removal of the bilayer and that the amount of detergent required for optimal fusion can be determined previously using the lipid-detergent solubility curve.

  20. Influence of encapsulated functional lipids on crystal structure and chemical stability in solid lipid nanoparticles: Towards bioactive-based design of delivery systems.

    Science.gov (United States)

    Salminen, Hanna; Gömmel, Christina; Leuenberger, Bruno H; Weiss, Jochen

    2016-01-01

    We investigated the influence of physicochemical properties of encapsulated functional lipids--vitamin A, β-carotene and ω-3 fish oil--on the structural arrangement of solid lipid nanoparticles (SLN). The relationship between the crystal structure and chemical stability of the incorporated bioactive lipids was evaluated with different emulsifier compositions of a saponin-rich, food-grade Quillaja extract alone or combined with high-melting or low-melting lecithins. The major factors influencing the structural arrangement and chemical stability of functional lipids in solid lipid dispersions were their solubility in the aqueous phase and their crystallization temperature in relation to that of the carrier lipid. The results showed that the stabilization of the α-subcell crystals in the lattice of the carrier lipid is a key parameter for forming stable solid lipid dispersions. This study contributes to a better understanding of SLN as a function of the bioactive lipid. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Buparvaquone loaded solid lipid nanoparticles for targeted delivery in theleriosis

    Science.gov (United States)

    Soni, Maheshkumar P.; Shelkar, Nilakash; Gaikwad, Rajiv V.; Vanage, Geeta R.; Samad, Abdul; Devarajan, Padma V.

    2014-01-01

    Background: Buparvaquone (BPQ), a hydroxynaphthoquinone derivative, has been investigated for the treatment of many infections and is recommended as the gold standard for the treatment of theileriosis. Theileriosis, an intramacrophage infection is localized mainly in reticuloendotheileial system (RES) organs. The present study investigates development of solid lipid nanoparticles (SLN) of BPQ for targeted delivery to the RES. Materials and Methods: BPQ SLN was prepared using melt method by adding a molten mixture into aqueous Lutrol F68 solution (80°C). Larger batches were prepared up to 6 g of BPQ with GMS: BPQ, 2:1. SLN of designed size were obtained using ultraturrax and high pressure homogenizer. A freeze and thaw study was used to optimize type and concentration of cryoprotectant with Sf: Mean particle size, Si: Initial particle size Solutol HS-15 and Lutrol F68 at 2% w/v and greater enabled the desired Sf/Si < 1.3. Differential scanning calorimetry and powder X-ray diffraction revealed decrease in crystallinity of BPQ in BPQ SLN while, scanning electron microscope revealed spherical morphology. BPQ SLN revealed good stability at 4°C and 25°C. Low hemolytic potential (<8%) and in vitro serum stability up to 5 h was observed. Cytotoxicity of SLN to the U937 cell was low. The macrophage cell line revealed high (52%) uptake of BPQ SLN in 1 h suggesting the potential to RES uptake. SLN revealed longer circulation and biodistrbution study confirmed high RES uptake (75%) in RES organs like liver lung spleen etc. Conclusion: The high RES uptake suggests BPQ SLN as a promising approach for targeted and improved delivery in theileriosis. PMID:24459400

  2. Novel Nanostructured Solid Materials for Modulating Oral Drug Delivery from Solid-State Lipid-Based Drug Delivery Systems.

    Science.gov (United States)

    Dening, Tahnee J; Rao, Shasha; Thomas, Nicky; Prestidge, Clive A

    2016-01-01

    Lipid-based drug delivery systems (LBDDS) have gained significant attention in recent times, owing to their ability to overcome the challenges limiting the oral delivery of poorly water-soluble drugs. Despite the successful commercialization of several LBDDS products over the years, a large discrepancy exists between the number of poorly water-soluble drugs displaying suboptimal in vivo performances and the application of LBDDS to mitigate their various delivery challenges. Conventional LBDDS, including lipid solutions and suspensions, emulsions, and self-emulsifying formulations, suffer from various drawbacks limiting their widespread use and commercialization. Accordingly, solid-state LBDDS, fabricated by adsorbing LBDDS onto a chemically inert solid carrier material, have attracted substantial interest as a viable means of stabilizing LBDDS whilst eliminating some of the various limitations. This review describes the impact of solid carrier choice on LBDDS performance and highlights the importance of appropriate solid carrier material selection when designing hybrid solid-state LBDDS. Specifically, emphasis is placed on discussing the ability of the specific solid carrier to modulate drug release, control lipase action and lipid digestion, and enhance biopharmaceutical performance above the original liquid-state LBDDS. To encourage the interested reader to consider their solid carrier choice on a higher level, various novel materials with the potential for future use as solid carriers for LBDDS are described. This review is highly significant in guiding future research directions in the solid-state LBDDS field and fostering the translation of these delivery systems to the pharmaceutical marketplace.

  3. In situ atomic force microscope imaging of supported lipid bilayers

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Leidy, Chad; Ipsen, John Hjorth

    2001-01-01

    In situ AFM images of phospholipase A/sub 2/ (PLA/sub 2/) hydrolysis of mica-supported one- and two-component lipid bilayers are presented. For one-component DPPC bilayers an enhanced enzymatic activity is observed towards preexisting defects in the bilayer. Phase separation is observed in two-co...

  4. Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) for pulmonary application: a review of the state of the art.

    Science.gov (United States)

    Weber, S; Zimmer, A; Pardeike, J

    2014-01-01

    Drug delivery by inhalation is a noninvasive means of administration that has following advantages for local treatment for airway diseases: reaching the epithelium directly, circumventing first pass metabolism and avoiding systemic toxicity. Moreover, from the physiological point of view, the lung provides advantages for systemic delivery of drugs including its large surface area, a thin alveolar epithelium and extensive vasculature which allow rapid and effective drug absorption. Therefore, pulmonary application is considered frequently for both, the local and the systemic delivery of drugs. Lipid nanoparticles - Solid Lipid Nanoparticles and Nanostructured Lipid Carriers - are nanosized carrier systems in which solid particles consisting of a lipid matrix are stabilized by surfactants in an aqueous phase. Advantages of lipid nanoparticles for the pulmonary application are the possibility of a deep lung deposition as they can be incorporated into respirables carriers due to their small size, prolonged release and low toxicity. This paper will give an overview of the existing literature about lipid nanoparticles for pulmonary application. Moreover, it will provide the reader with some background information for pulmonary drug delivery, i.e., anatomy and physiology of the respiratory system, formulation requirements, application forms, clearance from the lung, pharmacological benefits and nanotoxicity. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Cationic solid-lipid nanoparticles can efficiently bind and transfect plasmid DNA

    NARCIS (Netherlands)

    Olbrich, C; Bakowsky, U; Muller, RH; Kneuer, C

    2001-01-01

    The suitability of cationically modified solid-lipid nanoparticles (SLN) as a novel transfection agent was investigated. SLN were produced by hot homogenisation using either Compritol ATO 888 or paraffin as matrix lipid, a mixture of Tween 80 and Span 85 as tenside and either EQ1

  6. New Approach to Solid Lipid Microparticles USING Biocompatible ...

    African Journals Online (AJOL)

    Tallowation refers to the modification of lipid molecules using tallow fat while P90Gylation is the modification of lipid molecules by one or more phospholipid chains. Phospholipon® 90G (P90G) contains about 94.0 % of phosphatidylcholine stabilized with 0.1 % ascorbyl palmitate and is parenterally safe (GRAS) FDA ...

  7. Solid-state fermentation of Mortierella isabellina for lipid production from soybean hull.

    Science.gov (United States)

    Zhang, Jianguo; Hu, Bo

    2012-02-01

    Soybean hull, generated from soybean processing, is a lignocellulosic material with limited industrial applications and little market value. This research is exploring a new application of soybean hull to be converted to fungal lipids for biodiesel production through solid-state fermentation. Mortierella isabellina was selected as the oil producer because of its high lipid content at low C/N ratio. Several cultivation factors were investigated, including moisture content, inoculums size, fungal spore age, and nutrient supplements, in an attempt to enhance the lipid production of the solid-state fermentation process. The results showed that lipid production with the increase of the moisture content and the spore age, while decreased as the size of inoculums increased. Nutrients addition (KH₂PO₄ 1.2 mg and MgSO₄ 0.6 mg/g soybean hull) improved the lipid production. The total final lipid reached 47.9 mg lipid from 1 g soybean hull after the conversion, 3.3-fold higher than initial lipid reserve in the soybean hull. The fatty acid profile analysis indicated that fatty acid content consisted of 30.0% of total lipid, and 80.4% of total fatty acid was C16 and C18. Therefore, lipid production from soybean hull is a possible option to enable soybean hull as a new resource for biodiesel production and to enhance the overall oil production from soybeans.

  8. Evaluation of Gentamicin-Entrapped Solid Lipid Microparticles ...

    African Journals Online (AJOL)

    microbial infections, is limited by poor absorption, low bioavailability ... engineering of lipid drug delivery systems. (LBDDS) ... based SLMs), these problems could be surmounted. ..... addition to the burst effect, may also be related to high rate ...

  9. Lipid diffusion in the distal and proximal leaflets of supported lipid bilayer membranes studied by single particle tracking

    Science.gov (United States)

    Schoch, Rafael L.; Barel, Itay; Brown, Frank L. H.; Haran, Gilad

    2018-03-01

    Supported lipid bilayers (SLBs) have been studied extensively as simple but powerful models for cellular membranes. Yet, potential differences in the dynamics of the two leaflets of a SLB remain poorly understood. Here, using single particle tracking, we obtain a detailed picture of bilayer dynamics. We observe two clearly separate diffusing populations, fast and slow, that we associate with motion in the distal and proximal leaflets of the SLB, respectively, based on fluorescence quenching experiments. We estimate diffusion coefficients using standard techniques as well as a new method based on the blur of images due to motion. Fitting the observed diffusion coefficients to a two-leaflet membrane hydrodynamic model allows for the simultaneous determination of the intermonolayer friction coefficient and the substrate-membrane friction coefficient, without any prior assumptions on the strengths of the relevant interactions. Remarkably, our calculations suggest that the viscosity of the interfacial water confined between the membrane and the substrate is elevated by ˜104 as compared to bulk water. Using hidden Markov model analysis, we then obtain insight into the transbilayer movement of lipids. We find that lipid flip-flop dynamics are very fast, with half times in the range of seconds. Importantly, we find little evidence for membrane defect mediated lipid flip-flop for SLBs at temperatures well above the solid-to-liquid transition, though defects seem to be involved when the SLBs are cooled down. Our work thus shows that the combination of single particle tracking and advanced hydrodynamic modeling provides a powerful means to obtain insight into membrane dynamics.

  10. Atomic Force Microscope Image Contrast Mechanisms on Supported Lipid Bilayers

    OpenAIRE

    Schneider, James; Dufrêne, Yves F.; Barger Jr., William R.; Lee, Gil U.

    2000-01-01

    This work presents a methodology to measure and quantitatively interpret force curves on supported lipid bilayers in water. We then use this method to correlate topographic imaging contrast in atomic force microscopy (AFM) images of phase-separated Langmuir-Blodgett bilayers with imaging load. Force curves collected on pure monolayers of both distearoylphosphatidylethanolamine (DSPE) and monogalactosylethanolamine (MGDG) and dioleoylethanolamine (DOPE) deposited at similar surface pressures o...

  11. Preparation and characterization of etoricoxib solid dispersions using lipid carriers by spray drying technique

    OpenAIRE

    Chauhan, Bhaskar; Shimpi, Shyam; Paradkar, Anant

    2005-01-01

    The basic objectives of this study were to prepare and characterize solid dispersions of poorly water-soluble drug etoricoxib using lipid carriers by spray drying technique. The properties of solid dispersions were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), differential scanning calorimetry (DSC), hotstage microscopy (HSM), radiograph powder diffraction (XRPD), and dissolution studies. The absence of etoricoxib peaks in XRPD profiles of solid dispersions ...

  12. Supported Lipid Bilayers with Phosphatidylethanolamine as the Major Component.

    Science.gov (United States)

    Sendecki, Anne M; Poyton, Matthew F; Baxter, Alexis J; Yang, Tinglu; Cremer, Paul S

    2017-11-21

    Phosphatidylethanolamine (PE) is notoriously difficult to incorporate into model membrane systems, such as fluid supported lipid bilayers (SLBs), at high concentrations because of its intrinsic negative curvature. Using fluorescence-based techniques, we demonstrate that having fewer sites of unsaturation in the lipid tails leads to high-quality SLBs because these lipids help to minimize the curvature. Moreover, shorter saturated chains can help maintain the membranes in the fluid phase. Using these two guidelines, we find that up to 70 mol % PE can be incorporated into SLBs at room temperature and up to 90 mol % PE can be incorporated at 37 °C. Curiously, conditions under which three-dimensional tubules project outward from the planar surface as well as conditions under which domain formation occurs can be found. We have employed these model membrane systems to explore the ability of Ni 2+ to bind to PE. It was found that this transition metal ion binds 1000-fold tighter to PE than to phosphatidylcholine lipids. In the future, this platform could be exploited to monitor the binding of other transition metal ions or the binding of antimicrobial peptides. It could also be employed to explore the physical properties of PE-containing membranes, such as phase domain behavior and intermolecular hydrogen bonding.

  13. Brain-targeted solid lipid nanoparticles containing riluzole: preparation, characterization and biodistribution.

    Science.gov (United States)

    Bondì, Maria Luisa; Craparo, Emanuela Fabiola; Giammona, Gaetano; Drago, Filippo

    2010-01-01

    Developments within nanomedicine have revealed a great potential for drug delivery to the brain. In this study nanoparticulate systems as drug carriers for riluzole, with sufficiently high loading capacity and small particle size, were prepared to a reach therapeutic drug level in the brain. Solid lipid nanoparticles containing riluzole have great potential as drug-delivery systems for amyotrophic lateral sclerosis and were produced by using the warm oil-in-water microemulsion technique. The resulting systems obtained were approximately 88 nm in size and negatively charged. Drug-release profiles demonstrated that a drug release was dependent on medium pH. Biodistribution of riluzole blended into solid lipid nanoparticles was carried out after administration to rats and the results were compared with those obtained by riluzole aqueous dispersion administration. Rats were sacrificed at time intervals of 8, 16 and 30 h, and the riluzole concentration in the blood and organs such as the brain, liver, spleen, heart and kidney was determined. It was demonstrated that these solid lipid nanoparticles were able to successfully carry riluzole into the CNS. Moreover, a low drug biodistribution in organs such as the liver, spleen, heart, kidneys and lung was found when riluzole was administered as drug-loaded solid lipid nanoparticles. Riluzole-loaded solid lipid nanoparticles showed colloidal size and high drug loading, a greater efficacy than free riluzole in rats, a higher capability to carry the drug into the brain and a lower indiscriminate biodistribution.

  14. Characterization of Celecoxib-Loaded Solid Lipid Nanoparticles ...

    African Journals Online (AJOL)

    system with several advantages, including enhanced physical stability, dual loading ability for lipophilic and .... where kp is the release rate constant at the elapsed time t, n is a constant, where the value of n ≤ 0.45 indicates .... CXB and the hydrocarbon chain of the esterified fatty acids in the lipids. Upon emulsification CXB.

  15. Parvovirus B19 VLP recognizes globoside in supported lipid bilayers.

    Science.gov (United States)

    Nasir, Waqas; Nilsson, Jonas; Olofsson, Sigvard; Bally, Marta; Rydell, Gustaf E

    2014-05-01

    Studies have suggested that the glycosphingolipid globoside (Gb4Cer) is a receptor for human parvovirus B19. Virus-like particles bind to Gb4Cer on thin-layer chromatograms, but a direct interaction between the virus and lipid membrane-associated Gb4Cer has been debated. Here, we characterized the binding of parvovirus B19 VP1/VP2 virus-like particles to glycosphingolipids (i) on thin-layer chromatograms (TLCs) and (ii) incorporated into supported lipid bilayers (SLBs) acting as cell-membrane mimics. The binding specificities of parvovirus B19 determined in the two systems were in good agreement; the VLP recognized both Gb4Cer and the Forssman glycosphingolipid on TLCs and in SLBs compatible with the role of Gb4Cer as a receptor for this virus. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Effect of formulation variables on insulin localisation within solid lipid nanoparticles

    OpenAIRE

    Thong, Li Ming

    2016-01-01

    There has been a lot of interest on solid lipid nanoparticles (SLNs) as these colloidal submicron drug dosage forms present a promising frontier in drug delivery. It is possible to incorporate susceptible drugs such as protein intended for oral delivery. Here, we aim to develop an oral delivery system based on SLNs to deliver the peptide hormone, insulin using the double emulsion (W/O/W) solvent evaporation technique for formulating the SLNs. The choice of lipids was carefully selected to inc...

  17. [Preparation of Oenothera biennis Oil Solid Lipid Nanoparticles Based on Microemulsion Technique].

    Science.gov (United States)

    Piao, Lin-mei; Jin, Yong; Cui, Yan-lin; Yin, Shou-yu

    2015-06-01

    To study the preparation of Oenothera biennis oil solid lipid nanoparticles and its quality evaluation. The solid lipid nanoparticles were prepared by microemulsion technique. The optimum condition was performed based on the orthogonal design to examine the entrapment efficiency, the mean diameter of the particles and so on. The optimal preparation of Oenothera biennis oil solid lipid nanoparticles was as follows: Oenothera biennis dosage 300 mg, glycerol monostearate-Oenothera biennis (2: 3), Oenothera biennis -RH/40/PEG-400 (1: 2), RH-40/PEG-400 (1: 2). The resulting nanoparticles average encapsulation efficiency was (89.89 ± 0.71)%, the average particle size was 44.43 ± 0.08 nm, and the Zeta potential was 64.72 ± 1.24 mV. The preparation process is simple, stable and feasible.

  18. Introduction to solid supported membrane based electrophysiology.

    Science.gov (United States)

    Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

    2013-05-11

    The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

  19. Preparation and evaluation of carvedilol-loaded solid lipid ...

    African Journals Online (AJOL)

    The SLNs were characterized in terms of entrapment efficiency, particle size, zeta potential, polydispersity index, cytotoxicity, solid state characterization and drug release. The stability of the formulations was investigated by monitoring their properties for a period of 3 months. Results: The mean size of the nanoparticles was ...

  20. Solid-state NMR of the Yersinia pestis outer membrane protein Ail in lipid bilayer nanodiscs sedimented by ultracentrifugation

    International Nuclear Information System (INIS)

    Ding, Yi; Fujimoto, L. Miya; Yao, Yong; Marassi, Francesca M.

    2015-01-01

    Solid-state NMR studies of sedimented soluble proteins has been developed recently as an attractive approach for overcoming the size limitations of solution NMR spectroscopy while bypassing the need for sample crystallization or precipitation (Bertini et al. Proc Natl Acad Sci USA 108(26):10396–10399, 2011). Inspired by the potential benefits of this method, we have investigated the ability to sediment lipid bilayer nanodiscs reconstituted with a membrane protein. In this study, we show that nanodiscs containing the outer membrane protein Ail from Yersinia pestis can be sedimented for solid-state NMR structural studies, without the need for precipitation or lyophilization. Optimized preparations of Ail in phospholipid nanodiscs support both the structure and the fibronectin binding activity of the protein. The same sample can be used for solution NMR, solid-state NMR and activity assays, facilitating structure–activity correlation experiments across a wide range of timescales

  1. Solid-state NMR of the Yersinia pestis outer membrane protein Ail in lipid bilayer nanodiscs sedimented by ultracentrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yi; Fujimoto, L. Miya; Yao, Yong; Marassi, Francesca M., E-mail: fmarassi@sbmri.org [Sanford-Burnham Medical Research Institute (United States)

    2015-04-15

    Solid-state NMR studies of sedimented soluble proteins has been developed recently as an attractive approach for overcoming the size limitations of solution NMR spectroscopy while bypassing the need for sample crystallization or precipitation (Bertini et al. Proc Natl Acad Sci USA 108(26):10396–10399, 2011). Inspired by the potential benefits of this method, we have investigated the ability to sediment lipid bilayer nanodiscs reconstituted with a membrane protein. In this study, we show that nanodiscs containing the outer membrane protein Ail from Yersinia pestis can be sedimented for solid-state NMR structural studies, without the need for precipitation or lyophilization. Optimized preparations of Ail in phospholipid nanodiscs support both the structure and the fibronectin binding activity of the protein. The same sample can be used for solution NMR, solid-state NMR and activity assays, facilitating structure–activity correlation experiments across a wide range of timescales.

  2. Formulation and characterization of solid lipid nanoparticles loaded Neem oil for topical treatment of acne

    Directory of Open Access Journals (Sweden)

    V. Vijayan

    2013-01-01

    Conclusion: The result concluded that Neem oil loaded solid lipid nanoparticles with more lecithin content in their colloid exhibit sustained effect which satisfactorily produced the antibacterial action on Acne microbes. Therefore Neem oil loaded SLN was used successfully for prolonged treatment of Acne.

  3. Growth and lipid production of Umbelopsis isabellina on a solid substrate - Mechanistic modeling and validation

    NARCIS (Netherlands)

    Meeuwse, P.; Klok, A.J.; Haemers, S.; Tramper, J.; Rinzema, A.

    2012-01-01

    Microbial lipids are an interesting feedstock for biodiesel. Their production from agricultural waste streams by fungi cultivated in solid-state fermentation may be attractive, but the yield of this process is still quite low. In this article, a mechanistic model is presented that describes growth,

  4. Preparation of ultra-fine powders from polysaccharide-coated solid lipid nanoparticles and nanostructured lipid carriers by innovative nano spray drying technology.

    Science.gov (United States)

    Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-09-10

    In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20-30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Solid lipid nanoparticles mediate non-viral delivery of plasmid DNA to dendritic cells

    Science.gov (United States)

    Penumarthi, Alekhya; Parashar, Deepti; Abraham, Amanda N.; Dekiwadia, Chaitali; Macreadie, Ian; Shukla, Ravi; Smooker, Peter M.

    2017-06-01

    There is an increasing demand for novel DNA vaccine delivery systems, mainly for the non-viral type as they are considered relatively safe. Therefore, solid lipid nanoparticles (SLNs) were investigated for their suitability as a non-viral DNA vaccine delivery system. SLNs were synthesised by a modified solvent-emulsification method in order to study their potential to conjugate with plasmid DNA and deliver them in vitro to dendritic cells using eGFP as the reporter plasmid. The DNA-SLN complexes were characterised by electron microscopy, gel retardation assays and dynamic light scattering. The cytotoxicity assay data supported their biocompatibility and was used to estimate safe threshold concentration resulting in high transfection rate. The transfection efficiency of these complexes in a dendritic cell line was shown to increase significantly compared to plasmid alone, and was comparable to that mediated by lipofectamine. Transmission electron microscopy studies delineated the pathway of cellular uptake. Endosomal escape was observed supporting the mechanism of transfection.

  6. Heterogeneous silicon mesostructures for lipid-supported bioelectric interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yuanwen; Carvalho-de-Souza, João L.; Wong, Raymond C. S.; Luo, Zhiqiang; Isheim, Dieter; Zuo, Xiaobing; Nicholls, Alan W.; Jung, Il Woong; Yue, Jiping; Liu, Di-Jia; Wang, Yucai; De Andrade, Vincent; Xiao, Xianghui; Navrazhnykh, Luizetta; Weiss, Dara E.; Wu, Xiaoyang; Seidman, David N.; Bezanilla, Francisco; Tian, Bozhi

    2016-06-27

    Silicon-based materials have widespread application as biophysical tools and biomedical devices. Here we introduce a biocompatible and degradable mesostructured form of silicon with multi-scale structural and chemical heterogeneities. The material was synthesized using mesoporous silica as a template through a chemical vapour deposition process. It has an amorphous atomic structure, an ordered nanowire-based framework and random submicrometre voids, and shows an average Young’s modulus that is 2–3 orders of magnitude smaller than that of single-crystalline silicon. In addition, we used the heterogeneous silicon mesostructures to design a lipid-bilayer-supported bioelectric interface that is remotely controlled and temporally transient, and that permits non-genetic and subcellular optical modulation of the electrophysiology dynamics in single dorsal root ganglia neurons. Our findings suggest that the biomimetic expansion of silicon into heterogeneous and deformable forms can open up opportunities in extracellular biomaterial or bioelectric systems.

  7. Fabrication, appraisal, and transdermal permeation of sildenafil citrate-loaded nanostructured lipid carriers versus solid lipid nanoparticles

    Science.gov (United States)

    Elnaggar, Yosra SR; El-Massik, Magda A; Abdallah, Ossama Y

    2011-01-01

    Although sildenafil citrate (SC) is used extensively for erectile dysfunction, oral delivery of SC encounters many obstacles. Furthermore, the physicochemical characteristics of this amphoteric drug are challenging for delivery system formulation and transdermal permeation. This article concerns the assessment of the potential of nanomedicine for improving SC delivery and transdermal permeation. SC-loaded nanostructured lipid carriers (NLCs) and solid lipid nanoparticles (SLNs) were fabricated using a modified high-shear homogenization technique. Nanoparticle optimization steps included particle size analysis, entrapment efficiency (EE) determination, freeze-drying and reconstitution, differential scanning calorimetry, in vitro release, stability study and high-performance liquid chromatography analysis. Transdermal permeation of the nanocarriers compared with SC suspension across human skin was assessed using a modified Franz diffusion cell assembly. Results revealed that SLNs and NLCs could be optimized in the nanometric range (180 and 100 nm, respectively) with excellent EE (96.7% and 97.5%, respectively). Nanoparticles have significantly enhanced in vitro release and transdermal permeation of SC compared with its suspensions. Furthermore, transdermal permeation of SC exhibited higher initial release from both SLN and NLC formulations followed by controlled release, with promising implications for faster onset and longer drug duration. Nanomedicines prepared exhibited excellent physical stability for the study period. Solid nanoparticles optimized in this study successfully improved SC characteristics, paving the way for an efficient topical Viagra® product. PMID:22238508

  8. Solid polymer electrolyte composite membrane comprising laser micromachined porous support

    Science.gov (United States)

    Liu, Han [Waltham, MA; LaConti, Anthony B [Lynnfield, MA; Mittelsteadt, Cortney K [Natick, MA; McCallum, Thomas J [Ashland, MA

    2011-01-11

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 5 microns, are made by laser micromachining and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

  9. Encapsulation of solid dispersion in solid lipid particles for dissolution enhancement of poorly water-soluble drug.

    Science.gov (United States)

    Tran, Khanh Thi My; Vo, Toi Van; Tran, Phuong Ha-Lien; Lee, Beom-Jin; Duan, Wei; Tran, Thao Truong-Dinh

    2017-06-05

    The aim of this research was to engineer solid dispersion lipid particles (SD-SLs) in which a solid dispersion (SD) was encapsulated to form the core of solid lipid particles (SLs), thereby achieving an efficient enhancement in the dissolution of a poorly water-soluble drug. Ultrasonication was introduced into the process to obtain micro/nanoscale SLs. The mechanism of dissolution enhancement was investigated by analysing the crystalline structure, molecular interactions, and particle size of the formulations. The drug release from the SD-SLs was significantly greater than that from the SD or SLs alone. This enhancement in drug release was dependent on the preparation method and the drug-to-polymer ratio of the SD. With an appropriate amount of polymer in the SD, the solidification method had the potential to alter the drug crystallinity to an amorphous state, resulting in particle uniformity and molecular interactions in the SD-SLs. The proposed system provides a new strategy for enhancing the dissolution rate of poorly water-soluble drugs and further improving their bioavailability. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Solid lipid dispersions: potential delivery system for functional ingredients in foods.

    Science.gov (United States)

    Asumadu-Mensah, Aboagyewa; Smith, Kevin W; Ribeiro, Henelyta S

    2013-07-01

    Structured solid lipid (SL) systems have the advantages of long-term physical stability, low surfactant concentrations, and may exhibit controlled release of active ingredients. In this research work, the potential use of high-melting SLs for the production of the above structured SL carrier systems was investigated. Dispersions containing either SL or blend of solid lipid and oil (SL+O) were produced by a hot melt high-pressure homogenization method. Experiments involved the use of 3 different SLs for the disperse phase: stearic acid, candelilla wax and carnauba wax. Sunflower oil was incorporated in the disperse phase for the production of the dispersions containing lipid and oil. In order to evaluate the practical aspects of structured particles, analytical techniques were used including: static light scattering to measure particle sizes, transmission electron microscopy (TEM) for investigating particle morphology and differential scanning calorimetry (DSC) to investigate the crystallization behavior of lipids in bulk and in dispersions. Results showed different mean particle sizes depending on the type of lipid used in the disperse phase. Particle sizes for the 3 lipids were: stearic acid (SL: 195 ± 2.5 nm; SL+O: 138 ± 6.0 nm); candelilla wax (SL: 178 ± 1.7 nm; SL+O: 144 ± 0.6 nm); carnauba wax (SL: 303 ± 1.5 nm; SL+O: 295 ± 5.0 nm). TEM results gave an insight into the practical morphology, showing plate-like and needle-like structures. DSC investigations also revealed that SL dispersions melted and crystallized at lower temperatures than the bulk. This decrease can be explained by the small particle sizes of the dispersion, the high-specific surface area, and the presence of a surfactant. © 2013 Institute of Food Technologists®

  11. Solid lipid nanoparticles loaded with iron to overcome barriers for treatment of iron deficiency anemia

    Directory of Open Access Journals (Sweden)

    Hosny KM

    2015-01-01

    Full Text Available Khaled Mohamed Hosny,1,2 Zainy Mohammed Banjar,3 Amani H Hariri,4 Ali Habiballah Hassan5 1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt; 3Department of Clinical Biochemistry, Faculty of medicine, King Abdulaziz University, Jeddah, Saudi Arabia; 4Consultant Obstetrics and Gynecology, Hera Genaral Hospital, Makkah, Saudi Arabia; 5Department of Orthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: According to the World Health Organization, 46% of the world’s children suffer from anemia, which is usually treated with iron supplements such as ferrous sulfate. The aim of this study was to prepare iron as solid lipid nanoparticles, in order to find an innovative way for alleviating the disadvantages associated with commercially available tablets. These limitations include adverse effects on the digestive system resulting in constipation and blood in the stool. The second drawback is the high variability in the absorption of iron and thus in its bioavailability. Iron solid lipid nanoparticles (Fe-SLNs were prepared by hot homogenization/ultrasonication. Solubility of ferrous sulfate in different solid lipids was measured, and effects of process variables such as the surfactant type and concentration, homogenization and ultrasonication times, and charge-inducing agent on the particle size, zeta potential, and encapsulation efficiency were determined. Furthermore, in vitro drug release and in vivo pharmacokinetics were studied in rabbits. Results indicated that Fe-SLNs consisted of 3% Compritol 888 ATO, 1% Lecithin, 3% Poloxamer 188, and 0.2% dicetylphosphate, with an average particle size of 25 nm with 92.3% entrapment efficiency. In vivo pharmacokinetic study revealed more than fourfold enhanced bioavailability. In

  12. Transforming lipid-based oral drug delivery systems into solid dosage forms: an overview of solid carriers, physicochemical properties, and biopharmaceutical performance.

    Science.gov (United States)

    Tan, Angel; Rao, Shasha; Prestidge, Clive A

    2013-12-01

    The diversity of lipid excipients available commercially has enabled versatile formulation design of lipid-based drug delivery systems for enhancing the oral absorption of poorly water-soluble drugs, such as emulsions, microemulsions, micelles, liposomes, niosomes and various self-emulsifying systems. The transformation of liquid lipid-based systems into solid dosage forms has been investigated for several decades, and has recently become a core subject of pharmaceutical research as solidification is regarded as viable means for stabilising lipid colloidal systems while eliminating stringent processing requirements associated with liquid systems. This review describes the types of pharmaceutical grade excipients (silica nanoparticle/microparticle, polysaccharide, polymer and protein-based materials) used as solid carriers and the current state of knowledge on the liquid-to-solid conversion approaches. Details are primarily focused on the solid-state physicochemical properties and redispersion capacity of various dry lipid-based formulations, and how these relate to the in vitro drug release and solubilisation, lipid carrier digestion and cell permeation performances. Numerous in vivo proof-of-concept studies are presented to highlight the viability of these dry lipid-based formulations. This review is significant in directing future research work in fostering translation of dry lipid-based formulations into clinical applications.

  13. Using crosslinkable diacetylene phospholipids to construct two-dimensional packed beds in supported lipid bilayer separation platforms

    Directory of Open Access Journals (Sweden)

    Shu-Kai Hu, Sheng-Wen Hsiao, Hsun-Yen Mao, Ya-Ming Chen, Yung Chang and Ling Chao

    2013-01-01

    Full Text Available Separating and purifying cell membrane-associated biomolecules has been a challenge owing to their amphiphilic property. Taking these species out of their native lipid membrane environment usually results in biomolecule degradation. One of the new directions is to use supported lipid bilayer (SLB platforms to separate the membrane species while they are protected in their native environment. Here we used a type of crosslinkable diacetylene phospholipids, diynePC (1,2-bis(10,12-tricosadiynoyl-sn-glycero-3-phosphocholine, as a packed material to create a 'two-dimensional (2D packed bed' in a SLB platform. After the diynePC SLB is exposed to UV light, some of the diynePC lipids in the SLB can crosslink and the non-crosslinked monomer lipids can be washed away, leaving a 2D porous solid matrix. We incorporated the lipid vesicle deposition method with a microfluidic device to pattern the location of the packed-bed region and the feed region with species to be separated in a SLB platform. Our atomic force microscopy result shows that the nano-scaled structure density of the '2D packed bed' can be tuned by the UV dose applied to the diynePC membrane. When the model membrane biomolecules were forced to transport through the packed-bed region, their concentration front velocities were found to decrease linearly with the UV dose, indicating the successful creation of packed obstacles in these 2D lipid membrane separation platforms.

  14. Atomic force microscope image contrast mechanisms on supported lipid bilayers.

    Science.gov (United States)

    Schneider, J; Dufrêne, Y F; Barger, W R; Lee, G U

    2000-08-01

    This work presents a methodology to measure and quantitatively interpret force curves on supported lipid bilayers in water. We then use this method to correlate topographic imaging contrast in atomic force microscopy (AFM) images of phase-separated Langmuir-Blodgett bilayers with imaging load. Force curves collected on pure monolayers of both distearoylphosphatidylethanolamine (DSPE) and monogalactosylethanolamine (MGDG) and dioleoylethanolamine (DOPE) deposited at similar surface pressures onto a monolayer of DSPE show an abrupt breakthrough event at a repeatable, material-dependent force. The breakthrough force for DSPE and MGDG is sizable, whereas the breakthrough force for DOPE is too small to measure accurately. Contact-mode AFM images on 1:1 mixed monolayers of DSPE/DOPE and MGDG/DOPE have a high topographic contrast at loads between the breakthrough force of each phase, and a low topographic contrast at loads above the breakthrough force of both phases. Frictional contrast is inverted and magnified at loads above the breakthrough force of both phases. These results emphasize the important role that surface forces and mechanics can play in imaging multicomponent biomembranes with AFM.

  15. Paraffin scintillator for radioassay of solid support samples

    International Nuclear Information System (INIS)

    Fujii, Haruo; Takiue, Makoto

    1989-01-01

    A new paraffin scintillator used for solid support sample counting has been proposed, and its composition and various characteristics are described. The solid support sample treated with this scintillator can be easily handled because of rigid sample conditions. This technique provides great advantages such as the elimination of a large volume of scintillator and little radioactive waste material by using an economical polyethylene bag instead of the conventional counting vial. (author)

  16. Data supporting beta-amyloid dimer structural transitions and protein–lipid interactions on asymmetric lipid bilayer surfaces using MD simulations on experimentally derived NMR protein structures

    Directory of Open Access Journals (Sweden)

    Sara Y. Cheng

    2016-06-01

    Full Text Available This data article supports the research article entitled “Maximally Asymmetric Transbilayer Distribution of Anionic Lipids Alters the Structure and interaction with Lipids of an Amyloidogenic Protein Dimer Bound to the Membrane Surface” [1]. We describe supporting data on the binding kinetics, time evolution of secondary structure, and residue-contact maps of a surface-absorbed beta-amyloid dimer protein on different membrane surfaces. We further demonstrate the sorting of annular and non-annular regions of the protein/lipid bilayer simulation systems, and the correlation of lipid-number mismatch and surface area per lipid mismatch of asymmetric lipid membranes.

  17. Application of Response Surface Methodology for the Technological Improvement of Solid Lipid Nanoparticles.

    Science.gov (United States)

    Dal Pizzol, Carine; O'Reilly, Andre; Winter, Evelyn; Sonaglio, Diva; de Campos, Angela Machado; Creczynski-Pasa, Tânia Beatriz

    2016-02-01

    Solid lipid nanoparticles (SLN) are colloidal particles consisting of a matrix composed of solid (at room and body temperatures) lipids dispersed in aqueous emulsifier solution. During manufacture, their physicochemical properties may be affected by several formulation parameters, such as type and concentration of lipid, proportion of emulsifiers and amount of solvent. Thus, the aim of this work was to study the influence of these variables on the preparation of SLN. A D-optimal Response Surface Methodology design was used to establish a mathematical model for the optimization of SLN. A total of 30 SLN formulations were prepared using the ultrasound method, and then characterized on the basis of their physicochemical properties, including particle size, polydispersity index (PI) and Zeta Potential (s). Particle sizes ranged between 107 and 240 nm. All SLN formulations showed negative sigma and PI values below 0.28. Prediction of the optimal conditions was performed using the desirability function targeting the reduction of all responses. The optimized SLN formulation showed similar theoretical and experimental values, confirming the sturdiness and predictive ability of the mathematical model for SLN optimization.

  18. Loading of praziquantel in the crystal lattice of solid lipid nanoparticles - studies by DSC and SAXS

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A.L.R.; Cassimiro, D.L.; Almeida, A.E.; Ribeiro, C.A.; Gremiao, M.P.D. [UNESP, Araraquara, SP (Brazil); Sarmento, V.H.V. [Universidade Federal de Sergipe (UFS), Itabaiana, SE (Brazil); Andreani, T.; Silva, A.M.; Souto, E.B. [Universidade de Tras-os-Montes e Alto Douro, Vila Real (Portugal)

    2012-07-01

    Full text: Praziquantel (PZQ) is the drug of choice for oral treatment of schistosomiasis and other fluke infections that affect humans. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. In this work, solid lipid nanoparticles loaded with PZQ (PZQ-SLN) were prepared by a modified oil-in-water microemulsion method selecting stearic acid as lipid phase after solubility screening studies. The mean particle size (Z-Ave) and zeta potential (ZP) were 500 nm and -34.0 mV, respectively. Morphology and shape of PZQ-SLN were analysed by scanning electron microscopy revealing the presence of spherical particles with smooth surface. Differential scanning calorimetry suggested that SLN comprised a less ordered arrangement of crystals and the drug was molecularly dispersed in the lipid matrix. No supercooled melts were detected. The entrapment efficiency (EE) and loading capacity of PZQ, determined by high performance liquid chromatography, were 99.0 and 17.5, respectively. Effective incorporation of PZQ into the particles was confirmed by small angle X-ray scattering revealing the presence of a lipid lamellar structure. Stability parameters of PZQ-SLN stored at room temperature (25 deg C) and at 4 deg C were checked by analysing Z-Ave, ZP and the EE for a period of 60 days Results showed a relatively long-term physical stability after storage at 4 deg C, without drug expulsion. (author)

  19. Loading of praziquantel in the crystal lattice of solid lipid nanoparticles - studies by DSC and SAXS

    International Nuclear Information System (INIS)

    Souza, A.L.R.; Cassimiro, D.L.; Almeida, A.E.; Ribeiro, C.A.; Gremiao, M.P.D.; Sarmento, V.H.V.; Andreani, T.; Silva, A.M.; Souto, E.B.

    2012-01-01

    Full text: Praziquantel (PZQ) is the drug of choice for oral treatment of schistosomiasis and other fluke infections that affect humans. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. In this work, solid lipid nanoparticles loaded with PZQ (PZQ-SLN) were prepared by a modified oil-in-water microemulsion method selecting stearic acid as lipid phase after solubility screening studies. The mean particle size (Z-Ave) and zeta potential (ZP) were 500 nm and -34.0 mV, respectively. Morphology and shape of PZQ-SLN were analysed by scanning electron microscopy revealing the presence of spherical particles with smooth surface. Differential scanning calorimetry suggested that SLN comprised a less ordered arrangement of crystals and the drug was molecularly dispersed in the lipid matrix. No supercooled melts were detected. The entrapment efficiency (EE) and loading capacity of PZQ, determined by high performance liquid chromatography, were 99.0 and 17.5, respectively. Effective incorporation of PZQ into the particles was confirmed by small angle X-ray scattering revealing the presence of a lipid lamellar structure. Stability parameters of PZQ-SLN stored at room temperature (25 deg C) and at 4 deg C were checked by analysing Z-Ave, ZP and the EE for a period of 60 days Results showed a relatively long-term physical stability after storage at 4 deg C, without drug expulsion. (author)

  20. Cationic solid lipid nanoparticles enhance ocular hypotensive effect of melatonin in rabbit.

    Science.gov (United States)

    Leonardi, Antonio; Bucolo, Claudio; Drago, Filippo; Salomone, Salvatore; Pignatello, Rosario

    2015-01-15

    The study was aimed at evaluating whether the ocular hypotensive effect of melatonin (MEL) was enhanced by its encapsulation in cationic solid lipid nanoparticles (cSLN), as well as at determining the tolerability of these formulations on the ocular surface. MEL was loaded in cSLN that had already been shown to be suitable for ophthalmic use. The formulations were prepared using Softisan(®) 100 as the main lipid matrix, with the presence of either stearic (SA) or palmitic acid (PA) as lipid modifiers. A fixed positive charge was provided by the addition of a cationic lipid (didecyldimethylammonium bromide). The ocular hypotensive effect was evaluated by measuring the intraocular pressure (IOP) during 24h in albino rabbits. MEL elicited a significant (p<0.01) IOP reduction in rabbit eye. All the formulations tested in vivo demonstrated a good tolerability. The nanocarrier containing SA was the most effective in terms of IOP reduction (maximum IOP reduction: -7 mmHg), and its effect lasted approximately 24h. The experimental data indicate that the new formulations based on cSLN loaded with MEL represent a potent anti-glaucoma treatment with a safe profile, warranting further clinical evaluation of the proposed nanotechnological strategy. Copyright © 2014. Published by Elsevier B.V.

  1. Edible solid lipid nanoparticles (SLN as carrier system for antioxidants of different lipophilicity.

    Directory of Open Access Journals (Sweden)

    Kathleen Oehlke

    Full Text Available Ferulic acid (FA and tocopherol (Toc loaded solid lipid nanoparticles (SLN were prepared by a hot homogenisation method. The particle size distribution, zeta potential and melting behaviour of the SLN as well as the stability, encapsulation efficiency and radical scavenging activity of FA and Toc in the SLN were analysed. The different formulations containing up to 2.8 mg g-1 of FA or Toc were stable during at least 15 weeks of storage at room temperature. Despite partial degradation and / or release of FA and Toc during storage, significant radical scavenging activity was maintained. DSC measurements and radical scavenging tests after different time periods revealed that the re-structuring of the lipid matrix was connected to the enhanced antioxidant activity of Toc but did not affect the activity of FA.

  2. Development of terbinafine solid lipid nanoparticles as a topical delivery system

    Science.gov (United States)

    Chen, Ying-Chen; Liu, Der-Zen; Liu, Jun-Jen; Chang, Tsung-Wei; Ho, Hsiu-O; Sheu, Ming-Thau

    2012-01-01

    To resolve problems of long treatment durations and frequent administration of the antifungal agent terbinafine (TB), solid lipid nanoparticles (SLNs) with the ability to load lipophilic drugs and nanosize were developed. The SLNs were manufactured by a microemulsion technique in which glyceryl monostearate (GMS), glyceryl behenate (Compritol® 888; Gattefossé), and glyceryl palmitostearate (Precirol® ATO 5; Gattefossé) were used as the solid lipid phases, Tween® and Cremophor® series as the surfactants, and propylene glycol as the cosurfactant to construct ternary phase diagrams. The skin of nude mice was used as a barrier membrane, and penetration levels of TB of the designed formulations and a commercial product, Lamisil® Once™ (Novartis Pharmaceuticals), in the stratum corneum (SC), viable epidermis, and dermis were measured; particle sizes were determined as an indicator of stability. The optimal SLN system contained a 50% water phase. The addition of ethanol or etchants had no significant effect on enhancing the amount of TB that penetrated the skin layers, but it was enhanced by increasing the percentage of the lipid phase. Furthermore, the combination of GMS and Compritol® 888 was able to increase the stable amount of TB that penetrated all skin layers. For the ACP1-GM1 (4% lipid phase; Compritol® 888: GMS of 1:1) formulation, the amount of TB that penetrated the SC was similar to that of Lamisil® Once™, whereas the amount of TB of the dermis was higher than that of Lamisil® Once™ at 12 hours, and it was almost the same as that of Lamisil® Once™ at 24 hours. It was concluded that the application of ACP1-GM1 for 12 hours might have an efficacy comparable to that of Lamisil® Once™ for 24 hours, which would resolve the practical problem of the longer administration period that is necessary for Lamisil® Once™. PMID:22923986

  3. Mesophilic co-digestion of dairy manure and lipid rich solid slaughterhouse wastes: process efficiency, limitations and floating granules formation.

    Science.gov (United States)

    Pitk, Peep; Palatsi, Jordi; Kaparaju, Prasad; Fernández, Belén; Vilu, Raivo

    2014-08-01

    Lipid and protein rich solid slaughterhouse wastes are attractive co-substrates to increase volumetric biogas production in co-digestion with dairy manure. Addition of decanter sludge (DS), containing 42.2% of lipids and 35.8% of proteins (total solids basis), up to 5% of feed mixture resulted in a stable process without any indication of long chain fatty acids (LCFA) or free ammonia (NH3) inhibition and in 3.5-fold increase of volumetric biogas production. Contrary, only lipids addition as technical fat (TF) at over 2% of feed mixture resulted in formation of floating granules (FG) and process efficiency decrease. Formed FG had low biodegradability and its organic part was composed of lipids and calcium salts of LCFAs. Anaerobic digestion process intentionally directed to FG formation, could be a viable option for mitigation and control of lipids overload and derived LCFA inhibition. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Human serum albumin supported lipid patterns for the targeted recognition of microspheres coated by membrane based on ss-DNA hybridization

    International Nuclear Information System (INIS)

    Zhang Xiaoming; He Qiang; Cui Yue; Duan Li; Li Junbai

    2006-01-01

    Human serum albumin (HSA) patterns have been successfully fabricated for the deposition of lipid bilayer, 1,2-dimyristoyl-sglycerophosphate (DMPA), by making use of the micro-contact printing (μCP) technique and liposome fusion. Confocal laser scanning microscopy (CLSM) results indicate that lipid bilayer has been assembled in HSA patterns with a good stability. Such well-defined lipid patterns formed on HSA surface create possibility to incorporate specific components like channels or receptors for specific recognition. In view of this, microspheres coated with lipid membranes were immobilized in HSA-supported lipid patterns via the hybridization of complementary ss-DNAs. This procedure enables to transfer solid materials to a soft surface through a specific recognition

  5. Preparation and characterization of solid lipid nanoparticles loaded with frankincense and myrrh oil

    Directory of Open Access Journals (Sweden)

    Shi F

    2012-04-01

    Full Text Available Feng Shi, Ji-Hui Zhao, Ying Liu, Zhi Wang, Yong-Tai Zhang, Nian-Ping FengSchool of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of ChinaAbstract: The aim of the present study was to prepare solid lipid nanoparticles (SLNs for the oral delivery of frankincense and myrrh essential oils (FMO. Aqueous dispersions of SLNs were successfully prepared by a high-pressure homogenization method using Compritol 888 ATO as the solid lipid and soybean lecithin and Tween 80 as the surfactants. The properties of the SLNs such as particle size, zeta potential (ZP, and drug encapsulation efficiency (EE were investigated. The morphology of SLNs was observed by transmission electron microscopy (TEM. The crystallinity of the formulation was analyzed by differential scanning calorimetry (DSC and X-ray diffraction (XRD. In addition, drug evaporation release and antitumor activity were also studied. Round SLNs with a mean size of 113.3 ± 3.6 nm, a ZP of -16.8 ± 0.4 mV, and an EE of 80.60% ± 1.11% were obtained. DSC and XRD measurements revealed that less ordered structures were formed in the inner cores of the SLN particles. Evaporation loss of the active components in FMO could be reduced in the SLNs. Furthermore, the SLN formulation increased the antitumor efficacy of FMO in H22-bearing Kunming mice. Hence, the presented SLNs can be used as drug carriers for hydrophobic oil drugs extracted from traditional Chinese medicines.Keywords: solid lipid nanoparticles, frankincense oil, myrrh oil, evaporation release, antitumor activity, traditional Chinese medicine

  6. Alcohol dose dumping: The influence of ethanol on hot-melt extruded pellets comprising solid lipids.

    Science.gov (United States)

    Jedinger, N; Schrank, S; Mohr, S; Feichtinger, A; Khinast, J; Roblegg, E

    2015-05-01

    The objective of the present study was to investigate interactions between alcohol and hot-melt extruded pellets and the resulting drug release behavior. The pellets were composed of vegetable calcium stearate as matrix carrier and paracetamol or codeine phosphate as model drugs. Two solid lipids (Compritol® and Precirol®) were incorporated into the matrix to form robust/compact pellets. The drug release characteristics were a strong function of the API solubility, the addition of solid lipids, the dissolution media composition (i.e., alcohol concentration) and correspondingly, the pellet wettability. Pellets comprising paracetamol, which is highly soluble in ethanol, showed alcohol dose dumping regardless of the matrix composition. The wettability increased with increasing ethanol concentrations due to higher paracetamol solubilities yielding increased dissolution rates. For pellets containing codeine phosphate, which has a lower solubility in ethanol than in acidic media, the wettability was a function of the matrix composition. Dose dumping occurred for formulations comprising solid lipids as they showed increased wettabilities with increasing ethanol concentrations. In contrast, pellets comprising calcium stearate as single matrix component showed robustness in alcoholic media due to wettabilities that were not affected by the addition of ethanol. The results clearly indicate that the physico-chemical properties of the drug and the matrix systems are crucial for the design of ethanol-resistant dosage forms. Moreover, hydrophobic calcium stearate can be considered a suitable matrix system that minimizes the risk of ethanol-induced dose dumping for certain API's. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Solid Lipid Nanoparticles as Efficient Drug and Gene Delivery Systems: Recent Breakthroughs

    Directory of Open Access Journals (Sweden)

    Jafar Ezzati Nazhad Dolatabadi

    2015-06-01

    Full Text Available In recent years, nanomaterials have been widely applied as advanced drug and gene delivery nanosystems. Among them, solid lipid nanoparticles (SLNs have attracted great attention as colloidal drug delivery systems for incorporating hydrophilic or lipophilic drugs and various macromolecules as well as proteins and nucleic acids. Therefore, SLNs offer great promise for controlled and site specific drug and gene delivery. This article includes general information about SLN structures and properties, production procedures, characterization. In addition, recent progress on development of drug and gene delivery systems using SLNs was reviewed.

  8. Solid polymer electrolyte composite membrane comprising plasma etched porous support

    Science.gov (United States)

    Liu, Han; LaConti, Anthony B.

    2010-10-05

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 0.1 to 5 microns, are made by plasma etching and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

  9. Study of water diffusion on single-supported bilayer lipid membranes by quasielastic neutron scattering

    DEFF Research Database (Denmark)

    Bai, M.; Miskowiec, A.; Hansen, F. Y.

    2012-01-01

    High-energy-resolution quasielastic neutron scattering has been used to elucidate the diffusion of water molecules in proximity to single bilayer lipid membranes supported on a silicon substrate. By varying sample temperature, level of hydration, and deuteration, we identify three different types...... of diffusive water motion: bulk-like, confined, and bound. The motion of bulk-like and confined water molecules is fast compared to those bound to the lipid head groups (7-10 H2O molecules per lipid), which move on the same nanosecond time scale as H atoms within the lipid molecules. Copyright (C) EPLA, 2012...

  10. Lyophilized sponges loaded with curcumin solid lipid nanoparticles for buccal delivery: Development and characterization.

    Science.gov (United States)

    Hazzah, Heba A; Farid, Ragwa M; Nasra, Maha M A; El-Massik, Magda A; Abdallah, Ossama Y

    2015-08-15

    This study aimed to prepare and evaluate mucoadhesive sponges as dosage forms for delivering solid lipid nanoparticles. For this purpose curcumin (Cur) was formulated as solid nanoparticles (SLN) using Gelucire 50/13, and polaxomer 407. The prepared CurSLN dispersion was thickened with different mucoadhesive polymers. Different concentrations of glycerol, and mannitol of range (0.25-20%), and (0-1%), respectively were also examined. The formed gel was poured into oblong molds and freeze dried to form mucoadhesive sponge to be applied to the buccal mucosa. The prepared sponges were evaluated for their, in-vivo residence time, in-vitro and in-vivo drug release, and hydration capacity. Surface morphology for the different sponges were examined using SEM. TEM was also carried out for sponge fragments previously dispersed into water. Infrared spectroscopy was conducted to investigate interaction between used ingredients. The results showed that the CurSLN loaded HPMC, and Polycarbophil sponges showed 4, and 15 h in-vivo residence time, respectively, providing a considerable amount of curcumin into saliva. The incorporation of glycerol and mannitol at concentration of 1% provided elegant and flexible sponges. The SEM showed that the deposition of CurSLN differed according to the type of polymer used. TEM confirmed the integrity of liberated CurSLN from sponges. IR spectra showed an interaction between HPMC and poloxamer 407, which affected its behavior as a gelling agent. The obtained results provide an efficient approach for delivering solid lipid nanoparticles in a solid dosage form keeping the nanoparticle characters and integrity. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Evaluation of hypericin-loaded solid lipid nanoparticles: physicochemical properties, photostability and phototoxicity.

    Science.gov (United States)

    Youssef, Tareq; Fadel, Maha; Fahmy, Rania; Kassab, Kawser

    2012-01-01

    Hypericin (HYP), a natural photosensitizer, has powerful photo-oxidizing ability, tumor-seeking characteristics, and minimal dark toxicity; nevertheless, it has proven high lipid solubility compared to its sparingly water soluble nature. Therefore, its formulation into solid lipid nanoparticles (SLNs) has attracted increasing attention as a potential drug-delivery carrier. Two HYP-loaded SLNs formulations were prepared utilizing microemulsion-based technique. Thereafter, the physicochemical properties of the formulations were investigated and evaluated. HYP-loaded SLNs showed spherical shape with mean particle size ranging from 200-300 nm for both formulations (FA and FB). The encapsulation efficiencies reached above 80% and FA showed significant higher encapsulation than FB (Phypericin and lipids forming the cores in both formulations. Spectroscopic measurements of the photostability study showed that hypericin encapsulation into SLNs improved its photostability, compared to free HYP in 0.1% ethanolic solution. However, photocytotoxicity studies on HepG2 cells revealed an evident inhibition of the photodynamic efficacy of HYP-loaded SLNs, compared to free HYP. In conclusion, although the elevated entrapment efficiency of HYP into SLNs increased its photostability, it decreased its phototoxicity which might be due to the quenching deactivation of HYP molecules resulting from SLN compactness and thickness structure. © 2012 Informa Healthcare USA, Inc.

  12. Physical-Chemical Characterization and Formulation Considerations for Solid Lipid Nanoparticles.

    Science.gov (United States)

    Chauhan, Harsh; Mohapatra, Sarat; Munt, Daniel J; Chandratre, Shantanu; Dash, Alekha

    2016-06-01

    Pure glyceryl mono-oleate (GMO) (lipid) and different batches of GMO commonly used for the preparation of GMO-chitosan nanoparticles were characterized by modulated differential scanning calorimetry (MDSC), cryo-microscopy, and cryo-X-ray powder diffraction techniques. GMO-chitosan nanoparticles containing poloxamer 407 as a stabilizer in the absence and presence of polymers as crystallization inhibitors were prepared by ultrasonication. The effect of polymers (polyvinyl pyrrolidone (PVP), Eudragits, hydroxyl propyl methyl cellulose (HPMC), polyethylene glycol (PEG)), surfactants (poloxamer), and oils (mineral oil and olive oil) on the crystallization of GMO was investigated. GMO showed an exothermic peak at around -10°C while cooling and another exothermic peak at around -12°C while heating. It was followed by two endothermic peaks between 15 and 30 C, indicative of GMO melting. The results are corroborated by cryo-microscopy and cryo-X-ray. Significant differences in exothermic and endothermic transition were observed between different grades of GMO and pure GMO. GMO-chitosan nanoparticles resulted in a significant increase in particle size after lyophilization. MDSC confirmed that nanoparticles showed similar exothermic crystallization behavior of lipid GMO. MDSC experiments showed that PVP inhibits GMO crystallization and addition of PVP showed no significant increase in particle size of solid lipid nanoparticle (SLN) during lyophilization. The research highlights the importance of extensive physical-chemical characterization for successful formulation of SLN.

  13. Development, Characterization and Evaluation of Solid Lipid Nanoparticles as a potential Anticancer Drug Delivery System

    Science.gov (United States)

    Patel, Meghavi

    Solid lipid nanoparticles (SLNs) consist of spherical solid lipid particles in the nanometer size range, which are dispersed in water or in an aqueous surfactant solution. SLN technology represents a promising new approach to deliver hydrophilic as well as lipophilic drugs. The commercialization of SLN technology remains limited despite numerous efforts from researchers. The purpose of this research was to advance SLN preparation methodology by investigating the feasibility of preparing glyceryl monostearate (GMS) nanoparticles by using three preparation methods namely microemulsion technique, magnetic stirring technique and temperature modulated solidification technique of which the latter two were developed in our laboratory. An anticancer drug 5-fluorouracil was incorporated in the SLNs prepared via the temperature modulated solidification process. Optimization of the magnetic stirring process was performed to evaluate how the physicochemical properties of the SLN was influenced by systematically varying process parameters including concentration of the lipid, concentration of the surfactant, type of surfactant, time of stirring and temperature of storage. The results demonstrated 1:2 GMS to tween 80 ratio, 150 ml dispersion medium and 45 min stirring at 4000 RPM speed provided an optimum formulation via the temperature modulated solidification process. SLN dispersions were lyophilized to stabilize the solid lipid nanoparticles and the lyophilizates exhibited good redispersibility. The SLNs were characterized by particle size analysis via dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), drug encapsulation efficiency and in vitro drug release studies. Particle size of SLN dispersion prepared via the three preparation techniques was approximately 66 nm and that of redispersed lyophilizates was below 500 nm. TEM images showed spherical to oval particles that were less dense in the core

  14. Preparation and characterization of solid lipid nanoparticles containing cyclosporine by the emulsification-diffusion method

    Directory of Open Access Journals (Sweden)

    Zaida Urbán-Morlán

    2010-08-01

    Full Text Available Zaida Urbán-Morlán1, Adriana Ganem-Rondero1, Luz María Melgoza-Contreras2, José Juan Escobar-Chávez1,2, María Guadalupe Nava-Arzaluz1, David Quintanar-Guerrero11División de Estudios de Posgrado (Tecnología Farmacéutica, Facultad de Estudios Superiores Cuautitlán-Universidad Nacional Autónoma de México, Estado de México, México; 2Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso, Colonia Villa Quietud, MéxicoAbstract: Solid lipid nanoparticles (SLNs have been used for carrying different therapeutic agents because they improve absorption and bioavailability. The aim of the study was to prepare lipidic nanoparticles containing cyclosporine (CyA by the emulsification-diffusion method and to study their physicochemical stability. Glyceryl behenate (Compritol® ATO 888 and lauroyl macrogolglycerides (Gelucire® 44/14 were used as carrier materials. Nanoparticles with good stability were obtained with Gelucire®, while it was difficult to obtain stable systems with Compritol®. Systems with Gelucire® were characterized by particle size, Z-potential, differential scanning calorimetry (DSC, scanning electron microscopy (SEM, entrapment efficiency and in vitro release. Particle size and Z-potential were evaluated for at least three months. With a high CyA content (≥60 mg in Gelucire® SLNs, variations in size were greater and particle size also increased over time in all batches; this effect may have been caused by a probable expulsion of the drug due to the lipid’s partial rearrangement. While the Z-potential decreased 10 mV after three months, this effect may be explained by the superficial properties of the drug that make the molecules to be preferably oriented at the solid-liquid interface, causing a change in the net charge of the particle. SEM confirmed size and shape of the nanoparticles. DSC studies evidenced that CyA affects the lipid structure by a mechanism still unknown

  15. Encapsulation of fish oil into hollow solid lipid micro- and nanoparticles using carbon dioxide.

    Science.gov (United States)

    Yang, Junsi; Ciftci, Ozan Nazim

    2017-09-15

    Fish oil was encapsulated in hollow solid lipid micro- and nanoparticles formed from fully hydrogenated soybean oil (FHSO) using a novel green method based on atomization of supercritical carbon dioxide (SC-CO 2 )-expanded lipid. The highest fish oil loading efficiency (97.5%, w/w) was achieved at 50%, w/w, initial fish oil concentration. All particles were spherical and in the dry free-flowing form; however, less smooth surface with wrinkles was observed when the initial fish oil concentration was increased up to 50%. With increasing initial fish oil concentration, melting point of the fish oil-loaded particles shifted to lower onset melting temperatures, and major polymorphic form transformed from α to β and/or β'. Oxidative stability of the loaded fish oil was significantly increased compared to the free fish oil (p<0.05). This innovative method forms free-flowing powder products that are easy-to-use solid fish oil formulation, which makes the handling and storage feasible and convenient. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Corrugation of Phase-Separated Lipid Bilayers Supported by Nanoporous Silica Xerogel Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Goksu, E I; Nellis, B A; Lin, W; Satcher Jr., J H; Groves, J T; Risbud, S H; Longo, M L

    2008-10-30

    Lipid bilayers supported by substrates with nanometer-scale surface corrugations holds interest in understanding both nanoparticle-membrane interactions and the challenges of constructing models of cell membranes on surfaces with desirable properties, e.g. porosity. Here, we successfully form a two-phase (gel-fluid) lipid bilayer supported by nanoporous silica xerogel. Surface topology, diffusion, and lipid density in comparison to mica-supported lipid bilayers were characterized by AFM, FRAP, FCS, and quantitative fluorescence microscopy, respectively. We found that the two-phase lipid bilayer follows the xerogel surface contours. The corrugation imparted on the lipid bilayer results in a lipid density that is twice that on a flat mica surface. In direct agreement with the doubling of actual bilayer area in a projected area, we find that the lateral diffusion coefficient (D) of lipids on xerogel ({approx}1.7 {micro}m{sup 2}/s) is predictably lower than on mica ({approx}4.1 {micro}m{sup 2}/s) by both FRAP and FCS techniques. Furthermore, the gel-phase domains on xerogel compared to mica were larger and less numerous. Overall, our results suggest the presence of a relatively defect-free continuous two-phase bilayer that penetrates approximately midway into the first layer of {approx}50 nm xerogel beads.

  17. Microwave-Assisted Hydantoins Synthesis on Solid Support

    Science.gov (United States)

    Coursindel, Thibault; Martinez, Jean; Parrot, Isabelle

    2010-01-01

    In this laboratory activity, students are introduced to a three-step synthesis of hydantoin (imidazolidine-2,4-dione), a moiety that is found in many biologically active compounds. Using a microwave oven and solid-support technology, this synthetic experiment is designed for masters-degree candidates working in organic chemistry or upper-level…

  18. Characterization, pharmacokinetics, and hypoglycemic effect of berberine loaded solid lipid nanoparticles

    Directory of Open Access Journals (Sweden)

    Xue M

    2013-12-01

    Full Text Available Mei Xue, Ming-xing Yang, Wei Zhang, Xiu-min Li, De-hong Gao, Zhi-min Ou, Zhi-peng Li, Su-huan Liu, Xue-jun Li, Shu-yu Yang Xiamen Diabetes Institute, The First Affiliated Hospital of Xiamen University, Xiamen, People’s Republic of China Abstract: The high aqueous solubility, poor permeability, and absorption of berberine (BBR result in its low plasma level after oral administration, which greatly limits its clinical application. BBR solid lipid nanoparticles (SLNs were prepared to achieve improved bioavailability and prolonged effect. Developed SLNs showed homogeneous spherical shapes, small size (76.8 nm, zeta potential (7.87 mV, encapsulation efficiency (58%, and drug loading (4.2%. The power of X-ray diffraction combined with 1H nuclear magnetic resonance spectroscopy was employed to analyze chemical functional groups and the microstructure of BBR-SLNs, and indicated that the drug was wrapped in a lipid carrier. Single dose (50 mg/kg oral pharmacokinetic studies in rats showed significant improvement (P<0.05 in the peak plasma concentration, area under the curve, and variance of mean residence time of BBR-SLNs when compared to BBR alone (P<0.05, suggesting improved bioavailability. Furthermore, oral administration of both BBR and BBR-SLNs significantly suppressed body weight gain, fasting blood glucose levels, and homeostasis assessment of insulin resistance, and ameliorated impaired glucose tolerance and insulin tolerance in db/db diabetic mice. BBR-SLNs at high dose (100 mg/kg showed more potent effects when compared to an equivalent dose of BBR. Morphologic analysis demonstrated that BBR-SLNs potentially promoted islet function and protected the islet from regeneration. In conclusion, our study demonstrates that by entrapping BBR into SLNs the absorption of BBR and its anti-diabetic action were effectively enhanced. Keywords: berberine, solid lipid nanoparticles, pharmacokinetic, hypoglycemic effect

  19. Strength of Anode‐Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Faes, A.; Frandsen, Henrik Lund; Kaiser, Andreas

    2011-01-01

    Nickel oxide and yttria doped zirconia composite strength is crucial for anode‐supported solid oxide fuel cells, especially during transient operation, but also for the initial stacking process, where cell curvature after sintering can cause problems. This work first compares tensile and ball....... Even though the electrolyte is to the tensile side, it is found that the anode support fails due to the thermo‐mechanical residual stresses....

  20. Lactoferrin bioconjugated solid lipid nanoparticles: a new drug delivery system for potential brain targeting.

    Science.gov (United States)

    Singh, Indu; Swami, Rajan; Pooja, Deep; Jeengar, Manish Kumar; Khan, Wahid; Sistla, Ramakrishna

    2016-01-01

    Delivery of drugs to brain is a subtle task in the therapy of many severe neurological disorders. Solid lipid nanoparticles (SLN) easily diffuse the blood-brain barrier (BBB) due to their lipophilic nature. Furthermore, ligand conjugation on SLN surface enhances the targeting efficiency. Lactoferin (Lf) conjugated SLN system is first time attempted for effective brain targeting in this study. Preparation of Lf-modified docetaxel (DTX)-loaded SLN for proficient delivery of DTX to brain. DTX-loaded SLN were prepared using emulsification and solvent evaporation method and conjugation of Lf on SLN surface (C-SLN) was attained through carbodiimide chemistry. These lipidic nanoparticles were evaluated by DLS, AFM, FTIR, XRD techniques and in vitro release studies. Colloidal stability study was performed in biologically simulated environment (normal saline and serum). These lipidic nanoparticles were further evaluated for its targeting mechanism for uptake in brain tumour cells and brain via receptor saturation studies and distribution studies in brain, respectively. Particle size of lipidic nanoparticles was found to be optimum. Surface morphology (zeta potential, AFM) and surface chemistry (FTIR) confirmed conjugation of Lf on SLN surface. Cytotoxicity studies revealed augmented apoptotic activity of C-SLN than SLN and DTX. Enhanced cytotoxicity was demonstrated by receptor saturation and uptake studies. Brain concentration of DTX was elevated significantly with C-SLN than marketed formulation. It is evident from the cytotoxicity, uptake that SLN has potential to deliver drug to brain than marketed formulation but conjugating Lf on SLN surface (C-SLN) further increased the targeting potential for brain tumour. Moreover, brain distribution studies corroborated the use of C-SLN as a viable vehicle to target drug to brain. Hence, C-SLN was demonstrated to be a promising DTX delivery system to brain as it possessed remarkable biocompatibility, stability and efficacy than

  1. Novel sulpiride-loaded solid lipid nanoparticles with enhanced intestinal permeability

    Directory of Open Access Journals (Sweden)

    Ibrahim WM

    2013-12-01

    Full Text Available Waheed M Ibrahim,1 Abdullah H AlOmrani,2 Alaa Eldeen B Yassin31Drug Sector, Saudi Food and Drug Authority, 2Department of Pharmaceutics, College of Pharmacy, King Saud University, 3Department of Pharmaceutical Sciences, College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, National Guard Health Affairs, Riyadh, Saudi ArabiaBackground: Solid lipid nanoparticles (SLN, novel drug delivery carriers, can be utilized in enhancing both intestinal permeability and dissolution of poorly absorbed drugs. The aim of this work was to enhance the intestinal permeability of sulpiride by loading into SLN.Methods: A unique ultrasonic melt-emulsification method with minimum stress conditions was used for the preparation of SLN. The mixture of the drug and the melted lipids was simply dispersed in an aqueous solution of a surfactant at a temperature that was 10°C higher than the melting points of the lipids using probe sonication, and was then simultaneously dispersed in cold water. Several formulation parameters were optimized, including the drug-to-lipid ratio, and the types of lipids and surfactants used. The produced SLN were evaluated for their particle size and shape, surface charge, entrapment efficiency, crystallinity of the drug and lipids, and the drug release profile. The rat everted sac intestine model was utilized to evaluate the change in intestinal permeability of sulpiride by loading into SLN.Results: The method adopted allowed successful preparation of SLN with a monodispersed particle size of 147.8–298.8 nm. Both scanning electron microscopic and atomic force microscopic images showed uniform spherical particles and confirmed the sizes determined by the light scattering technique. Combination of triglycerides with stearic acid resulted in a marked increase in zeta potential, entrapment efficiency, and drug loading; however, the particle size was increased. The type of surfactant used was critical for particle size

  2. Technology of stable, prolonged-release eye-drops containing Cyclosporine A, distributed between lipid matrix and surface of the solid lipid microspheres (SLM).

    Science.gov (United States)

    Wolska, Eliza; Sznitowska, Małgorzata

    2013-01-30

    The aim of this study was to prepare solid lipid microspheres (SLM) with incorporated Cyclosporine A (Cs), suitable for ocular application. For this purpose, SLM were formulated by using different lipids and three different nonionic surfactants. The SLM were produced using a hot emulsification method. The SLM dispersions contained 10, 20 or 30% of lipid (w/w) and up to 2% (w/w) of Cs. The size of the microspheres with Cs ranged from 1 to 15 μm. Physically stable SLM with Cs were prepared using Compritol, as a lipid matrix, and Tween 80, as a surfactant. In contrast, dispersion with Precirol alone, formed semi-solid gels during storage, while in formulations with Precirol and Miglyol, crystals of Cs were observed. In vitro release profile of Compritol formulations showed that 40% of Cs is released within 1h, while the release of the following 40% takes more time, depending on lipid content in the formulations. The large part of Cs, added to SLM formulations (from 45 to 80%), was found on the surface of microparticles, but no drug crystallization occurred during a long-term storage. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. The effect of a lipid composition and a surfactant on the characteristics of the solid lipid microspheres and nanospheres (SLM and SLN).

    Science.gov (United States)

    Sznitowska, Malgorzata; Wolska, Eliza; Baranska, Helena; Cal, Krzysztof; Pietkiewicz, Justyna

    2017-01-01

    Solid lipid microparticles (SLM) were produced by a two-step process that, firstly, involved the emulsification of the molten lipid phase in a heated aqueous phase and, secondly, the system cooling. Compritol 888 ATO and Precirol ATO 5, including their mixtures with Miglyol 812 or Witepsol H15 were used as lipid components (10-30% w/w). The average size of the SLM prepared with Compritol and Tween 80 as an emulsifier was 3-7μm and the influence of lipid concentration and thermal sterilization was not large. Dispersions of SLM with Precirol (10-20% w/w) gellified upon storage. SLM stabilized with another surfactant, Tego Care 450, were larger in size and measured 40μm on average. The use of the sonication step (5-15min) in hot formulations containing 5% w/w of Compritol resulted in the formation of the solid lipid nanoparticles (SLN) with average size 200-300nm. The smallest SLN size (below 100nm on average) was obtained in SLN that contained Tego Care and an antimicrobial agent Euxyl PE 9010; such combination evoked synergism between the surfactant and Euxyl components. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Production of fungal antibiotics using polymeric solid supports in solid-state and liquid fermentation.

    Science.gov (United States)

    Bigelis, Ramunas; He, Haiyin; Yang, Hui Y; Chang, Li-Ping; Greenstein, Michael

    2006-10-01

    The use of inert absorbent polymeric supports for cellular attachment in solid-state fungal fermentation influenced growth, morphology, and production of bioactive secondary metabolites. Two filamentous fungi exemplified the utility of this approach to facilitate the discovery of new antimicrobial compounds. Cylindrocarpon sp. LL-Cyan426 produced pyrrocidines A and B and Acremonium sp. LL-Cyan416 produced acremonidins A-E when grown on agar bearing moist polyester-cellulose paper and generated distinctly different metabolite profiles than the conventional shaken or stationary liquid fermentations. Differences were also apparent when tenfold concentrated methanol extracts from these fermentations were tested against antibiotic-susceptible and antibiotic-resistant Gram-positive bacteria, and zones of inhibition were compared. Shaken broth cultures of Acremonium sp. or Cylindrocarpon sp. showed complex HPLC patterns, lower levels of target compounds, and high levels of unwanted compounds and medium components, while agar/solid support cultures showed significantly increased yields of pyrrocidines A and B and acremonidins A-E, respectively. This method, mixed-phase fermentation (fermentation with an inert solid support bearing liquid medium), exploited the increase in surface area available for fungal growth on the supports and the tendency of some microorganisms to adhere to solid surfaces, possibly mimicking their natural growth habits. The production of dimeric anthraquinones by Penicillium sp. LL-WF159 was investigated in liquid fermentation using various inert polymeric immobilization supports composed of polypropylene, polypropylene cellulose, polyester-cellulose, or polyurethane. This culture produced rugulosin, skyrin, flavomannin, and a new bisanthracene, WF159-A, after fermentation in the presence and absence of polymeric supports for mycelial attachment. The physical nature of the different support systems influenced culture morphology and relative

  5. Formation of supported lipid bilayers containing phase-segregated domains and their interaction with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Melby, Eric S.; Mensch, Arielle C.; Lohse, Samuel E.; Hu, Dehong; Orr, Galya; Murphy, Catherine J.; Hamers, Robert J.; Pedersen, Joel A.

    2016-01-01

    The cell membrane represents an important biological interface that nanoparticles may encounter after being released into the environment. Interaction of nanoparticles with cellular membranes may alter membrane structure and function, lead to their uptake into cells, and elicit adverse biological responses. Supported lipid bilayers have proven to be valuable ex vivo models for biological membranes, allowing investigation of their mechanisms of interaction with nanoparticles with a degree of control impossible in living cells. To date, the majority of research on nanoparticle interaction with supported lipid bilayers has employed membranes composed of single or binary mixtures of phospholipids. Cellular membranes contain a wide variety of lipids and exhibit lateral organization. Ordered membrane domains enriched in specific membrane components are referred to as lipid rafts and have not been explored with respect to their interaction with nanoparticles. Here we develop model lipid raft-containing membranes amenable to investigation by a variety of surface-sensitive analytical techniques and demonstrate that lipid rafts influence the extent of nanoparticle attachment to model membranes. We determined conditions that allow reliable formation of bilayers containing rafts enriched in sphingomyelin and cholesterol and confirmed their morphology by structured illumination and atomic force microscopies. We demonstrate that lipid rafts increase attachment of cationic gold nanoparticles to model membranes under near physiological ionic strength conditions (0.1 M NaCl) at pH 7.4. We anticipate that these results will serve as the foundation for and motivate further study of nanoparticle interaction with compositionally varied lipid rafts.

  6. In vivo evaluation of the efficacy of albendazole sulfoxide and albendazole sulfoxide loaded solid lipid nanoparticles against hydatid cyst.

    Science.gov (United States)

    Ahmadnia, Sara; Moazeni, Mohammad; Mohammadi-Samani, Soliman; Oryan, Ahmad

    2013-10-01

    Cystic echinococcosis (CE) is caused by the larval stage of Echinococcus granulosus, which in this disease the metacestode develop in visceral organs especially liver and lungs. The disease is present worldwide and affects humans as well as herbivores including cattle, sheep, camels, horses and others. Benzimidazole carbamate derivatives, such as mebendazole and albendazole, are currently used for chemotherapeutic treatment of CE in inoperable patients and have to be applied in high doses for extended periods of time, and therefore adverse side effects are frequently observed. This study was designed to evaluate and compare the in vivo effects of 0.5 mg/kg, BID, albendazole sulfoxide (ricobendazole) and two different therapeutic regimens of 0.5 mg/kg BID and 2 mg/kg every 48 h of albendazole sulfoxide loaded solid lipid nanoparticles. Albendazole sulfoxide loaded solid lipid nanoparticles was prepared by solvent diffusion-evaporation method. Fifty Balb/c mice were infected by intraperitoneal injection of protoscoleces and 8 months post infection, the infected mice were treated for 15 days with the above mentioned regimens. They were then euthanized and the size and weight of the cysts as well as their ultrastructural changes were investigated. Although the cysts showed reduced size and weight in the treated animals but these reductions were not statistically significant. The cysts in the animals which received albendazole sulfoxide loaded SLN every 48 h showed more ultrastructural modification. However, these ultrastructural changes should be supported by further biochemical and molecular studies before introducing it as an efficient therapeutic regimen for treatment of human and animal hydatid disease. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Solid state NMR investigations and MD simulations of triblock copolymers in lipid bilayers

    Czech Academy of Sciences Publication Activity Database

    Baerenwald, R.; Ferreira, T. M.; Ollila, Samuli; Saalwaechter, K.

    2017-01-01

    Roč. 46, Suppl 1 (2017), S117 ISSN 0175-7571. [IUPAB congress /19./ and EBSA congress /11./. 16.07.2017-20.07.2017, Edinburgh] Institutional support: RVO:61388963 Keywords : solid state NMR * molecular dynamic simulations Subject RIV: BO - Biophysics

  8. Dynamic patterns in a supported lipid bilayer driven by standing surface acoustic waves.

    Science.gov (United States)

    Hennig, Martin; Neumann, Jürgen; Wixforth, Achim; Rädler, Joachim O; Schneider, Matthias F

    2009-11-07

    In the past decades supported lipid bilayers (SLBs) have been an important tool in order to study the physical properties of biological membranes and cells. So far, controlled manipulation of SLBs is very limited. Here we present a new technology to create lateral patterns in lipid membranes controllable in both space and time. Surface acoustic waves (SAWs) are used to generate lateral standing waves on a piezoelectric substrate which create local "traps" in the lipid bilayer and lead to a lateral modulation in lipid concentration. We demonstrate that pattern formation is reversible and does not affect the integrity of the lipid bilayer as shown by extracting the diffusion constant of fluid membranes. The described method could possibly be used to design switchable interfaces for the lateral transport and organization of membrane bound macromolecules to create dynamic bioarrays and control biofilm formation.

  9. Multi-Stacked Supported Lipid Bilayer Micropatterning through Polymer Stencil Lift-Off

    Directory of Open Access Journals (Sweden)

    Yujie Zhu

    2015-08-01

    Full Text Available Complex multi-lamellar structures play a critical role in biological systems, where they are present as lamellar bodies, and as part of biological assemblies that control energy transduction processes. Multi-lamellar lipid layers not only provide interesting systems for fundamental research on membrane structure and bilayer-associated polypeptides, but can also serve as components in bioinspired materials or devices. Although the ability to pattern stacked lipid bilayers at the micron scale is of importance for these purposes, limited work has been done in developing such patterning techniques. Here, we present a simple and direct approach to pattern stacked supported lipid bilayers (SLBs using polymer stencil lift-off and the electrostatic interactions between cationic and anionic lipids. Both homogeneous and phase-segregated stacked SLB patterns were produced, demonstrating that the stacked lipid bilayers retain lateral diffusivity. We demonstrate patterned SLB stacks of up to four bilayers, where fluorescence resonance energy transfer (FRET and quenching was used to probe the interactions between lipid bilayers. Furthermore, the study of lipid phase behaviour showed that gel phase domains align between adjacent layers. The proposed stacked SLB pattern platform provides a robust model for studying lipid behaviour with a controlled number of bilayers, and an attractive means towards building functional bioinspired materials or devices.

  10. Solid Lipid Nanoparticles Carrying Temozolomide for Melanoma Treatment. Preliminary In Vitro and In Vivo Studies

    Directory of Open Access Journals (Sweden)

    Nausicaa Clemente

    2018-01-01

    Full Text Available Aim: To develop an innovative delivery system for temozolomide (TMZ in solid lipid nanoparticles (SLN, which has been preliminarily investigated for the treatment of melanoma. Materials and Methods: SLN-TMZ was obtained through fatty acid coacervation. Its pharmacological effects were assessed and compared with free TMZ in in vitro and in vivo models of melanoma and glioblastoma. Results: Compared to the standard free TMZ, SLN-TMZ exerted larger effects, when cell proliferation of melanoma cells, and neoangiogeneis were evaluated. SLN-TMZ also inhibited growth and vascularization of B16-F10 melanoma in C57/BL6 mice, without apparent toxic effects. Conclusion: SLN could be a promising strategy for the delivery of TMZ, allowing an increased stability of the drug and thereby its employment in the treatment of aggressive malignacies.

  11. Solid lipid nanoparticles as attractive drug vehicles: Composition, properties and therapeutic strategies.

    Science.gov (United States)

    Geszke-Moritz, Małgorzata; Moritz, Michał

    2016-11-01

    This work briefly reviews up-to-date developments in solid lipid nanoparticles (SLNs) as effective nanocolloidal system for drug delivery. It summarizes SLNs in terms of their preparation, surface modification and properties. The application of SLNs as a carrier system enables to improve the therapeutic efficacy of drugs from various therapeutic groups. Present uses of SLNs include cancer therapy, dermatology, bacterial infections, brain targeting and eye disorders among others. The usage of SLNs provides enhanced pharmacokinetic properties and modulated release of drugs. SLN ubiquitous application results from their specific features such as possibility of surface modification, increased permeation through biological barriers, resistance to chemical degradation, possibility of co-delivery of various therapeutic agents or stimuli-responsiveness. This paper will be useful to the scientists working in the domain of SLN-based drug delivery systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Solid Lipid Nanoparticles Carrying Temozolomide for Melanoma Treatment. Preliminary In Vitro and In Vivo Studies

    Science.gov (United States)

    Ferrara, Benedetta; Biasibetti, Elena; Schiffer, Davide; Mellai, Marta; Annovazzi, Laura; Cangemi, Luigi; Muntoni, Elisabetta; Dianzani, Umberto

    2018-01-01

    Aim: To develop an innovative delivery system for temozolomide (TMZ) in solid lipid nanoparticles (SLN), which has been preliminarily investigated for the treatment of melanoma. Materials and Methods: SLN-TMZ was obtained through fatty acid coacervation. Its pharmacological effects were assessed and compared with free TMZ in in vitro and in vivo models of melanoma and glioblastoma. Results: Compared to the standard free TMZ, SLN-TMZ exerted larger effects, when cell proliferation of melanoma cells, and neoangiogeneis were evaluated. SLN-TMZ also inhibited growth and vascularization of B16-F10 melanoma in C57/BL6 mice, without apparent toxic effects. Conclusion: SLN could be a promising strategy for the delivery of TMZ, allowing an increased stability of the drug and thereby its employment in the treatment of aggressive malignacies. PMID:29364157

  13. PEG-stearate coated solid lipid nanoparticles as levothyroxine carriers for oral administration

    Science.gov (United States)

    Kashanian, Soheila; Rostami, Elham

    2014-03-01

    In this study, poly ethylene glycol 100 stearate (PEG 100-S) was used to prepare coated solid lipid nanoparticles with loading levothyroxine sodium (levo-loaded PEG 100-S-coated SLNs) by microemulsification technique. Evaluation of the release kinetic of prepared colloidal carriers was conducted. The particle size and zeta potential of levo-loaded PEG 100-S-coated SLNs have been measured to be 187.5 nm and -23.0 mV, respectively, using photon correlation spectroscopy (PCS). Drug entrapment efficiency (EE) was calculated to be 99 %. Differential scanning calorimetry indicated that the majority of drug loaded in PEG 100-S-coated SLNs were in amorphous state which could be considered desirable for drug delivery. The purpose of this study was to develop a new nanoparticle system, consisting lipid nanoparticles coated with PEG 100-S. The modification procedure led to a reduction in the zeta potential values, varying from -40.0 to -23.0 mV for the uncoated and PEG-coated SLNs, respectively. Stability results of the nanoparticles in gastric and intestinal media show that the low pH of the gastric medium is responsible for the critical aggregation and degradation of the uncoated lipid nanoparticles. PEG 100-S-coated SLNs were more stable due to their polymer coating layer which prevented aggregation of SLNs. Consequently, it is possible that the PEG surrounds the particles reducing the attachment of enzymes and further degradation of the triglyceride cores. Shape and surface morphology of particles were determined by transition electron microscopy and scanning electron microscopy that revealed spherical shape of nanoparticles. In vitro drug release of PEG 100-S-coated SLNs was characterized using diffusion cell which showed a controlled release for drug.

  14. Solid lipid nanoparticles as insulin inhalation carriers for enhanced pulmonary delivery.

    Science.gov (United States)

    Bi, Ru; Shao, Wei; Wang, Qun; Zhang, Na

    2009-02-01

    Growing attentions have been paid to the pulmonary route for systemic delivery of peptide and protein drugs, such as insulin. Advantages of this non-injective route include rapid drug deposition in the target organ, fewer systemic side effects and avoiding first pass metabolism. However, sustained release formulations for pulmonary delivery have not been fully exploited till now. In our study, a novel dry powder inhalation (DPI) system of insulin loaded solid lipid nanoparticles (Ins-SLNs) was investigated for prolonged drug release, improved stability and effective inhalation. Firstly, the drug was incorporated into the lipid carriers for a maximum entrapment efficiency as high as 69.47 +/- 3.27% (n = 3). Secondly, DPI formulation was prepared by spray freeze drying of Ins-SLNs suspension, with optimized lyoprotectant and technique parameters in this procedure. The properties of DPI particles were characterized for their pulmonary delivery potency. Thirdly, the in vivo study of intratracheal instillation of Ins-SLNs to diabetic rats showed prolonged hypoglycemic effect and a relative pharmacological bioavailability of 44.40% could be achieved in the group of 8 IU/kg dosage. These results indicated that SLNs have shown increasing potential as an efficient and non-toxic lipophilic colloidal drug carrier for enhanced pulmonary delivery of insulin.

  15. Solid lipid nanoparticles as effective reservoir systems for long-term preservation of multidose formulations.

    Science.gov (United States)

    Cerreto, Felice; Paolicelli, Patrizia; Cesa, Stefania; Abu Amara, Hend M; D'Auria, Felicia Diodata; Simonetti, Giovanna; Casadei, Maria Antonietta

    2013-06-01

    Cosmetic multidose preparations, as well as pharmaceutical ones, are at risk of contamination by microorganisms, due to their high water content. Besides the risk of contamination during manufacturing, multidose cosmetic preparations may be contaminated by consumers during their use. In this paper, the results of the utilization of nanoparticles as reservoir systems of parabens, the most used class of preservatives, were reported. Two different systems, solid lipid nanoparticles (SLN) made of pure precirol and nanostructured lipid carriers (NLC) made of precirol and almond oil, containing three parabens as single molecules or as a mixture, were prepared and tested. All the systems were characterized for size, polydispersion index, zeta potential and encapsulation efficiency. Release experiments, carried out in steady state and sink conditions, allowed to evidence that both SLN and NLC were able to act as reservoir systems. The antimicrobial activity of the systems was tested against Candida albicans ATCC 10231 with repeat insult tests. The results of the release experiments and the antimicrobial tests showed very low water concentration of parabens still maintaining their antimicrobial activity.

  16. Development and characterization of controlled release polar lipid microparticles of candesartan cilexetil by solid dispersion

    Science.gov (United States)

    Kamalakkannan, V; Puratchikody, A; Ramanathan, L

    2013-01-01

    Candesartan cilexetil (CC) is a newer class of angiotensin II receptor antagonist used for the treatment of hypertension. The solubility of the CC is very poor and its oral bioavailability is only 15%. The controlledrelease polar lipid microparticles of CC (formulations F1, F2, F3 and F4) were prepared using variable erodible lipophilic excipients like hydrogenated castor oil, stearic acid, cetostearyl alcohol and carnauba wax by fusion method. The particle sizes of polar lipid microparticles were less than 50 microns and they were irregular in shape. Drug content ranged between 98.96 ± 2.1 and 101.9 ± 1.6% were present in all the formulations. The formulation F3 showed better drug release throughout the study period in a controlled release manner. Moreover, the in vitro release showed that all the formulations were best fitted to Higuchi model. Accelerated stability studies indicated that there was no significant changes in the chemical and physical characteristics of the formulated drug product during initial and at the end of the study period. The FTIR and DSC studies showed that there was no interaction between the drug and lipophilic excipients and no polymorphic transitions in all formulations. The X-ray diffraction peak of solid dispersion indicated that the crystalline nature of CC disappeared and no new peaks could be observed, suggesting the absence of interaction between drug and excipients. PMID:24019822

  17. Preparation and characterization of ketoprofen-loaded solid lipid nanoparticles made from beeswax and carnauba wax.

    Science.gov (United States)

    Kheradmandnia, Soheila; Vasheghani-Farahani, Ebrahim; Nosrati, Mohsen; Atyabi, Fatemeh

    2010-12-01

    Solid lipid nanoparticles (SLNs) have been proposed as suitable colloidal carriers for delivery of drugs with limited solubility. Ketoprofen as a model drug was incorporated into SLNs prepared from a mixture of beeswax and carnauba wax using Tween 80 and egg lecithin as emulsifiers. The characteristics of the SLNs with various lipid and surfactant composition were investigated. The mean particle size of drug-loaded SLNs decreased upon mixing with Tween 80 and egg lecithin as well as upon increasing total surfactant concentration. SLNs of 75 ± 4 nm with a polydispersity index of 0.2 ± 0.02 were obtained using 1% (vol/vol) mixed surfactant at a ratio of 60:40 Tween 80 to egg lecithin. The zeta potential of these SLNs varied in the range of -15 to -17 (mV), suggesting the presence of similar interface properties. High drug entrapment efficiency of 97% revealed the ability of SLNs to incorporate a poorly water-soluble drug such as ketoprofen. Differential scanning calorimetry thermograms and high-performance liquid chromatographic analysis indicated the stability of nanoparticles with negligible drug leakage after 45 days of storage. It was also found that nanoparticles with more beeswax content in their core exhibited faster drug release as compared with those containing more carnauba wax in their structure. Copyright © 2010 Elsevier Inc. All rights reserved.

  18. Pharmacodynamics of piroxicam from novel solid lipid microparticles formulated with homolipids from Bos indicus.

    Science.gov (United States)

    Nnamani, Petra O; Attama, Anthony A; Kenechukwu, Franklin C; Ibezim, Emmanuel C; Adikwu, Michael U

    2013-12-01

    The dissolution of piroxicam is a limiting step in its bioavailability on account of its hydrophobicity. The objective of this research was to formulate novel solid lipid microparticles (SLMs) based on homolipids (admixtures of tallow fat (TF) and Softisan(®) 142 (SFT) templated with Phospholipon(®) 90G (P90G), a heterolipid for the delivery of piroxicam. Lipid matrices consisting of TF and SFT in ratios of 1:1, 1:2 and 2:1 were templated with the heterolipid, P90G and characterized by differential scanning calorimetry (DSC). The SLMs produced by hot homogenization technique using the matrices were characterized in terms of thermal properties, particle size, morphology, drug encapsulation efficiency, stability studies and in vitro diffusion studies. In vivo pharmacodynamic study was performed using egg albumin- induced pedal edema in rats. The results showed that addition of Softisan(®) 142 improved the drug holding capacity of the micellar solution of 2:1 mixture of TF and SFT. The in vitro diffusion of piroxicam from this SLM showed maximum release of 87.53 % and followed non-Fickian diffusion kinetic mechanism. At dose equivalence of 10 mg, piroxicamloaded SLMs showed superior in vivo anti-inflammatory properties at 3 h than Feldene(®) and the pure drug sample. This study has shown that surface-modified SLMs could confer favourable properties with respect to drug release and antiinflammatory activity on SLMs for the delivery of piroxicam, thus encouraging further development of the formulations.

  19. Anti-Inflammatory Effects of Novel Standardized Solid Lipid Curcumin Formulations.

    Science.gov (United States)

    Nahar, Pragati P; Slitt, Angela L; Seeram, Navindra P

    2015-07-01

    Inflammation and the presence of pro-inflammatory cytokines are associated with numerous chronic diseases such as type-2 diabetes mellitus, cardiovascular disease, Alzheimer's disease, and cancer. An overwhelming amount of data indicates that curcumin, a polyphenol obtained from the Indian spice turmeric, Curcuma longa, is a potential chemopreventive agent for treating certain cancers and other chronic inflammatory diseases. However, the low bioavailability of curcumin, partly due to its low solubility and stability in the digestive tract, limits its therapeutic applications. Recent studies have demonstrated increased bioavailability and health-promoting effects of a novel solid lipid particle formulation of curcumin (Curcumin SLCP, Longvida(®)). The goal of this study was to evaluate the aqueous solubility and in vitro anti-inflammatory effects of solid lipid curcumin particle (SLCP) formulations using lipopolysaccharide (LPS)-stimulated RAW 264.7 cultured murine macrophages. SLCPs treatment significantly decreased nitric oxide (NO) and prostaglandin-E2 (PGE2) levels at concentrations ranging from 10 to 50 μg/mL, and reduced interleukin-6 (IL-6) levels in a concentration-dependent manner. Transient transfection experiments using a nuclear factor-kappa B (NF-κB) reporter construct indicate that SLCPs significantly inhibit the transcriptional activity of NF-κB in macrophages. Taken together, these results show that in RAW 264.7 murine macrophages, SLCPs have improved solubility over unformulated curcumin, and significantly decrease the LPS-induced pro-inflammatory mediators NO, PGE2, and IL-6 by inhibiting the activation of NF-κB.

  20. Stability and antimicrobial effect of amikacin-loaded solid lipid nanoparticles

    Directory of Open Access Journals (Sweden)

    Solmaz Ghaffari

    2010-12-01

    Full Text Available Solmaz Ghaffari1, Jaleh Varshosaz1, Afrooz Saadat2, Fatemeh Atyabi21Department of Pharmaceutics, Faculty of Pharmacy and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; 2Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, IranAbstract: Solid lipid nanoparticles (SLNs of amikacin were designed in this study for pulmonary delivery to reduce the dose or its administration intervals leading to reduction of its toxicities especially in long term treatment. Nanoparticles of amikacin were prepared from cholesterol by solvent diffusion technique and homogenization. The size, zeta potential, loading efficiency, and release profile of the nanoparticles were studied. The conventional broth macrodilution tube method was used to determine the minimum inhibitory concentration (MIC and minimum bacteriostatic concentration (MBC of amikacin SLNs with respect to Pseudomonas aeruginosa in vitro. To guarantee the stability of desired SLNs, they were lyophilized using cryoprotectants. Results showed that considering the release profile of amikacin from the studied nanocarrier, MIC and MBC of amikacin could be about two times less in SLNs of amikacin compared to the free drug. Therefore, fewer doses of amikacin in SLNs can clear the infection with less adverse effects and more safety. Particle size enlargement after lyophilization of desired SLNs after two months storage was limited in comparison with non-lyophilized particles, 996 and 194 nm, respectively. Zeta potential of lyophilized particles was increased to +17 mV from +4 mV before lyophilization. Storage of particles in higher temperature caused accelerated drug release.Keywords: amikacin, antimicrobial effects, Pseudomonas aeruginosa, solid lipid nanoparticles, stability

  1. Interactions of the spin-labeled chloroethylnitrosourea SLCNUgly with electrode-supported lipid films

    International Nuclear Information System (INIS)

    Tacheva, Bilyana; Georgieva, Radostina; Karabaliev, Miroslav

    2016-01-01

    The spin-labeled chloroethylnitrosourea containig glycine SLCNUgly is an analogue of the clinically used nitrosourea drug lomustine (1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, CCNU), showing promising properties and features in vitro as well as in vivo. In this work the interaction of SLCNUgly with a lipid model membrane is investigated. The presented results indicate penetration of the drug in the membranes without causing defects of the lipid structure and reveal the potential of both SLCNUgly and electrode-supported lipid films as models for investigating nitrosourea drugs-membrane interactions.

  2. Comparative study of sustained-release lipid microparticles and solid dispersions containing ibuprofen

    Directory of Open Access Journals (Sweden)

    Hugo Almeida

    2012-09-01

    Full Text Available Ibuprofen is one of the most important non-steroidal anti-inflammatory drugs used in the treatment of inflammatory diseases. In its pure state, ibuprofen presents poor physical and mechanical characteristics and its use in solid dosage forms needs the addition of excipients that improve these properties. The selection of the best excipients and the most suitable pharmaceutical dosage form to carry ibuprofen is very important for the industrial success of this drug. Given these factors, lipid microparticles and solid dispersions of ibuprofen with cetyl alcohol, stearic acid, and hydrogenated castor oil were prepared. These formulations were intended to improve the physical and mechanical characteristics and to sustain the release of this drug. Physical mixtures were also prepared with the same ingredients in similar proportions. The solid dispersions of ibuprofen/stearic acid and ibuprofen/hydrogenated castor oil showed the best flow characteristics compared with pure ibuprofen. Further, gelatin capsules filled with lipid microparticles and solid dispersions were submitted to dissolution tests in order to study the influence of the prepared systems in the release profiles of ibuprofen. Prolonged release of ibuprofen was achieved with the lipid microparticles and solid dispersions prepared with the different types of excipients.O ibuprofeno é um dos antiinflamatórios não esteróides mais utilizados no tratamento de patologias associadas a processos inflamatórios. Este fármaco, quando no seu estado puro, apresenta características físicas e mecânicas pouco satisfatórias e a sua utilização em formas sólidas só é possível se forem adicionados excipientes que permitam melhorar estas propriedades. A seleção dos excipientes ideais e da forma farmacêutica mais adequada para veicular o ibuprofeno é fundamental para o sucesso industrial deste fármaco. Tendo em conta estes fatores, prepararam-se micropartículas lipídicas e dispersões s

  3. Properties of POPC/POPE supported lipid bilayers modified with hydrophobic quantum dots on polyelectrolyte cushions.

    Science.gov (United States)

    Kolasinska-Sojka, Marta; Wlodek, Magdalena; Szuwarzynski, Michal; Kereiche, Sami; Kovacik, Lubomir; Warszynski, Piotr

    2017-10-01

    The formation and properties of supported lipid bilayers (SLB) containing hydrophobic nanoparticles (NP) was studied in relation to underlying cushion obtained from selected polyelectrolyte multilayers. Lipid vesicles were formed from zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) in phosphate buffer (PBS). As hydrophobic nanoparticles - quantum dots (QD) with size of 3.8nm (emission wavelength of 420nm) were used. Polyelectrolyte multilayers (PEM) were constructed by the sequential, i.e., layer-by-layer (LbL) adsorption of alternately charged polyelectrolytes from their solutions. Liposomes and Liposome-QDs complexes were studied with Transmission Cryo-Electron Microscopy (Cryo-TEM) to verify the quality of vesicles and the position of QD within lipid bilayer. Deposition of liposomes and liposomes with quantum dots on polyelectrolyte films was studied in situ using quartz crystal microbalance with dissipation (QCM-D) technique. The fluorescence emission spectra were analyzed for both: suspension of liposomes with nanoparticles and for supported lipid bilayers containing QD on PEM. It was demonstrated that quantum dots are located in the hydrophobic part of lipid bilayer. Moreover, we proved that such QD-modified liposomes formed supported lipid bilayers and their final structure depended on the type of underlying cushion. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Preparation, characterization and evaluation of moisturizing and UV protecting effects of topical solid lipid nanoparticles

    Directory of Open Access Journals (Sweden)

    Shiva Golmohammadzadeh

    2012-12-01

    Full Text Available Solid lipid nanoparticles (SLN were recently proposed as carriers for various pharmaceutical and cosmetic actives. These lipid nanoparticles can act as moisturizers and physical sunscreens on their own. Therefore, the full potential of these carriers has yet to be determined. The present study was aimed to determine and compare moisturizing and UV-protecting effects of different solid lipid nanoparticles (SLN prepared by different solid lipids including Glyceryl monostearate (GMS, Precirol® (P and cetyl palmitate (CP as carrier systems of moisturizers and sunscreens. The influence of the size and matrix crystallinity of the solid lipids on the occlusive factor, skin hydration and UV-protection were evaluated by in vitro and in vivo methods. The SLN were prepared by high-shear homogenization and ultrasound methods. Size, zeta potential and morphological characteristics of the samples were assessed by transmission electron microscopy (TEM and thermotropic properties with differential scanning calorimetry (DSC technique. Results of the assessments showed that SLN-CP significantly increases skin hydration and UV-protection, compared to SLN-GMS and SLN-P. It was demonstrated that the size of SLN, crystallinity index of solid lipid in SLN and probably other mechanisms besides the occlusive factor can influence skin hydration and UV-protection indices. Furthermore, findings of the assessments demonstrated significant difference between in vitro and in vivo assessments regarding occlusive factor and moisturizing effects. Findings of the present study indicate that the SLN-CP could be a promising carrier for sunscreens and moisturizers.Nanopartículas lipídicas sólidas (NLS foram, recentemente, propostas como carreadores de vários ativos cosméticos e farmacêuticos. Essas nanopartículas lipídicas podem atuar como hidratantes e protetores solares físicos por si só. Assim sendo, determinou-se o potencial desses carreadores. Os objetivos do

  5. Silicon supported lipid-DNA thin film structures at varying temperature studied by energy dispersive X-ray diffraction and neutron reflectivity.

    Science.gov (United States)

    Domenici, F; Castellano, C; Dell'Unto, F; Albinati, A; Congiu, A

    2011-11-01

    Non-viral gene transfection by means of lipid-based nanosystems, such as solid supported lipid assemblies, is often limited due to their lack of stability and the consequent loss of efficiency. Therefore not only a detailed thermo-lyotropic study of these DNA-lipid complexes is necessary to understand their interaction mechanisms, but it can also be considered as a first step in conceiving and developing new transfection biosystems. The aim of our study is a structural characterization of 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC)-dimethyl-dioctadecyl-ammonium bromide (DDAB)-DNA complex at varying temperature using the energy dispersive X-ray diffraction (EDXD) and neutron reflectivity (NR) techniques. We have shown the formation of a novel thermo-lyotropic structure of DOPC/DDAB thin film self-organized in multi-lamellar planes on (100)-oriented silicon support by spin coating, thus enlightening its ability to include DNA strands. Our NR measurements indicate that the DOPC/DDAB/DNA complex forms temperature-dependent structures. At 65°C and relative humidity of 100% DNA fragments are buried between single lamellar leaflets constituting the hydrocarbon core of the lipid bilayers. This finding supports the consistency of the hydrophobic interaction model, which implies that the coupling between lipid tails and hypo-hydrated DNA single strands could be the driving force of DNA-lipid complexation. Upon cooling to 25°C, EDXD analysis points out that full-hydrated DOPC-DDAB-DNA can switch in a different metastable complex supposed to be driven by lipid heads-DNA electrostatic interaction. Thermotropic response analysis also clarifies that DOPC has a pivotal role in promoting the formation of our observed thermophylic silicon supported lipids-DNA assembly. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Nitriles at Silica Interfaces Resemble Supported Lipid Bilayers.

    Science.gov (United States)

    Berne, Bruce J; Fourkas, John T; Walker, Robert A; Weeks, John D

    2016-09-20

    Nitriles are important solvents not just for bulk reactions but also for interfacial processes such as separations, heterogeneous catalysis, and electrochemistry. Although nitriles have a polar end and a lipophilic end, the cyano group is not hydrophilic enough for these substances to be thought of as prototypical amphiphiles. This picture is now changing, as research is revealing that at a silica surface nitriles can organize into structures that, in many ways, resemble lipid bilayers. This unexpected organization may be a key component of unique interfacial behavior of nitriles that make them the solvents of choice for so many applications. The first hints of this lipid-bilayer-like (LBL) organization of nitriles at silica interfaces came from optical Kerr effect (OKE) experiments on liquid acetonitrile confined in the pores of sol-gel glasses. The orientational dynamics revealed by OKE spectroscopy suggested that the confined liquid is composed of a relatively immobile sublayer of molecules that accept hydrogen bonds from the surface silanol groups and an interdigitated, antiparallel layer that is capable of exchanging into the centers of the pores. This picture of acetonitrile has been borne out by molecular dynamics simulations and vibrational sum-frequency generation (VSFG) experiments. Remarkably, these simulations further indicate that the LBL organization is repeated with increasing disorder at least 20 Å into the liquid from a flat silica surface. Simulations and VSFG and OKE experiments indicate that extending the alkyl chain to an ethyl group leads to the formation of even more tightly packed LBL organization featuring entangled alkyl tails. When the alkyl portion of the molecule is a bulky t-butyl group, packing constraints prevent well-ordered LBL organization of the liquid. In each case, the surface-induced organization of the liquid is reflected in its interfacial dynamics. Acetonitrile/water mixtures are favored solvent systems for separations

  7. Docetaxel-loaded solid lipid nanoparticles suppress breast cancer cells growth with reduced myelosuppression toxicity

    Directory of Open Access Journals (Sweden)

    Yuan Q

    2014-10-01

    Full Text Available Qing Yuan,1 Jing Han,1,2 Wenshu Cong,1 Ying Ge,3 Dandan Ma,1,3,4 Zhaoxia Dai,3,4 Yaping Li,5 Xiaolin Bi1,3,4 1CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 2School of Life Sciences, Anhui University, Hefei, 3Cancer Center, Institute of Cancer Stem Cell, Dalian Medical University, Dalian, 4Graduate School, Dalian Medical University, Dalian, 5Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People’s Republic of China Abstract: Docetaxel is an adjuvant chemotherapy drug widely used to treat multiple solid tumors; however, its toxicity and side effects limit its clinical efficacy. Herein, docetaxel-loaded solid lipid nanoparticles (DSNs were developed to reduce systemic toxicity of docetaxel while still keeping its anticancer activity. To evaluate its anticancer activity and toxicity, and to understand the molecular mechanisms of DSNs, different cellular, molecular, and whole genome transcription analysis approaches were utilized. The DSNs showed lower cytotoxicity compared with the commercial formulation of docetaxel (Taxotere® and induced more apoptosis at 24 hours after treatment in vitro. DSNs can cause the treated cancer cells to arrest in the G2/M phase in a dose-dependent manner similar to Taxotere. They can also suppress tumor growth very effectively in a mice model with human xenograft breast cancer. Systemic analysis of gene expression profiles by microarray and subsequent verification experiments suggested that both DSNs and Taxotere regulate gene expression and gene function, including DNA replication, DNA damage response, cell proliferation, apoptosis, and cell cycle regulation. Some of these genes expressed differentially at the protein level although their messenger RNA expression level was similar under Taxotere and DSN treatment. Moreover, DSNs improved the main side effect of Taxotere by greatly

  8. Influence of lipid membranes rigidity on properties of supporting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Majewski, Jaroslaw [Los Alamos National Laboratory; Singh, Saurabh [Los Alamos National Laboratory; Dubey, Manish [Intel, Pheonix, AZ

    2012-06-18

    The motivation of this study is: (1) Controllable release of cultured cell sheets - (a) NIPAAm is non-toxic and collapsed at physiological Temp, (b) good platform for cell adherence and growth, (c) below polymer transition temp, cultured sheets are released, (d) hydration of matrix possible cause of cell attachment/detachment, (e) need for understanding hydration of underlying support; (2) Matrix elasticity plays an important role in cell lineage specification - (a) matrices of known stiffness are utilized as supports to understand physical effect of in-vivo tissue microenvironment for therapeutic uses of stem cells, (b) it is believed that stem cells 'sense' the elasticity and transduce the information into morphological changes, (c) Imperative to consider the changes induced in matrix as a result of immobilized cells.

  9. Preparation, characterization and pharmacokinetics of enrofloxacin-loaded solid lipid nanoparticles: influences of fatty acids.

    Science.gov (United States)

    Xie, Shuyu; Zhu, Luyan; Dong, Zhao; Wang, Xiaofang; Wang, Yan; Li, Xihe; Zhou, WenZhong

    2011-04-01

    Enrofloxacin-loaded solid lipid nanoparticles (SLN) were prepared using fatty acids (tetradecanoic acid, palmitic acid, stearic acid) as lipid matrix by hot homogenization and ultrasonication method. The effect of fatty acids on the characteristics and pharmacokinetics of the SLN were investigated. The results showed that the encapsulation efficiency and loading capacity of nanoparticles varied with fatty acids in the order of stearic acid>palmitic acid>tetradecanoic acid. Furthermore, stearic acid-SLN had larger particle size, bigger polydispersity index (PDI) and higher zeta potential compared with the other two fatty acid formulated SLN. The SLN showed sustained releases in vitro and the released enrofloxacin had the same antibacterial activity as that of the native enrofloxacin. Although in vitro release exhibited similar patterns, within 24 h the releasing rates of the three formulations were significantly different (tetradecanoic acid-SLN>palmitic acid-SLN>stearic acid-SLN). Pharmacokinetic study after a single dose of intramuscular administration to mice demonstrated that tetradecanoic acid-SLN, palmitic acid-SLN, and stearic acid-SLN increased the bioavailability by 6.79, 3.56 and 2.39 folds, and extended the mean residence time (MRT) of the drug from 10.60 h to 180.36, 46.26 and 19.09 h, respectively. These results suggest that the enrofloxacin-fatty acid SLN are promising formulations for sustained release while fatty acids had significant influences on the characteristics and performances of the SLN. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. IVABRADINE LOADED SOLID LIPID MICROPARTICLES: FORMULATION, CHARACTERIZATION AND OPTIMIZATION BY CENTRAL COMPOSITE ROTATABLE DESIGN.

    Science.gov (United States)

    Hanif, Muhammad; Khan, Hafeez Ullah; Afzal, Samina; Sher, Muhammad

    2017-01-01

    The current research focused on improvement of oral bioavailability and decrease in dosing frequency of ivabradine (Iva) in order to enhance patient compliance by formulating novel sustained release Iva loaded solid lipid microparticles (SLMs) with the help of melt emulsification technique. SLMs formulations were designed with the help of three level central composite rotatable design (CCRD) to study the impact of independent variables like lipid concentration, surfactant concentration and stirring speed on responses - percentage yield (Y,) and entrapment efficiency (Y2). Compatibility between the drug and bees wax (BW) was checked by conducting Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRD). SLMs were further evaluated for rheological behavior, zeta potential, particle size and for morphology by scanning'electron microscope (SEM). The release of drug from SLMs was conducted by USP type-Il apparatus at pH 1.2, pH 6.8 and data were analyzed by different kinetic models like zero order, first order, Higuchi model, Korsmeyer-Peppas and Hixon-Crowell models. The rheo- logical studies approved the good flow behavior of SLMs and spherical smooth surface of SLMs was observed from SEM. DSC, FTIR and XRD studies concluded the lack of any possible interaction between formulation components. The size-of SLMs ranged from 300 to 500 pm and zeta potential study showed the presence of higher negative charge (-30 to -52 mV). Response Y, varied from 53 to 90% and response Y2 ranged from 29 to 78% indicating the effect of formulation variables. The obtained outcomes were analyzed by second order polynomial equation and suggested quadratic model was also validated. SLMs released Iva from 54 to 90% at pH 6.8 and was significantly (p 0.05) affected by BW concentration. The release mechanism followed the zero order and Korsmeyer-Peppas (n 0.85) kinetic models suggesting slow erosion along with diffusion

  11. Naringenin-loaded solid lipid nanoparticles: preparation, controlled delivery, cellular uptake, and pulmonary pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Ji P

    2016-03-01

    Full Text Available Peng Ji, Tong Yu, Ying Liu, Jie Jiang, Jie Xu, Ying Zhao, Yanna Hao, Yang Qiu, Wenming Zhao, Chao WuCollege of Pharmacy, Liaoning Medical University, Jinzhou, Liaoning Province, People’s Republic of ChinaAbstract: Naringenin (NRG, a flavonoid compound, had been reported to exhibit extensive pharmacological effects, but its water solubility and oral bioavailability are only ~46±6 µg/mL and 5.8%, respectively. The purpose of this study is to design and develop NRG-loaded solid lipid nanoparticles (NRG-SLNs to provide prolonged and sustained drug release, with improved stability, involving nontoxic nanocarriers, and increase the bioavailability by means of pulmonary administration. Initially, a group contribution method was used to screen the best solid lipid matrix for the preparation of SLNs. NRG-SLNs were prepared by an emulsification and low-temperature solidification method and optimized using an orthogonal experiment approach. The morphology was examined by transmission electron microscopy, and the particle size and zeta potential were determined by photon correlation spectroscopy. The total drug content of NRG-SLNs was measured by high-performance liquid chromatography, and the encapsulation efficiency (EE was determined by Sephadex gel-50 chromatography and high-performance liquid chromatography. The in vitro NRG release studies were carried out using a dialysis bag. The best cryoprotectant to prepare NRG-SLN lyophilized powder for future structural characterization was selected using differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy. The short-term stability, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT assay, cellular uptake, and pharmacokinetics in rats were studied after pulmonary administration of NRG-SLN lyophilized powder. Glycerol monostearate was selected to prepare SLNs, and the optimal formulation of NRG-SLNs was spherical in shape, with a particle

  12. Automated Solid-Phase Radiofluorination Using Polymer-Supported Phosphazenes

    DEFF Research Database (Denmark)

    Mathiessen, Bente; Zhuravlev, Fedor

    2013-01-01

    of [18F]FDG. The combination of compact form factor, simplicity of [18F]F− recovery and processing, and column reusability can make solid phase radiofluorination an attractive radiochemistry platform for the emerging dose-on-demand instruments for bedside production of PET radiotracers.......The polymer supported phosphazene bases PS-P2tBu and the novel PS-P2PEG allowed for efficient extraction of [18F]F− from proton irradiated [18O]H2O and subsequent radiofluorination of a broad range of substrates directly on the resin. The highest radiochemical yields were obtained with aliphatic...

  13. The effect of cetyl palmitate crystallinity on physical properties of gamma-oryzanol encapsulated in solid lipid nanoparticles.

    Science.gov (United States)

    Ruktanonchai, Uracha; Limpakdee, Surachai; Meejoo, Siwaporn; Sakulkhu, Usawadee; Bunyapraphatsara, Nuntavan; Junyaprasert, Varaporn; Puttipipatkhachorn, Satit

    2008-03-05

    This present study was aimed at investigating the effect of the crystallinity of cetyl palmitate based solid lipid nanoparticles (SLNs) on the physical properties of γ-oryzanol-loaded SLNs. SLNs consisting of varying ratios of cetyl palmitate and γ-oryzanol were prepared. Their hydrodynamic diameters were in the range 210-280 nm and the zeta potentials were in the range -27 to -35 mV. The size of SLNs increased as the amount of cetyl palmitate decreased whereas no significant change of zeta potentials was found. Atomic force microscopy pictures indicated the presence of disc-like particles. The crystallinity of SLNs, determined by differential scanning calorimetry and powder x-ray diffraction, was directly dependent on the ratio of cetyl palmitate to γ-oryzanol and decreased with decreasing cetyl palmitate content in the lipid matrix. Varying this ratio in the lipid mix resulted in a shift in the melting temperature and enthalpy, although the SLN structure remained unchanged as an orthorhombic lamellar lattice. This has been attributed to a potential inhibition by γ-oryzanol during lipid crystal growth as well as a less ordered structure of the SLNs. The results revealed that the crystallinity of the SLNs was mainly dependent on the solid lipid, and that the crystallinity has an important impact on the physical characteristics of active-loaded SLNs.

  14. The effect of cetyl palmitate crystallinity on physical properties of gamma-oryzanol encapsulated in solid lipid nanoparticles

    International Nuclear Information System (INIS)

    Ruktanonchai, Uracha; Sakulkhu, Usawadee; Limpakdee, Surachai; Meejoo, Siwaporn; Bunyapraphatsara, Nuntavan; Junyaprasert, Varaporn; Puttipipatkhachorn, Satit

    2008-01-01

    This present study was aimed at investigating the effect of the crystallinity of cetyl palmitate based solid lipid nanoparticles (SLNs) on the physical properties of γ-oryzanol-loaded SLNs. SLNs consisting of varying ratios of cetyl palmitate and γ-oryzanol were prepared. Their hydrodynamic diameters were in the range 210-280 nm and the zeta potentials were in the range -27 to -35 mV. The size of SLNs increased as the amount of cetyl palmitate decreased whereas no significant change of zeta potentials was found. Atomic force microscopy pictures indicated the presence of disc-like particles. The crystallinity of SLNs, determined by differential scanning calorimetry and powder x-ray diffraction, was directly dependent on the ratio of cetyl palmitate to γ-oryzanol and decreased with decreasing cetyl palmitate content in the lipid matrix. Varying this ratio in the lipid mix resulted in a shift in the melting temperature and enthalpy, although the SLN structure remained unchanged as an orthorhombic lamellar lattice. This has been attributed to a potential inhibition by γ-oryzanol during lipid crystal growth as well as a less ordered structure of the SLNs. The results revealed that the crystallinity of the SLNs was mainly dependent on the solid lipid, and that the crystallinity has an important impact on the physical characteristics of active-loaded SLNs

  15. Formulation and characterization of hydrophilic drug diclofenac sodium-loaded solid lipid nanoparticles based on phospholipid complexes technology.

    Science.gov (United States)

    Liu, Dongfei; Chen, Li; Jiang, Sunmin; Zhu, Shuning; Qian, Yong; Wang, Fengzhen; Li, Rui; Xu, Qunwei

    2014-03-01

    To successfully prepare the diclofenac sodium (DS)-loaded solid lipid nanoparticles (SLNs), phospholipid complexes (PCs) technology was applied here to improve the liposolubility of DS. Solid lipid nanoparticles (SLNs) loaded with phospholipid complexes (PCs) were prepared by the modified emulsion/solvent evaporation method. DS could be solubilized effectively in the organic solvents with the existence of phospholipid and apparent partition coefficient of DS in PCs increased significantly. X-ray diffraction analysis suggested that DS in PCs was either molecularly dispersed or in an amorphous form. However, no significant difference was observed between the Fourier transform infrared spectroscopy (FT-IR) spectra of physical mixture and that of PCs. Particles with small sizes, narrow polydispersity indexes and high entrapment efficiencies could be obtained with the addition of PCs. Furthermore, according to the transmission electron microscopy, a core-shell structure was likely to be formed. The presence of PCs caused the change of zeta potential and retarded the drug release of SLNs, which indicated that phospholipid formed multilayers around the solid lipid core of SLNs. Both FT-IR and differential scanning calorimetry analysis also illustrated that some weak interactions between DS and lipid materials might take place during the preparation of SLNs. In conclusion, the model hydrophilic drug-DS can be formulated into the SLNs with the help of PCs.

  16. Development and optimization of solid lipid nanoparticle formulation for ophthalmic delivery of chloramphenicol using a Box-Behnken design

    Science.gov (United States)

    Hao, Jifu; Fang, Xinsheng; Zhou, Yanfang; Wang, Jianzhu; Guo, Fengguang; Li, Fei; Peng, Xinsheng

    2011-01-01

    The purpose of the present study was to optimize a solid lipid nanoparticle (SLN) of chloramphenicol by investigating the relationship between design factors and experimental data using response surface methodology. A Box-Behnken design was constructed using solid lipid (X1), surfactant (X2), and drug/lipid ratio (X3) level as independent factors. SLN was successfully prepared by a modified method of melt-emulsion ultrasonication and low temperature-solidification technique using glyceryl monostearate as the solid lipid, and poloxamer 188 as the surfactant. The dependent variables were entrapment efficiency (EE), drug loading (DL), and turbidity. Properties of SLN such as the morphology, particle size, zeta potential, EE, DL, and drug release behavior were investigated, respectively. As a result, the nanoparticle designed showed nearly spherical particles with a mean particle size of 248 nm. The polydispersity index of particle size was 0.277 ± 0.058 and zeta potential was −8.74 mV. The EE (%) and DL (%) could reach up to 83.29% ± 1.23% and 10.11% ± 2.02%, respectively. In vitro release studies showed a burst release at the initial stage followed by a prolonged release of chloramphenicol from SLN up to 48 hours. The release kinetics of the optimized formulation best fitted the Peppas–Korsmeyer model. These results indicated that the chloramphenicol-loaded SLN could potentially be exploited as a delivery system with improved drug entrapment efficiency and controlled drug release. PMID:21556343

  17. Orodispersible tablets containing taste-masked solid lipid pellets with metformin hydrochloride: Influence of process parameters on tablet properties.

    Science.gov (United States)

    Petrovick, Gustavo Freire; Kleinebudde, Peter; Breitkreutz, Jörg

    2018-01-01

    Compaction of multiparticulates into tablets, particularly into orodispersible tablets (ODTs), is challenging. The compression of pellets, made by solid lipid extrusion/spheronization processes, presents peculiar difficulties since solid lipids usually soften or melt at relatively low temperature ranges and due to applied mechanical forces. Until now, there are no reports in literature about the development of ODTs based on solid lipid pellets. To investigate the feasibility of producing such tablets, a design of experiment (DoE) approach was performed to elucidate the influence of compression force and amount of two co-processed excipients (Ludiflash ® and Parteck ® ODT) on properties of the tablets (friability, tensile strength, and disintegration time). ODTs (15 mm, flat-faced) with solid lipid pellets (250-1000 µm in diameter) containing 500 mg of metformin HCl, presenting immediate drug release profile and taste-masked properties, were targeted. During compression, a strong lamination of the tablets containing Parteck ® ODT was observed. This phenomenon was prominently observed when high compression forces (≥5 kN) and high excipient amounts (≥40%; w/w) were used. On the other hand, the DoE focused on tablets with Ludiflash ® showed better results regarding the production of ODTs. A positive influence of the compression force on the tensile strength and disintegration time of the tablets, regarding specifications of the Ph. Eur., was observed. The increase in the amount of this excipient resulted in fast disintegrating tablets, however, a negative influence on the tensile strength was noticed. After optimization of the parameters and formulation, based on the DoE results and considering the Ph. Eur. specifications for tablets, ODTs based on lipid pellets containing metformin HCl presenting immediate release profile (85% drug release in less than 30 min) and taste-masked properties (determined by an electronic tongue) were successfully

  18. Two-Phase Contiguous Supported Lipid Bilayer Model for Membrane Rafts via Polymer Blotting and Stenciling.

    Science.gov (United States)

    Richards, Mark J; Daniel, Susan

    2017-02-07

    The supported lipid bilayer has been portrayed as a useful model of the cell membrane compatible with many biophysical tools and techniques that demonstrate its appeal in learning about the basic features of the plasma membrane. However, some of its potential has yet to be realized, particularly in the area of bilayer patterning and phase/composition heterogeneity. In this work, we generate contiguous bilayer patterns as a model system that captures the general features of membrane domains and lipid rafts. Micropatterned polymer templates of two types are investigated for generating patterned bilayer formation: polymer blotting and polymer lift-off stenciling. While these approaches have been used previously to create bilayer arrays by corralling bilayers patches with various types of boundaries impenetrable to bilayer diffusion, unique to the methods presented here, there are no physical barriers to diffusion. In this work, interfaces between contiguous lipid phases define the pattern shapes, with continuity between them allowing transfer of membrane-bound biomolecules between the phases. We examine effectors of membrane domain stability including temperature and cholesterol content to investigate domain dynamics. Contiguous patterning of supported bilayers as a model of lipid rafts expands the application of the SLB to an area with current appeal and brings with it a useful toolset for characterization and analysis. These combined tools should be helpful to researchers investigating lipid raft dynamics and function and biomolecule partitioning studies. Additionally, this patterning technique may be useful for applications such as bioseparations that exploit differences in lipid phase partitioning or creation of membranes that bind species like viruses preferentially at lipid phase boundaries, to name a few.

  19. Regulation of adhesion behavior of murine macrophage using supported lipid membranes displaying tunable mannose domains

    International Nuclear Information System (INIS)

    Kaindl, T; Oelke, J; Kaufmann, S; Tanaka, M; Pasc, A; Konovalov, O V; Funari, S S; Engel, U; Wixforth, A

    2010-01-01

    Highly uniform, strongly correlated domains of synthetically designed lipids can be incorporated into supported lipid membranes. The systematic characterization of membranes displaying a variety of domains revealed that the equilibrium size of domains significantly depends on the length of fluorocarbon chains, which can be quantitatively interpreted within the framework of an equivalent dipole model. A mono-dispersive, narrow size distribution of the domains enables us to treat the inter-domain correlations as two-dimensional colloidal crystallization and calculate the potentials of mean force. The obtained results demonstrated that both size and inter-domain correlation can precisely be controlled by the molecular structures. By coupling α-D-mannose to lipid head groups, we studied the adhesion behavior of the murine macrophage (J774A.1) on supported membranes. Specific adhesion and spreading of macrophages showed a clear dependence on the density of functional lipids. The obtained results suggest that such synthetic lipid domains can be used as a defined platform to study how cells sense the size and distribution of functional molecules during adhesion and spreading.

  20. Chitosan-solid lipid nanoparticles as carriers for topical delivery of tretinoin.

    Science.gov (United States)

    Ridolfi, Daniela M; Marcato, Priscyla D; Justo, Giselle Z; Cordi, Lívia; Machado, Daisy; Durán, Nelson

    2012-05-01

    Tretinoin (TRE) or all-trans retinoic acid is employed in the topical treatment of various skin diseases including acne and psoriasis. However, its use is strongly limited by side effects and high chemical instability. TRE encapsulation in nanostructured systems reduces these problems. Chitosan is a biopolymer that exhibits a number of interesting properties such as bioadhesion and antibacterial activity. The aim of this work was to prepare and characterize solid lipid nanoparticles (SLN) containing TRE, with and without addition of chitosan, to assess their in vitro cytotoxicity in keratinocytes and to evaluate their antibacterial activity against bacteria related to acne. SLN without (SLN-TRE) and with (SLN-chitosan-TRE) chitosan were prepared by hot high pressure homogenization. The hydrodynamic mean diameter and zeta potential were 162.7±1.4 nm and -31.9±2.0 mV for SLN-TRE, and 284.8±15.0 nm and 55.9±3.1 mV for SLN-chitosan-TRE. The SLN-chitosan-TRE exhibited high encapsulation efficiency, high physical stability in the tested period (one year), were not cytotoxic to keratinocytes and showed high antibacterial activity against P. acnes and S. aureus. Therefore chitosan-SLN can be good candidates to encapsulate TRE and to increase its therapeutic efficacy in the topical treatment of acne. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Solid Lipid Nanoparticles: A Potential Multifunctional Approach towards Rheumatoid Arthritis Theranostics

    Directory of Open Access Journals (Sweden)

    João Albuquerque

    2015-06-01

    Full Text Available Rheumatoid arthritis (RA is the most common joint-related autoimmune disease and one of the most severe. Despite intensive investigation, the RA inflammatory process remains largely unknown and finding effective and long lasting therapies that specifically target RA is a challenging task. This study proposes a different approach for RA therapy, taking advantage of the new emerging field of nanomedicine to develop a targeted theranostic system for intravenous administration, using solid lipid nanoparticles (SLN, a biocompatible and biodegradable colloidal delivery system, surface-functionalized with an anti-CD64 antibody that specifically targets macrophages in RA. Methotrexate (MTX and superparamagnetic iron oxide nanoparticles (SPIONs were co-encapsulated inside the SLNs to be used as therapeutic and imaging agents, respectively. All the formulations presented sizes under 250 nm and zeta potential values lower than −16 mV, suitable characteristics for intravenous administration. Transmission electron microscopy (TEM photographs indicated that the SPIONs were encapsulated inside the SLN matrix and MTX association efficiency values were higher than 98%. In vitro studies, using THP-1 cells, demonstrated that all formulations presented low cytotoxicity at concentrations lower than 500 μg/mL. It was proven that the proposed NPs were not cytotoxic, that both a therapeutic and imaging agent could be co-encapsulated and that the SLN could be functionalized for a potential future application such as anti-body specific targeting. The proposed formulations are, therefore, promising candidates for future theranostic applications.

  2. Solid lipid nanoparticles as oral delivery systems of phenolic compounds: Overcoming pharmacokinetic limitations for nutraceutical applications.

    Science.gov (United States)

    Nunes, Sara; Madureira, Ana Raquel; Campos, Débora; Sarmento, Bruno; Gomes, Ana Maria; Pintado, Manuela; Reis, Flávio

    2017-06-13

    Drug delivery systems, accompanied by nanoparticle technology, have recently emerged as prominent solutions to improve the pharmacokinetic properties, namely bioavailability, of therapeutic and nutraceutical agents. Solid lipid nanoparticles (SLNs) have received much attention from researchers due to their potential to protect or improve drug properties. SLNs have been reported to be an alternative system to traditional carriers, such as emulsions, liposomes, and polymeric nanoparticles. Phenolic compounds are widespread in plant-derived foodstuffs and therefore abundant in our diet. Over the last decades, phenolic compounds have received considerable attention due to several health promoting properties, mostly related to their antioxidant activity, which can have important implications for health. However, most of these compounds have been associated with poor bioavailability being poorly absorbed, rapidly metabolized and eliminated, which compromises its biological and pharmacological benefits. This paper provides a systematic review of the use of SLNs as oral delivery systems of phenolic compounds, in order to overcome pharmacokinetic limitations of these compounds and improved nutraceutical potential. In vitro studies, as well as works describing topical and oral treatments will be revisited and discussed. The classification, synthesis, and clinical application of these nanomaterials will be also considered in this review article.

  3. Solid lipid nanoparticles loaded with edaravone for inner ear protection after noise exposure.

    Science.gov (United States)

    Gao, Gang; Liu, Ya; Zhou, Chang-Hua; Jiang, Ping; Sun, Jian-Jun

    2015-01-20

    Antioxidants and the duration of treatment after noise exposure on hearing recovery are important. We investigated the protective effects of an antioxidant substance, edaravone, and its slow-release dosage form, edaravone solid lipid nanoparticles (SLNs), in steady noise-exposed guinea pigs. SLNs loaded with edaravone were produced by an ultrasound technique. Edaravone solution or edaravone SLNs were administered by intratympanic or intravenous injection after the 1 st day of noise exposure. Guinea pigs were exposed to 110 dB sound pressure level (SPL) noise, centered at 0.25-4.0 kHz, for 4 days at 2 h/d. After noise exposure, the guinea pigs underwent auditory brainstem response (ABR) threshold measurements, reactive oxygen species (ROS) were detected in their cochleas with electron spin resonance (ESR), and outer hair cells (OHCs) were counted with silvernitrate (AgNO 3 ) staining at 1, 4, and 6 days. The ultrasound technique was able to prepare adequate edaravone SLNs with a mean particle size of 93.6 nm and entrapment efficiency of 76.7%. Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea. Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group. Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL).

  4. Formulation, characterization and pharmacokinetics of praziquantel-loaded hydrogenated castor oil solid lipid nanoparticles.

    Science.gov (United States)

    Xie, Shuyu; Pan, Baoliang; Wang, Ming; Zhu, Luyan; Wang, Fenghua; Dong, Zhao; Wang, Xiaofang; Zhou, WenZhong

    2010-07-01

    The purpose of this study was to formulate praziquantel (PZQ)-loaded hydrogenated castor oil (HCO) solid lipid nanoparticles (SLN) to enhance the bioavailability and prolong the systemic circulation of the drug. PZQ was encapsulated into HCO nanoparticles by a hot homogenization and ultrasonication method. The physicochemical characteristics of SLN were investigated by optical microscope, scanning electron microscopy and photon correlation spectroscopy. Pharmacokinetics were studied after oral, subcutaneous and intramuscular administration in mice. The diameter, polydispersivity index, zeta potential, encapsulation efficiency and loading capacity of the nanoparticles were 344.0 +/- 15.1 nm, 0.31 +/- 0.08, -16.7 +/- 0.5 mV, 62.17 +/- 6.53% and 12.43 +/- 1.31%, respectively. In vitro release of PZQ-loaded HCO-SLN exhibited an initial burst release followed by a sustained release. SLN increased the bioavailability of PZQ by 14.9-, 16.1- and 2.6-fold, and extended the mean residence time of the drug from 7.6, 6.6 and 8.2 to 95.9, 151.6 and 48.2 h after oral, subcutaneous and intramuscular administration, respectively. The PZQ-loaded HCO-SLN could be a promising formulation to enhance the pharmacological activity of PZQ.

  5. Sustained release biodegradable solid lipid microparticles: Formulation, evaluation and statistical optimization by response surface methodology

    Directory of Open Access Journals (Sweden)

    Hanif Muhammad

    2017-12-01

    Full Text Available For preparing nebivolol loaded solid lipid microparticles (SLMs by the solvent evaporation microencapsulation process from carnauba wax and glyceryl monostearate, central composite design was used to study the impact of independent variables on yield (Y1, entrapment efficiency (Y2 and drug release (Y3. SLMs having a 10-40 μm size range, with good rheological behavior and spherical smooth surfaces, were produced. Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry pointed to compatibility between formulation components and the zeta-potential study confirmed better stability due to the presence of negative charge (-20 to -40 mV. The obtained outcomes for Y1 (29-86 %, Y2 (45-83 % and Y3 (49-86 % were analyzed by polynomial equations and the suggested quadratic model were validated. Nebivolol release from SLMs at pH 1.2 and 6.8 was significantly (p 0.85 value (Korsmeyer- Peppas suggested slow erosion along with diffusion. The optimized SLMs have the potential to improve nebivolol oral bioavailability.

  6. Sustained release biodegradable solid lipid microparticles: Formulation, evaluation and statistical optimization by response surface methodology.

    Science.gov (United States)

    Hanif, Muhammad; Khan, Hafeez Ullah; Afzal, Samina; Mahmood, Asif; Maheen, Safirah; Afzal, Khurram; Iqbal, Nabila; Andleeb, Mehwish; Abbas, Nazar

    2017-12-20

    For preparing nebivolol loaded solid lipid microparticles (SLMs) by the solvent evaporation microencapsulation process from carnauba wax and glyceryl monostearate, central composite design was used to study the impact of independent variables on yield (Y1), entrapment efficiency (Y2) and drug release (Y3). SLMs having a 10-40 μm size range, with good rheological behavior and spherical smooth surfaces, were produced. Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry pointed to compatibility between formulation components and the zeta-potential study confirmed better stability due to the presence of negative charge (-20 to -40 mV). The obtained outcomes for Y1 (29-86 %), Y2 (45-83 %) and Y3 (49-86 %) were analyzed by polynomial equations and the suggested quadratic model were validated. Nebivolol release from SLMs at pH 1.2 and 6.8 was significantly (p 0.85 value (Korsmeyer- Peppas) suggested slow erosion along with diffusion. The optimized SLMs have the potential to improve nebivolol oral bioavailability.

  7. Myricetin solid lipid nanoparticles: Stability assurance from system preparation to site of action.

    Science.gov (United States)

    Gaber, Dina M; Nafee, Noha; Abdallah, Osama Y

    2017-11-15

    Myricetin - a natural flavonoid - has attracted a great interest due to its antioxidant and free-radical scavenging potential. However, its physicochemical instability critically impairs its dosage form design, evaluation and administration. In an attempt to protect from degradation, MYR was encapsulated into Gelucire-based solid lipid nanoparticles (SLNs). The impact of medium pH, processing temperature and different additives on the drug degradation either in free or nanoencapsulated form was assessed. MYR stability was further monitored in essential biorelevant fluids. Investigations have led to the recommendation that the presence of fat-soluble antioxidant is necessary during SLN preparation to protect the drug at high temperature. Meanwhile, physiological buffers as well as simulated fluids should be supplemented with stabilizers as tween 80 and Poloxamer 407, in addition to water-soluble antioxidant such as sodium sulfite. Interestingly, mucin-containing fluids are suggested to provide better protection to MYR, in contrast, cell culture media do not guarantee MYR stability. The degradation kinetics changed from 1st to 2nd order mechanism after MYR nanoencapsulation. In presence of the aforementioned additives, MYR-SLNs significantly reduced the drug degradation rate constant up to 300-folds and prolonged the half-life time up to 4500-folds compared to free MYR in physiological buffers (One-way ANOVA, p8h with no signs of degradation. The study emphasizes virtuous guidance regarding appropriate nanoencapsulation conditions and evaluation attributes ensuing MYR physicochemical stability. Copyright © 2017. Published by Elsevier B.V.

  8. Evaluating Cytotoxicity of Hyaluronate Targeted Solid Lipid Nanoparticles of Etoposide on SK-OV-3 Cells

    Directory of Open Access Journals (Sweden)

    Parviz Mohammadi Ghalaei

    2014-01-01

    Full Text Available The epithelial ovarian carcinoma is one of the most fatal gynecological cancers. Etoposide is used in treating platinum-resistant ovarian cancer. Sodium hyaluronate is a substance that binds to the CD44 receptors overexpressed in SK-OV-3 cells of epithelial ovarian carcinoma. The aim of the present work was to study the cytotoxicity effect of hyaluronate targeted solid lipid nanoparticles (SLNs of etoposide on SK-OV-3 cells. The cytotoxicity of the targeted and nontargeted SLNs of etoposide was compared to free drug on the SK-OV-3 cells by MTT assay method. The cellular uptake of the targeted and nontargeted nanoparticles containing sodium fluorescein was also studied. The difference of cell vitality between nontargeted nanoparticles and also targeted nanoparticles with free drug was significant. Targeted nanoparticles also caused more toxicity than nontargeted nanoparticles (P<0.05. After 4 hours of incubating, the fluorescence was remarkably higher in the cells treated by targeted SLNs rather than nontargeted ones, and there was no observable fluorescence in cells incubated with pure sodium fluorescein. Hyaluronate targeted SLNs containing etoposide increased the cytotoxicity of etoposide on SK-OV-3 cells which may be a worthwhile potential method for reducing the prescribed dose and systemic side effects of this drug in epithelial ovarian carcinoma.

  9. Polymeric and Solid Lipid Nanoparticles for Sustained Release of Carbendazim and Tebuconazole in Agricultural Applications

    Science.gov (United States)

    Campos, Estefânia Vangelie Ramos; Oliveira, Jhones Luiz De; da Silva, Camila Morais Gonçalves; Pascoli, Mônica; Pasquoto, Tatiane; Lima, Renata; Abhilash, P. C.; Fernandes Fraceto, Leonardo

    2015-09-01

    Carbendazim (MBC) (methyl-2-benzimidazole carbamate) and tebuconazole (TBZ) ((RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol) are widely used in agriculture for the prevention and control of fungal diseases. Solid lipid nanoparticles and polymeric nanocapsules are carrier systems that offer advantages including changes in the release profiles of bioactive compounds and their transfer to the site of action, reduced losses due to leaching or degradation, and decreased toxicity in the environment and humans. The objective of this study was to prepare these two types of nanoparticle as carrier systems for a combination of TBZ and MBC, and then investigate the release profiles of the fungicides as well as the stabilities and cytotoxicities of the formulations. Both nanoparticle systems presented high association efficiency (>99%), indicating good interaction between the fungicides and the nanoparticles. The release profiles of MBC and TBZ were modified when the compounds were loaded in the nanoparticles, and cytotoxicity assays showed that encapsulation of the fungicides decreased their toxicity. These fungicide systems offer new options for the treatment and prevention of fungal diseases in plants.

  10. Oridonin Loaded Solid Lipid Nanoparticles Enhanced Antitumor Activity in MCF-7 Cells

    Directory of Open Access Journals (Sweden)

    Lu Wang

    2014-01-01

    Full Text Available Oridonin (ORI, a famous diterpenoid from Chinese herbal medicine, has drawn rising attention for its remarkable apoptosis and autophagy-inducing activity in human cancer therapy, while clinical application of ORI is limited by its strong hydrophobicity and rapid plasma clearance. The purpose of this study was to evaluate whether the antitumor activity of ORI could be enhanced by loading into solid lipid nanoparticles (SLNs. ORI-loaded SLNs were prepared by hot high pressure homogenization with narrow size distribution and good entrapment efficacy. MTT assay indicated that ORI-loaded SLNs enhanced the inhibition of proliferation against several human cancer cell lines including breast cancer MCF-7 cells, hepatocellular carcinoma HepG 2 cells, and lung carcinoma A549 cells compared with free ORI, while no significant enhancement of toxicity to human mammary epithelial MCF-10A cells was shown. Meanwhile, flow cytometric analysis demonstrated that ORI-SLNs induced more significant cell cycle arrest at S and decreased cell cycle arrest at G1/G0 phase in MCF-7 cells than bulk ORI solution. Hoechst 33342 staining and Annexin V/PI assay indicated that apoptotic rates of cells treated with ORI-loaded SLNs were higher compared with free ORI. In summary, our data indicated that SLNs may be a potential carrier for enhancing the antitumor effect of hydrophobic drug ORI.

  11. Bevacizumab loaded solid lipid nanoparticles prepared by the coacervation technique: preliminary in vitro studies

    Science.gov (United States)

    Battaglia, Luigi; Gallarate, Marina; Peira, Elena; Chirio, Daniela; Solazzi, Ilaria; Giordano, Susanna Marzia Adele; Gigliotti, Casimiro Luca; Riganti, Chiara; Dianzani, Chiara

    2015-06-01

    Glioblastoma, the most common primary brain tumor in adults, has an inauspicious prognosis, given that overcoming the blood-brain barrier is the major obstacle to the pharmacological treatment of brain tumors. As neoangiogenesis plays a key role in glioblastoma growth, the US Food and Drug Administration approved bevacizumab (BVZ), an antivascular endothelial growth factor antibody for the treatment of recurrent glioblastoma in patients whose the initial therapy has failed. In this experimental work, BVZ was entrapped in solid lipid nanoparticles (SLNs) prepared by the fatty-acid coacervation technique, thanks to the formation of a hydrophobic ion pair. BVZ activity, which was evaluated by means of four different in vitro tests on HUVEC cells, increased by 100- to 200-fold when delivered in SLNs. Moreover, SLNs can enhance the permeation of fluorescently labelled BVZ through an hCMEC/D3 cell monolayer—an in vitro model of the blood brain barrier. These results are promising, even if further in vivo studies are required to evaluate the effective potential of BVZ-loaded SLNs in glioblastoma treatment.

  12. Diclofenac sodium-loaded solid lipid nanoparticles prepared by emulsion/solvent evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Liu Dongfei; Jiang Sunmin [Nanjing Medical University, School of Pharmacy (China); Shen Hong [Nanjing Brain Hospital Affiliated to Nanjing Medical University, Neuro-Psychiatric Institute (China); Qin Shan; Liu Juanjuan; Zhang Qing; Li Rui, E-mail: chongloutougao@gmail.com; Xu Qunwei, E-mail: qunweixu@163.com [Nanjing Medical University, School of Pharmacy (China)

    2011-06-15

    The preparation of solid lipid nanoparticles (SLNs) suffers from the drawback of poor incorporation of water-soluble drugs. The aim of this study was therefore to assess various formulation and process parameters to enhance the incorporation of a water-soluble drug (diclofenac sodium, DS) into SLNs prepared by the emulsion/solvent evaporation method. Results showed that the entrapment efficiency (EE) of DS was increased to approximately 100% by lowering the pH of dispersed phase. The EE of DS-loaded SLNs (DS-SLNs) had been improved by the existence of cosurfactants and increment of PVA concentration. Stabilizers and their combination with PEG 400 in the dispersed phase also resulted in higher EE and drug loading (DL). EE increased and DL decreased as the phospholipid/DS ratio became greater, while the amount of DS had an opposite effect. Ethanol turned out to be the ideal solvent making DS-SLNs. EE and DL of DS-SLNs were not affected by either the stirring speed or the viscosity of aqueous and dispersed phase. According to the investigations, drug solubility in dispersion medium played the most important role in improving EE.

  13. On-Chip Electrophoresis in Supported Lipid Bilayer Membranes Achieved Using Low Potentials

    NARCIS (Netherlands)

    van Weerd, Jasper; Krabbenborg, Sven; Eijkel, Jan C.T.; Karperien, Hermanus Bernardus Johannes; Huskens, Jurriaan; Jonkheijm, Pascal

    2014-01-01

    A micro supported lipid bilayer (SLB) electrophoresis method was developed, which functions at low potentials and appreciable operating times. To this end, (hydroxymethyl)-ferrocene (FcCH2OH) was employed to provide an electrochemical reaction at the anode and cathode at low applied potential to

  14. Molecular Interaction of a New Antibacterial Polymer with a Supported Lipid Bilayer Measured by an in situ Label-Free Optical Technique

    Directory of Open Access Journals (Sweden)

    Robert Horvath

    2013-05-01

    Full Text Available The interaction of the antibacterial polymer–branched poly(ethylene imine substituted with quaternary ammonium groups, PEO and alkyl chains, PEI25QI5J5A815–with a solid supported lipid bilayer was investigated using surface sensitive optical waveguide spectroscopy. The analysis of the optogeometrical parameters was extended developing a new composite layer model in which the structural and optical anisotropy of the molecular layers was taken into consideration. Following in situ the change of optical birefringence we were able to determine the composition of the lipid/polymer surface layer as well as the displacement of lipid bilayer by the antibacterial polymer without using additional labeling. Comparative assessment of the data of layer thickness and optical anisotropy helps to reveal the molecular mechanism of antibacterial effect of the polymer investigated.

  15. Elasticity-based patterning of red blood cells on undulated lipid membranes supported on porous topographic substrates.

    Science.gov (United States)

    Lee, Sang-Wook; Jeong, Cherlhyun; Lee, Sin-Doo

    2009-03-26

    We describe elasticity-based patterning of human red blood cells (RBCs) into a microarray form on supported lipid membranes (SLMs) prepared on a solid substrate having two types of topographic patterns, porous and flat regions. The underlying concept is to precisely control the interplay between adhesion and the bending rigidity of the RBCs that interact with the SLMs. Attachment of the RBCs on highly undulated SLMs formed on the porous region is not energetically favorable, since membrane bending of the RBCs costs a high curvature elastic energy which exceeds adhesion. The RBCs are thus selectively confined within relatively flat regions of the SLMs without causing considerable elastic distortions. It was found that the population of the RBCs in a single corral is linearly proportional to the area of one element in our microarray.

  16. Solid lipid nanoparticles as promising tool for intraocular tobramycin delivery: Pharmacokinetic studies on rabbits.

    Science.gov (United States)

    Chetoni, Patrizia; Burgalassi, Susi; Monti, Daniela; Tampucci, Silvia; Tullio, Vivian; Cuffini, Anna Maria; Muntoni, Elisabetta; Spagnolo, Rita; Zara, Gian Paolo; Cavalli, Roberta

    2016-12-01

    Eye drops are widely accepted as formulations for targeting the anterior segment notwithstanding their limitations in terms of bioavailability. The unique structure of the eye requires specially-designed formulations able to favor the pharmacokinetic profile of administered drugs, mainly minimizing the influence of ocular barriers. Nanotechnology-based delivery systems lead to significant technological and therapeutical advantages in ophthalmic therapy. The aim of the present study was to determine whether tobramycin as ion-pair incorporated in mucoadhesive Solid Lipid Nanoparticles (SLN) reaches the inner parts of the eye favoring drug activity. After technological characterization of the tobramycin entrapped SLN formulation (Tobra-SLN), a pharmacokinetic study in rabbits after topical instillation and intravenous administration of the formulation has been carried out. In addition, the intracellular activity of Tobra-SLN formulation against phagocytosed Pseudomonas aeruginosa was investigated. The SLN were spherical in shape, and showed a hydrodynamic diameter of about 80nm, a negative zeta potential (-25.7mV) with a polydispersity index of 0.15, representative of a colloidal dispersion with high quality, characterized by an unimodal relatively narrow size distribution. As demonstrated by FTIR and DSC, tobramycin ion-pair could be concentrated into lipid inner core of SLN, without interaction with the stearic acid, thus promoting a slow and constant drug release profile in the dissolution medium. Surprisingly, the drug concentration was significantly higher in all ocular tissues after ocular and intravenous administration of Tobra-SLN formulation with respect to reference formulations and only Tobra-SLN allowed the penetration of drug into retina. Furthermore, the use of Tobra-SLN resulted in both higher intraphagocytic antibiotic concentrations in polymorphonuclear granulocytes and greater bactericidal activity against intracellular Pseudomonas aeruginosa

  17. Functional liposomes and supported lipid bilayers: towards the complexity of biological archetypes.

    Science.gov (United States)

    Berti, Debora; Caminati, Gabriella; Baglioni, Piero

    2011-05-21

    This perspective paper provides some illustrative examples on the interplay between information gathered on planar supported lipid bilayers (SLB) and unilamellar lipid vesicles (ULV) to get an integrated description of phenomena occurring at the nanoscale that involve locally bilayered structures. Similarities and differences are underlined and critically compared in terms of biomimetic fidelity and instrumental accessibility to structural and dynamical parameters, focusing on some recent reports that either explicitly address this comparison or introducing some studies that separately investigate the same process in SLB and lipid vesicles. Despite the structural similarity on the nanoscale, the different topology implies radically different characterization techniques that have evolved in sectorial and separated approaches. The quest for increasing levels of compositional complexity for bilayered systems should not result in a loss of structural and dynamical control: this is the central challenge of future research in this area, where the integrated approach highlighted in this contribution would enable improved levels of understanding. © The Owner Societies 2011

  18. Evaluation of radiolabeled curcumin-loaded solid lipid nanoparticles usage as an imaging agent in liver-spleen scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Ayan, Arif Kursad [Department of Nuclear Medicine, Ataturk University, 25240 Erzurum (Turkey); Yenilmez, Ayse, E-mail: yenilmez2014@gmail.com [Department of Nanoscience and Nanoengineering, Ataturk University, 25240 Erzurum (Turkey); Department of Molecular Biology and Genetics, Erzurum Technical University, 25240 Erzurum (Turkey); Eroglu, Hayrettin [Department of Biomedical Engineering, Ataturk University, 25240 Erzurum (Turkey)

    2017-06-01

    Curcumin-loaded solid lipid nanoparticles (C-SLNs) were prepared using micro emulsion and ultrasonication methods in the first stage of this study to determine the role of C-SLN on liver-spleen scintigraphy. It was concluded that the curcumin that was encapsulated in solid lipid nanoparticles had a β′ polymorph structure according to the X-ray diffraction (XRD) analysis. İt was concluded that these particles were at nano scale according to the laser diffraction (LD) analysis. Fourier transform infrared spectroscopy (FT-IR) analysis suggested an interaction between the curcumin and the solid lipid matrix, and the curcumin was loaded on the solid lipid nanoparticles. Moreover, the particles were concluded to be spherical and at nanoscale according to the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. On the other hand, thermogravimetric analysis (TGA) suggested that the curcumin loaded solid nanoparticles were stable against the temperature. C-SLNs were labeled with Technetium-99 m ({sup 99m}Tc) radioisotope in the second stage of the study, then using scintigraphic methods in-vivo studies were performed on New Zealand rabbit and made a comparison with Phytate colloid, routinely used in liver-spleen scintigraphy. After analyzing the images and the biological distributions obtained from the experiments, uptake was observed in the liver and the spleen. Following from the experiment results, {sup 99m}Tc-labeled C-SLNs was concluded to be a possible imaging agent. In particular, it could be a new radiopharmaceutical alternative to {sup 99m}Tc-labeled compounds that are used in liver and spleen imaging in colloid scintigraphy. - Graphıcal abstract: Display Omitted - Hıghlıghts: • Curcumin-loaded solid lipid nanoparticles (C-SLNs) were prepared and examined characterization studies. • The C-SLNs were labeled with {sup 99m}Tc and made a comparison with Phytate colloid, routinely used in liver-spleen scintigraphy. • In vivo

  19. Failure analysis of electrolyte-supported solid oxide fuel cells

    Science.gov (United States)

    Fleischhauer, Felix; Tiefenauer, Andreas; Graule, Thomas; Danzer, Robert; Mai, Andreas; Kuebler, Jakob

    2014-07-01

    For solid oxide fuel cells (SOFCs) one key aspect is the structural integrity of the cell and hence its thermo mechanical long term behaviour. The present study investigates the failure mechanisms and the actual causes for fracture of electrolyte supported SOFCs which were run using the current μ-CHP system of Hexis AG, Winterthur - Switzerland under lab conditions or at customer sites for up to 40,000 h. In a first step several operated stacks were demounted for post-mortem inspection, followed by a fractographic evaluation of the failed cells. The respective findings are then set into a larger picture including an analysis of the present stresses acting on the cell like thermal and residual stresses and the measurements regarding the temperature dependent electrolyte strength. For all investigated stacks, the mechanical failure of individual cells can be attributed to locally acting bending loads, which rise due to an inhomogeneous and uneven contact between the metallic interconnect and the cell.

  20. Development of seismic support snubber using solid lubricant

    International Nuclear Information System (INIS)

    Sunakoda, Katsuaki; Akimoto, Kohichi; Uchi, Toshiyasu

    1990-01-01

    Solid lubricant MoS 2 films deposited by radio-frequency sputtering and a new physical process were applied to bearings and ball screws used in seismic support mechanical snubbers. The lubricity of MoS 2 films was maintained throughout 720 hours of exposure at a temperature of 200 degC. The endurance life of MoS 2 films using both radio-frequency sputtering and a new physical process was investigated by subjecting the mechanical snubber to a drag force test. Cumulative drag length reached 100 meters and 400 meters, respectively, for the two methods. The dynamic characteristics and durability of mechanical snubbers in an abnormal environment were also investigated. (author)

  1. Solid Lipid Particles for Oral Delivery of Peptide and Protein Drugs II - The Digestion of Trilaurin Protects Desmopressin from Proteolytic Degradation

    DEFF Research Database (Denmark)

    Christophersen, Philip Carsten; Zhang, Long; Müllertz, Anette

    2014-01-01

    , which is the same rank order as the lipid degradation rate. A reverse rank order was found for the protection of desmopressin from enzymatic degradation due to spatial separation of desmopressin from the protease. TG12 accelerated the release of desmopressin from all lipid particles when added as either...... and protease was determined. Trilaurin (TG12), trimyristin (TG14), tripalmitin (TG16), and tristearin (TG18) were used as lipid excipients to produce solid lipid microparticles. RESULTS: In the presence of lipase, the rate of drug release from different lipid particles was in the order of TG14 > TG16 > TG18...... drug-free microparticles to the lipolysis medium or incorporated in TG16 particles. Additionally, TG12 particles protected desmopressin from degradation when present in the lipolysis medium with the other lipid microparticles. CONCLUSIONS: TG12 is a very interesting lipid for oral lipid formulations...

  2. Analysis of Solid and Aqueous Phase Products from Hydrothermal Carbonization of Whole and Lipid-Extracted Algae

    Directory of Open Access Journals (Sweden)

    Amber Broch

    2013-12-01

    Full Text Available Microalgae have tremendous potential as a feedstock for production of liquid biofuels, particularly biodiesel fuel via transesterification of algal lipids. However, biodiesel production results in significant amounts of algal residues, or “lipid extracted algae” (LEA. Suitable utilization of the LEA residue will improve the economics of algal biodiesel. In the present study, we evaluate the hydrothermal carbonization (HTC of whole and lipid extracted algal (Spirulina maxima feedstocks in order to produce a solid biofuel (hydrochar and value-added co-products in the aqueous phase. HTC experiments were performed using a 2-L Parr reactor (batch type at 175–215 °C with a 30-min holding time. Solid, aqueous and gaseous products were analyzed using various laboratory methods to evaluate the mass and carbon balances, and investigate the existence of high value chemicals in the aqueous phase. The HTC method is effective in creating an energy dense, solid hydrochar from both whole algae and LEA at lower temperatures as compared to lignocellulosic feedstocks, and is effective at reducing the ash content in the resulting hydrochar. However, under the treatment temperatures investigated, less than 1% of the starting dry algae mass was recovered as an identified high-value chemical in the aqueous phase.

  3. Alendronate Sodium as Enteric Coated Solid Lipid Nanoparticles; Preparation, Optimization, and In Vivo Evaluation to Enhance Its Oral Bioavailability.

    Directory of Open Access Journals (Sweden)

    Khaled Mohamed Hosny

    Full Text Available Treatment of osteoporosis with alendronate sodium has several challenges. The first challenge is the low bioavailability. The second main challenge is side effects, which include oesophageal ulceration. The aim of this research was to reformulate alendronate sodium as enteric coated solid lipid nanoparticles in order to enhance its bioavailability, and preventing the free alendronate sodium from coming into direct contact with the gastrointestinal mucosa, and thereby reducing the possibility of side effects. Enteric coated solid lipid nanoparticles were prepared according to the Box-Behnken design employing Design expert® software, and characterized for size, morphology, and entrapment efficiency. The optimized formula was coated with an Eudragit S100 and evaluated for drug release in acidic and basic media, stability studies and pharmacokinetic evaluations on rabbits. The results indicated that, using Derringer's desirability functional tool for optimization, the highest entrapment efficiency value of 74.3% and the smallest size value of 98 nm were predicted under optimum conditions with a desirability value of 0.917. The optimized nanoparticles released alendronate sodium only at an alkaline pH. The pharmacokinetic evaluation revealed that alendronate sodium bioavailability was enhanced by more than 7.4-fold in rabbits. In conclusion, enteric coated solid lipid nanoparticles is a promising formula for the delivery of alendronate sodium, eliminating its oesophageal side effects and enhancing its bioavailability.

  4. Solid Lipid Nanoparticles Loaded with Edaravone for Inner Ear Protection After Noise Exposure

    Directory of Open Access Journals (Sweden)

    Gang Gao

    2015-01-01

    Full Text Available Background: Antioxidants and the duration of treatment after noise exposure on hearing recovery are important. We investigated the protective effects of an antioxidant substance, edaravone, and its slow-release dosage form, edaravone solid lipid nanoparticles (SLNs, in steady noise-exposed guinea pigs. Methods: SLNs loaded with edaravone were produced by an ultrasound technique. Edaravone solution or edaravone SLNs were administered by intratympanic or intravenous injection after the 1 st day of noise exposure. Guinea pigs were exposed to 110 dB sound pressure level (SPL noise, centered at 0.25-4.0 kHz, for 4 days at 2 h/d. After noise exposure, the guinea pigs underwent auditory brainstem response (ABR threshold measurements, reactive oxygen species (ROS were detected in their cochleas with electron spin resonance (ESR, and outer hair cells (OHCs were counted with silvernitrate (AgNO 3 staining at 1, 4, and 6 days. Results: The ultrasound technique was able to prepare adequate edaravone SLNs with a mean particle size of 93.6 nm and entrapment efficiency of 76.7%. Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea. Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group. Conclusions: Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL.

  5. Optimization of methazolamide-loaded solid lipid nanoparticles for ophthalmic delivery using Box-Behnken design.

    Science.gov (United States)

    Wang, Fengzhen; Chen, Li; Jiang, Sunmin; He, Jun; Zhang, Xiumei; Peng, Jin; Xu, Qunwei; Li, Rui

    2014-09-01

    The purpose of the present study was to optimize methazolamide (MTZ)-loaded solid lipid nanoparticles (SLNs) which were used as topical eye drops by evaluating the relationship between design factors and experimental data. A three factor, three-level Box-Behnken design (BBD) was used for the optimization procedure, choosing the amount of GMS, the amount of phospholipid, the concentration of surfactant as the independent variables. The chosen dependent variables were entrapment efficiency, dosage loading, and particle size. The generated polynomial equations and response surface plots were used to relate the dependent and independent variables. The optimal nanoparticles were formulated with 100 mg GMS, 150 mg phospholipid, and 1% Tween80 and PEG 400 (1:1, w/v). A new formulation was prepared according to these levels. The observed responses were close to the predicted values of the optimized formulation. The particle size was 197.8 ± 4.9 nm. The polydispersity index of particle size was 0.239 ± 0.01 and the zeta potential was 32.7 ± 2.6 mV. The entrapment efficiency and dosage loading were about 68.39% and 2.49%, respectively. Fourier transform infrared spectroscopy (FT-IR) study indicated that the drug was entrapped in nanoparticles. The optimized formulation showed a sustained release followed the Peppas model. MTZ-SLNs showed significant prolonged decreasing intraocular pressure effect comparing with MTZ solution in vivo pharmacodynamics studies. The results of acute eye irritation study indicated that MTZ-SLNs and AZOPT both had no eye irritation. Furthermore, the MTZ-SLNs were suitable to be stored at low temperature (4 °C).

  6. Curcumin loaded solid lipid nanoparticles ameliorate adjuvant-induced arthritis in rats.

    Science.gov (United States)

    Arora, R; Kuhad, A; Kaur, I P; Chopra, K

    2015-08-01

    Rheumatoid arthritis (RA), a chronic and systemic inflammation, results in destruction of joints and cartilages. Effectiveness of curcumin has been established in a wide variety of inflammatory disorders, but its utility as a therapeutic agent is limited by its poor absorption, rapid metabolism and fast systemic elimination. To apprehend these limitations, we propose to use highly bioavailable curcumin loaded solid lipid nanoparticles (C-SLNs) for the treatment of RA. In the present study, the protective effect of curcumin and its SLNs was evaluated in complete Freund's adjuvant (CFA)-induced arthritis in rats. Arthritic rats exhibited marked decrease in paw withdrawal threshold in Randall-Selitto and von Frey hair test along with decreased reaction time in hot plate. Arthritic rats also showed significant joint hyperalgesia, joint stiffness and increased paw volume along with marked decrease in mobility score. Arthritic rats showed a significant increase in blood leukocyte count, oxidative-nitrosative stress, tumour necrosis factor-α, C-reactive protein, cyclic citrullinated peptide antibody levels and radiological alterations in tibiotarsal joint. C-SLN administration (10 and 30 mg/kg), when compared with free curcumin (10 and 30 mg/kg), significantly and dose dependently ameliorated various symptoms of arthritis in rats, improved biochemical markers and preserved radiological alterations in joints of arthritic rats. The current findings suggest the protective potential of curcumin-SLNs in ameliorating CFA-induced arthritis in rats through attenuation of oxido-inflammatory and immunomodulatory cascade. Further, the results emphasize that SLNs are a novel approach to deliver curcumin into the inflamed joints and improve its biopharmaceutical performance. © 2014 European Pain Federation - EFIC®

  7. Potential and limitations of S-layers as support for planar lipid bilayers

    International Nuclear Information System (INIS)

    Kiene, E.

    2011-01-01

    A huge step in the development of life was most certainly the formation of lipid membranes and the resulting possibility for generating confined volumes, structurally discrete from the environment. Yet, communication had to be maintained with the outside world, so these membrane borders were populated with functional units, like membrane receptors and transporters, enabling the exchange of material, energy and information. Therefore, from a scientific point of view, the requirement for analysis platforms for membrane proteins incorporated into model membrane scaffolds emerged. The membrane systems hosting arbitrary membrane proteins are desired to unite the features of stability and fluidity and to provide a quasi natural environment for the membrane proteins in order to maintain their structure and function. In the current state of the art there are hardly any relevant fluid membrane models, which is why in this project a prokaryotic protein-lipid architecture was mimicked as a promising supportive system for biological membranes. A large number of bacteria and archaea envelope their outer cell membrane with a proteinaceous lattice, the so-called surface- or S-layer. The present work deals with S-layer protein lattices as a support for anchored lipid bilayers. S-layer proteins show the intrinsic ability to self-assemble into periodically structured, two-dimensional patterns with a porous character. Genetic or chemical modification of the proteinaceous crystal layers can provide regularly spread binding moieties for functionalised lipids as components of a lipid membrane. In this project, a wildtype S-layer (SbpA from L. sphaericus exhibiting p4 lattice symmetry) was chemically activated to provide anchors for amino-functionalised lipids; and in a genetic approach a recombinant, HIS-tagged derivative was used for attracting Ni-functionalised lipids. The latter method seemed a more elegant way of lipid binding, since the anchoring regions were more regularly spread

  8. Study of ion separation through solid-supported liquid membrane

    International Nuclear Information System (INIS)

    Kang, Young Ho; Kim, Jung Do; Kim, Kyoung Ho

    1990-01-01

    The membranes used in this study consist of a microporous polymeric support with the solvent contraining alamine 336, Tri-N-Octyl phosphine oxide, Tri-N-butyl phosphate, Di-(2-ethylhexyl) phosphoric acid as a carrier within the pores by the capillary forces. When this liquid membrane is interposed between aqueous feed and product solutions, the carrier serving as a complexing agent, can pick up the uranium ions on the feed side of the membrane and carry them across the membrane by diffusion. In this study, the uranium flux through the solid-supported liquid membrane was analyzed as a function of carrier concentration and acidity of the feed solution for the carrier species. Also, the Gel-liquid extraction of uranium ions from aqueous solution was performed. The adsorbents were prepared by casting the polymer solution composed of polyvinyl chloride, TOPO, and additions. The extraction of uranyl nitrate ions has been investigated as a function of TOPO/PVC ratio, evaporation time, and the stability. The results show that is maybe possible to develop an alternative uranium purification process. (author)

  9. Functional reconstitution of rhodopsin into tubular lipid bilayers supported by nanoporous media.

    Science.gov (United States)

    Soubias, Olivier; Polozov, Ivan V; Teague, Walter E; Yeliseev, Alexei A; Gawrisch, Klaus

    2006-12-26

    We report on a novel reconstitution method for G-protein-coupled receptors (GPCRs) that yields detergent-free, single, tubular membranes in porous anodic aluminum oxide (AAO) filters at concentrations sufficient for structural studies by solid-state NMR. The tubular membranes line the inner surface of pores that traverse the filters, permitting easy removal of detergents during sample preparation as well as delivery of ligands for functional studies. Reconstitution of bovine rhodopsin into AAO filters did not interfere with rhodopsin function. Photoactivation of rhodopsin in AAO pores, monitored by UV-vis spectrophotometry, was indistinguishable from rhodopsin in unsupported unilamellar liposomes. The rhodopsin in AAO pores is G-protein binding competent as shown by a [35S]GTPgammaS binding assay. The lipid-rhodopsin interaction was investigated by 2H NMR on sn-1- or sn-2-chain perdeuterated 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phospholine as a matrix lipid. Rhodopsin incorporation increased mosaic spread of bilayer orientations and contributed to spectral density of motions with correlation times in the range of nano- to microseconds, detected as a significant reduction in spin-spin relaxation times. The change in lipid chain order parameters due to interaction with rhodopsin was insignificant.

  10. Evaluation of percutaneous absorption of the repellent diethyltoluamide and the sunscreen ethylhexyl p-methoxycinnamate-loaded solid lipid nanoparticles: an in-vitro study.

    Science.gov (United States)

    Puglia, Carmelo; Bonina, Francesco; Castelli, Francesco; Micieli, Dorotea; Sarpietro, Maria Grazia

    2009-08-01

    Diethyltoluamide and ethylhexyl p-methoxycinnamate (OMC) are two active ingredients in insect repellent and sunscreen products, respectively. The concurrent application of these two substances often increases their systemic absorption, compromising the safety and efficiency of the cosmetic product. In this study, diethyltoluamide and OMC were incorporated into solid lipid nanoparticles, a colloidal drug delivery system, to reduce percutaneous absorption and avoid toxic effects and also maintain the efficacy of the two active compounds on the skin surface for a long duration. Solid lipid nanoparticles were prepared based on an ultrasonication technique and characterized by differential scanning calorimetry (DSC) analyses. In-vitro studies determined the percutaneous absorption of diethyltoluamide and OMC. DSC data carried out on unloaded and diethyltoluamide- and/or OMC-loaded solid lipid nanoparticles highlighted that diethyltoluamide and OMC modified the temperature and the enthalpy change associated to the calorimetric peak of solid lipid nanoparticles. The concurrent presence of the two compounds in the solid lipid nanoparticles caused a synergic effect, indicating that the lipid matrix of nanoparticles guaranteed a high encapsulation of both diethyltoluamide and OMC. Results from the in-vitro study demonstrated that the particles were able to reduce the skin permeation of the two cosmetic ingredients in comparison with an oil-in-water emulsion. This study has provided supplementary evidence as to the potential of lipid nanoparticles as carriers for topical administration of cosmetic active compounds.

  11. Impact of monoolein on aquaporin1-based supported lipid bilayer membranes

    International Nuclear Information System (INIS)

    Wang, Zhining; Wang, Xida; Ding, Wande; Wang, Miaoqi; Gao, Congjie; Qi, Xin

    2015-01-01

    Aquaporin (AQP) based biomimetic membranes have attracted considerable attention for their potential water purification applications. In this paper, AQP1 incorporated biomimetic membranes were prepared and characterized. The morphology and structure of the biomimetic membranes were characterized by in situ atomic force microscopy (AFM), infrared absorption spectroscopy, fluorescence microscopy, and contact angle measurements. The nanofiltration performance of the AQP1 incorporated membranes was investigated at 4 bar by using 2 g l −1 NaCl as feed solution. Lipid mobility plays an important role in the performance of the AQP1 incorporated supported lipid bilayer (SLB) membranes. We demonstrated that the lipid mobility is successfully tuned by the addition of monoolein (MO). Through in situ AFM and fluorescence recovery after photo-bleaching (FRAP) measurements, the membrane morphology and the molecular mobility were studied. The lipid mobility increased in the sequence DPPC < DPPC/MO (R MO = 5/5) < DOPC/MO (R MO = 5/5) < DOPC, which is consistent with the flux increment and salt rejection. This study may provide some useful insights for improving the water purification performance of biomimetic membranes. (paper)

  12. SFG studies on interactions between antimicrobial peptides and supported lipid bilayers.

    Science.gov (United States)

    Chen, Xiaoyun; Chen, Zhan

    2006-09-01

    The mode of action of antimicrobial peptides (AMPs) in disrupting cell membrane bilayers is of fundamental importance in understanding the efficiency of different AMPs, which is crucial to design antibiotics with improved properties. Recent developments in the field of sum frequency generation (SFG) vibrational spectroscopy have made it a powerful and unique biophysical technique in investigating the interactions between AMPs and a single substrate supported planar lipid bilayer. We will review some of the recent progress in applying SFG to study membrane lipid bilayers and discuss how SFG can provide novel information such as real-time bilayer structure change and AMP orientation during AMP-lipid bilayer interactions in a very biologically relevant manner. Several examples of applying SFG to monitor such interactions between AMPs and a dipalmitoyl phosphatidylglycerol (DPPG) bilayer are presented. Different modes of actions are observed for melittin, tachyplesin I, d-magainin 2, MSI-843, and a synthetic antibacterial oligomer, demonstrating that SFG is very effective in the study of AMPs and AMP-lipid bilayer interactions.

  13. Study of the solid-solid surface adsorption of Eu2O3 on various Al2O3 supports

    International Nuclear Information System (INIS)

    Liu Rongchuan; Yu Zhi; Zhou Yuan; Yoshitake Yamazaki

    1997-12-01

    Solid-solid surface interactions of Eu 2 O 3 on various oxide substrates are investigated with X-ray and Moessbauer experiments. The results indicate that the interaction of Eu 2 O 3 on the complex support differs from that having simple support. An incorporation model is used to explain how Eu 2 O 3 disperses onto the surface of γ-alumina or η-alumina

  14. Recent advances in oral delivery of drugs and bioactive natural products using solid lipid nanoparticles as the carriers.

    Science.gov (United States)

    Lin, Chih-Hung; Chen, Chun-Han; Lin, Zih-Chan; Fang, Jia-You

    2017-04-01

    Chemical and enzymatic barriers in the gastrointestinal (GI) tract hamper the oral delivery of many labile drugs. The GI epithelium also contributes to poor permeability for numerous drugs. Drugs with poor aqueous solubility have difficulty dissolving in the GI tract, resulting in low bioavailability. Nanomedicine provides an opportunity to improve the delivery efficiency of orally administered drugs. Solid lipid nanoparticles (SLNs) are categorized as a new generation of lipid nanoparticles consisting of a complete solid lipid matrix. SLNs used for oral administration offer several benefits over conventional formulations, including increased solubility, enhanced stability, improved epithelium permeability and bioavailability, prolonged half-life, tissue targeting, and minimal side effects. The nontoxic excipients and sophisticated material engineering of SLNs tailor the controllable physicochemical properties of the nanoparticles for GI penetration via mucosal or lymphatic transport. In this review, we highlight the recent progress in the development of SLNs for disease treatment. Recent application of oral SLNs includes therapies for cancers, central nervous system-related disorders, cardiovascular-related diseases, infection, diabetes, and osteoporosis. In addition to drugs that may be active cargos in SLNs, some natural compounds with pharmacological activity are also suitable for SLN encapsulation to enhance oral bioavailability. In this article, we systematically introduce the concepts and amelioration mechanisms of the nanomedical techniques for drug- and natural compound-loaded SLNs. Copyright © 2017. Published by Elsevier B.V.

  15. Recent advances in oral delivery of drugs and bioactive natural products using solid lipid nanoparticles as the carriers

    Directory of Open Access Journals (Sweden)

    Chih-Hung Lin

    2017-04-01

    Full Text Available Chemical and enzymatic barriers in the gastrointestinal (GI tract hamper the oral delivery of many labile drugs. The GI epithelium also contributes to poor permeability for numerous drugs. Drugs with poor aqueous solubility have difficulty dissolving in the GI tract, resulting in low bioavailability. Nanomedicine provides an opportunity to improve the delivery efficiency of orally administered drugs. Solid lipid nanoparticles (SLNs are categorized as a new generation of lipid nanoparticles consisting of a complete solid lipid matrix. SLNs used for oral administration offer several benefits over conventional formulations, including increased solubility, enhanced stability, improved epithelium permeability and bioavailability, prolonged half-life, tissue targeting, and minimal side effects. The nontoxic excipients and sophisticated material engineering of SLNs tailor the controllable physicochemical properties of the nanoparticles for GI penetration via mucosal or lymphatic transport. In this review, we highlight the recent progress in the development of SLNs for disease treatment. Recent application of oral SLNs includes therapies for cancers, central nervous system-related disorders, cardiovascular-related diseases, infection, diabetes, and osteoporosis. In addition to drugs that may be active cargos in SLNs, some natural compounds with pharmacological activity are also suitable for SLN encapsulation to enhance oral bioavailability. In this article, we systematically introduce the concepts and amelioration mechanisms of the nanomedical techniques for drug- and natural compound-loaded SLNs.

  16. Delivery of kinesin spindle protein targeting siRNA in solid lipid nanoparticles to cellular models of tumor vasculature

    International Nuclear Information System (INIS)

    Ying, Bo; Campbell, Robert B.

    2014-01-01

    Highlights: • siRNA-lipid nanoparticles are solid particles not lipid bilayers with aqueous core. • High, but not low, PEG content can prevent nanoparticle encapsulation of siRNA. • PEG reduces cellular toxicity of cationic nanoparticles in vitro. • PEG reduces zeta potential while improving gene silencing of siRNA nanoparticles. • Kinesin spindle protein can be an effective target for tumor vascular targeting. - Abstract: The ideal siRNA delivery system should selectively deliver the construct to the target cell, avoid enzymatic degradation, and evade uptake by phagocytes. In the present study, we evaluated the importance of polyethylene glycol (PEG) on lipid-based carrier systems for encapsulating, and delivering, siRNA to tumor vessels using cellular models. Lipid nanoparticles containing different percentage of PEG were evaluated based on their physical chemical properties, density compared to water, siRNA encapsulation, toxicity, targeting efficiency and gene silencing in vitro. siRNA can be efficiently loaded into lipid nanoparticles (LNPs) when DOTAP is included in the formulation mixture. However, the total amount encapsulated decreased with increase in PEG content. In the presence of siRNA, the final formulations contained a mixed population of particles based on density. The major population which contains the majority of siRNA exhibited a density of 4% glucose, and the minor fraction associated with a decreased amount of siRNA had a density less than PBS. The inclusion of 10 mol% PEG resulted in a greater amount of siRNA associated with the minor fraction. Finally, when kinesin spindle protein (KSP) siRNA was encapsulated in lipid nanoparticles containing a modest amount of PEG, the proliferation of endothelial cells was inhibited due to the efficient knock down of KSP mRNA. The presence of siRNA resulted in the formation of solid lipid nanoparticles when prepared using the thin film and hydration method. LNPs with a relatively modest amount of

  17. Solid lipid nanoparticles for hydrophilic biotech drugs: optimization and cell viability studies (Caco-2 & HEPG-2 cell lines)

    Czech Academy of Sciences Publication Activity Database

    Severino, P.; Andreani, T.; Jäger, Alessandro; Chaud, M. V.; Santana, M. H. A.; Silva, A. M.; Souto, E. B.

    2014-01-01

    Roč. 81, 23 June (2014), s. 28-34 ISSN 0223-5234 R&D Projects: GA ČR GAP208/10/1600 Institutional support: RVO:61389013 Keywords : lipid nanoparticles * double emulsion * hydrophilic biotech drugs Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.447, year: 2014

  18. Municipal solid waste management system: decision support through systems analysis

    OpenAIRE

    Pires, Ana Lúcia Lourenço

    2010-01-01

    Thesis submitted to the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia for the degree of Doctor of Philosophy in Environmental Engineering The present study intends to show the development of systems analysis model applied to solid waste management system, applied into AMARSUL, a solid waste management system responsible for the management of municipal solid waste produced in Setúbal peninsula, Portugal. The model developed intended to promote sustainable decision making, ...

  19. Acute toxicity study of tilmicosin-loaded hydrogenated castor oil-solid lipid nanoparticles

    Directory of Open Access Journals (Sweden)

    Xie Shuyu

    2011-11-01

    Full Text Available Abstract Background Our previous studies demonstrated that tilmicosin-loaded hydrogenated castor oil solid lipid nanoparticles (Til-HCO-SLN are a promising formulation for enhanced pharmacological activity and therapeutic efficacy in veterinary use. The purpose of this work was to evaluate the acute toxicity of Til-HCO-SLN. Methods Two nanoparticle doses were used for the study in ICR mice. The low dose (766 mg/kg.bw with tilmicosin 7.5 times of the clinic dosage and below the median lethal dose (LD50 was subcutaneously administered twice on the first and 7th day. The single high dose (5 g/kg.bw was the practical upper limit in an acute toxicity study and was administered subcutaneously on the first day. Blank HCO-SLN, native tilmicosin, and saline solution were included as controls. After medication, animals were monitored over 14 days, and then necropsied. Signs of toxicity were evaluated via mortality, symptoms of treatment effect, gross and microscopic pathology, and hematologic and biochemical parameters. Results After administration of native tilmicosin, all mice died within 2 h in the high dose group, in the low dose group 3 died after the first and 2 died after the second injections. The surviving mice in the tilmicosin low dose group showed hypoactivity, accelerated breath, gloomy spirit and lethargy. In contrast, all mice in Til-HCO-SLN and blank HCO-SLN groups survived at both low and high doses. The high nanoparticle dose induced transient clinical symptoms of treatment effect such as transient reversible action retardation, anorexy and gloomy spirit, increased spleen and liver coefficients and decreased heart coefficients, microscopic pathological changes of liver, spleen and heart, and minor changes in hematologic and biochemical parameters, but no adverse effects were observed in the nanoparticle low dose group. Conclusions The results revealed that the LD50 of Til-HCO-SLN and blank HCO-SLN exceeded 5 g/kg.bw and thus the

  20. Preparation, characterization, and optimization of primaquine-loaded solid lipid nanoparticles

    Directory of Open Access Journals (Sweden)

    Omwoyo WN

    2014-08-01

    Full Text Available Wesley Nyaigoti Omwoyo,1,2 Bernhards Ogutu,3,4 Florence Oloo,3,5 Hulda Swai,6 Lonji Kalombo,6 Paula Melariri,6 Geoffrey Maroa Mahanga,2 Jeremiah Waweru Gathirwa3,4 1Department of Chemistry, Maasai Mara University, Narok, Kenya; 2Department of Chemistry, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya; 3Center for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya; 4Kenya Medical Research Institute, Nairobi, Kenya; 5Department of Chemical Sciences and Technology, Technical University of Kenya, Nairobi, Kenya; 6Department of Polymers and Composites, Council for Scientific and Industrial Research, Pretoria, South Africa Abstract: Primaquine (PQ is one of the most widely used antimalarial drugs and is the only available drug that combats the relapsing form of malaria. PQ use in higher doses is limited by severe tissue toxicity including hematological- and gastrointestinal-related side effects. Nanoformulation of drugs in an appropriate drug carrier system has been extensively studied and shown to have the potential to improve bioavailability, thereby enhancing activity, reducing dose frequency, and subsequently reducing toxicity. The aim of this work was to design, synthesize, and characterize PQ-loaded solid lipid nanoparticles (SLNs (PQ-SLNs as a potential drug-delivery system. SLNs were prepared by a modified solvent emulsification evaporation method based on a water-in-oil-in-water (w/o/w double emulsion. The mean particle size, zeta potential, drug loading, and encapsulation efficiency of the PQ-SLNs were 236 nm, +23 mV, 14%, and 75%, respectively. The zeta potential of the SLNs changed dramatically, from -6.54 mV to +23.0 mV, by binding positively charged chitosan as surface modifier. A spherical morphology of PQ-SLNs was seen by scanning electron microscope. In vitro, release profile depicted a steady drug release over 72 hours. Differential scanning calorimeter thermograms demonstrated presence

  1. Solid lipid nanoparticle suspension enhanced the therapeutic efficacy of praziquantel against tapeworm

    Directory of Open Access Journals (Sweden)

    Xie S

    2011-10-01

    Full Text Available Shuyu Xie1,*, Baoliang Pan1,*, Baoxin Shi2, Zhuangzhi Zhang2, Xu Zhang2, Ming Wang1, Wenzhong Zhou11Department of Preventive Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, People’s Republic of China; 2Veterinary Research Institute, Xinjiang Academy of Animal Science, Xinjiang, People’s Republic of China *These authors contributed equally to this study Abstract: Hydatid disease caused by tapeworm is an increasing public health and socioeconomic concern. In order to enhance the therapeutic efficacy of praziquantel (PZQ against tapeworm, PZQ-loaded hydrogenated castor oil solid lipid nanoparticle (PZQ-HCO-SLN suspension was prepared by a hot homogenization and ultrasonication method. The stability of the suspension at 4°C and room temperature was evaluated by the physicochemical characteristics of the nanoparticles and in-vitro release pattern of the suspension. Pharmacokinetics was studied after subcutaneous administration of the suspension in dogs. The therapeutic effect of the novel formulation was evaluated in dogs naturally infected with Echinococcus granulosus. The results showed that the drug recovery of the suspension was 97.59% ± 7.56%. Nanoparticle diameter, polydispersivity index, and zeta potential were 263.00 ± 11.15 nm, 0.34 ± 0.06, and -11.57 ± 1.12 mV, respectively and showed no significant changes after 4 months of storage at both 4°C and room temperature. The stored suspensions displayed similar in-vitro release patterns as that of the newly prepared one. SLNs increased the bioavailability of PZQ 5.67-fold and extended the mean residence time of the drug from 56.71 to 280.38 hours. Single subcutaneous administration of PZQ-HCO-SLN suspension obtained enhanced therapeutic efficacy against tapeworm in infected dogs. At the dose of 5 mg/kg, the stool-ova reduction and negative conversion rates and tapeworm removal rate of the suspension were 100%, while the native PZQ were 91

  2. Production of solid lipid submicron particles for protein delivery using a novel supercritical gas-assisted melting atomization process.

    Science.gov (United States)

    Salmaso, Stefano; Elvassore, Nicola; Bertucco, Alberto; Caliceti, Paolo

    2009-02-01

    A supercritical carbon dioxide micronization technique based on gas-assisted melting atomization has been designed to prepare protein-loaded solid lipid submicron particles. The supercritical process was applied to homogeneous dispersions of insulin in lipid mixtures: (1) tristearin, Tween-80, phosphatidylcholine and 5 kDa PEG (1:0.1:0.9:1 and 1:0.1:0.9:2 weight ratio); and (2) tristearin, dioctyl sulfosuccinate and phosphatidylcholine (1:1:0.5 weight ratio). Optimized process conditions yielded dry nonagglomerated powders with high product recovery (70%, w/w). Dynamic light scattering and transmission electron microscopy showed that two size fractions of particles, with 80-120 and 200-400 nm diameters, were produced. In all final products, dimethylsulfoxide used to prepare the insulin/lipid mixture was below 20 ppm. Protein encapsulation efficiency increased up to 80% as the DMSO content in the insulin/lipid mixture increased. Compared to the particles without PEG, the polymer-containing particles dispersed rapidly in water, and the dispersions were more stable under centrifugation as less than 20% of suspended particles precipitated after extensive centrifugation. In vitro, the protein was slowly released from the formulation without PEG, while a burst and faster release were obtained from the formulations containing PEG. Subcutaneous injection to diabetic mice of insulin extracted from the particles showed that the supercritical process did not impair the protein hypoglycemic activity.

  3. Ripple formation in unilamellar-supported lipid bilayer revealed by FRAPP.

    Science.gov (United States)

    Harb, Frédéric; Simon, Anne; Tinland, Bernard

    2013-12-01

    The mechanisms of formation and conditions of the existence of the ripple phase are fundamental thermodynamic questions with practical implications for medicine and pharmaceuticals. We reveal a new case of ripple formation occurring in unilamellar-supported bilayers in water, which results solely from the bilayer/support interaction, without using lipid mixtures or specific ions. This ripple phase is detected by FRAPP using diffusion coefficient measurements as a function of temperature: a diffusivity plateau is observed. It occurs in the same temperature range where ripple phase existence has been observed using other methods. When AFM experiments are performed in the appropriate temperature range the ripple phase is confirmed.

  4. Hansen solubility parameters (HSP) for prescreening formulation of solid lipid nanoparticles (SLN): in vitro testing of curcumin-loaded SLN in MCF-7 and BT-474 cell lines.

    Science.gov (United States)

    Doktorovova, Slavomira; Souto, Eliana B; Silva, Amélia M

    2018-01-01

    Curcumin, a phenolic compound from turmeric rhizome (Curcuma longa), has many interesting pharmacological effects, but shows very low aqueous solubility. Consequently, several drug delivery systems based on polymeric and lipid raw materials have been proposed to increase its bioavailability. Solid lipid nanoparticles (SLN), consisting of solid lipid matrix and a surfactant layer can load poorly water-soluble drugs, such as curcumin, deliver them at defined rates and enhance their intracellular uptake. In the present work, we demonstrate that, despite the drug's affinity to lipids frequently used in SLN production, the curcumin amount loaded in most SLN formulations may be too low to exhibit anticancer properties. The predictive curcumin solubility in solid lipids has been thoroughly analyzed by Hansen solubility parameters, in parallel with the lipid-screening solubility tests for a range of selected lipids. We identified the most suitable lipid materials for curcumin-loaded SLN, producing physicochemically stable particles with high encapsulation efficiency (>90%). Loading capacity of curcumin in SLN allowed preventing the cellular damage caused by cationic SLN on MCF-7 and BT-474 cells but was not sufficient to exhibit drug's anticancer properties. But curcumin-loaded SLN exhibited antioxidant properties, substantiating the conclusions that curcumin's effect in cancer cells is highly dose dependent.

  5. Flow-through lipid nanotube arrays for structure-function studies of membrane proteins by solid-state NMR spectroscopy.

    Science.gov (United States)

    Chekmenev, Eduard Y; Gor'kov, Peter L; Cross, Timothy A; Alaouie, Ali M; Smirnov, Alex I

    2006-10-15

    A novel method for studying membrane proteins in a native lipid bilayer environment by solid-state NMR spectroscopy is described and tested. Anodic aluminum oxide (AAO) substrates with flow-through 175 nm wide and 60-mum-long nanopores were employed to form macroscopically aligned peptide-containing lipid bilayers that are fluid and highly hydrated. We demonstrate that the surfaces of both leaflets of such bilayers are fully accessible to aqueous solutes. Thus, high hydration levels as well as pH and desirable ion and/or drug concentrations could be easily maintained and modified as desired in a series of experiments with the same sample. The method allows for membrane protein NMR experiments in a broad pH range that could be extended to as low as 1 and as high as 12 units for a period of up to a few hours and temperatures as high as 70 degrees C without losing the lipid alignment or bilayers from the nanopores. We demonstrate the utility of this method by a solid-state 19.6 T (17)O NMR study of reversible binding effects of mono- and divalent ions on the chemical shift properties of the Leu(10) carbonyl oxygen of transmembrane pore-forming peptide gramicidin A (gA). We further compare the (17)O shifts induced by binding metal ions to the binding of protons in the pH range from 1 to 12 and find a significant difference. This unexpected result points to a difference in mechanisms for ion and proton conduction by the gA pore. We believe that a large number of solid-state NMR-based studies, including structure-function, drug screening, proton exchange, pH, and other titration experiments, will benefit significantly from the method described here.

  6. Miconazole-loaded solid lipid nanoparticles: formulation and evaluation of a novel formula with high bioavailability and antifungal activity

    Directory of Open Access Journals (Sweden)

    Aljaeid BM

    2016-01-01

    Full Text Available Bader Mubarak Aljaeid,1 Khaled Mohamed Hosny1,2 1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt Background and objective: Miconazole is a broad-spectrum antifungal drug that has poor aqueous solubility (<1 µg/mL; as a result, a reduction in its therapeutic efficacy has been reported. The aim of this study was to formulate and evaluate miconazole-loaded solid lipid nanoparticles (MN-SLNs for oral administration to find an innovative way to alleviate the disadvantages associated with commercially available capsules. Methods: MN-SLNs were prepared by hot homogenization/ultrasonication. The solubility of miconazole in different solid lipids was measured. The effect of process variables, such as surfactant types, homogenization and ultrasonication times, and the charge-inducing agent on the particle size, zeta potential, and encapsulation efficiency were determined. Furthermore, in vitro drug release, antifungal activity against Candida albicans, and in vivo pharmacokinetics were studied in rabbits. Results: The MN-SLN, consisting of 1.5% miconazole, 2% Precirol ATO5, 2.5% Cremophor RH40, 0.5% Lecinol, and 0.1% Dicetylphosphate, had an average diameter of 23 nm with a 90.2% entrapment efficiency. Furthermore, the formulation of MN-SLNs enhanced the antifungal activity compared with miconazole capsules. An in vivo pharmacokinetic study revealed that the bioavailability was enhanced by >2.5-fold. Conclusion: MN-SLN was more efficient in the treatment of candidiasis with enhanced oral bioavailability and could be a promising carrier for the oral delivery of miconazole. Keywords: miconazole, Precirol ATO5, solid lipid nanoparticles, encapsulation, Cremophor RH40, antifungal activity

  7. Influence of natural organic matter (NOM) coatings on nanoparticle adsorption onto supported lipid bilayers.

    Science.gov (United States)

    Bo, Zhang; Avsar, Saziye Yorulmaz; Corliss, Michael K; Chung, Minsub; Cho, Nam-Joon

    2017-10-05

    As the worldwide usage of nanoparticles in commercial products continues to increase, there is growing concern about the environmental risks that nanoparticles pose to biological systems, including potential damage to cellular membranes. A detailed understanding of how different types of nanoparticles behave in environmentally relevant conditions is imperative for predicting and mitigating potential membrane-associated toxicities. Herein, we investigated the adsorption of two popular nanoparticles (silver and buckminsterfullerene) onto biomimetic supported lipid bilayers of varying membrane charge (positive and negative). The quartz crystal microbalance-dissipation (QCM-D) measurement technique was employed to track the adsorption kinetics. Particular attention was focused on understanding how natural organic matter (NOM) coatings affect nanoparticle-bilayer interactions. Both types of nanoparticles preferentially adsorbed onto the positively charged bilayers, although NOM coatings on the nanoparticle and lipid bilayer surfaces could either inhibit or promote adsorption in certain electrolyte conditions. While past findings showed that NOM coatings inhibit membrane adhesion, our findings demonstrate that the effects of NOM coatings are more nuanced depending on the type of nanoparticle and electrolyte condition. Taken together, the results demonstrate that NOM coatings can modulate the lipid membrane interactions of various nanoparticles, suggesting a possible way to improve the environmental safety of nanoparticles. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Evaluation of in-vitro cytotoxicity and cellular uptake efficiency of zidovudine-loaded solid lipid nanoparticles modified with Aloe Vera in glioma cells.

    Science.gov (United States)

    K S, Joshy; Sharma, Chandra P; Kalarikkal, Nandakumar; Sandeep, K; Thomas, Sabu; Pothen, Laly A

    2016-09-01

    Zidovudine loaded solid lipid nanoparticles of stearic acid modified with Aloe Vera (AV) have been prepared via simple emulsion solvent evaporation method which showed excellent stability at room temperature and refrigerated condition. The nanoparticles were examined by Fourier transform infrared spectroscopy (FT-IR), which revealed the overlap of the AV absorption peak with the absorption peak of modified stearic acid nanoparticles. The inclusion of AV to stearic acid decreased the crystallinity and improved the hydrophilicity of lipid nanoparticles and thereby improved the drug loading efficacy of lipid nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging revealed that, the average particle size of unmodified (bare) nanoparticles was 45.66±12.22nm and modified solid lipid nanoparticles showed an average size of 265.61±80.44nm. Solid lipid nanoparticles with well-defined morphology were tested in vitro for their possible application in drug delivery. Cell culture studies using C6 glioma cells on the nanoparticles showed enhanced growth and proliferation of cells without exhibiting any toxicity. In addition, normal cell morphology and improved uptake were observed by fluorescence microscopy images of rhodamine labeled modified solid lipid nanoparticles compared with unmodified nanoparticles. The cellular uptake study suggested that these nanoparticles could be a promising drug delivery system to enhance the uptake of antiviral drug by brain cells and it could be a suitable drug carrier system for the treatment of HIV. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Solubility enhancement of benfotiamine, a lipid derivative of thiamine by solid dispersion technique.

    Science.gov (United States)

    Patel, S M; Patel, R P; Prajapati, B G

    2012-03-01

    The present study was aimed to increase the solubility of the poorly water soluble drug benfotiamine using hydrophilic polymers (PVP K-30 and HPMC E4). Solid dispersions were prepared by kneading method. Phase solubility study, in-vitro dissolution of pure drug, physical mixtures and solid dispersions were carried out. PVP and HPMC were found to be effective in increasing the dissolution of Benfotiamine in solid dispersions when compared to pure drug. FT-IR, differential scanning calorimetry and X-ray diffractometry studies were carried out in order to characterize the drug and solid dispersion. To conclude that, the prepared solid dispersion of PVP-30 may to effectively used for the enhancement of solubility of poorly water soluble drugs such as benfotiamine.

  10. Solubility enhancement of benfotiamine, a lipid derivative of thiamine by solid dispersion technique

    Directory of Open Access Journals (Sweden)

    S M Patel

    2012-01-01

    Full Text Available The present study was aimed to increase the solubility of the poorly water soluble drug benfotiamine using hydrophilic polymers (PVP K-30 and HPMC E4. Solid dispersions were prepared by kneading method. Phase solubility study, in-vitro dissolution of pure drug, physical mixtures and solid dispersions were carried out. PVP and HPMC were found to be effective in increasing the dissolution of Benfotiamine in solid dispersions when compared to pure drug. FT-IR, differential scanning calorimetry and X-ray diffractometry studies were carried out in order to characterize the drug and solid dispersion. To conclude that, the prepared solid dispersion of PVP-30 may to effectively used for the enhancement of solubility of poorly water soluble drugs such as benfotiamine.

  11. Temperature-controlled continuous production of all-trans retinoic acid-loaded solid lipid nanoparticles using static mixers

    Science.gov (United States)

    Shao, Wenyao; Yan, Mengwen; Chen, Tingting; Chen, Yuqing; Xiao, Zongyuan

    2017-04-01

    This work aims to develop a temperature-controlled continuous solvent emulsification-diffusion process to synthesize all-trans retinoic acid (ATRA)-loaded solid lipid nanoparticles (SLNs) using static mixers. ATRA-loaded SLNs of around 200 nm were obtained when the flow rates of the organic and aqueous phases were 50 ml min-1 and 500 ml min-1, respectively. It was found that the lipid concentration played a dominant role in the size of the obtained SLNs, and higher drug concentration resulted in relatively low entrapment efficiency. The encapsulation of ATRA in the SLNs was effective in improving its stability according to the photo-degradation test. The in vitro release of SLN was slow without an initial burst. This study demonstrates that the solvent emulsification-diffusion technique with static mixing is an effective method of producing SLNs, and could easily be scaled up for industrial applications. Highlights Higher lipid concentration leads to larger SLNs. SLN transformation occurs due to Ostwald ripening. The ATRA-loaded SLNs around 200 nm were successfully produced with static mixers. ATRA-loaded SLNs show better stability towards sunlight. ATRA in SLNs exhibited a relatively slow release rate without a significant initial burst.

  12. Characterization and evaluation of sensory acceptability of ice creams incorporated with beta-carotene encapsulated in solid lipid microparticles

    Directory of Open Access Journals (Sweden)

    Juliana Gobbi de LIMA

    Full Text Available Abstract The feasibility of incorporating beta-carotene-loaded solid lipid microparticles (BCSLM into vanilla ice creams was investigated, through the physico-chemical characterization and evaluation of sensory acceptability of the products products. The BCSLM were produced with palm stearin as the lipid phase, hydrolyzed soy protein isolate as the surfactant, and xanthan gum as the thickener. The results showed similar values of proximate composition, total soluble solids, pH, and overrun for all formulations. On the other hand, colorimetric evaluations showed that the ice cream produced with partial substitution of artificial additives by BCSLM containing alpha-tocopherol presented a more intense color, while in the product with non-encapsulated beta-carotene, a fast degradation of carotenoid was confirmed, highlighting the importance of the encapsulation techniques. The results of the sensorial analysis of the products were highly satisfactory and showed that the panelists preferred the ice creams produced with BCSLM containing alpha-tocopherol and with partial substitution of artificial additives by BCSLM containing alpha-tocopherol, confirming the feasibility of incorporating BCSLM into ice creams to reduce the application of artificial dyes to the product.

  13. Microwave-assisted microemulsion technique for production of miconazole nitrate- and econazole nitrate-loaded solid lipid nanoparticles.

    Science.gov (United States)

    Shah, Rohan M; Eldridge, Daniel S; Palombo, Enzo A; Harding, Ian H

    2017-08-01

    The microwave-assisted production of solid lipid nanoparticles (SLNs) is a novel technique reported recently by our group. The small particle size, solid nature and use of physiologically well-tolerated lipid materials make SLNs an interesting and potentially efficacious drug carrier. The main purpose of this research work was to investigate the suitability of microwave-assisted microemulsion technique to encapsulate selected ionic drug substances such as miconazole nitrate and econazole nitrate. The microwave-produced SLNs had a small size (250-300nm), low polydispersity (microwave-produced SLNs. Data fitting of drug release data revealed that the release of both drugs from microwave-produced SLNs was governed by non-Fickian diffusion indicating that drug release was both diffusion- and dissolution- controlled. Anti-fungal efficacy of drug-loaded SLNs was evaluated on C. albicans. The cell viability studies showed that cytotoxicity of SLNs was concentration-dependent. These encouraging results suggest that the microwave-assisted procedure is suitable for encapsulation of ionic drugs and that microwave-produced SLNs can act as potential carriers of antifungal drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Skin penetration and photoprotection of topical formulations containing benzophenone-3 solid lipid microparticles prepared by the solvent-free spray-congealing technique.

    Science.gov (United States)

    Martins, Rodrigo Molina; Siqueira, Silvia; Fonseca, Maria José Vieira; Freitas, Luis Alexandre Pedro

    2014-01-01

    Solid-lipid microparticles loaded with high amounts of the sunscreen UV filter benzophenone-3 were prepared by spray congealing with the objective of decreasing its skin penetration and evaluate whether the sunscreen's photoprotection were impaired by the microencapsulation process. The microparticles were produced using the natural lipids carnauba wax or bees wax and three different concentrations of benzophenone-3 (30, 50 and 70%) using spray congealing technique. The microparticles presented properties suitable for topical application, such as spherical morphology, high encapsulation efficiency (95.53-102.2%), average particle sizes between 28.5 and 60.0 µm with polydispersivities from 1.2 to 2.5. In studies of in vitro skin penetration and preliminary stability, formulations of gel cream containing carnauba wax solid lipid microparticles and 70% benzophenone-3 when compared to the formulation added of bees wax solid-lipid microparticles containing 70% benzophenone-3, was stable considering the several parameters evaluated and were able to decrease the penetration of the UV filter into pig skin. Moreover, the formulations containing solid lipid microparticles with 70% benzophenone-3 increased the photoprotective capacity of benzophenone-3 under UV irradiation. The results show that spray-congealed microparticles are interesting solid forms to decrease the penetration solar filters in the skin without compromising their photoprotection.

  15. Applications of lipid nanocarriers for solid tumors therapy: literature review; Aplicacoes das nanoparticulas lipidicas no tratamento de tumores solidos: revisao de literatura

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Lidiane Correia de; Souza, Leonardo Gomes; Marreto, Ricardo Neves; Lima, Eliana Martins; Taveira, Stephania Fleury [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Fac. de Farmacia; Taveira, Eliseu Jose Fleury, E-mail: stephaniafleury@gmail.com [Hospital Erasto Gaertner, Curitiba, PR (Brazil). Oncologia Clinica

    2012-07-01

    Introduction: Lipid nanocarriers are systems used to target drugs to its site of action and have attracted attention of the scientific community because they are biocompatible and biodegradable. These systems can target drugs to solid tumors, providing sustained drug release in the site of action, thus increasing the utility of the antineoplastic chemotherapy. Objective: To review the available literature on in vivo experiments with lipid nanocarriers containing cytotoxic drugs for solid tumors treatment. Method: A search study was carried out in Pubmed{sup R} database from 2007 to 2011, with subject descriptors: liposomes, lipid nanoparticles, cancer and in vivo, with the boolean operator 'and' among them, in English. Results: 1,595 papers related to the use of liposomes and 77 related to lipid nanoparticles were found. Few studies reported in vivo experiments with lipid nanoparticles (28 papers) compared to liposomes (472 papers), since liposomes were developed two decades before lipid nanoparticles. Four liposomal medicines have already been approved and are used in the clinic while only one medicine containing lipid nanoparticles is in phase I of clinical studies. Conclusion: The number of papers related to the use of nanotechnology for cancer treatment is increasing rapidly, making important to know the different kinds of nanocarriers and, especially, those which are already used in the clinic. There are only few clinical studies on lipid nanocarriers; however, these systems present an enormous potential to improve the clinical practice in oncology. (author)

  16. Solid lipid nanoparticles loaded with insulin by sodium cholate-phosphatidylcholine-based mixed micelles: preparation and characterization.

    Science.gov (United States)

    Liu, Jie; Gong, Tao; Wang, Changguang; Zhong, Zhirong; Zhang, Zhirong

    2007-08-01

    Solid lipid nanoparticles (SLNs) loaded with insulin-mixed micelles (Ins-MMs) were prepared by a novel reverse micelle-double emulsion method, in which sodium cholate (SC) and soybean phosphatidylcholine (SPC) were employed to improve the liposolubility of insulin, and the mixture of stearic acid and palmitic acid were employed to prepare insulin loaded solid lipid nanoparticles (Ins-MM-SLNs). Some of the formulation parameters were optimized to obtain high quality nanoparticles. The particle size and zeta potential measured by photon correlation spectroscopy (PCS) were 114.7+/-4.68 nm and -51.36+/-2.04 mV, respectively. Nanospheres observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed extremely spherical shape. The entrapment efficiency (EE%) and drug loading capacity (DL%) determined with high performance liquid chromatogram (HPLC) by modified ultracentrifuge method were 97.78+/-0.37% and 18.92+/-0.07%, respectively. Differential scanning calorimetry (DSC) of Ins-MM-SLNs indicated no tendency of recrystallisation. The core-shell drug loading pattern of the SLNs was confirmed by fluorescence spectra and polyacrylamide gel electrophoresis (PAGE) which also proved the integrity of insulin after being incorporated into lipid carrier. The drug release behavior was studied by in situ and externally sink method and the release pattern of drug was found to follow Weibull and Higuchi equations. Results of stability evaluation showed a relatively long-term stability after storage at 4 degrees C for 6 months. In conclusion, SLNs with small particle size, excellent physical stability, high entrapment efficiency, good loading capacity for protein drug can be produced by this novel reverse micelle-double emulsion method in present study.

  17. Solid lipid particles for oral delivery of peptide and protein drugs III - the effect of fed state conditions on the in vitro release and degradation of desmopressin

    DEFF Research Database (Denmark)

    Christophersen, Philip C; Vaghela, Dimple; Müllertz, Anette

    2014-01-01

    The effect of food intake on the release and degradation of peptide drugs from solid lipid particles is unknown and was therefore investigated in vitro using different fed state media in a lipolysis model. Desmopressin was used as a model peptide and incorporated into solid lipid particles...... and the protease or desmopressin. Addition of a medium chain triglyceride, trilaurin, in combination with drug-loaded lipid particles diminished the food effect on the TG18 particles, and trilaurin is therefore proposed to be a suitable excipient for reduction of the food effect. Overall, the present study shows...... that strategies to reduce food effect, such as adding trilaurin, for lipid particle formulations should be considered as drug release from such formulations might be influenced by the presence of food in the gastrointestinal tract....

  18. Investigation of protein distribution in solid lipid particles and its impact on protein release using coherent anti-Stokes Raman scattering microscopy

    DEFF Research Database (Denmark)

    Christophersen, Philip C.; Birch, Ditlev; Saarinen, Jukka

    2015-01-01

    The aim of this study was to gain new insights into protein distribution in solid lipid microparticles (SLMs) and subsequent release mechanisms using a novel label-free chemical imaging method, coherent anti-Stokes Raman scattering (CARS) microscopy. Lysozyme-loaded SLMs were prepared using...... in the solid lipid matrix, which required full lipolysis of the entire matrix to release lysozyme completely. Therefore, SLMs with lysozyme incorporated in an aqueous solution released lysozyme much faster than with lysozyme incorporated as a solid. In conclusion, CARS microscopy was an efficient and non......-destructive method for elucidating the distribution of lysozyme in SLMs. The interpretation of protein distribution and release during lipolysis enabled elucidation of protein release mechanisms. In future, CARS microscopy analysis could facilitate development of a wide range of protein-lipid matrices with tailor...

  19. Study of the ion-channel behavior on glassy carbon electrode supported bilayer lipid membranes stimulated by perchlorate anion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiquan; Shi, Jun; Huang, Weimin, E-mail: huangwm@jlu.edu.cn

    2015-10-01

    In this paper, a kind of didodecyldimethylammonium bromide (DDAB) layer membranes was supported on a glassy carbon electrode (GCE). We studied the ion channel behavior of the supported bilayer lipid membrane by scanning electrochemical microscopy (SCEM) in tris(2,2′-bipyridine) ruthenium(II) solution. Perchlorate anion was used as a presence of stimulus and ruthenium(II) complex cations as the probing ions for the measurement of SECM, the lipid membrane channel was opened and exhibited the behavior of distinct SECM positive feedback curve. The channel was in a closed state in the absence of perchlorate anions while reflected the behavior of SECM negative feedback curve. The rates of electron transfer reaction in the lipid membranes surface were detected and it was dependant on the potential of SECM. - Highlights: • The rates of electron transfer reaction in the lipid membranes surface were detected. • Dynamic investigations of ion-channel behavior of supported bilayer lipid membranes by scanning electrochemical microscopy • A novel way to explore the interaction between molecules and supported bilayer lipid membranes.

  20. Poly(aniline) nanowires in sol-gel coated ITO: A pH-responsive substrate for planar supported lipid bilayers

    Science.gov (United States)

    Ge, Chenhao; Orosz, Kristina S.; Armstrong, Neal R.; Saavedra, S. Scott

    2011-01-01

    Facilitated ion transport across an artificial lipid bilayer coupled to a solid substrate is a function common to several types of bioelectronic devices based on supported membranes, including biomimetic fuel cells and ion channel biosensors. Described here is fabrication of a pH-sensitive transducer composed of a porous sol-gel layer derivatized with poly(aniline) (PANI) nanowires grown from an underlying planar indium-tin oxide (ITO) electrode. The upper sol-gel surface is hydrophilic, smooth, and compatible with deposition of a planar supported lipid bilayer (PSLB) formed via vesicle fusion. Conducting tip AFM was used to show that the PANI wires are connected to the ITO, which convert this electrode into a potentiometric pH sensor. The response to changes in the pH of the buffer contacting the PANI nanowire/sol-gel/ITO electrode is blocked by the very low ion permeability of the overlying, fluid PSLB. The feasibility of using this assembly to monitor facilitated proton transport across the PSLB was demonstrated by doping the membrane with lipophilic ionophores that respond to a transmembrane pH gradient, which produced an apparent proton permeability several orders of magnitude greater than values measured for undoped lipid bilayers. PMID:21707069

  1. Formulation and optimization of solid lipid nanoparticle formulation for pulmonary delivery of budesonide using Taguchi and Box-Behnken design.

    Science.gov (United States)

    Emami, J; Mohiti, H; Hamishehkar, H; Varshosaz, J

    2015-01-01

    Budesonide is a potent non-halogenated corticosteroid with high anti-inflammatory effects. The lungs are an attractive route for non-invasive drug delivery with advantages for both systemic and local applications. The aim of the present study was to develop, characterize and optimize a solid lipid nanoparticle system to deliver budesonide to the lungs. Budesonide-loaded solid lipid nanoparticles were prepared by the emulsification-solvent diffusion method. The impact of various processing variables including surfactant type and concentration, lipid content organic and aqueous volume, and sonication time were assessed on the particle size, zeta potential, entrapment efficiency, loading percent and mean dissolution time. Taguchi design with 12 formulations along with Box-Behnken design with 17 formulations was developed. The impact of each factor upon the eventual responses was evaluated, and the optimized formulation was finally selected. The size and morphology of the prepared nanoparticles were studied using scanning electron microscope. Based on the optimization made by Design Expert 7(®) software, a formulation made of glycerol monostearate, 1.2 % polyvinyl alcohol (PVA), weight ratio of lipid/drug of 10 and sonication time of 90 s was selected. Particle size, zeta potential, entrapment efficiency, loading percent, and mean dissolution time of adopted formulation were predicted and confirmed to be 218.2 ± 6.6 nm, -26.7 ± 1.9 mV, 92.5 ± 0.52 %, 5.8 ± 0.3 %, and 10.4 ± 0.29 h, respectively. Since the preparation and evaluation of the selected formulation within the laboratory yielded acceptable results with low error percent, the modeling and optimization was justified. The optimized formulation co-spray dried with lactose (hybrid microparticles) displayed desirable fine particle fraction, mass median aerodynamic diameter (MMAD), and geometric standard deviation of 49.5%, 2.06 μm, and 2.98 μm; respectively. Our results provide fundamental data for the

  2. Synthesis and binding studies of Alzheimer ligands on solid support.

    Science.gov (United States)

    Rzepecki, Petra; Geib, Nina; Peifer, Manuel; Biesemeier, Frank; Schrader, Thomas

    2007-05-11

    Aminopyrazole derivatives constitute the first class of nonpeptidic rationally designed beta-sheet ligands. Here we describe a double solid-phase protocol for both synthesis and affinity testing. The presented solid-phase synthesis of four types of hybrid compounds relies on the Fmoc strategy and circumvents subsequent HPLC purification by precipitating the final product from organic solution in pure form. Hexa- and octapeptide pendants with internal di- and tetrapeptide bridges are now amenable in high yields to combinatorial synthesis of compound libraries for high-throughput screening purposes. Solid-phase peptide synthesis (SPPS) on an acid-resistant PAM allows us, after PMB deprotection, to subject the free aminopyrazole binding sites in an immobilized state to on-bead assays with fluorescence-labeled peptides. From the fluorescence emission intensity decrease, individual binding constants can be calculated via reference curves by simple application of the law of mass action. Gratifyingly, host/guest complexation can be monitored quantitatively even for those ligands, which are almost insoluble in water.

  3. On the freezing behavior and diffusion of water in proximity to single-supported zwitterionic and anionic bilayer lipid membranes

    DEFF Research Database (Denmark)

    Miskowiec, A.; Buck, Z. N.; Brown, M. C.

    2014-01-01

    We compare the freezing/melting behavior of water hydrating single-supported bilayers of a zwitterionic lipid DMPC with that of an anionic lipid DMPG. For both membranes, the temperature dependence of the elastically scattered neutron intensity indicates distinct water types undergoing...... translational diffusion: bulk-like water probably located above the membrane and two types of confined water closer to the lipid head groups. The membranes differ in the greater width of the water freezing transition near the anionic DMPG bilayer compared to zwitterionic DMPC as well as in the abruptness...

  4. Single-component supported lipid bilayers probed using broadband nonlinear optics.

    Science.gov (United States)

    Olenick, Laura L; Chase, Hilary M; Fu, Li; Zhang, Yun; McGeachy, Alicia C; Dogangun, Merve; Walter, Stephanie R; Wang, Hong-Fei; Geiger, Franz M

    2018-01-31

    Broadband SFG spectroscopy is shown to offer considerable advantages over scanning systems in terms of signal-to-noise ratios when probing well-formed single-component supported lipid bilayers formed from zwitterionic lipids with PC headgroups. The SFG spectra obtained from bilayers formed from DOPC, POPC, DLPC, DMPC, DPPC and DSPC show a common peak at ∼2980 cm -1 , which is subject to interference between the C-H and the O-H stretches from the aqueous phase, while membranes having transition temperatures above the laboratory temperature produce SFG spectra with at least two additional peaks, one at ∼2920 cm -1 and another at ∼2880 cm -1 . The results validate spectroscopic and structural data from SFG experiments utilizing asymmetric bilayers in which one leaflet differs from the other in the extent of deuteration. Differences in H 2 O-D 2 O exchange experiments reveal that the lineshapes of the broadband SFG spectra are significantly influenced by interference from OH oscillators in the aqueous phase, even when those oscillators are not probed by the incident infrared light in our broadband setup. In the absence of spectral interference from the OH stretches of the solvent, the alkyl chain terminal methyl group of the bilayer is found to be tilted at an angle of 15° to 35° from the surface normal.

  5. Improved coupling of bacterial polysaccharides to macromolecules and solid supports

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method of producing a polysaccharide-carrier conjugate comprising coupling a polysaccharide to a carrier, said polysaccharide comprising at least one monosaccharide unit comprising a keto-carboxy group according to the formula -C(=O)COOR, where R is either hydrogen or C1......-alkoxyamine group of the carrier with a keto-carboxy group of said polysaccharide to form a covalent amide bond between the carrier and the polysaccharide. Another aspect of the present invention relates to a compound or solid surface obtained when performing the method of the present invention. A third aspect...

  6. Understanding the mechanism of protamine in solid lipid nanoparticle-based lipofection: the importance of the entry pathway.

    Science.gov (United States)

    Delgado, Diego; del Pozo-Rodríguez, Ana; Solinís, Maria Ángeles; Rodríguez-Gascón, Alicia

    2011-11-01

    The aim of our study was to evaluate the effect of protamine on the transfection capacity of solid lipid nanoparticles (SLNs) by correlating it to the internalization mechanisms and intracellular trafficking of the vectors. Vectors were prepared with SLN, DNA, and protamine. ARPE-19 and HEK-293 cells were used for the evaluation of the formulations. Protamine induced a 6-fold increase in the transfection of SLNs in retinal cells due to the presence of nuclear localization signals (NLS), its protection capacity, and a shift in the internalization mechanism from caveolae/raft-mediated to clathrin-mediated endocytosis. However, protamine produced an almost complete inhibition of transfection in HEK-293 cells. In spite of the high DNA condensation capacity of protamine and its content in NLS, this does not always lead to an improvement in cell transfection since it may impair some of the limiting steps of the transfection processes. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Preparation, characterization, and optimization of altretamine-loaded solid lipid nanoparticles using Box-Behnken design and response surface methodology.

    Science.gov (United States)

    Gidwani, Bina; Vyas, Amber

    2016-01-01

    The objective of the present study was to prepare solid lipid nanoparticles (SLNs) of altretamine (ALT) by the hot homogenization and ultrasonication method. The study was conducted using the Box-Behnken design (BBD), with a 3(3) design and a total of 17 experimental runs, performed in combination with response surface methodology (RSM). The SLNs were evaluated for mean particle size, entrapment efficiency, and drug-loading. The optimized formulation, with a desirability factor of 0.92, was selected and characterized. In vitro release studies showed a biphasic release pattern from the SLNs for up to 24 h. The results of % EE (93.21 ± 1.5), %DL (1.15 ± 0.6), and mean diameter of (100.6 ± 2.1) nm, were very close to the predicted values.

  8. Brain delivery of camptothecin by means of solid lipid nanoparticles: Formulation design, in vitro and in vivo studies

    DEFF Research Database (Denmark)

    Martins, S.; Tho, I.; Reimold, I.

    2012-01-01

    that fluorescently labelled SLN were detected in the brain after i.v. administration. This study indicates that the camptothecin-loaded SLN are a promising drug brain delivery system worth to explore further for brain tumour therapy. (C) 2012 Elsevier B. V. All rights reserved.......For the purpose of brain delivery upon intravenous injection, formulations of camptothecin-loaded solid lipid nanoparticles (SLN), prepared by hot high pressure homogenisation, were designed. Incorporation of camptothecin in the hydrophobic and acidic environment of SLN matrix was chosen...... to stabilise the lactone ring, which is essential for its antitumour activity, and for avoiding premature loss of drug on the way to target camptothecin to the brain. A multivariate approach was used to assess the influence of the qualitative and quantitative composition on the physicochemical properties...

  9. Porous Materials to Support Bilayer Lipid Membranes for Ion Channel Biosensors

    Directory of Open Access Journals (Sweden)

    Thai Phung

    2011-01-01

    Full Text Available To identify materials suitable as membrane supports for ion channel biosensors, six filter materials of varying hydrophobicity, tortuosity, and thickness were examined for their ability to support bilayer lipid membranes as determined by electrical impedance spectroscopy. Bilayers supported by hydrophobic materials (PTFE, polycarbonate, nylon, and silanised silver had optimal resistance (14–19 GΩ and capacitance (0.8–1.6 μF values whereas those with low hydrophobicity did not form BLMs (PVDF or were short-lived (unsilanised silver. The ability of ion channels to function in BLMs was assessed using a method recently reported to improve the efficiency of proteoliposome incorporation into PTFE-supported bilayers. Voltage-gated sodium channel activation by veratridine and inhibition by saxitoxin showed activity for PTFE, nylon, and silanised silver, but not polycarbonate. Bilayers on thicker, more tortuous, and hydrophobic materials produced higher current levels. Bilayers that self-assembled on PTFE filters were the longest lived and produced the most channel activity using this method.

  10. Solid Lipid Nanoparticle Formulations of Docetaxel Prepared with High Melting Point Triglycerides: In Vitro and in Vivo Evaluation

    Science.gov (United States)

    2015-01-01

    Docetaxel (DCX) is a second generation taxane. It is approved by the U.S. Food and Drug Administration for the treatment of various types of cancer, including breast, non-small cell lung, and head and neck cancers. However, side effects, including those related to Tween 80, an excipient in current DCX formulations, can be severe. In the present study, we developed a novel solid lipid nanoparticle (SLN) composition of DCX. Trimyristin was selected from a list of high melting point triglycerides as the core lipid component of the SLNs, based on the rate at which the DCX was released from the SLNs and the stability of the SLNs. The trimyristin-based, PEGylated DCX-incorporated SLNs (DCX-SLNs) showed significantly higher cytotoxicity against various human and murine cancer cells in culture, as compared to DCX solubilized in a Tween 80/ethanol solution. Moreover, in a mouse model with pre-established tumors, the new DCX-SLNs were significantly more effective than DCX solubilized in a Tween 80/ethanol solution in inhibiting tumor growth without toxicity, likely because the DCX-SLNs increased the concentration of DCX in tumor tissues, but decreased the levels of DCX in major organs such as liver, spleen, heart, lung, and kidney. DCX-incorporated SLNs prepared with one or more high-melting point triglycerides may represent an improved DCX formulation. PMID:24621456

  11. Polar Quassinoids in Standardized Eurycoma longifolia Extract Formulated into a Lipid-Based Solid Dispersion to Improve Rat Sperm Count.

    Science.gov (United States)

    Ma, Hai-Qiu; Ebrahimi, Forough; Low, Bin-Seng; Khan, Nurzalina Abdul Karim; Chan, Kit-Lam

    2017-12-01

    Eurycoma longifolia Jack is popularly sought in Southeast Asian countries for traditional remedies to improve sexual performance and fertility. 13α(21)-Epoxyeurycomanone and eurycomanone, two major quassinoids in a root extract (TAF2) were reported to improve rat spermatogenesis and fertility. Unfortunately, these quassinoids possess low bioavailability because of high aqueous solubility and low lipid membrane permeability. Often, other possible barriers may be P-glycoprotein (P-gp) efflux in the gut and presystemic hepatic metabolism. The present study attempted to solve these problems by formulating a lipid-based solid dispersion (TAF2-SD) of optimized mixture of TAF2 and emulsifiers, which was then orally administered to rats prior to sperm count analysis. The TAF2-SD-treated rats showed significantly twofold (p < 0.001) and fourfold (p < 0.001) higher sperm count than did TAF2-treated and vehicle-treated (control) rats, respectively. The study also demonstrated no significant in vitro ileal absorption changes of the quassinoids by P-gp efflux inhibitors and concentration change or secondary metabolite formation upon in vitro incubation with rat liver homogenates, suggesting that P-gp-mediated efflux and presystemic metabolism were not limiting their bioavailability. Further study on orally TAF2-treated rats confirmed that the area under the curve and bioavailability curve of each quassinoid in the absence and presence of ketoconazole were unchanged. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Novel formulation and evaluation of a Q10-loaded solid lipid nanoparticle cream: in vitro and in vivo studies

    Directory of Open Access Journals (Sweden)

    Farboud ES

    2011-03-01

    Full Text Available Effat Sadat Farboud, Saman Ahmad Nasrollahi, Zahra TabbakhiDepartment of Pharmaceutics, School of Pharmacy, Tehran University of Medical Sciences, Tehran, IranAbstract: Solid lipid nanoparticles (SLNs of coenzyme Q10 (CoQ10 were formulated by a high-pressure homogenization method. The best formulation of SLN dispersion consisted of 13% lipid (cetyl palmitate or stearic acid, 8% surfactant (Tween 80 or Tego Care 450, and water. Stability tests, particle size analysis, differential scanning calorimetry, transmission electron microscopy, and release study were conducted to find the best formulation. A simple cream of CoQ10 and a cream containing CoQ10-loaded SLNs were prepared and compared on volunteers aged 20–30 years. SLNs with particle size between 50 nm and100 nm exhibited the most suitable stability. In vitro release profiles of CoQ10 from simple cream, SLN alone, and CoQ10-loaded SLN cream showed prolonged release for SLNs compared with the simple cream, whereas there was no significant difference between SLN alone and SLN in cream. In vitro release studies also demonstrated that CoQ10-loaded SLN and SLN cream possessed a biphasic release pattern in comparison with simple cream. In vivo skin hydration and elasticity studies on 25 volunteers suggested good dermal penetration and useful activity of Q10 on skin as a hydratant and antiwrinkle cream.Keywords: coenzyme Q10, SLN, release study 

  13. Luteolin-loaded solid lipid nanoparticles synthesis, characterization, & improvement of bioavailability, pharmacokinetics in vitro and vivo studies

    Science.gov (United States)

    Dang, Hao; Meng, Murtaza Hasan Weiwei; Zhao, Haiwei; Iqbal, Javed; Dai, Rongji; Deng, Yulin; Lv, Fang

    2014-04-01

    Luteolin (LU, 5,7,3',4'-tetrahydroxyflavone) most active compound in Chinese herbal flavones has been acting as a antimicrobial, anti-inflammatory, anti-cancer, and antimutagen. However, its poor bioavailability, hydrophobicity, and pharmacokinetics restrict clinical application. Here in this study, LU-loaded solid lipid nanoparticles have been prepared by hot-microemulsion ultrasonic technique to improve the bioavailability & pharmacokinetics of compound. LU-loaded solid lipid nanoparticle size was confirmed by particle size analyzer with range from 47 to 118 nm, having zepta potential -9.2 mV and polydisperse index 0.247, respectively. Round-shaped SLNPs were obtained by using transmission electron microscope, and encapsulation efficiency 74.80 % was calculated by using HPLC. Both in vitro and vivo studies, LC-MS/MS technique was used for quantification of Luteolin in rat. The T max value of drug with LU-SLNs after the administration was Ten times shorter than pure Luteolin suspension administration. C max value of drug after the administration of LU-SLNs was five times higher than obtained with native drug suspension. Luteolin with SLNs has increased the half-life approximately up to 2 h. Distribution and clearance of drug with SLNs were significantly decreased by 2.16-10.57 fold, respectively. In the end, the relative bioavailability of SLNs has improved about 4.89 compared to Luteolin with SLNs. From this study, it can be concluded that LU-SLNs have not only great potential for improving solubility but also increased the drug concentration in plasma. Furthermore, use of LC-MS/MS for quantification of LU-SLNs in rat plasma is reliable and of therapeutic usefulness, especially for neurodegenerative and cancerous disorders in humans.

  14. Increased therapeutic efficacy of a newly synthesized tyrosinase inhibitor by solid lipid nanoparticles in the topical treatment of hyperpigmentation

    Directory of Open Access Journals (Sweden)

    Al-Amin M

    2016-12-01

    Full Text Available Md Al-Amin, Jiafu Cao, Muhammad Naeem, Hasanul Banna, Min-Soo Kim, Yunjin Jung, Hae Young Chung, Hyung Ryong Moon, Jin-Wook Yoo College of Pharmacy, Pusan National University, Busan, South Korea Abstract: Hyperpigmentation caused by melanin overproduction is a major skin disorder in humans. Inhibition of tyrosinase, a key regulator of melanin production, has been used as an effective strategy to treat hyperpigmentation. In this study, we investigated the use of solid lipid nanoparticles (SLNs as a highly effective and nontoxic means to deliver a newly synthesized potent tyrosinase inhibitor, MHY498, and to target melanocytes through the skin. MHY498-loaded SLNs (MHY-SLNs were prepared by an oil-in-water emulsion solvent-evaporation method, and their morphological and physicochemical properties were characterized. MHY-SLNs showed a prolonged drug-release profile and higher skin permeation than that of MHY solution. In an in vivo evaluation of antimelanogenic activity, MHY-SLNs showed a prominent inhibitory effect against ultraviolet B-induced melanogenesis, resulting in no change in the skin color of C57BL/6 mouse, compared with that observed in an MHY solution-treated group and an untreated control group. The antimelanogenic effect of MHY-SLNs was further confirmed through Fontana–Masson staining. Importantly, MHY-SLNs did not induce any toxic effects in the L929 cell line. Overall, these data indicate that MHY-SLNs show promise in the topical treatment of hyperpigmentation. Keywords: melanogenesis, hyperpigmentation, MHY498, solid lipid nanoparticles, skin delivery

  15. High resolution solid-state NMR spectroscopy of the Yersinia pestis outer membrane protein Ail in lipid membranes

    International Nuclear Information System (INIS)

    Yao, Yong; Dutta, Samit Kumar; Park, Sang Ho; Rai, Ratan; Fujimoto, L. Miya; Bobkov, Andrey A.; Opella, Stanley J.; Marassi, Francesca M.

    2017-01-01

    The outer membrane protein Ail (Adhesion invasion locus) is one of the most abundant proteins on the cell surface of Yersinia pestis during human infection. Its functions are expressed through interactions with a variety of human host proteins, and are essential for microbial virulence. Structures of Ail have been determined by X-ray diffraction and solution NMR spectroscopy, but those samples contained detergents that interfere with functionality, thus, precluding analysis of the structural basis for Ail’s biological activity. Here, we demonstrate that high-resolution solid-state NMR spectra can be obtained from samples of Ail in detergent-free phospholipid liposomes, prepared with a lipid to protein molar ratio of 100. The spectra, obtained with 13 C or 1 H detection, have very narrow line widths (0.40–0.60 ppm for 13 C, 0.11–0.15 ppm for 1 H, and 0.46–0.64 ppm for 15 N) that are consistent with a high level of sample homogeneity. The spectra enable resonance assignments to be obtained for N, CO, CA and CB atomic sites from 75 out of 156 residues in the sequence of Ail, including 80% of the transmembrane region. The 1 H-detected solid-state NMR 1 H/ 15 N correlation spectra obtained for Ail in liposomes compare very favorably with the solution NMR 1 H/ 15 N TROSY spectra obtained for Ail in nanodiscs prepared with a similar lipid to protein molar ratio. These results set the stage for studies of the molecular basis of the functional interactions of Ail with its protein partners from human host cells, as well as the development of drugs targeting Ail.

  16. High resolution solid-state NMR spectroscopy of the Yersinia pestis outer membrane protein Ail in lipid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yong; Dutta, Samit Kumar [Sanford Burnham Prebys Medical Discovery Institute (United States); Park, Sang Ho; Rai, Ratan [University of California San Diego, Department of Chemistry and Biochemistry (United States); Fujimoto, L. Miya; Bobkov, Andrey A. [Sanford Burnham Prebys Medical Discovery Institute (United States); Opella, Stanley J. [University of California San Diego, Department of Chemistry and Biochemistry (United States); Marassi, Francesca M., E-mail: fmarassi@sbp.edu [Sanford Burnham Prebys Medical Discovery Institute (United States)

    2017-03-15

    The outer membrane protein Ail (Adhesion invasion locus) is one of the most abundant proteins on the cell surface of Yersinia pestis during human infection. Its functions are expressed through interactions with a variety of human host proteins, and are essential for microbial virulence. Structures of Ail have been determined by X-ray diffraction and solution NMR spectroscopy, but those samples contained detergents that interfere with functionality, thus, precluding analysis of the structural basis for Ail’s biological activity. Here, we demonstrate that high-resolution solid-state NMR spectra can be obtained from samples of Ail in detergent-free phospholipid liposomes, prepared with a lipid to protein molar ratio of 100. The spectra, obtained with {sup 13}C or {sup 1}H detection, have very narrow line widths (0.40–0.60 ppm for {sup 13}C, 0.11–0.15 ppm for {sup 1}H, and 0.46–0.64 ppm for {sup 15}N) that are consistent with a high level of sample homogeneity. The spectra enable resonance assignments to be obtained for N, CO, CA and CB atomic sites from 75 out of 156 residues in the sequence of Ail, including 80% of the transmembrane region. The {sup 1}H-detected solid-state NMR {sup 1}H/{sup 15}N correlation spectra obtained for Ail in liposomes compare very favorably with the solution NMR {sup 1}H/{sup 15}N TROSY spectra obtained for Ail in nanodiscs prepared with a similar lipid to protein molar ratio. These results set the stage for studies of the molecular basis of the functional interactions of Ail with its protein partners from human host cells, as well as the development of drugs targeting Ail.

  17. Statistical analysis of solid lipid nanoparticles produced by high-pressure homogenization: a practical prediction approach

    Energy Technology Data Exchange (ETDEWEB)

    Duran-Lobato, Matilde, E-mail: mduran@us.es [Universidad de Sevilla, Dpto. Farmacia y Tecnologia Farmaceutica, Facultad de Farmacia (Espana) (Spain); Enguix-Gonzalez, Alicia [Universidad de Sevilla, Dpto. Estadistica e Investigacion Operativa, Facultad de Matematicas (Espana) (Spain); Fernandez-Arevalo, Mercedes; Martin-Banderas, Lucia [Universidad de Sevilla, Dpto. Farmacia y Tecnologia Farmaceutica, Facultad de Farmacia (Espana) (Spain)

    2013-02-15

    Lipid nanoparticles (LNPs) are a promising carrier for all administration routes due to their safety, small size, and high loading of lipophilic compounds. Among the LNP production techniques, the easy scale-up, lack of organic solvents, and short production times of the high-pressure homogenization technique (HPH) make this method stand out. In this study, a statistical analysis was applied to the production of LNP by HPH. Spherical LNPs with mean size ranging from 65 nm to 11.623 {mu}m, negative zeta potential under -30 mV, and smooth surface were produced. Manageable equations based on commonly used parameters in the pharmaceutical field were obtained. The lipid to emulsifier ratio (R{sub L/S}) was proved to statistically explain the influence of oil phase and surfactant concentration on final nanoparticles size. Besides, the homogenization pressure was found to ultimately determine LNP size for a given R{sub L/S}, while the number of passes applied mainly determined polydispersion. {alpha}-Tocopherol was used as a model drug to illustrate release properties of LNP as a function of particle size, which was optimized by the regression models. This study is intended as a first step to optimize production conditions prior to LNP production at both laboratory and industrial scale from an eminently practical approach, based on parameters extensively used in formulation.

  18. Statistical analysis of solid lipid nanoparticles produced by high-pressure homogenization: a practical prediction approach

    International Nuclear Information System (INIS)

    Durán-Lobato, Matilde; Enguix-González, Alicia; Fernández-Arévalo, Mercedes; Martín-Banderas, Lucía

    2013-01-01

    Lipid nanoparticles (LNPs) are a promising carrier for all administration routes due to their safety, small size, and high loading of lipophilic compounds. Among the LNP production techniques, the easy scale-up, lack of organic solvents, and short production times of the high-pressure homogenization technique (HPH) make this method stand out. In this study, a statistical analysis was applied to the production of LNP by HPH. Spherical LNPs with mean size ranging from 65 nm to 11.623 μm, negative zeta potential under –30 mV, and smooth surface were produced. Manageable equations based on commonly used parameters in the pharmaceutical field were obtained. The lipid to emulsifier ratio (R L/S ) was proved to statistically explain the influence of oil phase and surfactant concentration on final nanoparticles size. Besides, the homogenization pressure was found to ultimately determine LNP size for a given R L/S , while the number of passes applied mainly determined polydispersion. α-Tocopherol was used as a model drug to illustrate release properties of LNP as a function of particle size, which was optimized by the regression models. This study is intended as a first step to optimize production conditions prior to LNP production at both laboratory and industrial scale from an eminently practical approach, based on parameters extensively used in formulation.

  19. Development of solid supports for electrochemical study of biomimetic membrane systems

    DEFF Research Database (Denmark)

    Mech-Dorosz, Agnieszka

    cushion directly on a gold electrode microchip and on a polyethersulfone (PES) support grafted by in situ polymerized hydrogel. Both strategies proved to be suitable for immobilization of functional bRh loaded lipo-polymersomes. Amperometric monitoring showed that the PES membrane support facilitated......Biomimetic membranes are model membrane systems used as an experimental tool to study fundamental cellular membrane physics and functionality of reconstituted membrane proteins. By exploiting the properties of biomimetic membranes resembling the functions of biological membranes, it is possible...... to construct biosensors for high-throughput screening of potential drug candidates. Among a variety of membrane model systems used for biomimetic approach, lipid bilayers in the form of black lipid membranes (BLMs) and lipo-polymersomes (vesicle structures composed of lipids and polymers), both...

  20. Adipose tissue conditioned media support macrophage lipid-droplet biogenesis by interfering with autophagic flux.

    Science.gov (United States)

    Bechor, Sapir; Nachmias, Dikla; Elia, Natalie; Haim, Yulia; Vatarescu, Maayan; Leikin-Frenkel, Alicia; Gericke, Martin; Tarnovscki, Tanya; Las, Guy; Rudich, Assaf

    2017-09-01

    Obesity promotes the biogenesis of adipose tissue (AT) foam cells (FC), which contribute to AT insulin resistance. Autophagy, an evolutionarily-conserved house-keeping process, was implicated in cellular lipid handling by either feeding and/or degrading lipid-droplets (LDs). We hypothesized that beyond phagocytosis of dead adipocytes, AT-FC biogenesis is supported by the AT microenvironment by regulating autophagy. Non-polarized ("M0") RAW264.7 macrophages exposed to AT conditioned media (AT-CM) exhibited a markedly enhanced LDs biogenesis rate compared to control cells (8.3 Vs 0.3 LDs/cells/h, p<0.005). Autophagic flux was decreased by AT-CM, and fluorescently following autophagosomes over time revealed ~20% decline in new autophagic vesicles' formation rate, and 60-70% decrease in autophagosomal growth rate, without marked alternations in the acidic lysosomal compartment. Suppressing autophagy by either targeting autophagosome formation (pharmacologically, with 3-methyladenine or genetically, with Atg12±Atg7-siRNA), decreased the rate of LD formation induced by oleic acid. Conversely, interfering with late autophago-lysosomal function, either pharmacologically with bafilomycin-A1, chloroquine or leupeptin, enhanced LD formation in macrophages without affecting LD degradation rate. Similarly enhanced LD biogenesis rate was induced by siRNA targeting Lamp-1 or the V-ATPase. Collectively, we propose that secreted products from AT interrupt late autophagosome maturation in macrophages, supporting enhanced LDs biogenesis and AT-FC formation, thereby contributing to AT dysfunction in obesity. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  1. Solvent-Controlled Chemoselectivity in the Photolytic Release of Hydroxamic Acids and Carboxamides from Solid Support

    DEFF Research Database (Denmark)

    Qvortrup, Katrine; Petersen, Rico G; Dohn, Asmus Ougaard

    2017-01-01

    The synthetic utility and theoretical basis of a photolabile hydroxylamine-linker are presented. The developed protocols enable the efficient synthesis and chemoselective photolytic release of either hydroxamates or carboxamides from solid support. The bidetachable mode of the linker unit...

  2. On plate graphite supported sample processing for simultaneous lipid and protein identification by matrix assisted laser desorption ionization mass spectrometry.

    Science.gov (United States)

    Calvano, Cosima Damiana; van der Werf, Inez Dorothé; Sabbatini, Luigia; Palmisano, Francesco

    2015-05-01

    The simultaneous identification of lipids and proteins by matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) after direct on-plate processing of micro-samples supported on colloidal graphite is demonstrated. Taking advantages of large surface area and thermal conductivity, graphite provided an ideal substrate for on-plate proteolysis and lipid extraction. Indeed proteins could be efficiently digested on-plate within 15 min, providing sequence coverages comparable to those obtained by conventional in-solution overnight digestion. Interestingly, detection of hydrophilic phosphorylated peptides could be easily achieved without any further enrichment step. Furthermore, lipids could be simultaneously extracted/identified without any additional treatment/processing step as demonstrated for model complex samples such as milk and egg. The present approach is simple, efficient, of large applicability and offers great promise for protein and lipid identification in very small samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Temperature-controlled structure and kinetics of ripple phases in one- and two-component supported lipid bilayers

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Leidy, Chad; Crowe, J.H.

    2003-01-01

    Temperature-controlled atomic force microscopy (AFM) has been used to visualize and study the structure and kinetics of ripple phases in one-component dipalmitoylphosphaticlylcholine (DPPC) and two-component dimyristoylphosphatidylcholine-distearoylphosphatidylcholine (DMPC-DSPC) lipid bilayers....... The lipid bilayers are mica-supported double bilayers in which ripple-phase formation occurs in the top bilayer. In one-component DPPC lipid bilayers, the stable and metastable ripple phases were observed. In addition, a third ripple structure with approximately twice the wavelength of the metastable...... ripples was seen. From height profiles of the AFM images, estimates of the amplitudes of the different ripple phases are reported. To elucidate the processes of ripple formation and disappearance, a ripple-phase DPPC lipid bilayer was taken through the pretransition in the cooling and the heating...

  4. Utilization of solid lipid nanoparticles for enhanced delivery of curcumin in cocultures of HT29-MTX and Caco-2 cells.

    Science.gov (United States)

    Guri, Anilda; Gülseren, Ibrahim; Corredig, Milena

    2013-09-01

    Solid lipid nanoparticles (SLN) have shown potential for encapsulation, protection and delivery of lipophilic functional components. In this study, we have investigated the capabilities of SLN to deliver a hydrophobic polyphenol compound, curcumin, in a coculture system of absorptive Caco-2 and mucus secreting HT29-MTX cells. The cells were grown on transport filters to mimic the human intestinal epithelium. Because of the hydrophobic nature of curcumin, its delivery to the basolateral compartment is expected to take place via a paracellular route. The changes in curcumin concentration in various compartments (i.e., apical, basolateral, mucus, and cell lysates) were evaluated using fluorescence spectroscopy. Two SLN systems were prepared with different emulsifying agents. The encapsulation of curcumin in SLN caused enhanced delivery compared to unencapsulated curcumin. In addition, SLN showed enhanced delivery compared to emulsion droplets containing liquid soy oil. The SLN were retained on the apical mucosal layer to a greater extent than emulsion droplets. The presence of SLN did not affect the integrity of the cellular junctions, as indicated by the TEER values, and the route of transport of the solid particles was simple diffusion, with permeability rates of about 7 × 10(-6) cm s(-1). Approximately 1% of total curcumin was delivered to the basolateral compartment, suggesting that most of the curcumin was absorbed and metabolized by the cell.

  5. Multi criteria decision making to select the best method for the preparation of solid lipid nanoparticles of rasagiline mesylate using analytic hierarchy process

    Directory of Open Access Journals (Sweden)

    Viveksarathi Kunasekaran

    2014-01-01

    Full Text Available The objective of this study was to select best method for the development of rasagiline mesylate (RM loaded nanoscale solid lipid particles using analytic hierarchy process (AHP. Improper method selection may lead to waste of time, loss of material and financial resources. One of the possibilities to overcome these difficulties, AHP was employed to find the suitable method. In the AHP, a decision of hierarchy was constructed with a goal, criteria, sub-criteria, and alternatives. After constructing the AHP, the expert choice software was used to compute the overall priority of criteria, sub-criteria and alternatives. The best alternative selected was based on the highest priority. Nanoscale solid lipid particles of RM was formulated by the selected microemulsion method (M4 and it shows the particle size, polydispersity index and zeta potential were within acceptable limits. Drug content and entrapment efficiency of the RM-solid lipid nanoparticles were 97.26% and 86.57%, respectively. This study concludes that the AHP was viable and effective tool for selecting a most suitable method for the fabrication of RM loaded nanoscale solid lipid particles.

  6. Nanoscale science and engineering forum (706c) design of solid lipid particles with iron oxide quantum dots for the delivery of therapeutic agents

    Science.gov (United States)

    Solid lipid particles provide a method to encapsulate and control the release of drugs in vivo but lack the imaging capability provided by CdS quantum dots. This shortcoming was addressed by combining these two technologies into a model system that uses iron oxide as a non-toxic imaging component in...

  7. Exceptionally Stable and Efficient Solid Supported Hoveyda-Type Catalyst

    Czech Academy of Sciences Publication Activity Database

    Skowerski, K.; Pastva, J.; Czarnocki, S. J.; Janošcová, Jana

    2015-01-01

    Roč. 19, č. 7 (2015), s. 872-877 ISSN 1083-6160 Institutional support: RVO:61388955 Keywords : OLEFIN-METATHESIS CATALYSTS * RING-CLOSING METATHESIS * N-HETEROCYCLIC CARBENES Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.922, year: 2015

  8. Evaluation of in-vitro cytotoxicity and cellular uptake efficiency of zidovudine-loaded solid lipid nanoparticles modified with Aloe Vera in glioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Joshy, K.S. [Department of Chemistry, CMS College Kottayam, Kerala (India); International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Sharma, Chandra P. [Division of Biosurface Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Science and Technology, Poojappura, Thiruvananthapuram, Kerala (India); Kalarikkal, Nandakumar [International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Sandeep, K. [International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Thomas, Sabu, E-mail: sabuchathukulam@yahoo.co.uk [International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Pothen, Laly A. [Department of Chemistry, Bishop Moore College, Mavelikkara, Kerala (India)

    2016-09-01

    Zidovudine loaded solid lipid nanoparticles of stearic acid modified with Aloe Vera (AV) have been prepared via simple emulsion solvent evaporation method which showed excellent stability at room temperature and refrigerated condition. The nanoparticles were examined by Fourier transform infrared spectroscopy (FT-IR), which revealed the overlap of the AV absorption peak with the absorption peak of modified stearic acid nanoparticles. The inclusion of AV to stearic acid decreased the crystallinity and improved the hydrophilicity of lipid nanoparticles and thereby improved the drug loading efficacy of lipid nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging revealed that, the average particle size of unmodified (bare) nanoparticles was 45.66 ± 12.22 nm and modified solid lipid nanoparticles showed an average size of 265.61 ± 80.44 nm. Solid lipid nanoparticles with well-defined morphology were tested in vitro for their possible application in drug delivery. Cell culture studies using C6 glioma cells on the nanoparticles showed enhanced growth and proliferation of cells without exhibiting any toxicity. In addition, normal cell morphology and improved uptake were observed by fluorescence microscopy images of rhodamine labeled modified solid lipid nanoparticles compared with unmodified nanoparticles. The cellular uptake study suggested that these nanoparticles could be a promising drug delivery system to enhance the uptake of antiviral drug by brain cells and it could be a suitable drug carrier system for the treatment of HIV. - Highlights: • SLN of AZT-SA, AZT-SA-AV was developed • Better drug loading efficacy • Good uptake.

  9. Evaluation of in-vitro cytotoxicity and cellular uptake efficiency of zidovudine-loaded solid lipid nanoparticles modified with Aloe Vera in glioma cells

    International Nuclear Information System (INIS)

    Joshy, K.S.; Sharma, Chandra P.; Kalarikkal, Nandakumar; Sandeep, K.; Thomas, Sabu; Pothen, Laly A.

    2016-01-01

    Zidovudine loaded solid lipid nanoparticles of stearic acid modified with Aloe Vera (AV) have been prepared via simple emulsion solvent evaporation method which showed excellent stability at room temperature and refrigerated condition. The nanoparticles were examined by Fourier transform infrared spectroscopy (FT-IR), which revealed the overlap of the AV absorption peak with the absorption peak of modified stearic acid nanoparticles. The inclusion of AV to stearic acid decreased the crystallinity and improved the hydrophilicity of lipid nanoparticles and thereby improved the drug loading efficacy of lipid nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging revealed that, the average particle size of unmodified (bare) nanoparticles was 45.66 ± 12.22 nm and modified solid lipid nanoparticles showed an average size of 265.61 ± 80.44 nm. Solid lipid nanoparticles with well-defined morphology were tested in vitro for their possible application in drug delivery. Cell culture studies using C6 glioma cells on the nanoparticles showed enhanced growth and proliferation of cells without exhibiting any toxicity. In addition, normal cell morphology and improved uptake were observed by fluorescence microscopy images of rhodamine labeled modified solid lipid nanoparticles compared with unmodified nanoparticles. The cellular uptake study suggested that these nanoparticles could be a promising drug delivery system to enhance the uptake of antiviral drug by brain cells and it could be a suitable drug carrier system for the treatment of HIV. - Highlights: • SLN of AZT-SA, AZT-SA-AV was developed • Better drug loading efficacy • Good uptake

  10. Chemical cleavage reactions of DNA on solid support: application in mutation detection

    Directory of Open Access Journals (Sweden)

    Cotton Richard GH

    2003-05-01

    Full Text Available Abstract Background The conventional solution-phase Chemical Cleavage of Mismatch (CCM method is time-consuming, as the protocol requires purification of DNA after each reaction step. This paper describes a new version of CCM to overcome this problem by immobilizing DNA on silica solid supports. Results DNA test samples were loaded on to silica beads and the DNA bound to the solid supports underwent chemical modification reactions with KMnO4 (potassium permanganate and hydroxylamine in 3M TEAC (tetraethylammonium chloride solution. The resulting modified DNA was then simultaneously cleaved by piperidine and removed from the solid supports to afford DNA fragments without the requirement of DNA purification between reaction steps. Conclusions The new solid-phase version of CCM is a fast, cost-effective and sensitive method for detection of mismatches and mutations.

  11. The Effect of Millisecond Pulsed Electric Fields (msPEF) on Intracellular Drug Transport with Negatively Charged Large Nanocarriers Made of Solid Lipid Nanoparticles (SLN): In Vitro Study.

    Science.gov (United States)

    Kulbacka, Julita; Pucek, Agata; Wilk, Kazimiera Anna; Dubińska-Magiera, Magda; Rossowska, Joanna; Kulbacki, Marek; Kotulska, Małgorzata

    2016-10-01

    Drug delivery technology is still a dynamically developing field of medicine. The main direction in nanotechnology research (nanocarriers, nanovehicles, etc.) is efficient drug delivery to target cells with simultaneous drug reduction concentration. However, nanotechnology trends in reducing the carrier sizes to several nanometers limit the volume of the loaded substance and may pose a danger of uncontrolled access into the cells. On the other hand, nanoparticles larger than 200 nm in diameter have difficulties to undergo rapid diffusional transport through cell membranes. The main advantage of large nanoparticles is higher drug encapsulation efficiency and the ability to deliver a wider array of drugs. Our present study contributes a new approach with large Tween 80 solid lipid nanoparticles SLN (i.e., hydrodynamic GM-SLN-glycerol monostearate, GM, as the lipid and ATO5-SLNs-glyceryl palmitostearate, ATO5, as the lipid) with diameters DH of 379.4 nm and 547 nm, respectively. They are used as drug carriers alone and in combination with electroporation (EP) induced by millisecond pulsed electric fields. We evaluate if EP can support the transport of large nanocarriers into cells. The study was performed with two cell lines: human colon adenocarcinoma LoVo and hamster ovarian fibroblastoid CHO-K1 with coumarin 6 (C6) as a fluorescent marker for encapsulation. The biological safety of the potential treatment procedure was evaluated with cell viability after their exposure to nanoparticles and EP. The EP efficacy was evaluated by FACS method. The impact on intracellular structure organization of cytoskeleton was visualized by CLSM method with alpha-actin and beta-tubulin. The obtained results indicate low cytotoxicity of both carrier types, free and loaded with C6. The evaluation of cytoskeleton proteins indicated no intracellular structure damage. The intracellular uptake and accumulation show that SLNs do not support transport of C6 coumarin. Only application of

  12. The efficacy of Isotretinoin-loaded solid lipid nanoparticles in comparison to Isotrex® on acne treatment

    Directory of Open Access Journals (Sweden)

    Shiva Golmohammadzadeh

    2013-01-01

    Full Text Available Abstract: Topical retinoids are considered as the first line therapy in the treatment of acne vulgaris, but they are associated with cutaneous irritation. In this study, isotretinoin-loaded solid lipid nanoparticles(IT-SLN were prepared to treat the mild to moderate acne. Also using IT-SLN would minimize IT adverse effects in comparison to commercial product, Isotrex®. This study was conducted to prepare and characterize IT-SLN and assessing the efficiency of IT-SLN comparing to Isotrex® acne. IT-SLN was prepared using hot high pressure homogenization method.  IT-SLN contained 0.05% IT in 5% of lipid phase (Glyceryl monostearate- GMS and tween 80 (2.5 % w/v was used as surfactant in the aqueous phase. IT-SLN was characterized by particle size analyzing, differential scanning calorimetry and transmission electron microscopy. Encapsulation efficacy was also obtained using spectrophotometry. The efficacy of IT-SLN was evaluated in a randomized, single-blind, parallel-group study and compared with Isotrex®. Forty patients encountered in the study and divided in two groups. Treatment regimen was once-nightly topical administration accompanied with topical administration of clindamycin 2% solution twice a day for 8 weeks. The particle size of IT-SLN was around 60 nm with PDI of 0.4 and zeta potential was about -40 mV. Encapsulation efficacy of IT in SLN in crystalline form was 84±0.21%. IT-SLN produced significantly better treatment than Isotrex® in both non-inflammatory and inflammatory lesions according to its recovery percent after 8 weeks. Also IT-SLN gained better global assessment scores. Our results showed that IT-SLN had higher efficacy than Isotrex® to clear non-inflammatory and inflammatory lesions.

  13. Sustained release of piroxicam from solid lipid nanoparticle as an effective anti-inflammatory therapeutics in vivo.

    Science.gov (United States)

    Peng, Li-Hua; Wei, Wei; Shan, Ying-Hui; Chong, Yee-Song; Yu, Lian; Gao, Jian-Qing

    2017-01-01

    This study aims to investigate the solid lipid nanoparticle (SLN) as a novel vehicle for the sustained release and transdermal delivery of piroxicam, as well as to determine the anti-inflammation effect of piroxicam-loaded SLN. SLN formulation was optimized and the particle size, polydispersity index, zeta potential (ZP), encapsulation efficiency, drug release, and morphological properties were characterized. The transdermal efficiency and mechanism of the piroxicam-loaded SLNs were investigated in vitro. With the inflammation induced edema model in rat, the anti-inflammatory efficiency of piroxicam-enriched SLNs (Pir-SLNs) was evaluated. The SLN formulation was optimized as: lecithin 100 mg, glycerin monostearate 200 mg, and Tween (1%, w/w). The particle size is around 102 ± 5.2 nm with a PDI of 0.262. The ZP is 30.21 ± 2.05 mV. The prepared SLNs showed high entrapment efficiency of 87.5% for piroxicam. There is no interaction between piroxicam and the vehicle components. The presence of polymorphic form of lipid with higher drug content in the optimized Pir-SLNs enables the Pir-SLNs to release the drug with a sustained manner. Pir-SLNs with oleic acid as enhancer can radically diffuse into both the stratum corneum and dermal layer, as well as penetrate through the hair follicles and sebaceous glands with significantly higher density than the other control groups. Pir-SLNs promptly inhibited the inflammation since the 3rd hour after the treatment by decreasing the PGE 2 level. SLN was demonstrated to be a promising carrier for encapsulation and sustained release of piroxicam. Pir-SLN is a novel topical preparation with great potential for anti-inflammation application.

  14. Covalent attachment of proteins to solid supports and surfaces via Sortase-mediated ligation.

    Directory of Open Access Journals (Sweden)

    Lilyan Chan

    Full Text Available BACKGROUND: There is growing interest in the attachment of proteins to solid supports for the development of supported catalysts, affinity matrices, and micro devices as well as for the development of planar and bead based protein arrays for multiplexed assays of protein concentration, interactions, and activity. A critical requirement for these applications is the generation of a stable linkage between the solid support and the immobilized, but still functional, protein. METHODOLOGY: Solid supports including crosslinked polymer beads, beaded agarose, and planar glass surfaces, were modified to present an oligoglycine motif to solution. A range of proteins were ligated to the various surfaces using the Sortase A enzyme of S. aureus. Reactions were carried out in aqueous buffer conditions at room temperature for times between one and twelve hours. CONCLUSIONS: The Sortase A transpeptidase of S. aureus provides a general, robust, and gentle approach to the selective covalent immobilization of proteins on three very different solid supports. The proteins remain functional and accessible to solution. Sortase mediated ligation is therefore a straightforward methodology for the preparation of solid supported enzymes and bead based assays, as well as the modification of planar surfaces for microanalytical devices and protein arrays.

  15. Development of free-flowing peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles via atomization with carbon dioxide.

    Science.gov (United States)

    Yang, Junsi; Ciftci, Ozan Nazim

    2016-09-01

    The main objective of this study was to overcome the issues related to the volatility and strong smell that limit the efficient utilization of essential oils as "natural" antimicrobials in the food industry. Peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles were successfully formed using a novel "green" method based on atomization of CO 2 -expanded lipid mixture. The highest essential oil loading efficiency (47.5%) was achieved at 50% initial essential oil concentration at 200bar expansion pressure and 50μm nozzle diameter, whereas there was no significant difference between the loading efficiencies (35%-39%) at 5%, 7%, 10%, and 20% initial essential oil concentrations (p>0.05). Particles generated at all initial essential oil concentrations were spherical but increasing the initial essential oil concentration to 20% and 50% generated a less smooth particle surface. After 4weeks of storage, 61.2%, 42.5%, 0.2%, and 2.0% of the loaded essential oil was released from the particles formed at 5%, 10%, 20%, and 50% initial essential oil concentrations, respectively. This innovative simple and clean process is able to form spherical hollow micro- and nanoparticles loaded with essential oil that can be used as food grade antimicrobials. These novel hollow solid lipid micro- and nanoparticles are alternatives to the solid lipid nanoparticles, and overcome the issues associated with the solid lipid nanoparticles. The dry free-flowing products make the handling and storage more convenient, and the simple and clean process makes the scaling up more feasible. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Investigation on Secondary Structure Perturbations of Proteins Embedded in Solid Lipid Matrices as a Novel Indicator of their Biological Activity upon In Vitro Release

    DEFF Research Database (Denmark)

    Zeeshan, Farrukh; Tabbassum, Misbah; Jorgensen, Lene

    2018-01-01

    encased in solid lipid matrices as a novel indicator of their stability upon in vitro release. Model proteins namely catalase and lysozyme were incorporated into lipid namely Precirol® AT05 (glycerol palmitostearate, melting point 58°C) at 30% w/w loading using melting and mixing and wet granulation...... aggregation for catalase which was increased using wet granulation. The biological activity of catalase was statistically different from that of control and was affected by the incorporation method and was found to be in alignment with ATR spectral changes and extent of aggregation. In conclusion, ATR...

  17. 'Boomerang'-like insertion of a fusogenic peptide in a lipid membrane revealed by solid-state 19F NMR.

    Science.gov (United States)

    Afonin, Sergii; Dürr, Ulrich H N; Glaser, Ralf W; Ulrich, Anne S

    2004-02-01

    Solid state (19)F NMR revealed the conformation and alignment of the fusogenic peptide sequence B18 from the sea urchin fertilization protein bindin embedded in flat phospholipid bilayers. Single (19)F labels were introduced into nine distinct positions along the wild-type sequence by substituting each hydrophobic amino acid, one by one, with L-4-fluorophenylglycine. Their anisotropic chemical shifts were measured in uniaxially oriented membrane samples and used as orientational constraints to model the peptide structure in the membrane-bound state. Previous (1)H NMR studies of B18 in 30% TFE and in detergent micelles had shown that the peptide structure consists of two alpha-helical segments that are connected by a flexible hinge. This helix-break-helix motif was confirmed here by the solid-state (19)F NMR data, while no other secondary structure (beta-sheet, 3(10)-helix) was compatible with the set of orientational constraints. For both alpha-helical segments we found that the helical conformation extends all the way to the respective N- and C-termini of the peptide. Analysis of the corresponding tilt and azimuthal rotation angles showed that the N-terminal helix of B18 is immersed obliquely into the bilayer (at a tilt angle tau approximately 54 degrees), whereas the C-terminus is peripherally aligned (tau approximately 91 degrees). The azimuthal orientation of the two segments is consistent with the amphiphilic distribution of side-chains. The observed 'boomerang'-like mode of insertion into the membrane may thus explain how peptide binding leads to lipid dehydration and acyl chain perturbation as a prerequisite for bilayer fusion to occur. Copyright 2004 John Wiley & Sons, Ltd.

  18. Effects of biosurfactants, mannosylerythritol lipids, on the hydrophobicity of solid surfaces and infection behaviours of plant pathogenic fungi.

    Science.gov (United States)

    Yoshida, S; Koitabashi, M; Nakamura, J; Fukuoka, T; Sakai, H; Abe, M; Kitamoto, D; Kitamoto, H

    2015-07-01

    To investigate the effects of mannosylerythritol lipids (MELs) on the hydrophobicity of solid surfaces, their suppressive activity against the early infection behaviours of several phytopathogenic fungal conidia, and their suppressive activity against disease occurrences on fungal host plant leaves. The changes in the hydrophobicity of plastic film surfaces resulting from treatments with MEL solutions (MEL-A, MEL-B, MEL-C and isoMEL-B) and synthetic surfactant solutions were evaluated based on the changes in contact angles of water droplets placed on the surfaces. The droplet angles on surfaces treated with MELs were verified to decrease within 100 s after placement, with contact angles similar to those observed on Tween 20-treated surfaces, indicating decreases in surface hydrophobicity after MEL treatments. Next, conidial germination, germ tube elongation and the formation of appressorium of Blumeria graminis f. sp. tritici, Colletotrichum dematium, Glomerella cingulata and Magnaporthe grisea were evaluated on plastic surfaces that were pretreated with surfactant solutions. On the surfaces of MEL-treated plastic film, inhibition of conidial germination, germ tube elongation, and suppression of appressoria formation tended to be observed, although the level of effect was dependent on the combination of fungal species and type of MEL. Inoculation tests revealed that the powdery mildew symptom caused by B. graminis f. sp. tritici was significantly suppressed on wheat leaf segments treated with MELs. MELs exhibited superior abilities in reducing the hydrophobicity of solid surfaces, and have the potential to suppress powdery mildew in wheat plants, presumably due to the inhibition of conidial germination. This study provides significant evidence of the potential for MELs to be used as novel agricultural chemical pesticides. © 2015 The Society for Applied Microbiology.

  19. Porous nanoparticle-supported lipid bilayers (protocells) for targeted delivery and methods of using same

    Energy Technology Data Exchange (ETDEWEB)

    Brinker, C. Jeffrey; Carnes, Eric C.; Ashley, Carlee Erin; Willman, Cheryl L.

    2017-02-28

    The present invention is directed to protocells for specific targeting of hepatocellular and other cancer cells which comprise a nanoporous silica core with a supported lipid bilayer; at least one agent which facilitates cancer cell death (such as a traditional small molecule, a macromolecular cargo (e.g. siRNA or a protein toxin such as ricin toxin A-chain or diphtheria toxin A-chain) and/or a histone-packaged plasmid DNA disposed within the nanoporous silica core (preferably supercoiled in order to more efficiently package the DNA into protocells) which is optionally modified with a nuclear localization sequence to assist in localizing protocells within the nucleus of the cancer cell and the ability to express peptides involved in therapy (apoptosis/cell death) of the cancer cell or as a reporter, a targeting peptide which targets cancer cells in tissue to be treated such that binding of the protocell to the targeted cells is specific and enhanced and a fusogenic peptide that promotes endosomal escape of protocells and encapsulated DNA. Protocells according to the present invention may be used to treat cancer, especially including hepatocellular (liver) cancer using novel binding peptides (c-MET peptides) which selectively bind to hepatocellular tissue or to function in diagnosis of cancer, including cancer treatment and drug discovery.

  20. Determination of radiation-induced hydrocarbons in processed food and complex lipid matrices. A new solid phase extraction (SPE) method for detection of irradiated components in food

    International Nuclear Information System (INIS)

    Hartmann, M.; Ammon, J.; Berg, H.

    1997-01-01

    Detection of irradiated components in processed food with complex lipid matrices can be affected by two problems. First, the processed food may contain only a small amount of the irradiated component, and the radiation-induced hydrocarbons may be diluted throughout the lipid matrix of the whole food. Second, in complex lipid matrices, the detection of prior irradiation is often disturbed by fat-associated compounds. In these cases, common solid phase extraction (SPE) Florisil clean-up alone is inadequate in the detection of prior irradiation. Subsequent SPE argentation chromatography of the Florisil eluate allows the measurement of small amounts of irradiated lipid-containing ingredients in processed food as well as the detection of prior irradiation in complex lipid matrices such as paprika and chilli. SPE argetation chromatography is the first method available for the selective enrichment of radiation-specific hydrocarbons from even complex lipid matrices, thus enabling the detection of irradiation does as low as 0.025 kGy. Furthermore, by using radiation-induced hydrocarbons in the detection of prior irradiation of paprika and chilli powder, a second independent method, the first being measurement of thermoluminescence, is available for the analysis of these matrices. Such analysis could be achieved by using this highly sensitive, cheap and easy to perform combined SPE Florisil/argentation chromatography method, without the need for sophisticated techniques like SFE-GC/MS or LC-GC/MS, so that highly sensitive detection of prior irradiation colud be performed in almost every laboratory

  1. Lipid-drug-conjugate (LDC) solid lipid nanoparticles (SLN) for the delivery of nicotine to the oral cavity - optimization of nicotine loading efficiency.

    Science.gov (United States)

    Ding, Yuan; Nielsen, Kent A; Nielsen, Bruno P; Bøje, Niels W; Müller, Rainer H; Pyo, Sung Min

    2018-03-12

    Nicotine, obtained from tobacco leaves, has been used to promote the cessation of smoking and reduce the risk of COPD and lung cancer. Incorporating the active in lipid nanoparticles is an effective tool to minimize its irritation potential and to use the particles as intermediate to produce final products. However, as a hydrophilic active, it is a challenge to prepare nicotine loaded lipid nanoparticles with high drug loading. In this study, lipid-drug-conjugates (LDC) were formed by nicotine and different fatty acids to enable the production of sufficiently loaded nicotine lipid nanoparticles. The encapsulation efficiency of nicotine in LDC-containing SLN was about 50%, which increased at least fourfold compared to the non-LDC formulations (around 10%) due to the increased lipophilicity of nicotine by strong interactions between positively charged nicotine and negatively charged fatty acids (formation of LDCs). The z-average of all formulations (150 to 350 nm) proved to be in the required submicron size range with a narrow size distribution. In summary, nicotine loaded LDC lipid nanoparticles with high drug loading were successfully developed with Kolliwax® S and stearic acid as counter-ion forming the LDC and hydrogenated sunflower oil (HSO) as lipid particle matrix. Copyright © 2018. Published by Elsevier B.V.

  2. pH-Responsive therapeutic solid lipid nanoparticles for reducing P-glycoprotein-mediated drug efflux of multidrug resistant cancer cells

    Directory of Open Access Journals (Sweden)

    Chen HH

    2015-08-01

    Full Text Available Hsin-Hung Chen,1 Wen-Chia Huang,2 Wen-Hsuan Chiang,2 Te-I Liu,2 Ming-Yin Shen,2,3 Yuan-Hung Hsu,4 Sung-Chyr Lin,1 Hsin-Cheng Chiu2 1Department of Chemical Engineering, National Chung Hsing University, Taichung, 2Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 3Department of Surgery, National Taiwan University Hospital-Hsinchu Branch, 4Pharmaceutical Optimization Technology Division, Biomedical Technology and Device Research Laboratory, Industrial Technology Research Institute, Hsinchu, Taiwan Abstract: In this study, a novel pH-responsive cholesterol-PEG adduct-coated solid lipid nanoparticles (C-PEG-SLNs carrying doxorubicin (DOX capable of overcoming multidrug resistance (MDR breast cancer cells is presented. The DOX-loaded SLNs have a mean hydrodynamic diameter of ~100 nm and a low polydispersity index (under 0.20 with a high drug-loading efficiency ranging from 80.8% to 90.6%. The in vitro drug release profiles show that the DOX-loaded SLNs exhibit a pH-controlled drug release behavior with the maximum and minimum unloading percentages of 63.4% at pH 4.7 and 25.2% at pH 7.4, respectively. The DOX-loaded C-PEG-SLNs displayed a superior ability in inhibiting the proliferation of MCF-7/MDR cells. At a DOX concentration of 80 µM, the cell viabilities treated with C-PEG-SLNs were approximately one-third of the group treated with free DOX. The inhibition activity of C-PEG-SLNs could be attributed to the transport of C-PEG to cell membrane, leading to the change of the composition of the cell membrane and thus the inhibition of permeability glycoprotein activity. This hypothesis is supported by the confocal images showing the accumulation of DOX in the nuclei of cancer cells and the localization of C-PEG on the cell membranes. The results of in vivo study further demonstrated that the DOX delivered by the SLNs accumulates predominantly in tumor via enhanced permeability and retention effect, the

  3. Solid lipid nanoparticles carrying chemotherapeutic drug across the blood-brain barrier through insulin receptor-mediated pathway.

    Science.gov (United States)

    Kuo, Yung-Chih; Shih-Huang, Chun-Yuan

    2013-09-01

    Carmustine (BCNU)-loaded solid lipid nanoparticles (SLNs) were grafted with 83-14 monoclonal antibody (MAb) (83-14 MAb/BCNU-SLNs) and applied to the brain-targeting delivery. Human brain-microvascular endothelial cells (HBMECs) incubated with 83-14 MAb/BCNU-SLNs were stained to demonstrate the interaction between the nanocarriers and expressed insulin receptors (IRs). The results revealed that the particle size of 83-14 MAb/BCNU-SLNs decreased with an increasing weight percentage of Dynasan 114 (DYN). Storage at 4 °C for 6 weeks slightly deformed the colloidal morphology. In addition, poloxamer 407 on 83-14 MAb/BCNU-SLNs induced cytotoxicity to RAW264.7 cells and inhibited phagocytosis by RAW264.7 cells. An increase in the weight percentage of DYN from 0% to 67% slightly reduced the viability of RAW264.7 cells and promoted phagocytosis. Moreover, the transport ability of 83-14 MAb/BCNU-SLNs across the blood-brain barrier (BBB) in vitro enhanced with an increasing weight percentage of Tween 80. 83-14 MAb on MAb/BCNU-SLNs stimulated endocytosis by HBMECs via IRs and enhanced the permeability of BCNU across the BBB. 83-14 MAb/BCNU-SLNs can be a promising antitumor drug delivery system for transporting BCNU to the brain.

  4. Investigation of the effects of solid lipid curcumin on cognition and mood in a healthy older population.

    Science.gov (United States)

    Cox, Katherine H M; Pipingas, Andrew; Scholey, Andrew B

    2015-05-01

    Curcumin possesses many properties which may prevent or ameliorate pathological processes underlying age-related cognitive decline, dementia or mood disorders. These benefits in preclinical studies have not been established in humans. This randomized, double-blind, placebo-controlled trial examined the acute (1 and 3 h after a single dose), chronic (4 weeks) and acute-on-chronic (1 and 3 h after single dose following chronic treatment) effects of solid lipid curcumin formulation (400 mg as Longvida®) on cognitive function, mood and blood biomarkers in 60 healthy adults aged 60-85. One hour after administration curcumin significantly improved performance on sustained attention and working memory tasks, compared with placebo. Working memory and mood (general fatigue and change in state calmness, contentedness and fatigue induced by psychological stress) were significantly better following chronic treatment. A significant acute-on-chronic treatment effect on alertness and contentedness was also observed. Curcumin was associated with significantly reduced total and LDL cholesterol and had no effect on hematological safety measures. To our knowledge this is the first study to examine the effects of curcumin on cognition and mood in a healthy older population or to examine any acute behavioral effects in humans. Results highlight the need for further investigation of the potential psychological and cognitive benefits of curcumin in an older population. © The Author(s) 2014.

  5. Transferrin-tailored solid lipid nanoparticles as vectors for site-specific delivery of temozolomide to brain

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Aviral, E-mail: draviraljain@gmail.com; Singhai, Priyanka; Gurnany, Ekta; Updhayay, Satish; Mody, Nishi [Adina Institute of Pharmaceutical Sciences, Pharmaceutics Research Laboratory, Department of Pharmaceutics (India)

    2013-03-15

    Blood-brain barrier restricts the uptake of many important hydrophilic drugs and limits their efficacy in the treatment of brain diseases because of the presence of tight junctions, high metabolic capacity, low pinocytic vesicular traffic, and efficient efflux mechanisms. In the present project, transferrin (Tf)-conjugated solid lipid nanoparticles (Tf-SLNs) were investigated for their ability to deliver temozolomide (TMZ) to the brain. SLNs were prepared by an ethanol injection method using hydrogenated soya phosphatidylcholine, triolein, cholesterol and distearoylphosphatidylethanolamine. Conjugation of SLNs with Tf was achieved by incubation of Tf with TMZ-loaded SLNs in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in phosphate buffered saline (pH 7.4) as a cross linker. SLNs preparation were characterized for particle size, polydispersity index, zeta potential, surface morphology, percent drug entrapment efficiency, in vitro drug release, and hemolytic toxicity studies. In vitro cytotoxicity studies were performed on human cancer cell lines. The average size was found to be 221 {+-} 3.22 nm with entrapment efficiency of 69.83 {+-} 2.52 and 249 {+-} 2.61 nm with entrapment efficiency decreased to 64.21 {+-} 2.27 % for unconjugated SLNs and Tf-SLNs, respectively. Fluorescence studies revealed the enhanced uptake of Tf-SLNs in brain tissue compared with unconjugated SLNs.

  6. Development of Houttuynia cordata Extract-Loaded Solid Lipid Nanoparticles for Oral Delivery: High Drug Loading Efficiency and Controlled Release

    Directory of Open Access Journals (Sweden)

    Ju-Heon Kim

    2017-12-01

    Full Text Available Houttuynia cordata (H. cordata has been used for diuresis and detoxification in folk medicine as well as a herbal medicine with antiviral and antibacterial activities. H. cordata extract-loaded solid lipid nanoparticles (H-SLNs were prepared with various concentration of poloxamer 188 or poloxamer 407 by a hot homogenization and ultrasonication method. H-SLNs dispersion was freeze-dried with or without trehalose as a cryoprotectant. The physicochemical characteristics of H-SLNs were evaluated by dynamic laser scattering (DLS, differential scanning calorimetry (DSC, Fourier transform infrared spectroscopy (FT-IR, and scanning electron microscopy (SEM. Additionally, the in vitro release and in vitro cytotoxicity of H-SLNs were measured. Encapsulation efficiencies of H-SLNs (as quercitrin were 92.9–95.9%. The SEM images of H-SLNs showed that H-SLNs have a spherical morphology. DSC and FT-IR showed that there were no interactions between ingredients. The increased extent of particle size of freeze-dried H-SLNs with trehalose was significantly lower than that of H-SLNs without trehalose. H-SLNs provided sustained release of quercitrin from H. cordata extracts. Cell viability of Caco-2 cells was over 70% according to the concentration of various formulation. Therefore, it was suggested that SLNs could be good carrier for administering H. cordata extracts.

  7. Safety profile of solid lipid nanoparticles loaded with rosmarinic acid for oral use: in vitro and animal approaches.

    Science.gov (United States)

    Madureira, Ana Raquel; Nunes, Sara; Campos, Débora A; Fernandes, João C; Marques, Cláudia; Zuzarte, Monica; Gullón, Beatriz; Rodríguez-Alcalá, Luís M; Calhau, Conceição; Sarmento, Bruno; Gomes, Ana Maria; Pintado, Maria Manuela; Reis, Flávio

    2016-01-01

    Rosmarinic acid (RA) possesses several protective bioactivities that have attracted increasing interest by nutraceutical/pharmaceutical industries. Considering the reduced bioavailability after oral use, effective (and safe) delivery systems are crucial to protect RA from gastrointestinal degradation. This study aims to characterize the safety profile of solid lipid nanoparticles produced with Witepsol and Carnauba waxes and loaded with RA, using in vitro and in vivo approaches, focused on genotoxicity and cytotoxicity assays, redox status markers, hematological and biochemical profile, liver and kidney function, gut bacterial microbiota, and fecal fatty acids composition. Free RA and sage extract, empty nanoparticles, or nanoparticles loaded with RA or sage extract (0.15 and 1.5 mg/mL) were evaluated for cell (lymphocytes) viability, necrosis and apoptosis, and antioxidant/prooxidant effects upon DNA. Wistar rats were orally treated for 14 days with vehicle (control) and with Witepsol or Carnauba nanoparticles loaded with RA at 1 and 10 mg/kg body weight/d. Blood, urine, feces, and several tissues were collected for analysis. Free and loaded RA, at 0.15 mg/mL, presented a safe profile, while genotoxic potential was found for the higher dose (1.5 mg/mL), mainly by necrosis. Our data suggest that both types of nanoparticles are safe when loaded with moderate concentrations of RA, without in vitro genotoxicity and cytotoxicity and with an in vivo safety profile in rats orally treated, thus opening new avenues for use in nutraceutical applications.

  8. Transferrin-tailored solid lipid nanoparticles as vectors for site-specific delivery of temozolomide to brain

    Science.gov (United States)

    Jain, Aviral; Singhai, Priyanka; Gurnany, Ekta; Updhayay, Satish; Mody, Nishi

    2013-03-01

    Blood-brain barrier restricts the uptake of many important hydrophilic drugs and limits their efficacy in the treatment of brain diseases because of the presence of tight junctions, high metabolic capacity, low pinocytic vesicular traffic, and efficient efflux mechanisms. In the present project, transferrin (Tf)-conjugated solid lipid nanoparticles (Tf-SLNs) were investigated for their ability to deliver temozolomide (TMZ) to the brain. SLNs were prepared by an ethanol injection method using hydrogenated soya phosphatidylcholine, triolein, cholesterol and distearoylphosphatidylethanolamine. Conjugation of SLNs with Tf was achieved by incubation of Tf with TMZ-loaded SLNs in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in phosphate buffered saline (pH 7.4) as a cross linker. SLNs preparation were characterized for particle size, polydispersity index, zeta potential, surface morphology, percent drug entrapment efficiency, in vitro drug release, and hemolytic toxicity studies. In vitro cytotoxicity studies were performed on human cancer cell lines. The average size was found to be 221 ± 3.22 nm with entrapment efficiency of 69.83 ± 2.52 and 249 ± 2.61 nm with entrapment efficiency decreased to 64.21 ± 2.27 % for unconjugated SLNs and Tf-SLNs, respectively. Fluorescence studies revealed the enhanced uptake of Tf-SLNs in brain tissue compared with unconjugated SLNs.

  9. Preparation of oridonin-loaded solid lipid nanoparticles and studies on them in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Dianrui [College of Life Science and Technology, Beijing University of Chemical Technology, 15 Bei Sanhuan Donglu, Beijing 100029 (China); Tan Tianwei [College of Life Science and Technology, Beijing University of Chemical Technology, 15 Bei Sanhuan Donglu, Beijing 100029 (China); Gao Lei [Department of Pharmaceutics, College of Pharmacy, Shandong University, 44 Wenhua Xilu, Jinan 250012 (China)

    2006-12-14

    Oridonin, a lipophilic Chinese medicine, has very low oral bioavailability due to its poor solubility. Solid lipid nanoparticle (SLN) delivery systems of oridonin have been formed using stearic acid, soybean lecithin and pluronic F{sub 68} in our studies to overcome this problem. Emulsion evaporation-solidification at low temperature was used to prepare SLN dispersions. The particle size and morphology were examined by transmission electron microscopy (TEM), and the zeta potential was measured by a television micro-electrophoresis apparatus. Process and formulation variables have been studied and optimized on the basis of entrapment efficiency. Differential scanning calorimetry (DSC) and powder x-ray diffraction (PXRD) studies were performed to characterize the state of the drug. In vitro release studies were performed in phosphate-buffer solution (PBS) (pH 7.4). The tissue distribution in mice and the pharmacokinetics in rabbits were studied to evaluate the tissue targeted property of SLNs. Stable SLN formulations of oridonin having a mean size range of 15-35 nm and mean zeta potential -45.07 mV were developed. More than 40% oridonin was entrapped in SLNs. DSC and PXRD analysis showed that oridonin is dispersed in SLNs in an amorphous state. The release pattern of the drug was analysed and found to follow the Higuchi equations. In vivo studies demonstrated that oridonin-loaded SLNs obviously increased the concentration of oridonin in liver, lung and spleen, while its distribution in heart and kidney decreased.

  10. Characterization and evaluation of 5-fluorouracil-loaded solid lipid nanoparticles prepared via a temperature-modulated solidification technique.

    Science.gov (United States)

    Patel, Meghavi N; Lakkadwala, Sushant; Majrad, Mohamed S; Injeti, Elisha R; Gollmer, Steven M; Shah, Zahoor A; Boddu, Sai Hanuman Sagar; Nesamony, Jerry

    2014-12-01

    The aim of this research was to advance solid lipid nanoparticle (SLN) preparation methodology by preparing glyceryl monostearate (GMS) nanoparticles using a temperature-modulated solidification process. The technique was reproducible and prepared nanoparticles without the need of organic solvents. An anticancer agent, 5-fluorouracil (5-FU), was incorporated in the SLNs. The SLNs were characterized by particle size analysis, zeta potential analysis, differential scanning calorimetry (DSC), infrared spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), drug encapsulation efficiency, in vitro drug release, and in vitro cell viability studies. Particle size of the SLN dispersion was below 100 nm, and that of redispersed lyophilizates was ~500 nm. DSC and infrared spectroscopy suggested that the degree of crystallinity did not decrease appreciably when compared to GMS. TEM and AFM images showed well-defined spherical to oval particles. The drug encapsulation efficiency was found to be approximately 46%. In vitro drug release studies showed that 80% of the encapsulated drug was released within 1 h. In vitro cell cultures were biocompatible with blank SLNs but demonstrated concentration-dependent changes in cell viability to 5-FU-loaded SLNs. The 5-FU-loaded SLNs can potentially be utilized in an anticancer drug delivery system.

  11. Temoporfin-loaded 1-tetradecanol-based thermoresponsive solid lipid nanoparticles for photodynamic therapy

    Czech Academy of Sciences Publication Activity Database

    Brezaniova, I.; Hrubý, Martin; Králová, Jarmila; Král, V.; Černochová, Zulfiya; Černoch, Peter; Šlouf, Miroslav; Kredatusová, Jana; Štěpánek, Petr

    2016-01-01

    Roč. 241, 10 November (2016), s. 34-44 ISSN 0168-3659 R&D Projects: GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109; GA TA ČR(CZ) TE01020118; GA MŠk(CZ) LO1507; GA MŠk(CZ) 7F14009 Institutional support: RVO:61389013 ; RVO:68378050 Keywords : photodynamic therapy * nanomedicine * drug delivery Subject RIV: CD - Macromolecular Chemistry; EB - Genetics ; Molecular Biology (UMG-J) Impact factor: 7.786, year: 2016

  12. Decision support models for solid waste management: Review and game-theoretic approaches

    International Nuclear Information System (INIS)

    Karmperis, Athanasios C.; Aravossis, Konstantinos; Tatsiopoulos, Ilias P.; Sotirchos, Anastasios

    2013-01-01

    Highlights: ► The mainly used decision support frameworks for solid waste management are reviewed. ► The LCA, CBA and MCDM models are presented and their strengths, weaknesses, similarities and possible combinations are analyzed. ► The game-theoretic approach in a solid waste management context is presented. ► The waste management bargaining game is introduced as a specific decision support framework. ► Cooperative and non-cooperative game-theoretic approaches to decision support for solid waste management are discussed. - Abstract: This paper surveys decision support models that are commonly used in the solid waste management area. Most models are mainly developed within three decision support frameworks, which are the life-cycle assessment, the cost–benefit analysis and the multi-criteria decision-making. These frameworks are reviewed and their strengths and weaknesses as well as their critical issues are analyzed, while their possible combinations and extensions are also discussed. Furthermore, the paper presents how cooperative and non-cooperative game-theoretic approaches can be used for the purpose of modeling and analyzing decision-making in situations with multiple stakeholders. Specifically, since a waste management model is sustainable when considering not only environmental and economic but also social aspects, the waste management bargaining game is introduced as a specific decision support framework in which future models can be developed

  13. Decision support models for solid waste management: Review and game-theoretic approaches

    Energy Technology Data Exchange (ETDEWEB)

    Karmperis, Athanasios C., E-mail: athkarmp@mail.ntua.gr [Sector of Industrial Management and Operational Research, School of Mechanical Engineering, National Technical University of Athens, Iroon Polytechniou 9, 15780 Athens (Greece); Army Corps of Engineers, Hellenic Army General Staff, Ministry of Defence (Greece); Aravossis, Konstantinos; Tatsiopoulos, Ilias P.; Sotirchos, Anastasios [Sector of Industrial Management and Operational Research, School of Mechanical Engineering, National Technical University of Athens, Iroon Polytechniou 9, 15780 Athens (Greece)

    2013-05-15

    Highlights: ► The mainly used decision support frameworks for solid waste management are reviewed. ► The LCA, CBA and MCDM models are presented and their strengths, weaknesses, similarities and possible combinations are analyzed. ► The game-theoretic approach in a solid waste management context is presented. ► The waste management bargaining game is introduced as a specific decision support framework. ► Cooperative and non-cooperative game-theoretic approaches to decision support for solid waste management are discussed. - Abstract: This paper surveys decision support models that are commonly used in the solid waste management area. Most models are mainly developed within three decision support frameworks, which are the life-cycle assessment, the cost–benefit analysis and the multi-criteria decision-making. These frameworks are reviewed and their strengths and weaknesses as well as their critical issues are analyzed, while their possible combinations and extensions are also discussed. Furthermore, the paper presents how cooperative and non-cooperative game-theoretic approaches can be used for the purpose of modeling and analyzing decision-making in situations with multiple stakeholders. Specifically, since a waste management model is sustainable when considering not only environmental and economic but also social aspects, the waste management bargaining game is introduced as a specific decision support framework in which future models can be developed.

  14. Recovery of Terephthalic Acid by employing magnetic nanoparticles as a solid support

    Directory of Open Access Journals (Sweden)

    Elmira Ghamary

    2018-03-01

    Full Text Available Abstract The aim of this research work is focused on the improvement of Terephthalic acid recovery from PET wastes by using organically modified nano-Fe3O4@Cyanuric Chloride as the solid support. The performance of organically modified nano magnetic was examined in detail and the obtained results were compared with the unsupported reaction data. Required reaction time for complete glycolysis of the wastes, consumption of the solvent as well as catalyst decreases up 99%, 37.5% and 40% respectively. Result showed that nano-Fe 3O4@Cyanuric Chloride delivered good performance as solid support in depolymerizing of PET to the terephthalic acid.

  15. Combinatorial chemistry on solid support in the search for central nervous system agents.

    Science.gov (United States)

    Zajdel, Paweł; Pawłowski, Maciej; Martinez, Jean; Subra, Gilles

    2009-08-01

    The advent of combinatorial chemistry was one of the most important developments, that has significantly contributed to the drug discovery process. Within just a few years, its initial concept aimed at production of libraries containing huge number of compounds (thousands to millions), so called screening libraries, has shifted towards preparation of small and medium-sized rationally designed libraries. When applicable, the use of solid supports for the generation of libraries has been a real breakthrough in enhancing productivity. With a limited amount of resin and simple manual workups, the split/mix procedure may generate thousands of bead-tethered compounds. Beads can be chemically or physically encoded to facilitate the identification of a hit after the biological assay. Compartmentalization of solid supports using small reactors like teabags, kans or pellicular discrete supports like Lanterns resulted in powerful sort and combine technologies, relying on codes 'written' on the reactor, and thus reducing the need for automation and improving the number of compounds synthesized. These methods of solid-phase combinatorial chemistry have been recently supported by introduction of solid-supported reagents and scavenger resins. The first part of this review discusses the general premises of combinatorial chemistry and some methods used in the design of primary and focused combinatorial libraries. The aim of the second part is to present combinatorial chemistry methodologies aimed at discovering bioactive compounds acting on diverse GPCR involved in central nervous system disorders.

  16. Numerical evaluation of micro-structural parameters of porous supports in metal-supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Reiss, Georg; Frandsen, Henrik Lund; Brandstätter, Wilhelm

    2014-01-01

    Metallic supported Solid Oxide Fuel Cells (SOFCs) are considered as a durable and cost effective alternative to the state-of-the-art ceramic supported cell designs. In order to understand the mass and charge transport in the metal-support of this new type of cell a novel technique involving X......-ray tomography and micro-structural modelling is presented in this work. The simulation technique comprises a novel treatment of the boundary conditions, which leads to more accurate effective transport parameters compared to those, which can be achieved with the conventional homogenisation procedures....... Furthermore, the porosity distribution in the metal-support was determined, which provided information about the inhomogeneous nature of the material. In addition to that, transport parameters for two identified, different dense layers of the metal-support are evaluated separately. The results...

  17. The Use of Quasi-Isothermal Modulated Temperature Differential Scanning Calorimetry for the Characterization of Slow Crystallization Processes in Lipid-Based Solid Self-Emulsifying Systems

    OpenAIRE

    Otun, Sarah O.; Meehan, Elizabeth; Qi, Sheng; Craig, Duncan Q. M.

    2014-01-01

    Purpose Slow or incomplete crystallization may be a significant manufacturing issue for solid lipid-based dosage forms, yet little information is available on this phenomenon. In this investigation we suggest a novel means by which slow solidification may be monitored in Gelucire 44/14 using quasi-isothermal modulated temperature DSC (QiMTDSC). Methods Conventional linear heating and cooling DSC methods were employed, along with hot stage microscopy (HSM), for basic thermal profiling of Geluc...

  18. Supported zirconium sulfate on carbon nanotubes as water-tolerant solid acid catalyst

    International Nuclear Information System (INIS)

    Juan, Joon Ching; Jiang Yajie; Meng Xiujuan; Cao Weiliang; Yarmo, Mohd Ambar; Zhang Jingchang

    2007-01-01

    A new solid acid of zirconium sulfate (CZ) was successfully supported on carbon nanotube (CNT) for esterification reaction. Preparation conditions of the supported CZ have been investigated, to obtain highest catalytic activity for esterification reaction. XRD, TEM, BET, X-ray photoelectron spectra (XPS) and in situ FTIR analysis has also been carried out to understand the characteristics of the catalyst. In the esterification of acrylic acid with n-octanol, the supported CZ exhibited high catalytic activity and stability. The catalytic activity was nearly unchanged during four times of reuse. XRD and TEM analysis indicated that CZ was finely dispersed on CNT. XPS analysis shows that the CZ species was preserved and the chemical environment of the CZ has changed after loaded on CNT. This finding show that CNT as CZ support is an efficient water-tolerant solid acid

  19. Safety profile of solid lipid nanoparticles loaded with rosmarinic acid for oral use: in vitro and animal approaches

    Directory of Open Access Journals (Sweden)

    Madureira AR

    2016-08-01

    Full Text Available Ana Raquel Madureira,1 Sara Nunes,2 Débora A Campos,1 João C Fernandes,2 Cláudia Marques,3 Monica Zuzarte,2 Beatriz Gullón,1 Luís M Rodríguez-Alcalá,1 Conceição Calhau,3,4 Bruno Sarmento,5–7 Ana Maria Gomes,1 Maria Manuela Pintado,1 Flávio Reis2 1Catholic University of Portugal, CBQF – Center for Biotechnology and Fine Chemistry – Associate Laboratory, Faculty of Biotechnology, Porto, Portugal; 2Laboratory of Pharmacology and Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI, Faculty of Medicine, and CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal; 3Department of Biochemistry, Faculty of Medicine, University of Porto, Porto, Portugal; 4Center for Health Technology and Services Research (CINTESIS, Porto, Portugal; 5Department of Pharmaceutical Sciences, Institute of Health Sciences-North, CESPU, Gandra, Portugal; 6“I3S” Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal; 7INEB, Institute of Biomedical Engineering, University of Porto, Porto, Portugal Abstract: Rosmarinic acid (RA possesses several protective bioactivities that have attracted increasing interest by nutraceutical/pharmaceutical industries. Considering the reduced bioavailability after oral use, effective (and safe delivery systems are crucial to protect RA from gastrointestinal degradation. This study aims to characterize the safety profile of solid lipid nanoparticles produced with Witepsol and Carnauba waxes and loaded with RA, using in vitro and in vivo approaches, focused on genotoxicity and cytotoxicity assays, redox status markers, hematological and biochemical profile, liver and kidney function, gut bacterial microbiota, and fecal fatty acids composition. Free RA and sage extract, empty nanoparticles, or nanoparticles loaded with RA or sage extract (0.15 and 1.5 mg/mL were evaluated for cell (lymphocytes viability, necrosis and apoptosis, and antioxidant

  20. Defined media and inert supports : their potential as solid-state fermentation production systems

    NARCIS (Netherlands)

    Ooijkaas, L.P.; Weber, F.J.; Buitelaar, R.M.; Tramper, J.; Rinzema, A.

    2000-01-01

    Solid-state fermentation (SSF) using inert supports impregnated with chemically defined liquid media has several potential applications in both scientific studies and in the industrial production of high-value products, such as metabolites, biological control agents and enzymes. As a result of its

  1. Magnetron sputtered gadolinia-doped ceria diffusion barriers for metal-supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Sønderby, Steffen; Klemensø, Trine; Christensen, Bjarke H.

    2014-01-01

    Gadolinia-doped ceria (GDC) thin films are deposited by reactive magnetron sputtering in an industrial-scale setup and implemented as barrier layers between the cathode and electrolyte in metal-based solid oxide fuel cells consisting of a metal support, an electrolyte of ZrO2 co-doped with Sc2O3...

  2. Smectite clays as solid supports for immobilization of beta-glucosidase : Synthesis, characterization, and biochemical properties

    NARCIS (Netherlands)

    Serefoglou, Evangelia; Litina, Kiriaki; Gournis, Dimitrios; Kalogeris, Emmanuel; Tzialla, Aikaterini A.; Pavlidis, Ioannis V.; Stamatis, Haralambos; Maccallini, Enrico; Lubomska, Monika; Rudolf, Petra

    2008-01-01

    Nanomaterials as solid supports can improve the efficiency of immobilized enzymes by reducing diffusional limitation as well as by increasing the surface area per mass unit and therefore improving enzyme loading. In this work, beta-glucosidase from almonds was immobilized on two smectite nanoclays.

  3. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane

    Directory of Open Access Journals (Sweden)

    A. G. Gaikwad

    2012-06-01

    Full Text Available Transport of carbonate ions was explored through fiber supported solid membrane. A novel fiber supported solid membrane was prepared by chemical modification of cellulose fiber with citric acid, 2′2-bipyridine and magnesium carbonate. The factors affecting the permeability of carbonate ions such as immobilization of citric acid-magnesium metal ion -2′2-bipyridine complex (0 to 2.5 mmol/g range over cellulose fiber, carbon-ate ion concentration in source phase and NaOH concentration in receiving phase were investigated. Ki-netic of carbonate, sulfate, and nitrate ions was investigated through fiber supported solid membrane. Transport of carbonate ions with/without bubbling of CO2 (0 to 10 ml/min in source phase was explored from source to receiving phase. The novel idea is to explore the adsorptive transport of CO2 from source to receiving phase through cellulose fiber containing magnesium metal ion organic framework. Copyright © 2012 BCREC UNDIP. All rights reserved.Received: 25th November 2011; Revised: 17th December 2011; Accepted: 19th December 2011[How to Cite: A.G. Gaikwad. (2012. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 49– 57.  doi:10.9767/bcrec.7.1.1225.49-57][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1225.49-57 ] | View in 

  4. Towards High Power Density Metal Supported Solid Oxide Fuel Cell for Mobile Applications

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Persson, Åsa H.; Muhl, Thuy Thanh

    2018-01-01

    For use of metal supported solid oxide fuel cell (MS-SOFC) in mobile applications it is important to reduce the thermal mass to enable fast startup, increase stack power density in terms of weight and volume and reduce costs. In the present study, we report on the effect of reducing the Technical...

  5. Investigation of Novel Electrocatalysts for Metal Supported Solid Oxide Fuel Cells - Ru:GDC

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmy; Thydén, Karl Tor Sune

    2015-01-01

    The electrochemical performance and stability of the planar metal supported solid oxide fuel cells (MS-SOFC) with two different electrocatalytically active materials, namely, Ni:GDC and Ru:GDC were investigated. Ru:GDC with an ASR of 0.322 Ωcm2 performed better than Ni:GDC with an ASR of 0.453 Ωc...

  6. Preliminary formulation and characterization of solid lipid nanoparticles containing chloroquine and a P-glycoprotein inhibitor: Influences of lipid-surfactant ratios

    CSIR Research Space (South Africa)

    Nzekwe, IT

    2015-02-01

    Full Text Available . In this work, the inclusion of a P-gp inhibitor, chlorpheniramine, and chloroquine in a lipid-based nanoparticle carrier is proposed, with the aim of ensuring that adequate drug levels are attained, so as to overcome drug resistance. Methods: The nanoparticles...

  7. Vitamin E TPGS emulsified vinorelbine bitartrate loaded solid lipid nanoparticles (SLN): Formulation development, optimization and in vitro characterization.

    Science.gov (United States)

    Maurya, Lakshmi; Rajamanickam, Vijayakumar Mahalingam; Narayan, Gopeshwar; Singh, Sanjay

    2018-04-08

    Vinorelbine bitartrate (VRL), a semi synthetic vinca alkaloid approved for breast cancer, has been proved to beneficial as first line and subsequent therapies. However, it's hydrophilic and thermo labile nature provides hindrance to oral clinical translation. The current work focused on the application of DOE a modern statistical optimization tool for the development and optimization of a solid lipid nanoparticle (SLN) formulation that can encapsulate hydrophilic and thermolabile Vinorelbine bitartrate (VRL) to a maximum extent without compromising integrity and anticancer activity of the drug. SLNs were prepared by solvent diffusion technique employing Taguchi orthogonal array design with optimized formulation and process variables. The emulsifying nature and low melting point of glyceryl mono-oleate (GMO) were exploited to enhance entrapment and minimizing temperature associated degradation, respectively. Moreover, two types of surfactants, Vitamin E TPGS (TPGS) and Poloxamer-188 were utilized to obtain TPGS-VRL-SLNs and PL-VRL-SLNs, respectively. The SLNs were characterized for various physicochemical properties, in-vitro drug release kinetics and anticancer activity by MTT assay on MCF-7 cancer cell lines. The SLNs were found to be spherical in shape with entrapment efficiency (EE) up to 58 %. In-vitro release studies showed biphasic release pattern following Korsemeyer peppas model with fickian release kinetics. Results of MTT assay revealed that TPGS-VRL-SLNs and PL-VRL-SLNs were 39.5 and 18.5 fold more effective, respectively, compared to the pristine VRL. DOE approach was successfully applied for the development of VRL-SLNs. Enhanced entrapment and anticancer efficacy of TPGS-VRL-SLN can be attributed to emulsifying nature of GMO and inherent cytotoxic nature of TPGS, respectively, which synergizes with VRL. Therefore, TPGS associated SLNs may be potential carrier in cancer chemotherapeutics. Copyright© Bentham Science Publishers; For any queries, please

  8. Enhanced intracellular delivery and antibacterial efficacy of enrofloxacin-loaded docosanoic acid solid lipid nanoparticles against intracellular Salmonella.

    Science.gov (United States)

    Xie, Shuyu; Yang, Fei; Tao, Yanfei; Chen, Dongmei; Qu, Wei; Huang, Lingli; Liu, Zhenli; Pan, Yuanhu; Yuan, Zonghui

    2017-01-23

    Enrofloxacin-loaded docosanoic acid solid lipid nanoparticles (SLNs) with different physicochemical properties were developed to enhance activity against intracellular Salmonella. Their cellular uptake, intracellular elimination and antibacterial activity were studied in RAW 264.7 cells. During the experimental period, SLN-encapsulated enrofloxacin accumulated in the cells approximately 27.06-37.71 times more efficiently than free drugs at the same extracellular concentration. After incubation for 0.5 h, the intracellular enrofloxacin was enhanced from 0.336 to 1.147 μg/mg of protein as the sizes of nanoparticles were increased from 150 to 605 nm, and from 0.960 to 1.147 μg/mg of protein when the charge was improved from -8.1 to -24.9 mv. The cellular uptake was more significantly influenced by the size than it was by the charge, and was not affected by whether the charge was positive or negative. The elimination of optimal SLN-encapsulated enrofloxacin from the cells was significantly slower than that of free enrofloxacin after removing extracellular drug. The inhibition effect against intracellular Salmonella CVCC541 of 0.24 and 0.06 μg/mL encapsulated enrofloxacin was stronger than 0.6 μg/mL free drug after all of the incubation periods and at 48 h, respectively. Docosanoic acid SLNs are thus considered as a promising carrier for intracellular bacterial treatment.

  9. Histological assessment of follicular delivery of flutamide by solid lipid nanoparticles: potential tool for the treatment of androgenic alopecia.

    Science.gov (United States)

    Hamishehkar, Hamed; Ghanbarzadeh, Saeed; Sepehran, Sasan; Javadzadeh, Yousef; Adib, Zahra Mardhiah; Kouhsoltani, Maryam

    2016-01-01

    Flutamide is a potent anti-androgen with the several unwanted side effects in systemic administration, therefore, it has attracted special interest in the development of topically applied formulations for the treatment of androgenic alopecia. The purpose of this study was to prepare and characterize the solid lipid nanoparticles (SLNs) of Flutamide for follicular targeting in the treatment of the androgenic alopecia. Flutamide-loaded SLNs, promising drug carriers for topical application were prepared by hot melt homogenization method. Drug permeation and accumulation in the exercised rat skin and histological study on the male hamsters were performed to assess drug delivery efficiency in vitro and in vivo, respectively. The optimized Flutamide-loaded SLNs (size 198 nm, encapsulation efficiency percentage 65% and loading efficiency percentage 3.27%) exhibited a good stability during the period of at least 2 months. The results of X-ray diffraction showed Flutamide amorphous state confirming uniform drug dispersion in the SLNs structure. Higher skin drug deposition (1.75 times) of SLN formulation compared to Flutamide hydroalcoholic solution represented better localization of the drug in the skin. The in vivo studies showed more new hair follicle growth by utilizing Flutamide-loaded SLNs than Flutamide hydroalcoholic solution which could be due to the higher accumulation of SLNs in the hair follicles as well as slowly and continues release of the Flutamide through the SLNs maximizing hair follicle exposure by antiandrogenic drug. It was concluded Flutamide-loaded SLN formulation can be used as a promising colloidal drug carriers for topical administration of Flutamide in the treatment of androgenic alopecia.

  10. Solid lipid nanoparticles as anti-inflammatory drug delivery system in a human inflammatory bowel disease whole-blood model.

    Science.gov (United States)

    Serpe, Loredana; Canaparo, Roberto; Daperno, Marco; Sostegni, Raffaello; Martinasso, Germana; Muntoni, Elisabetta; Ippolito, Laura; Vivenza, Nicoletta; Pera, Angelo; Eandi, Mario; Gasco, Maria Rosa; Zara, Gian Paolo

    2010-03-18

    Standard treatment for inflammatory bowel diseases (IBD) necessitates frequent intake of anti-inflammatory and/or immunosuppressive drugs, leading to significant adverse events. To evaluate the role solid lipid nanoparticles (SLN) play as drug delivery system in enhancing anti-inflammatory activity for drugs such as dexamethasone and butyrate in a human inflammatory bowel diseases whole-blood model. ELISA assay and the peripheral blood mononuclear cell (PBMC) cytokine mRNA expression levels were evaluated by quantitative SYBR Green real-time RT-PCR to determine the IL-1beta, TNF-alpha, IFN-gamma and IL-10 secretion in inflammatory bowel diseases patients' PBMC culture supernatants. There was a significant decrease in IL-1beta (p<0.01) and TNF-alpha (p<0.001) secretion, whilst IL-10 (p<0.05) secretion significantly increased after cholesteryl butyrate administration, compared to that of butyrate alone at the highest concentration tested (100 microM), at 24h exposure. There was a significant decrease in IL-1beta (p<0.01), TNF-alpha (p<0.001) and IL-10 (p<0.001) secretion after dexamethasone loaded SLN administration, compared to dexamethasone alone at the highest concentration tested (250 nM) at 24h exposure. No IFN-gamma was detected under any conditions and no cytotoxic effects observed even at the highest concentration tested. The incorporation of butyrate and dexamethasone into SLN has a significant positive anti-inflammatory effect in the human inflammatory bowel disease whole-blood model. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Development of "all natural" layer-by-layer redispersible solid lipid nanoparticles by nano spray drying technology.

    Science.gov (United States)

    Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xia, Yan; Nieh, Mu-Ping; Luo, Yangchao

    2016-10-01

    Solid lipid nanoparticles (SLNs) have gained tremendous attraction as carriers for controlled drug delivery. Despite numerous advances in the field, one long-standing historical challenge for their practical applications remains unmet: redispersibility after drying. In this work, a novel design of SLNs using a layer-by-layer (LbL) technique was developed and the formulations were optimized by surface response methodology (Box-Behnken design). To the best of our knowledge, this is the first study reporting the fabrication of SLNs from all natural ingredients in the absence of any synthetic surfactants or coatings. The SLNs were prepared by a combined solvent-diffusion and hot homogenization method, with soy lecithin as natural emulsifier (first layer), followed by the subsequent coating with sodium caseinate (second layer) and pectin (third layer), both of which are natural food biopolymers. The adsorption of pectin coating onto caseinate was reinforced by hydrophobic and electrostatic interactions induced by a pH-driven process along with thermal treatment. The innovative nano spray drying technology was further explored to obtain ultra-fine powders of SLNs. Compared to uncoated or single-layer coated SLNs powders, which showed severe aggregation after spray drying, the well-separated particles with spherical shape and smooth surface were obtained for layer-by-layer (LbL) SLNs, which were redispersible into water without variation of dimension, shape and morphology. The SLNs were characterized by Fourier transform infrared and high-performance differential scanning calorimetry for their physical properties. The LbL-coated SLNs based on all natural ingredients have promising features for future applications as drug delivery systems, overcoming the major obstacles in conventional spray drying and redispersing SLNs-based formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Preparation, characterization, and pharmacokinetics of tilmicosin- and florfenicol-loaded hydrogenated castor oil-solid lipid nanoparticles.

    Science.gov (United States)

    Ling, Z; Yonghong, L; Changqing, S; Junfeng, L; Li, Z; Chunyu, J; Xianqiang, L

    2017-06-01

    To effectively control bovine mastitis, tilmicosin (TIL)- and florfenicol (FF)-loaded solid lipid nanoparticles (SLN) with hydrogenated castor oil (HCO) were prepared by a hot homogenization and ultrasonication method. In vitro antibacterial activity, properties, and pharmacokinetics of the TIL-FF-SLN were studied. The results demonstrated that TIL and FF had a synergistic or additive antibacterial activity against Streptococcus dysgalactiae, Streptococcus uberis, and Streptococcus agalactiae. The size, polydispersity index, and zeta potential of nanoparticles were 289.1 ± 13.7 nm, 0.31 ± 0.05, and -26.7 ± 1.3 mV, respectively. The encapsulation efficiencies for TIL and FF were 62.3 ± 5.9% and 85.1 ± 5.2%, and the loading capacities for TIL and FF were 8.2 ± 0.6% and 3.3 ± 0.2%, respectively. The TIL-FF-SLN showed no irritation in the injection site and sustained release in vitro. After medication, TIL and FF could maintain about 0.1 μg/mL for 122 and 6 h. Compared to the control solution, the SLN increased the area under the concentration-time curve (AUC 0-t ), elimination half-life (T ½ke ), and mean residence time (MRT) of TIL by 33.09-, 23.29-, and 37.53-fold, and 1.69-, 5.00-, and 3.83-fold for FF, respectively. These results of this exploratory study suggest that the HCO-SLN could be a useful system for the delivery of TIL and FF for bovine mastitis therapy. © 2016 John Wiley & Sons Ltd.

  13. Neutron reflectivity studies of single lipid bilayers supported on planar substrates

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, S.; Orts, W.J.; Berk, N.F.; Majkrzak, C.F. [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Koenig, B.W. [National Inst. of Health, Bethesda, MD (United States)

    1994-12-31

    Neutron reflectivity was used to probe the structure of single phosphatidylcholine (PC) lipid bilayers adsorbed onto a planar silicon surface in an aqueous environment. Fluctuations in the neutron scattering length density profiles perpendicular to the silicon/water interface were determined for different lipids as a function of the hydrocarbon chain length. The lipids were studied in both the gel and liquid crystalline phases by monitoring changes in the specularly-reflected neutron intensity as a function of temperature. Contrast variation of the neutron scattering length density was applied to both the lipid and the solvent. Scattering length density profiles were determined using both model-independent and model-dependent fitting methods. During the reflectivity measurements, a novel experimental set-up was implemented to decrease the incoherent background scattering due to the solvent. Thus, the reflectivity was measured to Q {approx} 0.3{Angstrom}{sup -1}, covering up to seven orders of magnitude in reflected intensity, for PC bilayers in D{sub 2}O and silicon-matched (38% D{sub 2}O/62% H{sub 2}O) water. The kinetics of lipid adsorption at the silicon/water interface were also explored by observing changes in the reflectivity at low Q values under silicon-matched water conditions.

  14. Neutron reflectivity studies of single lipid bilayers supported on planar substrates

    International Nuclear Information System (INIS)

    Krueger, S.; Orts, W.J.; Berk, N.F.; Majkrzak, C.F.; Koenig, B.W.

    1994-01-01

    Neutron reflectivity was used to probe the structure of single phosphatidylcholine (PC) lipid bilayers adsorbed onto a planar silicon surface in an aqueous environment. Fluctuations in the neutron scattering length density profiles perpendicular to the silicon/water interface were determined for different lipids as a function of the hydrocarbon chain length. The lipids were studied in both the gel and liquid crystalline phases by monitoring changes in the specularly-reflected neutron intensity as a function of temperature. Contrast variation of the neutron scattering length density was applied to both the lipid and the solvent. Scattering length density profiles were determined using both model-independent and model-dependent fitting methods. During the reflectivity measurements, a novel experimental set-up was implemented to decrease the incoherent background scattering due to the solvent. Thus, the reflectivity was measured to Q ∼ 0.3 Angstrom -1 , covering up to seven orders of magnitude in reflected intensity, for PC bilayers in D 2 O and silicon-matched (38% D 2 O/62% H 2 O) water. The kinetics of lipid adsorption at the silicon/water interface were also explored by observing changes in the reflectivity at low Q values under silicon-matched water conditions

  15. A novel method to produce solid lipid nanoparticles using n-butanol as an additional co-surfactant according to the o/w microemulsion quenching technique.

    Science.gov (United States)

    Mojahedian, Mohammad M; Daneshamouz, Saeid; Samani, Soliman Mohammadi; Zargaran, Arman

    2013-09-01

    Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) are novel medicinal carriers for controlled drug release and drug targeting in different roots of administration such as parenteral, oral, ophthalmic and topical. These carriers have some benefits such as increased drug stability, high drug payload, the incorporation of lipophilic and hydrophilic drugs, and no biotoxicity. Therefore, due to the cost-efficient, proportionally increasable, and reproducible preparation of SLN/NLC and the avoidance of organic solvents used, the warm microemulsion quenching method was selected from among several preparation methods for development in this research. To prepare the warm O/W microemulsion, lipids (distearin, stearic acid, beeswax, triolein alone or in combination with others) were melted at a temperature of 65°C. After that, different ratios of Tween60 (10-22.5%) and glyceryl monostearate (surfactant and co-surfactant) and water were added, and the combination was stirred. Then, 1-butanol (co-surfactant) was added dropwise until a clear microemulsion was formed and titration continued to achieve cloudiness (to obtain the microemulsion zone). The warm o/w microemulsions were added dropwise into 4°C water (1:5 volume ratio) while being stirred at 400 or 600 rpm. Lipid nanosuspensions were created upon the addition of the warm o/w microemulsion to the cold water. The SLN were obtained over a range of concentrations of co-surfactants and lipids and observed for microemulsion stability (clearness). For selected preparations, characterization involved also determination of mean particle size, polydispersity and shape. According to the aim of this study, the optimum formulations requiring the minimum amounts of 1-butanol (1.2%) and lower temperatures for creation were selected. Mono-disperse lipid nanoparticles were prepared in the size range 77 ± 1 nm to 124 ± 21 nm according to a laser diffraction particle size analyzer and transmission electron

  16. into Solid Lipid Nanoparticles

    Directory of Open Access Journals (Sweden)

    Farhad Jahanfar

    2016-09-01

    Conclusion:The results of the present study indicated that the entrapment of 5-azacytidine into SLNs enhanced its cytotoxicity performance and may pave a way for the future design of a desired dosage form for 5-azacytidine.

  17. Regenerable mixed copper-iron-inert support oxygen carriers for solid fuel chemical looping combustion process

    Energy Technology Data Exchange (ETDEWEB)

    Siriwardane, Ranjani V.; Tian, Hanjing

    2016-12-20

    The disclosure provides an oxygen carrier for a chemical looping cycle, such as the chemical looping combustion of solid carbonaceous fuels, such as coal, coke, coal and biomass char, and the like. The oxygen carrier is comprised of at least 24 weight % (wt %) CuO, at least 10 wt % Fe2O3, and an inert support, and is typically a calcine. The oxygen carrier exhibits a CuO crystalline structure and an absence of iron oxide crystalline structures under XRD crystallography, and provides an improved and sustained combustion reactivity in the temperature range of 600.degree. C.-1000.degree. C. particularly for solid fuels such as carbon and coal.

  18. Peptide Synthesis Method and Solid Support for Use in the Method

    DEFF Research Database (Denmark)

    1994-01-01

    A method for the solid-phase synthesis of peptides or proteins in high yield and high purity uses a solid support consisting of a functionalized polystyrene-grafted polymer substrate, the grafted polystyrene chains being substantially non-cross-linked and having a chain molecular weight, not incl...... is immersed in a solution of optionally substituted styrene monomer in an alcohol such as methanol, the volume percentage of styrene in the solution preferably being about 30% v/v, and subjected to gamma irradiation....

  19. Lipid somersaults

    DEFF Research Database (Denmark)

    Günther-Pomorski, Thomas; Menon, Anant K.

    2016-01-01

    Membrane lipids diffuse rapidly in the plane of the membrane but their ability to flip spontaneously across a membrane bilayer is hampered by a significant energy barrier. Thus spontaneous flip-flop of polar lipids across membranes is very slow, even though it must occur rapidly to support diverse...... aspects of cellular life. Here we discuss the mechanisms by which rapid flip-flop occurs, and what role lipid flipping plays in membrane homeostasis and cell growth. We focus on conceptual aspects, highlighting mechanistic insights from biochemical and in silico experiments, and the recent, ground......-breaking identification of a number of lipid scramblases....

  20. Stereoselective Reduction of Imines with Trichlorosilane Using Solid-Supported Chiral Picolinamides

    Directory of Open Access Journals (Sweden)

    Sílvia D. Fernandes

    2016-09-01

    Full Text Available The stereoselective reduction of imines with trichlorosilane catalyzed by chiral Lewis bases is a well-established procedure for the synthesis of enantio-enriched amines. Five supported cinchona-based picolinamides have been prepared and their activity tested in a model reaction. The comparison of different supporting materials revealed that polystyrene gave better results than silica in terms of stereoselectivity. The applicability of the solid-supported catalyst of choice to the reduction of different imines was also demonstrated. Additionally, for the first time, a catalytic reactor containing a polymer-immobilized chiral picolinamide has been employed for the stereoselective reduction of imines with trichlorosilane under continuous flow conditions.

  1. Interaction of Melittin with Negatively Charged Lipid Bilayers Supported on Gold Electrodes

    International Nuclear Information System (INIS)

    Juhaniewicz, Joanna; Sek, Slawomir

    2016-01-01

    ABSTRACT: The interactions of melittin, a cationic antimicrobial peptide, with model lipid membranes consisting of negatively charged phospholipids: 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or 1,2-dimyristoyl-sn-glycero-3-phosphoserine (DMPS) were investigated using electrochemical techniques and atomic force microscopy. Lipid bilayers were deposited on gold electrodes using a combination of Langmuir-Blodgett and Langmuir-Schaefer methods and the resulting membranes established a barrier for electron transfer between the electrode and the redox probe in the solution. After exposure to melittin, the blocking properties of the membranes were monitored using cyclic voltammetry and electrochemical impedance spectroscopy. It was observed that after treatment with peptide, the charge transfer through lipid bilayer is initially strongly inhibited. However, after longer exposure to melittin, the structure of the lipid film becomes less compact and the electrode reactions are facilitated due to the presence of numerous defect sites exposing bare substrate. We have assumed that such behavior reflects initial adsorption of melittin on top of the membrane and its further insertion which leads to formation of the pores or partial micellization of the lipid film. AFM imaging revealed that the exposure to 10 μM melittin solution induces significant structural changes in DMPG and DMPS membranes. However, melittin seems to affect their organization in a different manner. DMPG film appears to be more susceptible to peptide action compared with DMPS bilayer. In the latter case, long-time exposure to melittin does not result in the rupture of the membrane but rather leads to formation of pore-like defects. This observation is explained in terms of different nanomechanical properties of DMPG and DMPS films and different barrier for the reorientation and insertion of the peptide molecules into the membranes.

  2. Solid polymer electrolyte composite membrane comprising a porous support and a solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide

    Science.gov (United States)

    Liu, Han; Mittelsteadt, Cortney K; Norman, Timothy J; Griffith, Arthur E; LaConti, Anthony B

    2015-02-24

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a thin, rigid, dimensionally-stable, non-electrically-conducting support, the support having a plurality of cylindrical, straight-through pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores are unevenly distributed, with some or no pores located along the periphery and more pores located centrally. The pores are completely filled with a solid polymer electrolyte, the solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide. The solid polymer electrolyte may also be deposited over the top and/or bottom surfaces of the support.

  3. Creep Behavior of Porous Supports in Metal-support Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Boccaccini, Dino; Frandsen, Henrik Lund; Blennow Tullmar, Peter

    2013-01-01

    Creep is the inelastic deformation of a material at high temperatures over long periods of time. It can be defined as timedependent deformation at absolute temperatures greater than one half the absolute melting. Creep resistance is a key parameter for high temperature steel components, e.g. SOFC...... metal supports, where high corrosion resistance is a major design requirement. The four variables affecting creep rate are strain, time, temperature, and stress level and make creep difficult to quantify. In this work, the creep parameters of a SOFC metal support have been determined for the first time...... by means of a thermo mechanical analyzer (TMA) for stresses in the range of 1-17 MPa and temperatures between 650-750 °C. The creep parameters of Crofer® 22 APU were also acquired and compared with values obtained from literature to validate the technique....

  4. Protein sorting by lipid phase-like domains supports emergent signaling function in B lymphocyte plasma membranes.

    Science.gov (United States)

    Stone, Matthew B; Shelby, Sarah A; Núñez, Marcos F; Wisser, Kathleen; Veatch, Sarah L

    2017-02-01

    Diverse cellular signaling events, including B cell receptor (BCR) activation, are hypothesized to be facilitated by domains enriched in specific plasma membrane lipids and proteins that resemble liquid-ordered phase-separated domains in model membranes. This concept remains controversial and lacks direct experimental support in intact cells. Here, we visualize ordered and disordered domains in mouse B lymphoma cell membranes using super-resolution fluorescence localization microscopy, demonstrate that clustered BCR resides within ordered phase-like domains capable of sorting key regulators of BCR activation, and present a minimal, predictive model where clustering receptors leads to their collective activation by stabilizing an extended ordered domain. These results provide evidence for the role of membrane domains in BCR signaling and a plausible mechanism of BCR activation via receptor clustering that could be generalized to other signaling pathways. Overall, these studies demonstrate that lipid mediated forces can bias biochemical networks in ways that broadly impact signal transduction.

  5. Systematic Approach for the Formulation and Optimization of Solid Lipid Nanoparticles of Efavirenz by High Pressure Homogenization Using Design of Experiments for Brain Targeting and Enhanced Bioavailability

    Science.gov (United States)

    Gupta, Shweta; Kesarla, Rajesh; Chotai, Narendra; Misra, Ambikanandan

    2017-01-01

    The nonnucleoside reverse transcriptase inhibitors, used for the treatment of HIV infections, are reported to have low bioavailability pertaining to high first-pass metabolism, high protein binding, and enzymatic metabolism. They also show low permeability across blood brain barrier. The CNS is reported to be the most important HIV reservoir site. In the present study, solid lipid nanoparticles of efavirenz were prepared with the objective of providing increased permeability and protection of drug due to biocompatible lipidic content and nanoscale size and thus developing formulation having potential for enhanced bioavailability and brain targeting. Solid lipid nanoparticles were prepared by high pressure homogenization technique using a systematic approach of design of experiments (DoE) and evaluated for particle size, polydispersity index, zeta potential, and entrapment efficiency. Particles of average size 108.5 nm having PDI of 0.172 with 64.9% entrapment efficiency were produced. Zeta potential was found to be −21.2 mV and the formulation was found stable. The in-vivo pharmacokinetic studies revealed increased concentration of the drug in brain, as desired, when administered through intranasal route indicating its potential for an attempt towards complete eradication of HIV and cure of HIV-infected patients. PMID:28243600

  6. CSBB-ConeExclusion, adapting structure based solution virtual screening to libraries on solid support.

    Science.gov (United States)

    Shave, Steven; Auer, Manfred

    2013-12-23

    Combinatorial chemical libraries produced on solid support offer fast and cost-effective access to a large number of unique compounds. If such libraries are screened directly on-bead, the speed at which chemical space can be explored by chemists is much greater than that addressable using solution based synthesis and screening methods. Solution based screening has a large supporting body of software such as structure-based virtual screening tools which enable the prediction of protein-ligand complexes. Use of these techniques to predict the protein bound complexes of compounds synthesized on solid support neglects to take into account the conjugation site on the small molecule ligand. This may invalidate predicted binding modes, the linker may be clashing with protein atoms. We present CSBB-ConeExclusion, a methodology and computer program which provides a measure of the applicability of solution dockings to solid support. Output is given in the form of statistics for each docking pose, a unique 2D visualization method which can be used to determine applicability at a glance, and automatically generated PyMol scripts allowing visualization of protein atom incursion into a defined exclusion volume. CSBB-ConeExclusion is then exemplarically used to determine the optimum attachment point for a purine library targeting cyclin-dependent kinase 2 CDK2.

  7. Anti-inflammatory effects and hepatotoxicity of Tripterygium-loaded solid lipid nanoparticles on adjuvant-induced arthritis in rats.

    Science.gov (United States)

    Xue, Mei; Jiang, Zhen-zhou; Wu, Tao; Li, Ji; Zhang, Liang; Zhao, Yan; Li, Xue-jun; Zhang, Lu-Yong; Yang, Shu-yu

    2012-08-15

    Tripterygium wilfordii Hook f. (TWHF) has been demonstrated to have anti-inflammatory, immunosuppressive effects and its clinical use was restricted to some extent due to some toxic effects on the digestive, urogenital, and blood circulatory systems, especially the male reproductive system. In the previous study, we had confirmed that TWHF-loaded solid lipid nanoparticles (SLN) have protective effects on male reproductive toxicity in rats. Anti-inflammatory effects and hepatotoxicity of TWHF-SLN remain to be unidentified. The present study was focused on the anti-inflammatory effect of complete Freund's adjuvant-induced arthritis in rats treated with TWHF-SLN as well as the effects of SLN delivery system on decreasing the hepatotoxicity induced by tripterygium. Sixty-four healthy male rats were randomly divided into eight groups with eight rats each. From day 18 after FCA injection, TWHF-SLN group (120, 60, 30 mg/kg) and TWHF group (120, 60, 30 mg/kg) were administered by oral gavage for 24 consecutive days. The control group was with saline and model control group was without any treatment. The volume of the right hind paws was evaluated at 0, 4, 8, 12, 18, 24, 30, 36 and 42 days post-injection of FCA by a home-made connected device. The serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyl transpeptidase (GGT), total bilirubin (TBIL) and albumin (ALB) levels were evaluated by an autoanalyzer. Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) malondialdehyde (MDA) and xanthine oxidase (XOD) levels were determined using commercial kits. The PG level in sera was examined by double antibody sandwich method. Tissue histopathology was evaluated with hematoxylin and eosin (H&E). The results show that TWHF-SLN can significantly reduce rat paw volume at 60 mg/kg (psystem can enhance the anti-inflammatory activity of TWHF, and meanwhile has a protective effect against TWHF

  8. Application of solid-phase extraction coupled with freezing-lipid filtration clean-up for the determination of endocrine-disrupting phenols in fish

    International Nuclear Information System (INIS)

    Ahn, Yun Gyong; Shin, Jeoung Hwa; Kim, Hye-Young; Khim, Jeehyeong; Lee, Mi-Kyoung; Hong, Jongki

    2007-01-01

    An analytical method has been developed for the determination of endocrine-disrupting phenols (eight alkylphenols and bisphenol A) in fish samples. The extraction of nine phenols from fish samples was carried out by ultrasonification. After the extraction, high levels of lipids were removed by freezing-lipid filtration instead of the traditional methods of column chromatography or saponification. During freezing-lipid filtration, about 90% of the lipids were eliminated without any significant loss of phenolic compounds. For further purification, hydrophilic-lipophilic balanced copolymer (HLB) sorbent with a poly(divinylbenzene-co-N-vinylpyrrolidone) phase and Florisil-solid-phase extraction (SPE) cartridges were used to eliminate the remaining interferences. Silyl-derivatization, with N,N'-methyl-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA), was applied to enhance the sensitivity of detection of phenolic compounds. Quantification was performed by gas chromatography/mass spectrometry (GC/MS)-selected ion monitoring (SIM) mode, using deuterium-labeled internal standards. Spiking experiments were carried out to determine the recovery, precision and detection limit of the method. The overall recoveries ranged between 70 and 120%, with relative standard deviations of 3-17% for the entire procedure. The detection limits of the method for the nine phenols ranged from 0.02 to 0.41 ng g -1 . The method provided simultaneous screening and accurate confirmation of each phenol when applied to biological samples

  9. Application of solid-phase extraction coupled with freezing-lipid filtration clean-up for the determination of endocrine-disrupting phenols in fish

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Yun Gyong [Hazardous Substance Research Team, Korea Basic Science Institute, Seoul 136-701 (Korea, Republic of); Department of Civil Environment Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Shin, Jeoung Hwa; Kim, Hye-Young [Hazardous Substance Research Team, Korea Basic Science Institute, Seoul 136-701 (Korea, Republic of); Khim, Jeehyeong [Department of Civil Environment Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Lee, Mi-Kyoung [College of Pharmacy, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Hong, Jongki [College of Pharmacy, Kyung Hee University, Seoul 130-701 (Korea, Republic of)], E-mail: jhong@khu.ac.kr

    2007-11-05

    An analytical method has been developed for the determination of endocrine-disrupting phenols (eight alkylphenols and bisphenol A) in fish samples. The extraction of nine phenols from fish samples was carried out by ultrasonification. After the extraction, high levels of lipids were removed by freezing-lipid filtration instead of the traditional methods of column chromatography or saponification. During freezing-lipid filtration, about 90% of the lipids were eliminated without any significant loss of phenolic compounds. For further purification, hydrophilic-lipophilic balanced copolymer (HLB) sorbent with a poly(divinylbenzene-co-N-vinylpyrrolidone) phase and Florisil-solid-phase extraction (SPE) cartridges were used to eliminate the remaining interferences. Silyl-derivatization, with N,N'-methyl-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA), was applied to enhance the sensitivity of detection of phenolic compounds. Quantification was performed by gas chromatography/mass spectrometry (GC/MS)-selected ion monitoring (SIM) mode, using deuterium-labeled internal standards. Spiking experiments were carried out to determine the recovery, precision and detection limit of the method. The overall recoveries ranged between 70 and 120%, with relative standard deviations of 3-17% for the entire procedure. The detection limits of the method for the nine phenols ranged from 0.02 to 0.41 ng g{sup -1}. The method provided simultaneous screening and accurate confirmation of each phenol when applied to biological samples.

  10. Electrochemical growth of highly oriented organic-inorganic superlattices using solid-supported multilamellar membranes as templates.

    Science.gov (United States)

    Xing, Li-Li; Li, Da-Peng; Hu, Shu-Xin; Jing, Huai-Yu; Fu, Honglan; Mai, Zhen-Hong; Li, Ming

    2006-02-08

    Controllable depositing of relatively thick inorganic sublayers into organic templates to fabricate organic-inorganic superlattices is of great importance. We report a novel approach to fabricating phospholipid/Ni(OH)(2) superlattices by electrochemical deposition of the inorganic component into solid-supported multilamellar templates. The well-ordered and highly oriented multilamellar templates are produced by spreading small drops of lipid solution on silicon surfaces and letting the solvent evaporate slowly. The templates which are used as working electrodes preserve the lamellar structure in the electrolyte solution. The resulting superlattices are highly oriented. The thickness of the nickel hydroxide is controlled by the concentration of nickel ions in the electrolyte bath. The electron density profiles derived from the X-ray diffraction data reveal that the thickness of the nickel hydroxide sublayers increases from 15 to 27 A as the concentration of nickel nitrate increases from 0.005 mol/L to 0.08 mol/L. We expect that the new method can be extended to depositing a variety of inorganic components including metals, oxides, and semiconductors.

  11. A reusable device for electrochemical applications of hydrogel supported black lipid membranes

    DEFF Research Database (Denmark)

    Mech-Dorosz, Agnieszka; Heiskanen, Arto; Bäckström, Sania

    2015-01-01

    the ETFE substrate and a gold electrode microchip, thus allowing direct electrochemical studies with the integrated working electrodes. Using electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy and contact angle measurements, we demonstrate the optimized chemical modifications...... of the gold electrode microchips and plasma modification of the ETFE aperture arrays facilitating covalent "sandwiching" of the hydrogel. Both fluorescence microscopy and EIS were used to demonstrate the induced spontaneous thinning of a deposited lipid solution, leading to formation of stabilized hs...

  12. Tubular solid oxide fuel cells with porous metal supports and ceramic interconnections

    Science.gov (United States)

    Huang, Kevin [Export, PA; Ruka, Roswell J [Pittsburgh, PA

    2012-05-08

    An intermediate temperature solid oxide fuel cell structure capable of operating at from 600.degree. C. to 800.degree. C. having a very thin porous hollow elongated metallic support tube having a thickness from 0.10 mm to 1.0 mm, preferably 0.10 mm to 0.35 mm, a porosity of from 25 vol. % to 50 vol. % and a tensile strength from 700 GPa to 900 GPa, which metallic tube supports a reduced thickness air electrode having a thickness from 0.010 mm to 0.2 mm, a solid oxide electrolyte, a cermet fuel electrode, a ceramic interconnection and an electrically conductive cell to cell contact layer.

  13. Effects of accelerated degradation on metal supported thin film-based solid oxide fuel cell

    DEFF Research Database (Denmark)

    Reolon, R. P.; Sanna, S.; Xu, Yu

    2018-01-01

    A thin film-based solid oxide fuel cell is deposited on a Ni-based metal porous support by pulsed laser deposition with a multi-scale-graded microstructure design. The fuel cell, around 1 μm in thickness, is composed of a stabilized-zirconia/doped-ceria bi-layered dense electrolyte and nanostruct......A thin film-based solid oxide fuel cell is deposited on a Ni-based metal porous support by pulsed laser deposition with a multi-scale-graded microstructure design. The fuel cell, around 1 μm in thickness, is composed of a stabilized-zirconia/doped-ceria bi-layered dense electrolyte......, electrochemical performances are steady, indicating the stability of the cell. Under electrical load, a progressive degradation is activated. Post-test analysis reveals both mechanical and chemical degradation of the cell. Cracks and delamination of the thin films promote a significant nickel diffusion and new...

  14. Assaying the proton transport and regulation of UCP1 using solid supported membranes.

    Science.gov (United States)

    Blesneac, Iulia; Ravaud, Stéphanie; Machillot, Paul; Zoonens, Manuela; Masscheylen, Sandrine; Miroux, Bruno; Vivaudou, Michel; Pebay-Peyroula, Eva

    2012-08-01

    The uncoupling protein 1 (UCP1) is a mitochondrial protein that carries protons across the inner mitochondrial membrane. It has an important role in non-shivering thermogenesis, and recent evidence suggests its role in human adult metabolism. Using rapid solution exchange on solid supported membranes, we succeeded in measuring electrical currents generated by the transport activity of UCP1. The protein was purified from mouse brown adipose tissue, reconstituted in liposomes and absorbed on solid supported membranes. A fast pH jump activated the ion transport, and electrical signals could be recorded. The currents were characterized by a fast rise and a slow decay, were stable over time, inhibited by purine nucleotides and activated by fatty acids. This new assay permits direct observation of UCP1 activity in controlled cell-free conditions, and opens up new possibilities for UCP1 functional characterization and drug screening because of its robustness and its potential for automation.

  15. Typical Mexican agroindustrial residues as supports for solid-state fermentation

    DEFF Research Database (Denmark)

    Flores-Maltos, Dulce A.; Mussatto, Solange Ines; Contreras Esquivel, Juan Carlos

    2014-01-01

    . These biological wastes can be used as support-substrates in Solid-State Fermentation (SSF) to produce industrially relevant metabolites with great economical advantage. In addition, it is an environment friendly method of waste management. In this study were analyzed six different Mexican agro industrial residues...... process. The results provided important knowledge about the characteristics of these materials revealing their potential for use in fermentation processes....

  16. Visual monitoring of solid-phase extraction using chromogenic fluorous synthesis supports.

    Science.gov (United States)

    Blackburn, Christopher

    2012-03-12

    Reductive aminations and further transformations of an azo dye and fluorous tagged aldehyde are described. The intensely colored 2,4-dialkoxybenzyl protected amines undergo Fmoc-based peptide coupling, Suzuki reactions, and sulfonamide formation with product isolation facilitated by visual monitoring of fluorous solid phase extraction. Target compounds are released from the supports in high yields and purities by treatment with trifluoroacetic acid (TFA).

  17. Simple automated system for simultaneous production of 11C-labeled tracers by solid supported methylation

    International Nuclear Information System (INIS)

    Quincoces, Gemma; Penuelas, Ivan; Valero, Marta; Serra, Patricia; Collantes, Maria; Marti-Climent, Josep; Arbizu, Javier; Jose Garcia-Velloso, Maria; Angel Richter, Jose

    2006-01-01

    We herein describe a simple setup for the automated simultaneous synthesis of L-[methyl- 11 C]methionine and N-[methyl- 11 C]choline by solid-supported methylation . The setup is extremely simple and easy to adapt to other automated systems and due to its versatility, the method can be utilized for the production of other radiopharmaceuticals requiring a simple [ 11 C]methylation step. Furthermore, it can be used for multiple simultaneous synthesis

  18. Break‐down of Losses in High Performing Metal‐Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Kromp, A.; Nielsen, Jimmi; Blennow Tullmar, Peter

    2013-01-01

    in the metal support, the electrochemical fuel oxidation at the anode and the oxygen reduction in the mixed ionic electronic conducting cathode. An additional process with a rather high relaxation frequency was attributed to the formation of insulating interlayers at the cathode/electrolyte‐interface. Based...... on these results, selective measures to improve performance and stability, such as (i) PVD‐deposited CGO buffer layer preventing solid state reaction between cathode and the zirconia‐based electrolyte, (ii) LSC‐CGO based in‐situ sintered cathodes and (iii) reduced corrosion of the metal support, were adopted...

  19. Modulation of butyrate anticancer activity by solid lipid nanoparticle delivery: an in vitro investigation on human breast cancer and leukemia cell lines.

    Science.gov (United States)

    Foglietta, Federica; Serpe, Loredana; Canaparo, Roberto; Vivenza, Nicoletta; Riccio, Giovanna; Imbalzano, Erica; Gasco, Paolo; Zara, Gian Paolo

    2014-01-01

    Histone modification has emerged as a promising approach to cancer therapy. The short-chain fatty acid, butyric acid, a histone deacetylase (HD) inhibitor, has shown anticancer activity. Butyrate transcriptional activation is indeed able to withdraw cancer cells from the cell cycle, leading to programmed cell death. Since butyrate's clinical use is hampered by unfavorable pharmacokinetic and pharmacodynamic properties, delivery systems, such as solid lipid nanoparticles (SLN), have been developed to overcome these constraints. In order to outline the influence of butyrate delivery on its anticancer activity, the effects of butyrate as a free (sodium butyrate, NB) or nanoparticle (cholesteryl butyrate solid lipid nanoparticles, CBSLN) formulation on the growth of different human cancer cell lines, such as the promyelocytic leukemia, HL-60, and the breast cancer, MCF-7 was investigated. A detailed investigation into the mechanism of the induced cytotoxicity was also carried out, with a special focus on the modulation of HD and cyclin-dependent kinase (CDK) mRNA gene expression by real time PCR analysis. In HL-60 cells, CBSLN induced a higher and prolonged expression level of the butyrate target genes at lower concentrations than NB. This led to a significant decrease in cell proliferation, along with considerable apoptosis, cell cycle block in the G0/G1 phase, significant inhibition of total HD activity and overexpression of the p21 protein. Conversely, in MCF-7 cells, CBSLN did not enhance the level of expression of the butyrate target genes, leading to the same anticancer activity as that of NB. Solid lipid nanoparticles were able to improve butyrate anticancer activity in HL-60, but not in MCF-7 cells. This is consistent with difference in properties of the cells under study, such as expression of the TP53 tumor suppressor, or the transporter for short-chain fatty acids, SLC5A8.

  20. Probing the role of ceramide hydroxylation in skin barrier lipid models by 2H solid-state NMR spectroscopy and X-ray powder diffraction.

    Science.gov (United States)

    Kováčik, Andrej; Vogel, Alexander; Adler, Juliane; Pullmannová, Petra; Vávrová, Kateřina; Huster, Daniel

    2018-05-01

    In this work, we studied model stratum corneum lipid mixtures composed of the hydroxylated skin ceramides N-lignoceroyl 6-hydroxysphingosine (Cer[NH]) and α-hydroxylignoceroyl phytosphingosine (Cer[AP]). Two model skin lipid mixtures of the composition Cer[NH] or Cer[AP], N-lignoceroyl sphingosine (Cer[NS]), lignoceric acid (C24:0) and cholesterol in a 0.5:0.5:1:1 molar ratio were compared. Model membranes were investigated by differential scanning calorimetry and 2 H solid-state NMR spectroscopy at temperatures from 25 °C to 80 °C. Each component of the model mixture was specifically deuterated for selective detection by 2 H NMR. Thus, the exact phase composition of the mixture at varying temperatures could be quantified. Moreover, using X-ray powder diffraction we investigated the lamellar phase formation. From the solid-state NMR and DSC studies, we found that both hydroxylated Cer[NH] and Cer[AP] exhibit a similar phase behavior. At physiological skin temperature of 32 °C, the lipids form a crystalline (orthorhombic) phase. With increasing temperature, most of the lipids become fluid and form a liquid-crystalline phase, which converts to the isotropic phase at higher temperatures (65-80 °C). Interestingly, lignoceric acid in the Cer[NH]-containing mixture has a tendency to form two types of fluid phases at 65 °C. This tendency was also observed in Cer[AP]-containing membranes at 80 °C. While Cer[AP]-containing lipid models formed a short periodicity phase featuring a repeat spacing of d = 5.4 nm, in the Cer[NH]-based model skin lipid membranes, the formation of unusual long periodicity phase with a repeat spacing of d = 10.7 nm was observed. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy as an Analytical Method to Investigate the Secondary Structure of a Model Protein Embedded in Solid Lipid Matrices.

    Science.gov (United States)

    Zeeshan, Farrukh; Tabbassum, Misbah; Jorgensen, Lene; Medlicott, Natalie J

    2018-02-01

    Protein drugs may encounter conformational perturbations during the formulation processing of lipid-based solid dosage forms. In aqueous protein solutions, attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy can investigate these conformational changes following the subtraction of spectral interference of solvent with protein amide I bands. However, in solid dosage forms, the possible spectral contribution of lipid carriers to protein amide I band may be an obstacle to determine conformational alterations. The objective of this study was to develop an ATR FT-IR spectroscopic method for the analysis of protein secondary structure embedded in solid lipid matrices. Bovine serum albumin (BSA) was chosen as a model protein, while Precirol AT05 (glycerol palmitostearate, melting point 58 ℃) was employed as the model lipid matrix. Bovine serum albumin was incorporated into lipid using physical mixing, melting and mixing, or wet granulation mixing methods. Attenuated total reflection FT-IR spectroscopy and size exclusion chromatography (SEC) were performed for the analysis of BSA secondary structure and its dissolution in aqueous media, respectively. The results showed significant interference of Precirol ATO5 with BSA amide I band which was subtracted up to 90% w/w lipid content to analyze BSA secondary structure. In addition, ATR FT-IR spectroscopy also detected thermally denatured BSA solid alone and in the presence of lipid matrix indicating its suitability for the detection of denatured protein solids in lipid matrices. Despite being in the solid state, conformational changes occurred to BSA upon incorporation into solid lipid matrices. However, the extent of these conformational alterations was found to be dependent on the mixing method employed as indicated by area overlap calculations. For instance, the melting and mixing method imparted negligible effect on BSA secondary structure, whereas the wet granulation mixing method promoted

  2. Process for preparation of a solid-phase radioimmunoassay support and use thereof

    International Nuclear Information System (INIS)

    Meriadec, B.; Roubertie, P.

    1979-01-01

    A process is described for the preparation of a support useful in radioimmunoassay chromatographic columns. The process involves the preparation of a chromatographic gel capable of selectively retaining one or more components contained in an antigen-antibody-containing solution. The gel is bound to the appropriate antiserum, then freeze-dried, pulverized and compressed into a tablet. The tablet support swells upon contact with an antigen-antibody-containing solution to conform to the shape of the columns. An example of the application of this support in the radioimmunoassay of thyroid-stimulating hormone is described. This type of support is also particularly useful in second antibody solid phase radioimmunoassays since there is no limit to the size of the antigen to which this technology may be applied. (U.K.)

  3. Binding of monoclonal antibody to protein antigen in fluid phase or bound to solid supports

    Energy Technology Data Exchange (ETDEWEB)

    Kennel, S J

    1982-01-01

    Rat monoclonal antibody (MoAb) to fragment D (FgD) of human fibrinogen was used to characterize the direct binding of antibody to protein in solution or bound to solid supports. Purified IgG, F(ab')/sub 2/ and Fab' were prepared from ascites fluid of hybridoma 104-14B which is a fusion product of spleen cells from a rat immunized with FgD and the mouse myeloma cell line, P3-X63-Ag8. Two-dimensional electrophoresis of radioiodinated antibody preparations demonstrated the presence of hybrid immunoglobulin molecules, but only structures having rat heavy and rat light chains had active antibody combinig sites. The affinity constant for IgG as well as F(ab')/sub 2/ and Fab', 6x10/sup 9/ M/sup -1/, was identical when tested using fluid phase antigen (/sup 125/I-labeled FgD). Affinity constants determined for direct binding of iodinated IgG using FgD immobilized on solid supports showed a slight dependence on the antigen concentration used in the measurement. These values ranged from 0.5x10/sup 9/ M/sup -1/ at high antigen concentrations (1.3x10/sup -7/ M) to 9x10/sup 9/ M/sup -1/ at low antigen concentration (1.3x10/sup -10/ M). Binding constants for F(ab')/sub 2/ and Fab' gave similar results indicating that binding was homogeneous and univalent. The capacity of solid state antigen to bind antibody varied with the method used to bind FgD to the solid support. FgD bound directly to polystyrene plates was least efficient at binding labeled antibody; FgD bound to plates through intermediate carriers poly(L-lysine) was only slightly more efficient, while antigen bound to Sepharose beads by cyanogen bromide activation was the most active.

  4. Technologies and decision support systems to aid solid-waste management: a systematic review.

    Science.gov (United States)

    Vitorino de Souza Melaré, Angelina; Montenegro González, Sahudy; Faceli, Katti; Casadei, Vitor

    2017-01-01

    Population growth associated with population migration to urban areas and industrial development have led to a consumption relation that results in environmental, social, and economic problems. With respect to the environment, a critical concern is the lack of control and the inadequate management of the solid waste generated in urban centers. Among the challenges are proper waste-collection management, treatment, and disposal, with an emphasis on sustainable management. This paper presents a systematic review on scientific publications concerning decision support systems applied to Solid Waste Management (SWM) using ICTs and OR in the period of 2010-2013. A statistical analysis of the eighty-seven most relevant publications is presented, encompassing the ICTs and OR methods adopted in SWM, the processes of solid-waste management where they were adopted, and which countries are investigating solutions for the management of solid waste. A detailed discussion on how the ICTs and OR methods have been combined in the solutions was also presented. The analysis and discussion provided aims to help researchers and managers to gather insights on technologies/methods suitable the SWM challenges they have at hand, and on gaps that can be explored regarding technologies/methods that could be useful as well as the processes in SWM that currently do not benefit from using ICTs and OR methods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. 15N and 31P solid-state NMR study of transmembrane domain alignment of M2 protein of influenza A virus in hydrated cylindrical lipid bilayers confined to anodic aluminum oxide nanopores.

    Science.gov (United States)

    Chekmenev, Eduard Y; Hu, Jun; Gor'kov, Peter L; Brey, William W; Cross, Timothy A; Ruuge, Andres; Smirnov, Alex I

    2005-04-01

    This communication reports the first example of a high resolution solid-state 15N 2D PISEMA NMR spectrum of a transmembrane peptide aligned using hydrated cylindrical lipid bilayers formed inside nanoporous anodic aluminum oxide (AAO) substrates. The transmembrane domain SSDPLVVA(A-15N)SIIGILHLILWILDRL of M2 protein from influenza A virus was reconstituted in hydrated 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine bilayers that were macroscopically aligned by a conventional micro slide glass support or by the AAO nanoporous substrate. 15N and 31P NMR spectra demonstrate that both the phospholipids and the protein transmembrane domain are uniformly aligned in the nanopores. Importantly, nanoporous AAO substrates may offer several advantages for membrane protein alignment in solid-state NMR studies compared to conventional methods. Specifically, higher thermal conductivity of aluminum oxide is expected to suppress thermal gradients associated with inhomogeneous radio frequency heating. Another important advantage of the nanoporous AAO substrate is its excellent accessibility to the bilayer surface for exposure to solute molecules. Such high accessibility achieved through the substrate nanochannel network could facilitate a wide range of structure-function studies of membrane proteins by solid-state NMR.

  6. FSILP: fuzzy-stochastic-interval linear programming for supporting municipal solid waste management.

    Science.gov (United States)

    Li, Pu; Chen, Bing

    2011-04-01

    Although many studies on municipal solid waste management (MSW management) were conducted under uncertain conditions of fuzzy, stochastic, and interval coexistence, the solution to the conventional linear programming problems of integrating fuzzy method with the other two was inefficient. In this study, a fuzzy-stochastic-interval linear programming (FSILP) method is developed by integrating Nguyen's method with conventional linear programming for supporting municipal solid waste management. The Nguyen's method was used to convert the fuzzy and fuzzy-stochastic linear programming problems into the conventional linear programs, by measuring the attainment values of fuzzy numbers and/or fuzzy random variables, as well as superiority and inferiority between triangular fuzzy numbers/triangular fuzzy-stochastic variables. The developed method can effectively tackle uncertainties described in terms of probability density functions, fuzzy membership functions, and discrete intervals. Moreover, the method can also improve upon the conventional interval fuzzy programming and two-stage stochastic programming approaches, with advantageous capabilities that are easily achieved with fewer constraints and significantly reduces consumption time. The developed model was applied to a case study of municipal solid waste management system in a city. The results indicated that reasonable solutions had been generated. The solution can help quantify the relationship between the change of system cost and the uncertainties, which could support further analysis of tradeoffs between the waste management cost and the system failure risk. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Protein production by Arthrospira (Spirulina platensis in solid state cultivation using sugarcane bagasse as support

    Directory of Open Access Journals (Sweden)

    Lúcia Helena Pelizer

    2015-03-01

    Full Text Available The genus Arthrospira comprises a group of filamentous multicellular cyanobacteria and can be used for animal feed and human food. Solid state fermentation or cultivation (SSF involves the use of a culture medium composed of solid material with given moisture content. No studies have been published about the cultivation of microalgae or cyanobacteria on solid medium. Furthermore, although sugar-cane bagasse is used as source of energy in alcohol distilleries in Brazil, the excess could be a support to photosynthetic microorganism growth. The experimental design methodology was used to evaluate the protein production by Arthrospira platensis under SSF using sugarcane bagasse as support, taking into account the moisture content of the medium, light intensity and inoculum concentration. Moisture was found to have a strong influence on the performance of the process. The best conditions were: moisture of 98.8%; inoculum concentration of 0.15 g biomass·kg wet culture medium−1 and light intensity of 6.0 klx.

  8. Does the commonly used pH-stat method with back titration really quantify the enzymatic digestibility of lipid drug delivery systems? A case study on solid lipid nanoparticles (SLN).

    Science.gov (United States)

    Heider, Martha; Hause, Gerd; Mäder, Karsten

    2016-12-01

    Enzymatic digestion of lipid drug carriers is very important. Commonly, pancreatin induced formation of fatty acids is monitored by the pH-stat method, which provides a fast, but unspecific readout. However, according to the literature, the pKa values of long chain fatty acids are strongly dependent on the local environment and might vary between 4.2 and 10.15. The high pKa values would lead to an incomplete detection of the lipid digestion and false results. In order to investigate these issues in more detail, we produced cetyl palmitate solid lipid nanoparticles (CP-SLN) stabilized with poloxamer 188 or polysorbate 80. The digestion of CP-SLN was investigated by two different and independent readouts. A HPTLC assay was used in addition to the pH-stat method (with or without back titration). An incomplete digestion of CP-SLN was observed with all methods. Partial digestion of polysorbate 80 contributed to the formation of fatty acids. Depending on the investigated system and the experimental conditions (FaSSIF or FeSSIF) the results of both readout methods were comparable or not. For example, in FeSSIF conditions, the values detected by HPTLC were roughly twice as high as the pH-stat results. Our findings on solid lipids agree with data from Helbig et al. on lipid emulsions, where a gas chromatography method detected much higher values than the pH-stat assay (Food Hydrocoll. 28 (2012) 10-19). The results of our pH-stat experiments with back titration at different pH values showed increased values for fatty acids from pH 7.5 to pH 10. The values obtained by back titration at high pH values (pH 9 or higher) did exceed the digestion values measured by HPTLC. Therefore, we conclude that the pH-stat method might give the same results as more specific reference methods, but it might also both under- (without back titration) or overestimate (with back titration) the enzymatic digestion of lipid drug delivery systems. A further outcome of our study was the proof that

  9. Towards supported bolaamphiphile membranes for water filtration: Roles of lipid and substrate

    NARCIS (Netherlands)

    Kaufman, Y.; Grinberg, S.; Linder, C..; Heldman, E.; Gilron, J.; Shen, Yue-xiao; Kumar, M.; Lammertink, Rob G.H.; Freger, V.

    2014-01-01

    Supported biomimetic membranes hold potential for applications such as biosensors and water purification by filtration. The current paper reports on the preparation of a supported bolaamphiphile membrane on two polymeric nanofiltration membranes: NF-270 made of polyamide with carboxylic surface

  10. ITO/Poly(Aniline/Sol-Gel Glass: An Optically Transparent, pH-Responsive Substrate for Supported Lipid Bilayers

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Obeidi

    2013-01-01

    Full Text Available Described here is fabrication of a pH-sensitive, optically transparent transducer composed of a planar indium-tin oxide (ITO electrode overcoated with a poly(aniline (PANI thin film and a porous sol-gel layer. Adsorption of the PANI film renders the ITO electrode sensitive to pH, whereas the sol-gel spin-coated layer makes the upper surface compatible with fusion of phospholipid vesicles to form a planar supported lipid bilayer (PSLB. The response to changes in the pH of the buffer contacting the sol-gel/PANI/ITO electrode is pseudo-Nernstian with a slope of 52 mV/pH over a pH range of 4–9. Vesicle fusion forms a laterally continuous PSLB on the upper sol-gel surface that is fluid with a lateral lipid diffusion coefficient of 2.2 μm2/s measured by fluorescence recovery after photobleaching. Due to its lateral continuity and lack of defects, the PSLB blocks the pH response of the underlying electrode to changes in the pH of the overlying buffer. This architecture is simpler to fabricate than previously reported ITO electrodes derivatized for PSLB formation and should be useful for optical monitoring of proton transport across supported membranes derivatized with ionophores and ion channels.

  11. Development of a Novel Ceramic Support Layer for Planar Solid Oxide Cells

    DEFF Research Database (Denmark)

    Klemensø, Trine; Boccaccini, Dino; Brodersen, Karen

    2014-01-01

    The conventional solid oxide cell is based on a Ni–YSZ support layer, placed on the fuel side of the cell, also known as the anode supported SOFC. An alternative design, based on a support of porous 3YSZ (3 mol.% Y2O3–doped ZrO2), placed on the oxygen electrode side of the cell, is proposed...... of the support can be done simultaneously with forming the oxygen electrode, since some of the best performing oxygen electrodes are based on infiltrated LSC. The potential of the proposed structure was investigated by testing the mechanical and electrical properties of the support layer. Comparable strength...... properties to the conventional Ni/YSZ support were seen, and sufficient and fairly stable conductivity of LSC infiltrated 3YSZ was observed. The conductivity of 8–15 S cm–1 at 850 °C seen for over 600 h, corresponds to a serial resistance of less than 3.5 m Ω cm2 of a 300 μm thick support layer....

  12. Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers

    International Nuclear Information System (INIS)

    Mote, Kaustubh R.; Gopinath, T.; Traaseth, Nathaniel J.; Kitchen, Jason; Gor’kov, Peter L.; Brey, William W.; Veglia, Gianluigi

    2011-01-01

    Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring 1 H- 15 N dipolar couplings (DC) and 15 N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal (rotational) angles of the protein domains can be directly derived from analytical expression of DC and CSA values, or, alternatively, obtained by refining protein structures using these values as harmonic restraints in simulated annealing calculations. The Achilles’ heel of this approach is the lack of suitable experiments for sequential assignment of the amide resonances. In this Article, we present a new pulse sequence that integrates proton driven spin diffusion (PDSD) with sensitivity-enhanced PISEMA in a 3D experiment ([ 1 H, 15 N]-SE-PISEMA-PDSD). The incorporation of 2D 15 N/ 15 N spin diffusion experiments into this new 3D experiment leads to the complete and unambiguous assignment of the 15 N resonances. The feasibility of this approach is demonstrated for the membrane protein sarcolipin reconstituted in magnetically aligned lipid bicelles. Taken with low electric field probe technology, this approach will propel the determination of sequential assignment as well as structure and topology of larger integral membrane proteins in aligned lipid bilayers.

  13. Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers.

    Science.gov (United States)

    Mote, Kaustubh R; Gopinath, T; Traaseth, Nathaniel J; Kitchen, Jason; Gor'kov, Peter L; Brey, William W; Veglia, Gianluigi

    2011-11-01

    Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring (1)H-(15)N dipolar couplings (DC) and (15)N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal (rotational) angles of the protein domains can be directly derived from analytical expression of DC and CSA values, or, alternatively, obtained by refining protein structures using these values as harmonic restraints in simulated annealing calculations. The Achilles' heel of this approach is the lack of suitable experiments for sequential assignment of the amide resonances. In this Article, we present a new pulse sequence that integrates proton driven spin diffusion (PDSD) with sensitivity-enhanced PISEMA in a 3D experiment ([(1)H,(15)N]-SE-PISEMA-PDSD). The incorporation of 2D (15)N/(15)N spin diffusion experiments into this new 3D experiment leads to the complete and unambiguous assignment of the (15)N resonances. The feasibility of this approach is demonstrated for the membrane protein sarcolipin reconstituted in magnetically aligned lipid bicelles. Taken with low electric field probe technology, this approach will propel the determination of sequential assignment as well as structure and topology of larger integral membrane proteins in aligned lipid bilayers. © Springer Science+Business Media B.V. 2011

  14. The use of quasi-isothermal modulated temperature differential scanning calorimetry for the characterization of slow crystallization processes in lipid-based solid self-emulsifying systems.

    Science.gov (United States)

    Otun, Sarah O; Meehan, Elizabeth; Qi, Sheng; Craig, Duncan Q M

    2015-04-01

    Slow or incomplete crystallization may be a significant manufacturing issue for solid lipid-based dosage forms, yet little information is available on this phenomenon. In this investigation we suggest a novel means by which slow solidification may be monitored in Gelucire 44/14 using quasi-isothermal modulated temperature DSC (QiMTDSC). Conventional linear heating and cooling DSC methods were employed, along with hot stage microscopy (HSM), for basic thermal profiling of Gelucire 44/14. QiMTDSC experiments were performed on cooling from the melt, using a range of incremental decreases in temperature and isothermal measurement periods. DSC and HSM highlighted the main (primary) crystallization transition; solid fat content analysis and kinetic analysis were used to profile the solidification process. The heat capacity profile from QiMTDSC indicated that after an initial energetic primary crystallisation, the lipid underwent a slower period of crystallization which continued to manifest at much lower temperatures than indicated by standard DSC. We present evidence that Gelucire 44/14 undergoes an initial crystallization followed by a secondary, slower process. QIMTDSC appears to be a promising tool in the investigation of this secondary crystallization process.

  15. Targeting the Endocannabinoid/CB1 Receptor System For Treating Major Depression Through Antidepressant Activities of Curcumin and Dexanabinol-Loaded Solid Lipid Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xiaolie He

    2017-08-01

    Full Text Available Background/Aims: This study investigated the underlying mechanisms of the antidepressant effects of curcumin and dexanabinol-loaded solid lipid nanoparticles in corticosterone-induced cell and mice depression models. Methods: Curcumin and dexanabinol-loaded solid lipid nanoparticles (Cur/SLNs-HU-211 were synthesized via an emulsifcation and low-temperature solidification method. Antidepressant activities of nanoparticles in a corticosterone-induced major depression model were investigated by MTT assay, cellular uptake by flow cytometry, behaviour by Forced Swimming Test and rotarod test, neurotransmitters by High Performance Liquid Chromatography, Western blotting, qPCR and immunofluorescence. Results: Treatment with Cur/SLNs-HU-211 induced greater dopamine (DA/5-hydroxytryptamine (5-HT release with reduced corticosterone-induced apoptotic cell death in PC12 cells. Additionally, in vivo Cur/SLNs-HU-211 significantly induced recovery from depressive behaviour with increased DA/5-HT levels, CB1 mRNA levels and CB1, p-MEK1 and p-ERK1/2 protein expression levels in the hippocampus and striatum. Cur/SLNs-HU-211 improved CB1 expression and inspired the proliferation of astrocytes in the hippocampus and striatum, exerted neuroprotective effects by preventing corticosterone -induced BDNF/NeuN expression reduction. Conclusion: Our study implies that Cur/SLNs-HU-211 may be a useful approach for treatment of major depression.

  16. Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment

    International Nuclear Information System (INIS)

    Fan Ying; Shi Lichi; Ladizhansky, Vladimir; Brown, Leonid S.

    2011-01-01

    Overexpression of isotope-labeled multi-spanning eukaryotic membrane proteins for structural NMR studies is often challenging. On the one hand, difficulties with achieving proper folding, membrane insertion, and native-like post-translational modifications frequently disqualify bacterial expression systems. On the other hand, eukaryotic cell cultures can be prohibitively expensive. One of the viable alternatives, successfully used for producing proteins for solution NMR studies, is yeast expression systems, particularly Pichia pastoris. We report on successful implementation and optimization of isotope labeling protocols, previously used for soluble secreted proteins, to produce homogeneous samples of a eukaryotic seven-transmembrane helical protein, rhodopsin from Leptosphaeria maculans. Even in shake-flask cultures, yields exceeded 5 mg of purified uniformly 13 C, 15 N-labeled protein per liter of culture. The protein was stable (at least several weeks at 5°C) and functionally active upon reconstitution into lipid membranes at high protein-to-lipid ratio required for solid-state NMR. The samples gave high-resolution 13 C and 15 N solid-state magic angle spinning NMR spectra, amenable to a detailed structural analysis. We believe that similar protocols can be adopted for challenging mammalian targets, which often resist characterization by other structural methods.

  17. Lipid Dynamics Studied by Calculation of 31P Solid-State NMR Spectra Using Ensembles from Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Hansen, Sara Krogh; Vestergaard, Mikkel; Thøgersen, Lea

    2014-01-01

    , for example, order parameters. Therefore, valuable insight into the dynamics of biomolecules may be achieved by the present method. We have applied this method to study the dynamics of lipid bilayers containing the antimicrobial peptide alamethicin, and we show that the calculated 31P spectra obtained...

  18. Optimization of total vaporization solid-phase microextraction (TV-SPME) for the determination of lipid profiles of Phormia regina, a forensically important blow fly species.

    Science.gov (United States)

    Kranz, William; Carroll, Clinton; Dixon, Darren; Picard, Christine; Goodpaster, John

    2017-11-01

    A new method has been developed for the determination of fatty acids, sterols, and other lipids which naturally occur within pupae of the blow fly Phormia regina. The method relies upon liquid extraction in non-polar solvent, followed by derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) w/ 1% trimethylchlorsilane (TMCS) carried out inside the sample vial. The analysis is facilitated by total vaporization solid-phase microextraction (TV-SPME), with gas chromatography-mass spectrometry (GC-MS) serving as the instrumentation for analysis. The TV-SPME delivery technique is approximately a factor of five more sensitive than traditional liquid injection, which may alleviate the need for rotary evaporation, reconstitution, collection of high performance liquid chromatography fractions, and many of the other pre-concentration steps that are commonplace in the current literature. Furthermore, the ability to derivatize the liquid extract in a single easy step while increasing sensitivity represents an improvement over current derivatization methods. The most common lipids identified in fly pupae were various saturated and unsaturated fatty acids ranging from lauric acid (12:0) to arachinoic acid (20:4), as well as cholesterol. The concentrations of myristic acid (14:0), palmitelaidic acid (16:2), and palmitoleic acid (16:1) were the most reliable indicators of the age of the pupae. Graphical abstract Blow fly pupae were extracted prior to emerging as adults. The extracts were analyzed via total vaporization solid-phase microextraction (TV-SPME), revealing a complex mixture of lipids that could be associated with the age of the insect. This information may assist in determining a post-mortum interval (PMI) in a death investigation.

  19. The Progress of SBIR Supported R and D of Solid State Pulse Modulators

    International Nuclear Information System (INIS)

    Koontz, R

    2004-01-01

    The Small Business Innovative Research (SBIR) grant program funded by the US Department of Energy makes a number of awards each year for R and D in the field of accelerator technology including high power pulse modulators and their components. This paper outlines program requirements, and reviews some of the awards made in the last three years in support of high power modulator systems and solid state switching. A number of award recipients are presenting the results of their SBIR R and D at this workshop

  20. Performance of a novel type of electrolyte-supported solid oxide fuel cell with honeycomb structure

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Morales, Juan Carlos; Savvin, Stanislav N.; Nunez, Pedro [Departmento de Quimica Inorganica, Universidad de La Laguna, 38200 Tenerife (Spain); Marrero-Lopez, David [Departamento de Fisica Aplicada I, Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, Juan; Canales-Vazquez, Jesus [Instituto de Energias Renovables-Universidad de Castilla la Mancha, 02006 Albacete (Spain); Roa, Joan Josep; Segarra, Merce [DIOPMA, Departamento de Ciencia de los Materiales e Ing. Metalurgica, 08028 Barcelona (Spain)

    2010-01-15

    A novel design, alternative to the conventional electrolyte-supported solid oxide fuel cell (SOFC) is presented. In this new design, a honeycomb-electrolyte is fabricated from hexagonal cells, providing high mechanical strength to the whole structure and supporting the thin layer used as electrolyte of a SOFC. This new design allows a reduction of {proportional_to}70% of the electrolyte material and it renders modest performances over 320 mW cm{sup -2} but high volumetric power densities, i.e. 1.22 W cm{sup -3} under pure CH{sub 4} at 900 C, with a high OCV of 1.13 V, using the standard Ni-YSZ cermet as anode, Pt as cathode material and air as the oxidant gas. (author)

  1. Accelerated creep in solid oxide fuel cell anode supports during reduction

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Makowska, Malgorzata Grazyna; Greco, Fabio

    2016-01-01

    To evaluate the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. The creep of reduced Ni-YSZ anode support at operating conditions has been...... studied previously. In this work a newly discovered creep phenomenon taking place during the reduction is reported. This relaxes stresses at a much higher rate (∼ x104) than creep during operation. The phenomenon was studied both in three-point bending and uniaxial tension. Differences between the two...... the NiO and the YSZ phases occurs during reduction. The accelerated creep should practically eliminate any residual stress in the anode support in an SOFC stack, as has previously been indirectly observed. This phenomenon has to be taken into account both in the production of stacks and in the simulation...

  2. Direct on-chip DNA synthesis using electrochemically modified gold electrodes as solid support

    Science.gov (United States)

    Levrie, Karen; Jans, Karolien; Schepers, Guy; Vos, Rita; Van Dorpe, Pol; Lagae, Liesbet; Van Hoof, Chris; Van Aerschot, Arthur; Stakenborg, Tim

    2018-04-01

    DNA microarrays have propelled important advancements in the field of genomic research by enabling the monitoring of thousands of genes in parallel. The throughput can be increased even further by scaling down the microarray feature size. In this respect, microelectronics-based DNA arrays are promising as they can leverage semiconductor processing techniques with lithographic resolutions. We propose a method that enables the use of metal electrodes for de novo DNA synthesis without the need for an insulating support. By electrochemically functionalizing gold electrodes, these electrodes can act as solid support for phosphoramidite-based synthesis. The proposed method relies on the electrochemical reduction of diazonium salts, enabling site-specific incorporation of hydroxyl groups onto the metal electrodes. An automated DNA synthesizer was used to couple phosphoramidite moieties directly onto the OH-modified electrodes to obtain the desired oligonucleotide sequence. Characterization was done via cyclic voltammetry and fluorescence microscopy. Our results present a valuable proof-of-concept for the integration of solid-phase DNA synthesis with microelectronics.

  3. Requirements Development Issues for Advanced Life Support Systems: Solid Waste Management

    Science.gov (United States)

    Levri, Julie A.; Fisher, John W.; Alazraki, Michael P.; Hogan, John A.

    2002-01-01

    Long duration missions pose substantial new challenges for solid waste management in Advanced Life Support (ALS) systems. These possibly include storing large volumes of waste material in a safe manner, rendering wastes stable or sterilized for extended periods of time, and/or processing wastes for recovery of vital resources. This is further complicated because future missions remain ill-defined with respect to waste stream quantity, composition and generation schedule. Without definitive knowledge of this information, development of requirements is hampered. Additionally, even if waste streams were well characterized, other operational and processing needs require clarification (e.g. resource recovery requirements, planetary protection constraints). Therefore, the development of solid waste management (SWM) subsystem requirements for long duration space missions is an inherently uncertain, complex and iterative process. The intent of this paper is to address some of the difficulties in writing requirements for missions that are not completely defined. This paper discusses an approach and motivation for ALS SWM requirements development, the characteristics of effective requirements, and the presence of those characteristics in requirements that are developed for uncertain missions. Associated drivers for life support system technological capability are also presented. A general means of requirements forecasting is discussed, including successive modification of requirements and the need to consider requirements integration among subsystems.

  4. Determination of structural topology of a membrane protein in lipid bilayers using polarization optimized experiments (POE) for static and MAS solid state NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mote, Kaustubh R. [University of Minnesota, Department of Chemistry (United States); Gopinath, T. [University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics (United States); Veglia, Gianluigi, E-mail: vegli001@umn.edu [University of Minnesota, Department of Chemistry (United States)

    2013-10-15

    The low sensitivity inherent to both the static and magic angle spinning techniques of solid-state NMR (ssNMR) spectroscopy has thus far limited the routine application of multidimensional experiments to determine the structure of membrane proteins in lipid bilayers. Here, we demonstrate the advantage of using a recently developed class of experiments, polarization optimized experiments, for both static and MAS spectroscopy to achieve higher sensitivity and substantial time-savings for 2D and 3D experiments. We used sarcolipin, a single pass membrane protein, reconstituted in oriented bicelles (for oriented ssNMR) and multilamellar vesicles (for MAS ssNMR) as a benchmark. The restraints derived by these experiments are then combined into a hybrid energy function to allow simultaneous determination of structure and topology. The resulting structural ensemble converged to a helical conformation with a backbone RMSD {approx}0.44 A, a tilt angle of 24 Degree-Sign {+-} 1 Degree-Sign , and an azimuthal angle of 55 Degree-Sign {+-} 6 Degree-Sign . This work represents a crucial first step toward obtaining high-resolution structures of large membrane proteins using combined multidimensional oriented solid-state NMR and magic angle spinning solid-state NMR.

  5. Development of curcumin-loaded solid lipid nanoparticles utilizing glyceryl monostearate as single lipid using QbD approach: Characterization and Evaluation of anticancer activity against human breast cancer cell line.

    Science.gov (United States)

    Bhatt, Himanshu; Rompicharla, Sri Vishnu Kiran; Komanduri, Neeraja; Shah, Aashma; Paradkar, Sateja; Ghosh, Balaram; Biswas, Swati

    2018-05-03

    Solid lipid nanoparticles (SLNs) represent an affordable, easily scalable, stable and biocompatible drug delivery system with a high drug to lipid ratio which also improves solubility of poorly soluble drugs. SLNs were developed by using glyceryl monostearate as the single lipid in presence of surfactant Poloxamer 188 and evaluated the efficiency of the SLNs to load the therapeutic cargo, curcumin (CUR). The nano-formulation was optimized by Quality by Design approach to understand the effect of various process parameters on various quality attributes, including drug loadability, particle size and polydispersity. The nanoparticles were characterized using Differential scanning calorimetry (DSC), Fourier Transform Infra-red Spectroscopy (FT-IR) and X-Ray Diffraction (XRD) analysis. These novel SLNs were evaluated for in-vitro anticancer activity using breast adenocarcinoma cells (MDA-MB-231). The optimized formulation had particle size of 226.802±3.92 nm with low polydispersity index of 0.244±0.018. The % encapsulation of CUR into SLNs was found to be 67.88±2.08 %. DSC, FT-IR and XRD confirmed that the CUR was encapsulated stably into the lipid matrix, thereby improving the solubility of the drug. CUR-SLN showed sustained drug release in comparison to the free CUR solution. CUR-SLNs exhibited higher cellular uptake in human breast adenocarcinoma cells compared to free CUR at both 1 and 4 h time points. CUR-SLNs demonstrated decreased cell viability (43.97±1.53%) compared to free CUR (59.33±0.95%) at a concentration of 50 μg/mL after 24 h treatment. Further, treatment of MDA-MB-231 cells with CUR-SLNs for 24 h induced significantly higher apoptosis (37.28±5.3%) in cells compared to the free CUR (21.06±0.97%). The results provide strong rationale for further exploration of the newly developed CUR-SLN to be utilized as a potent chemotherapeutic agent in cancer therapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Characterization of a Cyclic Nucleotide-Activated K+ Channel and its Lipid Environment by Using Solid-State NMR Spectroscopy

    NARCIS (Netherlands)

    Cukkemane, A.A.; Baldus, M.

    2013-01-01

    Voltage-gated ion channels are large tetrameric multidomain membrane proteins that play crucial roles in various cellular transduction pathways. Because of their large size and domain-related mobility, structural characterization has proved challenging. We analyzed high-resolution solid-state NMR

  7. Physico-chemical characterisation, cytotoxic activity, and biocompatibility studies of tamoxifen-loaded solid lipid nanoparticles prepared via a temperature-modulated solidification method.

    Science.gov (United States)

    Lakkadwala, Sushant; Nguyen, Sanko; Lawrence, Joseph; Nauli, Surya M; Nesamony, Jerry

    2014-01-01

    Solid lipid nanoparticles (SLNs) can efficiently and efficaciously incorporate anti-cancer agents. To prepare and characterise tamoxifen (TAM)-loaded SLNs. Glyceryl monostearate, Tween-80, and trehalose were used in SLNs. SLNs were tested via dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Characterisation studies revealed SLNs of about 540 nm with a negative surface charge and confirmed the entrapment of TAM in the SLNs. The entrapment efficiency was estimated to be 60%. The in vitro drug release profile demonstrated a gradual increase followed by a release plateau for several days. A drug concentration-dependent increase in cytotoxic activity was observed when the SLNs were evaluated in cell cultures. Biocompatible and stable lyophilised SLNs were successfully prepared and found to possess properties that may be utilised in an anti-cancer drug delivery system.

  8. Municipal solid waste composition determination supporting the integrated solid waste management system in the island of Crete

    International Nuclear Information System (INIS)

    Gidarakos, E.; Havas, G.; Ntzamilis, P.

    2006-01-01

    A one-year survey was conducted in the greater region of Crete (located at the lower region of the Aegean Sea) for the purpose of identifying waste composition (including chemical and physical characterization), as well as any seasonal variation. The investigation was carried out repeatedly at seven landfills and one transfer station in Crete, in four phases. Each sampling phase corresponded to a season (autumn, winter, spring, summer). ASTM D5231-92(2003) standard method and RCRA Waste Sampling Draft Technical Guidance were used. Hand sorting was used for classifying the collected wastes into the following categories: plastics, paper, metals, aluminium, leather-wood-textiles-rubbers, organic wastes, non-combustibles and miscellaneous. Further analysis included proximate and ultimate analysis of combustible materials. Metals such as lead, cadmium and mercury were also investigated. The results show that there has been a significant decrease of organic wastes during the last decade due to the increase of packaging materials, as a result of a change in consumption patterns. Three main waste categories were determined: organic wastes, paper and plastics, which combined represent 76% of the total waste in Crete. Furthermore, a high fraction of glass and a seasonal variation of aluminium indicate a strong correlation of waste composition with certain human activities, such as tourism. There is also a variation between the municipal solid waste (MSW) composition in the region of Crete (2003-2004) and MSW composition suggested in the National Solid Waste Planning (2000) [National Solid Waste Planning, 2000. Completion and particularization of Common Ministerial Act 113944//1944/1997: National Solid Waste Planning, June 2000]. The results of this survey are to be utilized by the regional solid waste authorities in order to establish an integrated waste treatment site, capable of fulfilling the regional waste management demands

  9. Municipal solid waste composition determination supporting the integrated solid waste management system in the island of Crete.

    Science.gov (United States)

    Gidarakos, E; Havas, G; Ntzamilis, P

    2006-01-01

    A one-year survey was conducted in the greater region of Crete (located at the lower region of the Aegean Sea) for the purpose of identifying waste composition (including chemical and physical characterization), as well as any seasonal variation. The investigation was carried out repeatedly at seven landfills and one transfer station in Crete, in four phases. Each sampling phase corresponded to a season (autumn, winter, spring, summer). ASTM D5231-92(2003) standard method and RCRA Waste Sampling Draft Technical Guidance were used. Hand sorting was used for classifying the collected wastes into the following categories: plastics, paper, metals, aluminium, leather-wood-textiles-rubbers, organic wastes, non-combustibles and miscellaneous. Further analysis included proximate and ultimate analysis of combustible materials. Metals such as lead, cadmium and mercury were also investigated. The results show that there has been a significant decrease of organic wastes during the last decade due to the increase of packaging materials, as a result of a change in consumption patterns. Three main waste categories were determined: organic wastes, paper and plastics, which combined represent 76% of the total waste in Crete. Furthermore, a high fraction of glass and a seasonal variation of aluminium indicate a strong correlation of waste composition with certain human activities, such as tourism. There is also a variation between the municipal solid waste (MSW) composition in the region of Crete (2003-2004) and MSW composition suggested in the National Solid Waste Planning (2000) [National Solid Waste Planning, 2000. Completion and particularization of Common Ministerial Act 113944//1944/1997: National Solid Waste Planning, June 2000]. The results of this survey are to be utilized by the regional solid waste authorities in order to establish an integrated waste treatment site, capable of fulfilling the regional waste management demands.

  10. A new optimized formulation of cationic solid lipid nanoparticles intended for gene delivery: development, characterization and DNA binding efficiency of TCERG1 expression plasmid.

    Science.gov (United States)

    Fàbregas, Anna; Sánchez-Hernández, Noemí; Ticó, Josep Ramon; García-Montoya, Encarna; Pérez-Lozano, Pilar; Suñé-Negre, Josep M; Hernández-Munain, Cristina; Suñé, Carlos; Miñarro, Montserrat

    2014-10-01

    Solid lipid nanoparticles (SLNs) are being considered as a new approach for therapeutics for many known diseases. In addition to drug delivery, their use as non-viral vectors for gene delivery can be achieved by the inclusion of cationic lipids, which provide a positive surface potential that favours binding to the DNA backbone. This work is based on the idea that the optimization of the components is required as the first step in simplifying the qualitative and quantitative composition of SLNs as much as possible without affecting the essential properties that define SLNs as optimal non-viral vectors for gene delivery. We selected the best lipids and surfactants in terms of particle size and zeta potential and characterized the properties of the resulting nanoparticles using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The SLNs had a particle size of approximately 120 nm and a positive surface charge of 42 mV. In addition, we analysed the main physicochemical characteristics of the bulk components of the nanoparticles using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and mass spectrometry (MS). The suitability of the optimized SLNs for DNA binding was evaluated after the lyophilisation process using a carboxyl-terminal region of the TCERG1 gene, a human factor that has been implicated in several diseases. We show that the SLNs presented high efficiency in the binding of DNA, and importantly, they presented no toxicity when assayed in an in vivo system. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Solid-State Nuclear Magnetic Resonance Investigation of the Structural Topology and Lipid Interactions of a Viral Fusion Protein Chimera Containing the Fusion Peptide and Transmembrane Domain.

    Science.gov (United States)

    Yao, Hongwei; Lee, Myungwoon; Liao, Shu-Yu; Hong, Mei

    2016-12-13

    The fusion peptide (FP) and transmembrane domain (TMD) of viral fusion proteins play important roles during virus-cell membrane fusion, by inducing membrane curvature and transient dehydration. The structure of the water-soluble ectodomain of viral fusion proteins has been extensively studied crystallographically, but the structures of the FP and TMD bound to phospholipid membranes are not well understood. We recently investigated the conformations and lipid interactions of the separate FP and TMD peptides of parainfluenza virus 5 (PIV5) fusion protein F using solid-state nuclear magnetic resonance. These studies provide structural information about the two domains when they are spatially well separated in the fusion process. To investigate how these two domains are structured relative to each other in the postfusion state, when the ectodomain forms a six-helix bundle that is thought to force the FP and TMD together in the membrane, we have now expressed and purified a chimera of the FP and TMD, connected by a Gly-Lys linker, and measured the chemical shifts and interdomain contacts of the protein in several lipid membranes. The FP-TMD chimera exhibits α-helical chemical shifts in all the membranes examined and does not cause strong curvature of lamellar membranes or membranes with negative spontaneous curvature. These properties differ qualitatively from those of the separate peptides, indicating that the FP and TMD interact with each other in the lipid membrane. However, no 13 C- 13 C cross peaks are observed in two-dimensional correlation spectra, suggesting that the two helices are not tightly associated. These results suggest that the ectodomain six-helix bundle does not propagate into the membrane to the two hydrophobic termini. However, the loosely associated FP and TMD helices are found to generate significant negative Gaussian curvature to membranes that possess spontaneous positive curvature, consistent with the notion that the FP-TMD assembly may

  12. Solid waste accident analysis in support of the Savannah River Waste Management Environmental Impact Statement

    International Nuclear Information System (INIS)

    Copeland, W.J.; Crumm, A.T.; Kearnaghan, D.P.; Rabin, M.S.; Rossi, D.E.

    1994-07-01

    The potential for facility accidents and the magnitude of their impacts are important factors in the evaluation of the solid waste management addressed in the Environmental Impact Statement. The purpose of this document is to address the potential solid waste management facility accidents for comparative use in support of the Environmental Impact Statement. This document must not be construed as an Authorization Basis document for any of the SRS waste management facilities. Because of the time constraints placed on preparing this accident impact analysis, all accident information was derived from existing safety documentation that has been prepared for SRS waste management facilities. A list of facilities to include in the accident impact analysis was provided as input by the Savannah River Technology Section. The accident impact analyses include existing SRS waste management facilities as well as proposed facilities. Safety documentation exists for all existing and many of the proposed facilities. Information was extracted from this existing documentation for this impact analysis. There are a few proposed facilities for which safety analyses have not been prepared. However, these facilities have similar processes to existing facilities and will treat, store, or dispose of the same type of material that is in existing facilities; therefore, the accidents can be expected to be similar

  13. Total phenolic contents, antioxidant activities, and lipid fractions from berry pomaces obtained by solid-state fermentation of two Sambucus species with Aspergillus niger.

    Science.gov (United States)

    Dulf, Francisc Vasile; Vodnar, Dan Cristian; Dulf, Eva-Henrietta; Toşa, Monica Ioana

    2015-04-08

    The aim of this study was to investigate the effect of solid-state fermentation (SSF) by Aspergillus niger on phenolic contents and antioxidant activity in Sambucus nigra L. and Sambucus ebulus L. berry pomaces. The effect of fermentation time on the total fats and major lipid classes (neutral and polar) was also investigated. During the SSF, the extractable phenolics increased with 18.82% for S. ebulus L. and 11.11% for S. nigra L. The levels of antioxidant activity of methanolic extracts were also significantly enhanced. The HPLC-MS analysis indicated that the cyanidin 3-sambubioside-5-glucoside is the major phenolic compound in both fermented Sambucus fruit residues. In the early stages of fungal growth, the extracted oils (with TAGs as major lipid fraction) increased with 12% for S. nigra L. and 10.50% for S. ebulus L. The GC-MS analysis showed that the SSF resulted in a slight increase of the linoleic and oleic acids level.

  14. Omega-3 PUFA Loaded in Resveratrol-Based Solid Lipid Nanoparticles: Physicochemical Properties and Antineoplastic Activities in Human Colorectal Cancer Cells In Vitro

    Directory of Open Access Journals (Sweden)

    Simona Serini

    2018-02-01

    Full Text Available New strategies are being investigated to ameliorate the efficacy and reduce the toxicity of the drugs currently used in colorectal cancer (CRC, one of the most common malignancies in the Western world. Data have been accumulated demonstrating that the antineoplastic therapies with either conventional or single-targeted drugs could take advantage from a combined treatment with omega-3 polyunsaturated fatty acids (omega-3 PUFA. These nutrients, shown to be safe at the dosage generally used in human trials, are able to modulate molecules involved in colon cancer cell growth and survival. They have also the potential to act against inflammation, which plays a critical role in CRC development, and to increase the anti-cancer immune response. In the present study, omega-3 PUFA were encapsulated in solid lipid nanoparticles (SLN having a lipid matrix containing resveratrol esterified to stearic acid. Our aim was to increase the efficiency of the incorporation of these fatty acids into the cells and prevent their peroxidation and degradation. The Resveratrol-based SLN were characterized and investigated for their antioxidant activity. It was observed that the encapsulation of omega-3 PUFA into the SLN enhanced significantly their incorporation in human HT-29 CRC cells in vitro, and their growth inhibitory effects in these cancer cells, mainly by reducing cell proliferation.

  15. Conversion of polar and non-polar algae oil lipids to fatty acid methyl esters with solid acid catalysts--A model compound study.

    Science.gov (United States)

    Asikainen, Martta; Munter, Tony; Linnekoski, Juha

    2015-09-01

    Bio-based fuels are becoming more and more important due to the depleting fossil resources. The production of biodiesel from algae oil is challenging compared to terrestrial vegetable oils, as algae oil consists of polar fatty acids, such as phospholipids and glycolipids, as well as non-polar triglycerides and free fatty acids common in vegetable oils. It is shown that a single sulphonated solid acid catalyst can perform the esterification and transesterification reactions of both polar and non-polar lipids. In mild reaction conditions (60-70 °C) Nafion NR50 catalyst produces methyl palmitate (FAME) from the palmitic acid derivatives of di-, and tri-glyceride, free fatty acid, and phospholipid with over 80% yields, with the glycolipid derivative giving nearly 40% yields of FAME. These results demonstrate how the polar and non-polar lipid derivatives of algal oil can be utilised as feedstocks for biodiesel production with a single catalyst in one reaction step. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

    International Nuclear Information System (INIS)

    Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral; Florio, Daniel Zanetti de

    2017-01-01

    Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

  17. Accelerated creep in solid oxide fuel cell anode supports during reduction

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Makowska, Malgorzata Grazyna; Greco, Fabio

    2016-01-01

    To evaluate the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. The creep of reduced Ni-YSZ anode support at operating conditions has been...... studied previously. In this work a newly discovered creep phenomenon taking place during the reduction is reported. This relaxes stresses at a much higher rate (∼ x104) than creep during operation. The phenomenon was studied both in three-point bending and uniaxial tension. Differences between the two...... measurements could be explained by newly observed stress promoted reduction. Finally, samples exposed to a small tensile stress (∼ 0.004 MPa) were observed to expand during reduction, which is in contradiction to previous literature. These observations suggest that release of internal residual stresses between...

  18. Recent Developments in the Site-Specific Immobilization of Proteins onto Solid Supports

    Energy Technology Data Exchange (ETDEWEB)

    Camarero, J A

    2007-02-21

    Immobilization of proteins onto surfaces is of great importance in numerous applications, including protein analysis, drug screening, and medical diagnostics, among others. The success of all these technologies relies on the immobilization technique employed to attach a protein to the corresponding surface. Non-specific physical adsorption or chemical cross-linking with appropriate surfaces results in the immobilization of the protein in random orientations. Site-specific covalent attachment, on the other hand, leads to molecules being arranged in a definite, orderly fashion and allows the use of spacers and linkers to help minimize steric hindrances between the protein and the surface. The present work reviews the latest chemical and biochemical developments for the site-specific covalent attachment of proteins onto solid supports.

  19. Controlled Clustering of Gold Nanoparticles using Solid-support for Surface-enhanced Raman Spectroscopic Probes

    International Nuclear Information System (INIS)

    Chang, Hyejin; Chae, Jinjoo; Jeong, Hong; Kang, Homan; Lee, Yoonsik

    2014-01-01

    We fabricated small clusters of gold nanoparticles by using solid-supported aggregation of gold nanoparticles. The fabricated Au nanoclusters consisting mainly of dimers showed homogeneous characteristics in cluster size and SERS intensity. The SERS enhancement of 4-ABT molecules in an effective area within 2-nm gap appeared to be approximately 10. Detachment process by ultrasonication was successively carried out in order to use the nanoclusters as SERS probes. The possibility of these clusters as SERS probe was proved in terms of signal and cluster size. Single molecule-level sensitivity of surface-enhanced Raman scattering (SERS) was known approximately fifteen years ago. Ever since there have been many different applications benefiting from the ultra-high sensitivity such as single molecule detection, chemical sensing and bio-molecular probes. Especially, SERS has drawn much attention in bio-multiplexing probes owing to its unique optical characteristics claiming extremely narrow bandwidth, high sensitivity of light signals, and non-bleaching feature

  20. Data supporting the comparative life cycle assessment of different municipal solid waste management scenarios

    Science.gov (United States)

    Ali Rajaeifar, Mohammad; Tabatabaei, Meisam; Ghanavati, Hossein

    2015-01-01

    Environmental assessment of municipal solid waste (MSW) management scenarios would help to select eco-friendly scenarios. In this study, the inventory data in support of life cycle assessment of different MSW are presented. The scenarios were defined as: anaerobic digestion (AD, Sc-0), landfilling combined with composting (Sc-1), incineration (Sc-2), incineration combined with composting (Sc-3), and AD combined with incineration (Sc-4). The current article contains flowcharts of the different scenarios. Additionally, six supplementary files including inventory data on the different scenarios, data on the different damage assessment categories, normalization, and single scores are presented (Supplementary files 1–6). The analysis of the different scenarios revealed that the most eco-friendly scenario to be implemented in the future would be the combination of AD and incineration (Sc-4). PMID:26217743

  1. Data supporting the comparative life cycle assessment of different municipal solid waste management scenarios

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Rajaeifar

    2015-06-01

    Full Text Available Environmental assessment of municipal solid waste (MSW management scenarios would help to select eco-friendly scenarios. In this study, the inventory data in support of life cycle assessment of different MSW are presented. The scenarios were defined as: anaerobic digestion (AD, Sc-0, landfilling combined with composting (Sc-1, incineration (Sc-2, incineration combined with composting (Sc-3, and AD combined with incineration (Sc-4. The current article contains flowcharts of the different scenarios. Additionally, six supplementary files including inventory data on the different scenarios, data on the different damage assessment categories, normalization, and single scores are presented (Supplementary files 1–6. The analysis of the different scenarios revealed that the most eco-friendly scenario to be implemented in the future would be the combination of AD and incineration (Sc-4.

  2. Solid Waste Management Requirements Definition for Advanced Life Support Missions: Results

    Science.gov (United States)

    Alazraki, Michael P.; Hogan, John; Levri, Julie; Fisher, John; Drysdale, Alan

    2002-01-01

    Prior to determining what Solid Waste Management (SWM) technologies should be researched and developed by the Advanced Life Support (ALS) Project for future missions, there is a need to define SWM requirements. Because future waste streams will be highly mission-dependent, missions need to be defined prior to developing SWM requirements. The SWM Working Group has used the mission architecture outlined in the System Integration, Modeling and Analysis (SIMA) Element Reference Missions Document (RMD) as a starting point in the requirement development process. The missions examined include the International Space Station (ISS), a Mars Dual Lander mission, and a Mars Base. The SWM Element has also identified common SWM functionalities needed for future missions. These functionalities include: acceptance, transport, processing, storage, monitoring and control, and disposal. Requirements in each of these six areas are currently being developed for the selected missions. This paper reviews the results of this ongoing effort and identifies mission-dependent resource recovery requirements.

  3. Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral, E-mail: shaynnedn@hotmail.com, E-mail: nataliakm@usp.br, E-mail: fntabuti@ipen.br, E-mail: fabiocf@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Florio, Daniel Zanetti de, E-mail: daniel.florio@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2017-01-15

    Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

  4. Fabrication and characterization of a cathode-supported tubular solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chunhua; Liu, Renzhu; Wang, Shaorong; Wang, Zhenrong; Qian, Jiqin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

    2009-07-15

    A cathode-supported tubular solid oxide fuel cell (CTSOFC) with the length of 6.0 cm and outside diameter of 1.0 cm has been successfully fabricated via dip-coating and co-sintering techniques. A crack-free electrolyte film with a thickness of {proportional_to}14 {mu}m was obtained by co-firing of cathode/cathode active layer/electrolyte/anode at 1250 C. The relative low densifying temperature for electrolyte was attributed to the large shrinkage of the green tubular which assisted the densification of electrolyte. The assembled cell was electrochemically characterized with humidified H{sub 2} as fuel and O{sub 2} as oxidant. The open circuit voltages (OCV) were 1.1, 1.08 and 1.06 V at 750, 800 and 850 C, respectively, with the maximum power densities of 157, 272 and 358 mW cm{sup -2} at corresponding temperatures. (author)

  5. Controlled Clustering of Gold Nanoparticles using Solid-support for Surface-enhanced Raman Spectroscopic Probes

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hyejin; Chae, Jinjoo; Jeong, Hong [Department of Chemistry Education, Seoul (Korea, Republic of); Kang, Homan; Lee, Yoonsik [Interdisciplinary Program in Nano-Science and Technology, Pohang (Korea, Republic of)

    2014-03-15

    We fabricated small clusters of gold nanoparticles by using solid-supported aggregation of gold nanoparticles. The fabricated Au nanoclusters consisting mainly of dimers showed homogeneous characteristics in cluster size and SERS intensity. The SERS enhancement of 4-ABT molecules in an effective area within 2-nm gap appeared to be approximately 10. Detachment process by ultrasonication was successively carried out in order to use the nanoclusters as SERS probes. The possibility of these clusters as SERS probe was proved in terms of signal and cluster size. Single molecule-level sensitivity of surface-enhanced Raman scattering (SERS) was known approximately fifteen years ago. Ever since there have been many different applications benefiting from the ultra-high sensitivity such as single molecule detection, chemical sensing and bio-molecular probes. Especially, SERS has drawn much attention in bio-multiplexing probes owing to its unique optical characteristics claiming extremely narrow bandwidth, high sensitivity of light signals, and non-bleaching feature.

  6. Break-down of Losses in High Performing Metal-Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Kromp, Alexander; Nielsen, Jimmi; Blennow Tullmar, Peter

    2012-01-01

    Metal supported SOFC designs offer competitive advantages such as reduced material costs and improved mechanical robustness. On the other hand, disadvantages might arise due to possible corrosion of the porous metal parts during processing and operation at high fuel utilization. In this paper we...... in hydrogen. The electrochemically active parts were applied by infiltrating CGO-Ni precursor solution into the porous metal and anode backbone and screenprinting (La,Sr)(Co,Fe)O3-based cathodes. To prevent a solid state reaction between cathode and zirconia electrolyte, CGO buffer layers were applied...... in between cathode and electrolyte. The detailed electrochemical characterization by means of impedance spectroscopy and a subsequent data analysis by the distribution of relaxation times enabled us to separate the different loss contributions in the cell. Based on an appropriate equivalent circuit model...

  7. Secondary creep of porous metal supports for solid oxide fuel cells by a CDM approach

    DEFF Research Database (Denmark)

    Esposito, L.; Boccaccini, D. N.; Pucillo, G. P.

    2017-01-01

    The creep behaviour of porous iron-chromium alloy used in solid oxide fuel cells (SOFCs) becomes relevant under SOFC operating temperatures. In this paper, the secondary creep stage of infiltrated and non-infiltrated porous metal supports (MS) was investigated and theoretically modelled...... as function of temperature, determined by the high temperature impulse excitation technique, was directly used to account for the porosity and the related effective stress acting during the creep tests. The proposed creep rate formulation was used to extend the Crofer® 22 APU Monkman-Grant diagram...... in the viscous creep regime. The influence of oxide scale formation on creep behaviour of the porous MS was assessed by comparing the creep data of pre-oxidised samples tested in reducing atmosphere....

  8. Creep behaviour of porous metal supports for solid oxide fuel cells

    DEFF Research Database (Denmark)

    Boccaccini, Dino; Frandsen, Henrik Lund; Sudireddy, Bhaskar Reddy

    2014-01-01

    The creep behaviour of porous ironechromium alloy used as solid oxide fuel cell support was investigated, and the creep parameters are compared with those of dense strips of similar composition under different testing conditions. The creep parameters were determined using a thermo......-mechanical analyser with applied stresses in the range from 1 to 15 MPa and temperatures between 650 and 800 _C. The GibsoneAshby and Mueller models developed for uniaxial creep of open-cell foams were used to analyse the results. The influence of scale formation on creep behaviour was assessed by comparing the creep...... data for the samples tested in reducing and oxidising atmospheres. The influence of preoxidation on creep behaviour was also investigated. In-situ oxidation during creep experiments increases the strain rate while pre-oxidation of samples reduces it. Debonding of scales at high stress regime plays...

  9. Investigation of methane steam reforming in planar porous support of solid oxide fuel cell

    International Nuclear Information System (INIS)

    Yang Yongping; Du Xiaoze; Yang Lijun; Huang Yuan; Xian Haizhen

    2009-01-01

    Adopting the porous support in integrated-planar solid oxide fuel cell (IP-SOFC) can reduce the operating temperature by reducing thickness of electrolyte layer, and also, provide internal reforming environment for hydrogen-rich fuel gas. The distributions of reactant and product components, and temperature of methane steam reforming for IP-SOFC were investigated by the developed physical and mathematical model with thermodynamic analysis, in which eleven possible reaction mechanisms were considered by the source terms and Arrhenius relationship. Numerical simulation of the model revealed that the progress of reforming reaction and the distribution of the product, H 2 , were influenced by the operating conditions, included that of temperature, ratio of H 2 O and CH 4 , as well as by the porosity of the supporting material. The simulating results indicate that the methane conversion rate can reach its maximum value under the operating temperature of 800 deg. C and porosity of ε = 0.4, which rather approximate to the practical operating conditions of IP-SOFC. In addition, characteristics of carbon deposition on surface of catalyst were discussed under various operating conditions and configuration parameters of the porous support. The present works provided some theoretical explanations to the numerous experimental observations and engineered practices

  10. Novel dual-reverse thermosensitive solid lipid nanoparticle-loaded hydrogel for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect.

    Science.gov (United States)

    Din, Fakhar Ud; Mustapha, Omer; Kim, Dong Wuk; Rashid, Rehmana; Park, Jong Hyuck; Choi, Ju Yeon; Ku, Sae Kwang; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

    2015-08-01

    The purpose of this study was to develop novel solid lipid nanoparticle (SLN)-loaded dual-reverse thermosensitive hydrogel (DRTH) for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect. The flurbiprofen-loaded SLNs were prepared by hot homogenisation technique, after optimising the amounts of lipid mixture (tricaprin and triethanolamine in 8:2 weight ratio), drug and surfactant. The flurbiprofen-loaded thermosensitive SLN composed of drug, lipid mixture and surfactant at a weight ratio of 10/15/1.3 was a solid at room temperature, and changed to liquid form at physiological temperature due to its melting point of about 32°C. This SLN gave the mean particle size of about 190nm and entrapment efficiency of around 90%. The DRTHs were prepared by adding this flurbiprofen-loaded thermosensitive SLN in various poloxamer solutions. Their rheological characterisation, release and stability were investigated while a morphological and pharmacokinetic study was performed after its rectal administration to rats compared with the drug and hydrogel. Poloxamer 188 and SLN decreased the gelation temperature and gelation time, but increased the viscosity at 25°C, gel strength and mucoadhesive force of DRTHs. In particular, the DRTH composed of [SLN/P 407/P 188 (10%/15%/25%)] with the gelation temperature of about 35°C existed as liquid at room temperature, but gelled at 30-36°C, leading to opposite reversible property of SLN. Thus, it was easy to administer rectally, and it gelled rapidly inside the body. This DRTH gave a significantly increased dissolution rate of the drug as compared to the flurbiprofen, but significantly retarded as compared to the hydrogel, including the initial dissolution rate. Moreover, this DRTH gave significantly higher plasma concentration and 7.5-fold AUC values compared to the drug, and lower initial plasma concentration and Cmax value compared to the hydrogel due to reduced initial burst effect. No

  11. Local mobility in lipid domains of supported bilayers characterized by atomic force microscopy and fluorescence correlation spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Frankel, Daniel J.; Buranda, T. (University of New Mexico, Albuquerque, NM); Burns, Alan Richard

    2005-01-01

    Fluorescence correlation spectroscopy (FCS) is used to examine mobility of labeled probes at specific sites in supported bilayers consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid domains in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). Those sites are mapped beforehand with simultaneous atomic force microscopy and submicron confocal fluorescence imaging, allowing characterization of probe partitioning between gel DPPC and disordered liquid DOPC domains with corresponding topography of domain structure. We thus examine the relative partitioning and mobility in gel and disordered liquid phases for headgroup- and tailgroup-labeled GM1 ganglioside probes and for headgroup- and tailgroup-labeled phospholipid probes. For the GM1 probes, large differences in mobility between fluid and gel domains are observed; whereas unexpected mobility is observed in submicron gel domains for the phospholipid probes. We attribute the latter to domain heterogeneities that could be induced by the probe. Furthermore, fits to the FCS data for the phospholipid probes in the DOPC fluid phase require two components (fast and slow). Although proximity to the glass substrate may be a factor, local distortion of the probe by the fluorophore could also be important. Overall, we observe nonideal aspects of phospholipid probe mobility and partitioning that may not be restricted to supported bilayers.

  12. Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin

    2012-01-01

    An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3_δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell...... was tested at 700 deg. C under a current density of 0.5 A cm-2 for 1500 h using air as oxidant and humidified hydrogen as fuel. The electrochemical performance of the cell was analyzed by impedance spectroscopy and current evoltage relationships. No measurable degradation in the cell voltage or increase...... in the resistance from the recorded impedance was observed during long term testing. The power density reached 0.79Wcm-2 at a cell voltage of 0.6 V at 750 deg. C. Post test analysis of the LSC infiltrated-CGO cathode by scanning electron microscopy revealed no significant micro-structural difference...

  13. Interaction of poly(amidoamine) dendrimers with supported lipid bilayers and cells: hole formation and the relation to transport.

    Science.gov (United States)

    Hong, Seungpyo; Bielinska, Anna U; Mecke, Almut; Keszler, Balazs; Beals, James L; Shi, Xiangyang; Balogh, Lajos; Orr, Bradford G; Baker, James R; Banaszak Holl, Mark M

    2004-01-01

    We have investigated poly(amidoamine) (PAMAM) dendrimer interactions with supported 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers and KB and Rat2 cell membranes using atomic force microscopy (AFM), enzyme assays, flow cell cytometry, and fluorescence microscopy. Amine-terminated generation 7 (G7) PAMAM dendrimers (10-100 nM) were observed to form holes of 15-40 nm in diameter in aqueous, supported lipid bilayers. G5 amine-terminated dendrimers did not initiate hole formation but expanded holes at existing defects. Acetamide-terminated G5 PAMAM dendrimers did not cause hole formation in this concentration range. The interactions between PAMAM dendrimers and cell membranes were studied in vitro using KB and Rat 2 cell lines. Neither G5 amine- nor acetamide-terminated PAMAM dendrimers were cytotoxic up to a 500 nM concentration. However, the dose dependent release of the cytoplasmic proteins lactate dehydrogenase (LDH) and luciferase (Luc) indicated that the presence of the amine-terminated G5 PAMAM dendrimer decreased the integrity of the cell membrane. In contrast, the presence of acetamide-terminated G5 PAMAM dendrimer had little effect on membrane integrity up to a 500 nM concentration. The induction of permeability caused by the amine-terminated dendrimers was not permanent, and leaking of cytosolic enzymes returned to normal levels upon removal of the dendrimers. The mechanism of how PAMAM dendrimers altered cells was investigated using fluorescence microscopy, LDH and Luc assays, and flow cytometry. This study revealed that (1) a hole formation mechanism is consistent with the observations of dendrimer internalization, (2) cytosolic proteins can diffuse out of the cell via these holes, and (3) dye molecules can be detected diffusing into the cell or out of the cell through the same membrane holes. Diffusion of dendrimers through holes is sufficient to explain the uptake of G5 amine-terminated PAMAM dendrimers into cells and is consistent

  14. Operator models for delivering municipal solid waste management services in developing countries: Part B: Decision support.

    Science.gov (United States)

    Soós, Reka; Whiteman, Andrew D; Wilson, David C; Briciu, Cosmin; Nürnberger, Sofia; Oelz, Barbara; Gunsilius, Ellen; Schwehn, Ekkehard

    2017-08-01

    This is the second of two papers reporting the results of a major study considering 'operator models' for municipal solid waste management (MSWM) in emerging and developing countries. Part A documents the evidence base, while Part B presents a four-step decision support system for selecting an appropriate operator model in a particular local situation. Step 1 focuses on understanding local problems and framework conditions; Step 2 on formulating and prioritising local objectives; and Step 3 on assessing capacities and conditions, and thus identifying strengths and weaknesses, which underpin selection of the operator model. Step 4A addresses three generic questions, including public versus private operation, inter-municipal co-operation and integration of services. For steps 1-4A, checklists have been developed as decision support tools. Step 4B helps choose locally appropriate models from an evidence-based set of 42 common operator models ( coms); decision support tools here are a detailed catalogue of the coms, setting out advantages and disadvantages of each, and a decision-making flowchart. The decision-making process is iterative, repeating steps 2-4 as required. The advantages of a more formal process include avoiding pre-selection of a particular com known to and favoured by one decision maker, and also its assistance in identifying the possible weaknesses and aspects to consider in the selection and design of operator models. To make the best of whichever operator models are selected, key issues which need to be addressed include the capacity of the public authority as 'client', management in general and financial management in particular.

  15. Efficient synthesis of sulfonamide derivatives on solid supports catalyzed using solvent-free and microwave-assisted methods

    Energy Technology Data Exchange (ETDEWEB)

    Camargo-Ordonez, Argelia; Moreno-Reyes, Christian; Olazaran-Santibanez, Fabian; Martinez-Hernandez, Sheila; Bocanegra-Garcia, Virgilio; Rivera, Gildardo [Universidad Autonoma de Tamaulipas, Reynosa (Mexico). Dep. de Farmacia y Quimica Medicinal

    2011-07-01

    In this work we report the synthesis of sulfonamide derivatives using a conventional procedure and with solid supports, such as silica gel, florisil, alumina, 4A molecular sieves, montmorillonite KSF, and montmorillonite K10 using solvent-free and microwave-assisted methods. Our results show that solid supports have a catalytic activity in the formation of sulfonamide derivatives. We found that florisil, montmorillonite KSF, and K10 could be used as inexpensive alternative catalysts that are easily separated from the reaction media. Additionally, solvent-free and microwave-assisted methods were more efficient in reducing reaction time and in increasing yield. (author)

  16. Efficient synthesis of sulfonamide derivatives on solid supports catalyzed using solvent-free and microwave-assisted methods

    International Nuclear Information System (INIS)

    Camargo-Ordonez, Argelia; Moreno-Reyes, Christian; Olazaran-Santibanez, Fabian; Martinez-Hernandez, Sheila; Bocanegra-Garcia, Virgilio; Rivera, Gildardo

    2011-01-01

    In this work we report the synthesis of sulfonamide derivatives using a conventional procedure and with solid supports, such as silica gel, florisil, alumina, 4A molecular sieves, montmorillonite KSF, and montmorillonite K10 using solvent-free and microwave-assisted methods. Our results show that solid supports have a catalytic activity in the formation of sulfonamide derivatives. We found that florisil, montmorillonite KSF, and K10 could be used as inexpensive alternative catalysts that are easily separated from the reaction media. Additionally, solvent-free and microwave-assisted methods were more efficient in reducing reaction time and in increasing yield. (author)

  17. Stability study of cermet-supported solid oxide fuel cells with bi-layered electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinge; Gazzarri, Javier; Robertson, Mark; Deces-Petit, Cyrille [National Research Council, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC (Canada); Kesler, Olivera [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, ON (Canada)

    2008-12-01

    Performance and stability of five cermet-supported button-type solid oxide fuel cells featuring a bi-layered electrolyte (SSZ/SDC), an SSC cathode, and a Ni-SSZ anode, were analyzed using polarization curves, impedance spectroscopy, and post-mortem SEM observation. The cell performance degradation at 650 C in H{sub 2}/air both with and without DC bias conditions was manifested primarily as an increase in polarization resistance, approximately at a rate of 2.3 m{omega} cm{sup 2} h{sup -1} at OCV, suggesting a decrease in electrochemical kinetics as the main phenomenon responsible for the performance decay. In addition, the initial series resistance was about ten times higher than the calculated resistance corresponding to the electrolyte, reflecting a possible inter-reaction between the electrolyte layers that occurred during the sintering stage. In situ and ex situ sintered cathodes showed no obvious difference in cell performance or decay rate. The stability of the cells with and without electrical load was also investigated and no significant influence of DC bias was recorded. Based on the experimental results presented, we preliminarily attribute the performance degradation to electrochemical and microstructural degradation of the cathode. (author)

  18. Stability study of cermet-supported solid oxide fuel cells with bi-layered electrolyte

    Science.gov (United States)

    Zhang, Xinge; Gazzarri, Javier; Robertson, Mark; Decès-Petit, Cyrille; Kesler, Olivera

    Performance and stability of five cermet-supported button-type solid oxide fuel cells featuring a bi-layered electrolyte (SSZ/SDC), an SSC cathode, and a Ni-SSZ anode, were analyzed using polarization curves, impedance spectroscopy, and post-mortem SEM observation. The cell performance degradation at 650 °C in H 2/air both with and without DC bias conditions was manifested primarily as an increase in polarization resistance, approximately at a rate of 2.3 mΩ cm 2 h -1 at OCV, suggesting a decrease in electrochemical kinetics as the main phenomenon responsible for the performance decay. In addition, the initial series resistance was about ten times higher than the calculated resistance corresponding to the electrolyte, reflecting a possible inter-reaction between the electrolyte layers that occurred during the sintering stage. In situ and ex situ sintered cathodes showed no obvious difference in cell performance or decay rate. The stability of the cells with and without electrical load was also investigated and no significant influence of DC bias was recorded. Based on the experimental results presented, we preliminarily attribute the performance degradation to electrochemical and microstructural degradation of the cathode.

  19. Long-term Steam Electrolysis with Electrolyte-Supported Solid Oxide Cells

    International Nuclear Information System (INIS)

    Schefold, Josef; Brisse, Annabelle; Poepke, Hendrik

    2015-01-01

    Steam electrolysis over 11000 h with an electrolyte-supported solid oxide cell is discussed. The cell of 45 cm"2 area consists of a scandia/ceria doped zirconia electrolyte (6Sc1CeSZ), CGO diffusion-barrier/adhesion layers, a lanthanum strontium cobaltite ferrite (LSCF) oxygen electrode, and a nickel steam/hydrogen electrode. After initial 2500 h operation with lower current-density magnitude, the current density was set to j = -0.9 A cm"−"2 and the steam conversion rate to 51%. This led to a cell voltage of 1.185 V at 847 °C cell temperature. Average voltage degradation was 7.3 mV/1000 h ( 100% throughout the test (with an external heat source for evaporation). Impedance spectroscopic measurements revealed a degradation almost entirely due to increasing ohmic resistance. The rate of resistance increase was initially faster (up to 40 mΩ cm"2/1000 h) and stabilised after several 1000 h operation. After 9000 h a small (non-ohmic) electrode degradation became detectable (<2 mV/1000 h), superimposed to ohmic degradation. The small electrode degradation is understood as indication for largely reversible (electrolysis cell/fuel cell) behaviour.

  20. Metal Chlorides Supported Solid Catalysts for F-C Acylations of Arenes

    Institute of Scientific and Technical Information of China (English)

    李阳; 刘云龙; 穆曼曼; 陈立功

    2015-01-01

    A series of metal chlorides supported solid catalysts were prepared by simple wet impregnation method. Their catalytic performances for Friedel-Crafts acylation of toluene with benzoyl chloride were evaluated and the excellent results were obtained over FeCl3/SiO2. These catalysts were characterized by BET, NH3-TPD and FT-IR of pyridine adsorption to clarify the structure-activity relationship. It was found that FeCl3/SiO2 has larger pore size and pore volume than other catalysts, which increased the accessibility of the catalyst. In addition, FeCl3/SiO2 ex-hibited higher molar ratio of Lewis acid sites and Brφnsted acid sites, which might be another reason for the in-crease of toluene conversion. Furthermore, the reaction parameters, including temperature, time and molar ratio, were optimized. Under the optimized conditions, 91.2%, conversion and 82.0%, selectivity were obtained. Mean-while, the generality of the catalyst was demonstrated by the acylations of alkyl substituted aromatics. Finally, the catalyst was reused for four runs with slight loss in catalytic activity, which attributed to the drain of the active component.

  1. Mobile magnetic particles as solid-supports for rapid surface-based bioanalysis in continuous flow.

    Science.gov (United States)

    Peyman, Sally A; Iles, Alexander; Pamme, Nicole

    2009-11-07

    An extremely versatile microfluidic device is demonstrated in which multi-step (bio)chemical procedures can be performed in continuous flow. The system operates by generating several co-laminar flow streams, which contain reagents for specific (bio)reactions across a rectangular reaction chamber. Functionalized magnetic microparticles are employed as mobile solid-supports and are pulled from one side of the reaction chamber to the other by use of an external magnetic field. As the particles traverse the co-laminar reagent streams, binding and washing steps are performed on their surface in one operation in continuous flow. The applicability of the platform was first demonstrated by performing a proof-of-principle binding assay between streptavidin coated magnetic particles and biotin in free solution with a limit of detection of 20 ng mL(-1) of free biotin. The system was then applied to a mouse IgG sandwich immunoassay as a first example of a process involving two binding steps and two washing steps, all performed within 60 s, a fraction of the time required for conventional testing.

  2. A framework for a decision support system for municipal solid waste landfill design.

    Science.gov (United States)

    Verge, Ashley; Rowe, R Kerry

    2013-12-01

    A decision support system (Landfill Advisor or LFAdvisor) was developed to integrate current knowledge of barrier systems into a computer application to assist in landfill design. The program was developed in Visual Basic and includes an integrated database to store information. LFAdvisor presents the choices available for each liner component (e.g. leachate collection system, geomembrane liner, clay liners) and provides advice on their suitability for different situations related to municipal solid waste landfills (e.g. final cover, base liner, lagoon liner). Unique to LFAdvisor, the service life of each engineered component is estimated based on results from the latest research. LFAdvisor considers the interactions between liner components, operating conditions, and the existing site environment. LFAdvisor can be used in the initial stage of design to give designers a good idea of what liner components will likely be required, while alerting them to issues that are likely to arise. A systems approach is taken to landfill design with the ultimate goal of maximising long-term performance and service life.

  3. Multi-layer thin-film electrolytes for metal supported solid oxide fuel cells

    Science.gov (United States)

    Haydn, Markus; Ortner, Kai; Franco, Thomas; Uhlenbruck, Sven; Menzler, Norbert H.; Stöver, Detlev; Bräuer, Günter; Venskutonis, Andreas; Sigl, Lorenz S.; Buchkremer, Hans-Peter; Vaßen, Robert

    2014-06-01

    A key to the development of metal-supported solid oxide fuel cells (MSCs) is the manufacturing of gas-tight thin-film electrolytes, which separate the cathode from the anode. This paper focuses the electrolyte manufacturing on the basis of 8YSZ (8 mol.-% Y2O3 stabilized ZrO2). The electrolyte layers are applied by a physical vapor deposition (PVD) gas flow sputtering (GFS) process. The gas-tightness of the electrolyte is significantly improved when sequential oxidic and metallic thin-film multi-layers are deposited, which interrupt the columnar grain structure of single-layer electrolytes. Such electrolytes with two or eight oxide/metal layers and a total thickness of about 4 μm obtain leakage rates of less than 3 × 10-4 hPa dm3 s-1 cm-2 (Δp: 100 hPa) at room temperature and therefore fulfill the gas tightness requirements. They are also highly tolerant with respect to surface flaws and particulate impurities which can be present on the graded anode underground. MSC cell tests with double-layer and multilayer electrolytes feature high power densities more than 1.4 W cm-2 at 850 °C and underline the high potential of MSC cells.

  4. Development of solid lipid nanoparticles containing total flavonoid extract from Dracocephalum moldavica L. and their therapeutic effect against myocardial ischemia–reperfusion injury in rats

    Directory of Open Access Journals (Sweden)

    Tan ME

    2017-04-01

    Full Text Available Mei-e Tan,1–3,* Cheng-hui He,3,* Wen Jiang,4 Cheng Zeng,2–4 Ning Yu,3 Wei Huang,2 Zhong-gao Gao,2 Jian-guo Xing3 1Key Laboratory of Xinjiang Endemic Phytomedicine Resources of Ministry of Education, School of Pharmacy, Shihezi University, Shihezi, 2State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 3Xinjiang Key Laboratory of Uighur Medicines, Xinjiang Institute of Materia Medica, 4Xinjiang Medical University, Urumqi, People’s Republic of China *These authors contributed equally to this work Abstract: Total flavonoid extract from Dracocephalum moldavica L. (TFDM contains effective components of D. moldavica L. that have myocardial protective function. However, the cardioprotection function of TFDM is undesirable due to its poor solubility. In order to improve the solubility and efficacy of TFDM, we developed TFDM-loaded solid lipid nanoparticles (TFDM-SLNs and optimized the formulation of TFDM-SLNs using central composite design and response surface methodology. The physicochemical properties of TFDM-SLNs were characterized, and the pharmacodynamics was investigated using the myocardial ischemia–reperfusion injury model in rats. The nanoparticles of optimal formulation for TFDM-SLNs were spherical in shape with the average particle size of 104.83 nm and had a uniform size distribution with the polydispersity index value of 0.201. TFDM-SLNs also had a negative zeta potential of -28.7 mV to ensure the stability of the TFDM-SLNs emulsion system. The results of pharmacodynamics demonstrated that both TFDM and TFDM-SLN groups afforded myocardial protection, and the protective effect of TFDM-SLNs was significantly superior to that of TFDM alone, based on the infarct area, histopathological examination, cardiac enzyme levels and inflammatory factors in serum. Due to the optimal

  5. Application of Box-Behnken design for preparation of levofloxacin-loaded stearic acid solid lipid nanoparticles for ocular delivery: Optimization, in vitro release, ocular tolerance, and antibacterial activity.

    Science.gov (United States)

    Baig, Mirza Salman; Ahad, Abdul; Aslam, Mohammed; Imam, Syed Sarim; Aqil, Mohd; Ali, Asgar

    2016-04-01

    The aim of the present study was to develop and optimize levofloxacin loaded solid lipid nanoparticles for the treatment of conjunctivitis. Box-Behnken experimental design was applied for optimization of solid lipid nanoparticles. The independent variables were stearic acid as lipid (X1), Tween 80 as surfactant (X2) and sodium deoxycholate as co-surfactant (X3) while particle size (Y1) and entrapment efficiency (Y2) were the dependent variables. Further in vitro release and antibacterial activity in vitro were also performed. The optimized formulation of levofloxacin provides particle size of 237.82 nm and showed 78.71% entrapment efficiency and achieved flux 0.2,493 μg/cm(2)/h across excised goat cornea. In vitro release study showed prolonged drug release from the optimized formulation following Korsmeyer-Peppas model. Antimicrobial study revealed that the developed formulation possesses antibacterial activity against Staphylococcus aureus, and Escherichia coli equivalent to marketed eye drops. HET-CAM test demonstrated that optimized formulation was found to be non-irritant and safe for topical ophthalmic use. Our results concluded that solid lipid nanoparticles are an efficient carrier for ocular delivery of levofloxacin and other drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Selective Aerobic Oxidation of 5-Hydroxymethylfurfural in Water Over Solid Ruthenium Hydroxide Catalysts with Magnesium-Based Supports

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

    Solid catalyst systems comprised of ruthenium hydroxide supported on magnesium-based carrier materials (spinel, magnesium oxide and hydrotalcite) were investigated for the selective, aqueous aerobic oxidation of the biomass-derived chemical 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid...

  7. Paddy Husk as Support for Solid State Fermentation to Produce Xylanase from Bacillus pumilus

    Directory of Open Access Journals (Sweden)

    Ranganathan KAPILAN

    2011-03-01

    Full Text Available To optimize culture conditions for xylanase production by solid state fermentation (SSF using Bacillus pumilus, with paddy husk as support, solid medium contained 200 g of paddy husk with 800 mL of liquid fermentation medium [xylan, 20.0 g/L; peptone, 2.0 g/L; yeast extract, 2.5 g/L; K2HPO4, 2.5 g/L; KH2PO4, 1.0 g/L; NaCl, 0.1 g/L; (NH42SO4, 2.0 g/L, CaCl2·2H2O, 0.005 g/L; MgCl2·6H2O, 0.005 g/L; and FeCl3, 0.005 g/L] at pH 9.0 was applied. The highest xylanase activity (142.0 ±0.47 U/g DM] was obtained on the 6th day at 30°C. The optimized paddy husk to liquid fermentation medium ratio was 2:9, and the optimized culture temperature was 40°C. When commercial Birchwood xylan was replaced with different concentrations of corncob, xylanase production was maximized (224.2 U/g DM in the medium with 150 g/L corncob. Xylanase production was increased by sucrose, fructose and arabinose, whereas reduced by glucose, galactose, lactose and amylose. When organic nitrogen sources were replaced with locally available nitrogen sources such as groundnut powder or sesame seedcake powder or coconut seedcake powder or soy meal powder, the highest xylanase production (290.7 U/g DM was obtained in the medium with soy meal powder and 16.0 g/L of soy meal powder was the optimum (326.5±0.34 U/g DM. Based on the optimization studies, B. pumilus produced 2.3 times higher xylanase activity. The medium cost was reduced from 2 458.3 to 178.3 SLR/kg and the total activity which could be obtained from 1 kg of the medium was increased from 48 624 to 220 253 Units.

  8. How Assessment Methods Can Support Solid Waste Management in Developing Countries—A Critical Review

    Directory of Open Access Journals (Sweden)

    Christian Zurbrügg

    2014-01-01

    Full Text Available Selecting actions for improvement of solid waste management in low and middle income countries and understanding how a specific decision choice will fit and impact on a local context is key to identifying sustainable solutions. Assessment of the choice (be it technical or managerial and assessment of the local enabling or disabling conditions are both important steps in the decision making process. Various assessment tools and methods are currently available to support decision-making in solid waste management. Assessment can be used to identify weaknesses or strengths of existing systems in a structured way and hereby highlight factors of success and failure. Assessment methods can also evaluate and compare different possible choices as in project scenarios. This overview describes established and innovative assessment methods serving both these purposes. A range of assessment tools are often designed to assess a specific sustainability domain (technical, environmental and health, economic and financial, social and institutional, organizational aspects, others attempt to provide a more holistic picture by integrating different sustainability domains into the same tool. This paper reviews a number of methods describing and discussing each of them, and referring to their use in low and middle-income countries if published in scientific literature. The overview concludes that in low- and middle-income countries the use of comprehensive assessment methods is yet very limited. We hypothesize that most formal methods of assessment are still too complex and generally overburden the weak local capacities intended for their usage. The few applications identified, were conducted by academia for scientific purposes. Lack of resources to collect the vast data required for some assessment methods is a further restriction to their practical application. Future development is suggested to improve user friendliness of existing tools or to simplify certain

  9. Surface-enhanced Raman scattering of self-assembled thiol monolayers and supported lipid membranes on thin anodic porous alumina

    Directory of Open Access Journals (Sweden)

    Marco Salerno

    2017-01-01

    Full Text Available Thin anodic porous alumina (tAPA was fabricated from a 500 nm thick aluminum (Al layer coated on silicon wafers, through single-step anodization performed in a Teflon electrochemical cell in 0.4 M aqueous phosphoric acid at 110 V. Post-fabrication etching in the same acid allowed obtaining tAPA surfaces with ≈160 nm pore diameter and ≈80 nm corresponding wall thickness to be prepared. The tAPA surfaces were made SERS-active by coating with a thin (≈25 nm gold (Au layer. The as obtained tAPA–Au substrates were incubated first with different thiols, namely mercaptobenzoic acid (MbA and aminothiol (AT, and then with phospholipid vesicles of different composition to form a supported lipid bilayer (SLB. At each step, the SERS substrate functionality was assessed, demonstrating acceptable enhancement (≥100×. The chemisorption of thiols during the first step and the formation of SLB from the vesicles during the second step, were independently monitored by using a quartz crystal microbalance with dissipation monitoring (QCM-D technique. The SLB membranes represent a simplified model system of the living cells membranes, which makes the successful observation of SERS on these films promising in view of the use of tAPA–Au substrates as a platform for the development of surface-enhanced Raman spectroscopy (SERS biosensors on living cells. In the future, these tAPA–Au-SLB substrates will be investigated also for drug delivery of bioactive agents from the APA pores.

  10. Surface modification of solid lipid nanoparticles for oral delivery of curcumin: Improvement of bioavailability through enhanced cellular uptake, and lymphatic uptake.

    Science.gov (United States)

    Baek, Jong-Suep; Cho, Cheong-Weon

    2017-08-01

    Curcumin has been reported to exhibit potent anticancer effects. However, poor solubility, bioavailability and stability of curcumin limit its in vivo efficacy for the cancer treatment. Solid lipid nanoparticles (SLN) are a promising delivery system for the enhancement of bioavailability of hydrophobic drugs. However, burst release of drug from SLN in acidic environment limits its usage as oral delivery system. Hence, we prepared N-carboxymethyl chitosan (NCC) coated curcumin-loaded SLN (NCC-SLN) to inhibit the rapid release of curcumin in acidic environment and enhance the bioavailability. The NCC-SLN exhibited suppressed burst release in simulated gastric fluid while sustained release was observed in simulated intestinal fluid. Furthermore, NCC-SLN exhibited increased cytotoxicity and cellular uptake on MCF-7 cells. The lymphatic uptake and oral bioavailability of NCC-SLN were found to be 6.3-fold and 9.5-fold higher than that of curcumin solution, respectively. These results suggest that NCC-SLN could be an efficient oral delivery system for curcumin. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Curcumin-loaded solid lipid nanoparticles with Brij78 and TPGS improved in vivo oral bioavailability and in situ intestinal absorption of curcumin.

    Science.gov (United States)

    Ji, Hongyu; Tang, Jingling; Li, Mengting; Ren, Jinmei; Zheng, Nannan; Wu, Linhua

    2016-01-01

    The present study was to formulate curcumin solid lipid nanoparticles (Cur-SLNs) with P-gp modulator excipients, TPGS and Brij78, to enhance the solubility and bioavailability of curcumin. The formulation was optimized by Plackett-Burman screening design and Box-Behnken experiment design. Then physiochemical properties, entrapment efficiency and in vitro release of Cur-SLNs were characterized. In vivo pharmacokinetics study and in situ single-pass intestinal perfusion were performed to investigate the effects of Cur-SLNs on the bioavailability and intestinal absorption of curcumin. The optimized formulations showed an average size of 135.3 ± 1.5 nm with a zeta potential value of -24.7 ± 2.1 mV and 91.09% ± 1.23% drug entrapment efficiency, meanwhile displayed a sustained release profile. In vivo pharmacokinetic study showed AUC0→t for Cur-SLNs was 12.27-folds greater than curcumin suspension and the relative bioavailability of Cur-SLNs was 942.53%. Meanwhile, Tmax and t(1/2) of curcumin for Cur-SLNs were both delayed comparing to the suspensions (p curcumin for SLNs was significantly improved (p curcumin solution. Cur-SLNs with TPGS and Brij78 could improve the oral bioavailability and intestinal absorption of curcumin effectively.

  12. Development of solid lipid nanoparticles containing total flavonoid extract from Dracocephalum moldavica L. and their therapeutic effect against myocardial ischemia-reperfusion injury in rats.

    Science.gov (United States)

    Tan, Mei-E; He, Cheng-Hui; Jiang, Wen; Zeng, Cheng; Yu, Ning; Huang, Wei; Gao, Zhong-Gao; Xing, Jian-Guo

    2017-01-01

    Total flavonoid extract from Dracocephalum moldavica L. (TFDM) contains effective components of D. moldavica L. that have myocardial protective function. However, the cardioprotection function of TFDM is undesirable due to its poor solubility. In order to improve the solubility and efficacy of TFDM, we developed TFDM-loaded solid lipid nanoparticles (TFDM-SLNs) and optimized the formulation of TFDM-SLNs using central composite design and response surface methodology. The physicochemical properties of TFDM-SLNs were characterized, and the pharmacodynamics was investigated using the myocardial ischemia-reperfusion injury model in rats. The nanoparticles of optimal formulation for TFDM-SLNs were spherical in shape with the average particle size of 104.83 nm and had a uniform size distribution with the polydispersity index value of 0.201. TFDM-SLNs also had a negative zeta potential of -28.7 mV to ensure the stability of the TFDM-SLNs emulsion system. The results of pharmacodynamics demonstrated that both TFDM and TFDM-SLN groups afforded myocardial protection, and the protective effect of TFDM-SLNs was significantly superior to that of TFDM alone, based on the infarct area, histopathological examination, cardiac enzyme levels and inflammatory factors in serum. Due to the optimal quality and the better myocardial protective effect, TFDM-SLNs are expected to become a safe and effective nanocarrier for the oral delivery of TFDM.

  13. Sustained-release diclofenac potassium-loaded solid lipid microparticle based on solidified reverse micellar solution: in vitro and in vivo evaluation.

    Science.gov (United States)

    Chime, Salome Amarachi; Attama, Anthony Amaechi; Builders, Philip F; Onunkwo, Godswill C

    2013-01-01

    To formulate sustained-release diclofenac potassium-loaded solid lipid microparticles (SLMs) based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties. SRMS consisting of mixtures of Phospholipon® 90H and Softisan® 154 were used to formulate diclofenac potassium-loaded SLMs. Characterization based on the particle size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release was carried out in simulated intestinal fluid (pH 7.5). Anti-inflammatory and ulcerogenic properties were studied using rats. Maximum EE% of 95%, 94% and 93% were obtained for SLMs formulated with SRMS 1:1, 2:1 and 1:2, respectively. In vitro release showed about 85-90% drug release at 13 h. Diclofenac potassium-loaded SLMs showed good anti-inflammatory and gastro-protective properties. Diclofenac potassium-loaded SLMs based on SRMS could be used orally or parenterally under controlled conditions, for once daily administration.

  14. Gadolinium-Loaded Solid Lipid Nanoparticles as a Tumor-Absorbable Contrast Agent for Early Diagnosis of Colorectal Tumors Using Magnetic Resonance Colonography.

    Science.gov (United States)

    Sun, Jihong; Zhang, Shizheng; Jiang, Shaojie; Bai, Weixian; Liu, Fei; Yuan, Hong; Ji, Jiansong; Luo, Jingfeng; Han, Guocan; Chen, Lumin; Jin, Yin; Hu, Peng; Yu, Lei; Yang, Xiaoming

    2016-09-01

    Magnetic resonance (MR) contrast agents focusing on special functions are required to improve cancer diagnosis, particularly in the early stages. Here, we designed multifunctional solid lipid nanoparticles (SLNs) with simultaneous loading of gadolinium (Gd) diethylenetriaminepentaacetic acid (Gd-DTPA) and octadecylamine fluorescein isothiocyanate (FITC) to obtain Gd-FITC-SLNs as a tumor-absorbable nanoparticle contrast agent for the histological confirmation of MR imaging (MRI) findings. Colorectal tumors were evaluated in vitro and in vivo via direct uptake of this contrast agent, which displayed reasonable T1 relaxivity and no significant cytotoxicity at the experimental concentrations in human colon carcinoma cells (HT29) and mouse colon carcinoma cells (CT26). In vitro cell uptake experiments demonstrated that contrast agent absorption by the two types of cancer cells was concentration-dependent in the safe concentration range. During in vivo MRI, transrectal infusion of Gd-FITC-SLNs showed more significant enhancement at the tumor site compared with the infusion of Gd-DTPA in female C57/BL mice with azoxymethane/dextran sulfate sodium-induced colorectal highgrade intraepithelial neoplasia. Subsequent confocal fluorescence microscopy demonstrated Gd-FITC-SLNs as highly concentrated green fluorescent spots distributed from the tumor capsule into the tumor. This study establishes the "proof-of-principle" of a new MRI technique wherein colorectal tumors are enhanced via direct absorption or uptake of the nanoparticle contrast agent.

  15. Comparative Neuroprotective Effects of Dietary Curcumin and Solid Lipid Curcumin Particles in Cultured Mouse Neuroblastoma Cells after Exposure to Aβ42

    Directory of Open Access Journals (Sweden)

    Panchanan Maiti

    2017-01-01

    Full Text Available Aggregation of amyloid beta protein (Aβ and phosphorylated tau (p-Tau plays critical roles in pathogenesis of Alzheimer’s disease (AD. As an antiamyloid natural polyphenol, curcumin (Cur has a potential role in prevention of neurodegeneration in AD. However, due to limited absorption of the dietary Cur, the solid lipid Cur particles (SLCP have been suggested as being more effective for AD therapy. In the present study, we compared the role of dietary Cur and SLCP on oxidative stress, neuronal death, p-Tau level, and certain cell survival markers in vitro, after exposure to Aβ42. Mouse neuroblastoma cells were exposed to Aβ42 for 24 h and incubated with or without dietary Cur and/or SLCP. Reactive oxygen species (ROS, apoptotic cell death, p-Tau, and tau kinase (including GSK-3β and cell survival markers, such as total Akt, phosphorylated Akt, and PSD95 levels were investigated. SLCP showed greater permeability than dietary Cur in vitro, decreased ROS production, and prevented apoptotic death. In addition, SLCP also inhibited p-Tau formation and significantly decreased GSK-3β levels. Further, the cell survival markers, such as total Akt, p-Akt, and PSD95 levels, were more effectively maintained by SLCP than dietary Cur in Aβ42 exposed cells. Therefore, SLCP may provide greater neuroprotection than dietary Cur in Alzheimer’s disease.

  16. In vitro antitumor efficacy of berberine: solid lipid nanoparticles against human HepG2, Huh7 and EC9706 cancer cell lines

    Science.gov (United States)

    Meng, Xiang-Ping; Wang, Xiao; Wang, Huai-ling; Chen, Tong-sheng; Wang, Yi-fei; Wang, Zhi-ping

    2016-03-01

    Hepatocarcinoma and esophageal squamous cell carcinomas threaten human life badly. It is a current issue to seek the effective natural remedy from plant to treat cancer due to the resistance of the advanced hepatocarcinoma and esophageal carcinoma to chemotherapy. Berberine (Ber), an isoquinoline derivative alkaloid, has a wide range of pharmacological properties and is considered to have anti-hepatocarcinoma and antiesophageal carcinoma effects. However its low oral bioavailability restricts its wide application. In this report, Ber loaded solid lipid nanoparticles (Ber-SLN) was prepared by hot melting and then high pressure homogenization technique. The in vitro anti-hepatocarcinoma and antiesophageal carcinoma effects of Ber-SLN relative to efficacy of bulk Ber were evaluated. The particle size and zeta potential of Ber-SLN were 154.3 ± 4.1 nm and -11.7 ± 1.8 mV, respectively. MTT assay showed that Ber-SLN effectively inhibited the proliferation of human HepG2 and Huh7 and EC9706 cells, and the corresponding IC50 value was 10.6 μg/ml, 5.1 μg/ml, and 7.3 μg/ml (18.3μg/ml, 6.5μg/ml, and 12.4μg/ml μg/ml of bulk Ber solution), respectively. These results suggest that the delivery of Ber-SLN is a promising approach for treating tumors.

  17. Lamellar crystalline self-assembly behaviour and solid lipid nanoparticles of a palmityl prodrug analogue of Capecitabine—A chemotherapy agent

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Xiaojuan; Moghaddam, Minoo J.; Sagnella, Sharon M.; Conn, Charlotte E.; Danon, Stephen J.; Waddington, Lynne J.; Drummond, Calum J. [CSIRO/MSE

    2014-09-24

    An amphiphile prodrug, 5'-deoxy-5-fluoro-N4-(palmityloxycarbonyl) cytidine or 5'-deoxy-5-fluoro-N4-(hexadecanaloxycarbonyl) cytidine (5-FCPal), consisting of the same head group as the commercially available chemotherapeutic agent Capecitabine, linked to a palmityl hydrocarbon chain via a carbamate bond is reported. Thermal analysis of this prodrug indicates that it melts at ~115 °C followed quickly by degradation beginning at ~120 °C. The neat solid 5-FCPal amphiphile acquires a lamellar crystalline arrangement with a d-spacing of 28.6 ± 0.3 Å, indicating interdigitation of the hydrocarbon chains. Under aqueous conditions, solid 5-FCPal is non-swelling and no lyotropic liquid crystalline phase formation is observed. In order to assess the in vitro toxicity and in vivo efficacy in colloidal form, solid lipid nanoparticles (SLNs) with an average size of ~700 nm were produced via high pressure homogenization. The in vitro toxicity of the 5-FCPal SLNs against several different cancer and normal cell types was assessed over a 48 h period, and IC50 values were comparable to those observed for Capecitabine. The in vivo efficacy of the 5-FCPal SLNs was then assessed against the highly aggressive mouse 4T1 breast cancer model. To do so, the prodrug SLNs were administered orally at 3 different dosages (0.1, 0.25, 0.5 mmol/mouse/day) and compared to Capecitabine delivered at the same dosages. After 21 days of receiving the treatments, the 0.5 mmol dose of 5-FCPal exhibited the smallest average tumour volume. Since 5-FCPal is activated in a similar manner to Capecitabine via a 3 step enzymatic pathway with the final step occurring preferentially at the tumour site, formulation of the prodrug into SLNs combines the advantage of selective, localized activation with the sustained release properties of nanostructured amphiphile self-assembly and multiple payload materials thereby potentially creating a more effective anticancer agent.

  18. Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams

    International Nuclear Information System (INIS)

    Thakur, Neha; Kumar, Sanjukta A.; Wagh, D.N.; Das, Sadananda; Pandey, Ashok K.; Kumar, Sangita D.; Reddy, A.V.R.

    2012-01-01

    Highlights: ► Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. ► Membranes offered high capacity and selectivity for fluoride in aqueous media. ► Quantitative uptake (80 ± 5%) of fluoride. ► Fast sorption kinetics. ► Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic–organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for ≈76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg −1 ), was higher than fibrous and any other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

  19. In Situ Lipolysis and Synchrotron Small-Angle X-ray Scattering for the Direct Determination of the Precipitation and Solid-State Form of a Poorly Water-Soluble Drug During Digestion of a Lipid-Based Formulation

    DEFF Research Database (Denmark)

    Khan, Jamal; Hawley, Adrian; Rades, Thomas

    2016-01-01

    In situ lipolysis and synchrotron small-angle X-ray scattering (SAXS) were used to directly detect and elucidate the solid-state form of precipitated fenofibrate from the digestion of a model lipid-based formulation (LBF). This method was developed in light of recent findings that indicate variab...... on drugs, and experimental conditions, which are anticipated to produce altered solid-state forms upon the precipitation of drug (i.e., polymorphs, amorphous forms, and salts). © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci....

  20. Evaluation of alternative environmentally friendly matrix solid phase dispersion solid supports for the simultaneous extraction of 15 pesticides of different chemical classes from drinking water treatment sludge.

    Science.gov (United States)

    Soares, Karina Lotz; Cerqueira, Maristela Barnes Rodrigues; Caldas, Sergiane Souza; Primel, Ednei Gilberto

    2017-09-01

    This study describes the development, optimization and validation of a method for the extraction of 15 pesticides of different chemical classes in drinking water treatment sludge (DWTS) by vortex-assisted Matrix Solid Phase Dispersion (MSPD) with determination by gas chromatography coupled to mass spectrometry. It focused on the application of alternative and different solid supports to the extraction step of the MSPD. The main parameters that influenced the extraction were studied in order to obtain better recovery responses. Recoveries ranged from 70 to 120% with RSD below 20% for all analytes. Limits of quantification (LOQ) of the method ranged from 5 to 500 μg kg -1 whereas the analytical curves showed correlation coefficients above 0.997. The method under investigation used low volume of solvent (5 mL), low sample mass (1.5 g) and low mass of chitin (0.5 g), an environmentally friendly support. It has advantages, such as speed, simplicity and low cost material, over other methods. When the method was applied, 4 out of 15 pesticides were detected in the DWTS samples in concentrations below the LOQ. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Human life support during interplanetary travel and domicile. V - Mars expedition technology trade study for solid waste management

    Science.gov (United States)

    Ferrall, Joe; Rohatgi, Naresh K.; Seshan, P. K.

    1992-01-01

    A model has been developed for NASA to quantitatively compare and select life support systems and technology options. The model consists of a modular, top-down hierarchical breakdown of the life support system into subsystems, and further breakdown of subsystems into functional elements representing individual processing technologies. This paper includes the technology trades for a Mars mission, using solid waste treatment technologies to recover water from selected liquid and solid waste streams. Technologies include freeze drying, thermal drying, wet oxidation, combustion, and supercritical-water oxidation. The use of these technologies does not have any significant advantages with respect to weight; however, significant power penalties are incurred. A benefit is the ability to convert hazardous waste into a useful resource, namely water.

  2. Fabrication of cathode supported tubular solid oxide electrolysis cell for high temperature steam electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Le; Wang, Shaorong; Qian, Jiqin; Xue, Yanjie; Liu, Renzhu

    2011-01-15

    In recent years, hydrogen has been identified as a potential alternative fuel and energy carrier for the future energy supply. Water electrolysis is one of the important hydrogen production technologies which do not emit carbon dioxide. High temperature steam electrolysis (HTSE) consumes even less electrical energy than low temperature water electrolysis. Theoretically, HTSE using solid oxide electrolysis cells (SOEC) can efficiently utilize renewable energy to produce hydrogen, and it is also possible to operate the SOEC in reverse mode as the solid oxide fuel cell (SOFC) to produce electricity. Tubular SOFC have been widely investigated. In this study, tubular solid oxide cells were fabricated by dip-coating and cosintering techniques. In SOEC mode, results suggested that steam ratio had a strong impact on the performance of the tubular cell; the tubular SOEC preferred to be operated at high steam ratio in order to avoid concentration polarization. The microstructure of the tubular SOEC should therefore be optimized for high temperature steam electrolysis.

  3. Solid lipid nanoparticles of amphotericin B (AmbiOnp): in vitro and in vivo assessment towards safe and effective oral treatment module.

    Science.gov (United States)

    Chaudhari, Manisha B; Desai, Preshita P; Patel, Pratikkumar A; Patravale, Vandana B

    2016-08-01

    Amphotericin B, a gold standard broad spectrum antibiotic used in treatment of systemic fungal infections and visceral leishmaniasis, though is effective parenterally offers severe nephrotoxicity whereas the oral delivery is reported to give very meager oral bioavailability. Thus, to alleviate the toxicity and to improve oral bioavailability, an effective oral delivery approach in the form of solid lipid nanoparticles of amphotericin B (AmbiOnp) was reported earlier by our group. In this investigation, we report the predominant formation of nontoxic superaggregated form of amphotericin B, resulting from the probe sonication-assisted nanoprecipitation technique. The developed formulation was further confirmed to retain this nontoxic form and was found to be stable over the varied gastrointestinal conditions. Further, in vitro antifungal activity of AmbiOnp against Candida albicans showed minimum inhibitory concentration value of 7.812 μg/mL attributed to controlled release of drug from nanoparticulate matrix. In vivo pharmacokinetic studies revealed a relative bioavailability of AmbiOnp to be 1.05-fold with a Cmax of 1109.31 ± 104.79 ng/mL at the end of 24 h which was comparable to Cmax of 1417.49 ± 85.52 ng/mL achieved with that of marketed formulation (Fungizone®) given intravenously establishing efficacy of AmbiOnp. In vivo biodistribution studies indicated very low levels of Amphotericin B in kidneys when given as AmbiOnp as compared to that of marketed formulation proving its safety and was further corroborated by renal toxicity studies. Further, the formulations were found to be stable under refrigeration condition over a period of 3 months.

  4. Docetaxel-loaded solid lipid nanoparticles as a basis for a targeted and dose-sparing personalized breast cancer treatment strategy

    Directory of Open Access Journals (Sweden)

    Danilova NV

    2015-03-01

    Full Text Available Natalia V Danilova,1,2 Zhomart R Kalzhanov,3 Nina A Nefedova,2 Pavel G Mal’kov,2 Ioannis P Kosmas,1,4 Marina Y Eliseeva,1,5 Ospan A Mynbaev1,5,6 1International Translational Medicine and Biomodeling Research Team, MIPT Center for Human Physiology, Laboratory of Cellular and Molecular Technologies, Moscow Institute of Physics and Technology, State University, 2Department of Physiology and Basic Pathology, Faculty of Fundamental Medicine, Lomonosov Moscow State University, Moscow, Russia; 3Department of Human Metabolism, Academic Unit of Reproductive and Developmental Medicine, Sheffield University, Sheffield, UK; 4Department of Obstetrics and Gynecology, Ioannina State General Hospital G Chatzikosta, Ioannina, Greece; 5Department of Obstetrics, Gynecology and Reproductive Medicine, Peoples’ Friendship University of Russia, 6Laboratory of Immunology, Moscow State University of Medicine and Dentistry named after AI Evdokimov, Moscow, Russia The long-term survival rate of patients with breast cancer was improved by the application of systemic adjuvant chemotherapy,1 although the primary breast cancer treatment strategy consists of mastectomy with lymphadenectomy and radiotherapy followed by breast reconstruction.2–5 Unfortunately, most adjuvant chemotherapeutic agents trigger major side effects.1,6 Therefore, we have read with great interest an article in the International Journal of Nanomedicine on the design of docetaxel-loaded solid lipid nanoparticles (DSNs aimed at reducing the systemic toxicity of standardized docetaxel treatment.7 Read the original article 

  5. Continuous production of fenofibrate solid lipid nanoparticles by hot-melt extrusion technology: a systematic study based on a quality by design approach.

    Science.gov (United States)

    Patil, Hemlata; Feng, Xin; Ye, Xingyou; Majumdar, Soumyajit; Repka, Michael A

    2015-01-01

    This contribution describes a continuous process for the production of solid lipid nanoparticles (SLN) as drug-carrier systems via hot-melt extrusion (HME). Presently, HME technology has not been used for the manufacturing of SLN. Generally, SLN are prepared as a batch process, which is time consuming and may result in variability of end-product quality attributes. In this study, using Quality by Design (QbD) principles, we were able to achieve continuous production of SLN by combining two processes: HME technology for melt-emulsification and high-pressure homogenization (HPH) for size reduction. Fenofibrate (FBT), a poorly water-soluble model drug, was incorporated into SLN using HME-HPH methods. The developed novel platform demonstrated better process control and size reduction compared to the conventional process of hot homogenization (batch process). Varying the process parameters enabled the production of SLN below 200 nm. The dissolution profile of the FBT SLN prepared by the novel HME-HPH method was faster than that of the crude FBT and a micronized marketed FBT formulation. At the end of a 5-h in vitro dissolution study, a SLN formulation released 92-93% of drug, whereas drug release was approximately 65 and 45% for the marketed micronized formulation and crude drug, respectively. Also, pharmacokinetic study results demonstrated a statistical increase in Cmax, Tmax, and AUC0-24 h in the rate of drug absorption from SLN formulations as compared to the crude drug and marketed micronized formulation. In summary, the present study demonstrated the potential use of hot-melt extrusion technology for continuous and large-scale production of SLN.

  6. Alternative Processes for Water Reclamation and Solid Waste Processing in a Physical/chemical Bioregenerative Life Support System

    Science.gov (United States)

    Rogers, Tom D.

    1990-01-01

    Viewgraphs on alternative processes for water reclamation and solid waste processing in a physical/chemical-bioregenerative life support system are presented. The main objective is to focus attention on emerging influences of secondary factors (i.e., waste composition, type and level of chemical contaminants, and effects of microorganisms, primarily bacteria) and to constructively address these issues by discussing approaches which attack them in a direct manner.

  7. Directing chondrogenic differentiation of mesenchymal stem cells with a solid-supported chitosan thermogel for cartilage tissue engineering

    International Nuclear Information System (INIS)

    Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Dai, Linghui; Zhu, Jingxian; Man, Zhentao; Ao, Yingfang; Chen, Haifeng; Zhou, Chunyan

    2014-01-01

    Hydrogels are attractive for cartilage tissue engineering because of their high plasticity and similarity with the native cartilage matrix. However, one critical drawback of hydrogels for osteochondral repair is their inadequate mechanical strength. To address this limitation, we constructed a solid-supported thermogel comprising a chitosan hydrogel system and demineralized bone matrix. Scanning electron microscopy, the equilibrium scanning ratio, the biodegradation rate, biomechanical tests, biochemical assays, metabolic activity tests, immunostaining and cartilage-specific gene expression analysis were used to evaluate the solid-supported thermogel. Compared with pure hydrogel or demineralized matrix, the hybrid biomaterial showed superior porosity, equilibrium swelling and degradation rate. The hybrid scaffolds exhibited an increased mechanical strength: 75% and 30% higher compared with pure hydrogels and demineralized matrix, respectively. After three days culture, bone-derived mesenchymal stem cells (BMSCs) maintained viability above 90% in all three materials; however, the cell retention of the hybrid scaffolds was more efficient and uniform than the other materials. Matrix production and chondrogenic differentiation of BMSCs in the hybrid scaffolds were superior to its precursors, based on glycosaminoglycan quantification and hyaline cartilage marker expression after three weeks in culture. Its easy preparation, favourable biophysical properties and chondrogenic capacity indicated that this solid-supported thermogel could be an attractive biomaterial framework for cartilage tissue engineering. (paper)

  8. Saponification of esters of chiral alpha-amino acids anchored through their amine function on solid support.

    Science.gov (United States)

    Cantel, Sonia; Desgranges, Stéphane; Martinez, Jean; Fehrentz, Jean-Alain

    2004-06-01

    Anchoring an alpha-amino acid residue by its amine function onto a solid support is an alternative to develop chemistry on its carboxylic function. This strategy can involve the use of amino-acid esters as precursors of the carboxylic function. A complete study on the Wang-resin was performed to determine the non racemizing saponification conditions of anchored alpha-amino esters. The use of LiOH, NaOH, NaOSi(Me)3, various solvents and temperatures were tested for this reaction. After saponification and cleavage from the support, samples were examined through their Marfey's derivatives by reversed phase HPLC to evaluate the percentage of racemization.

  9. Rhodopsin-lipid interactions studied by NMR.

    Science.gov (United States)

    Soubias, Olivier; Gawrisch, Klaus

    2013-01-01

    The biophysical properties of the lipid matrix are known to influence function of integral membrane proteins. We report on a sample preparation method for reconstitution of membrane proteins which uses porous anodic aluminum oxide (AAO) filters with 200-nm-wide pores of high density. The substrate permits formation of tubular, single membranes that line the inner surface of pores. One square centimeter of filter with a thickness of 60μm yields on the order of 500cm(2) of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated, and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By (2)H NMR order parameter measurements, it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by (1)H saturation-transfer NMR under conditions of magic angle spinning, we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Inducing morphological changes in lipid bilayer membranes with microfabricated substrates

    Science.gov (United States)

    Liu, Fangjie; Collins, Liam F.; Ashkar, Rana; Heberle, Frederick A.; Srijanto, Bernadeta R.; Collier, C. Patrick

    2016-11-01

    Lateral organization of lipids and proteins into distinct domains and anchoring to a cytoskeleton are two important strategies employed by biological membranes to carry out many cellular functions. However, these interactions are difficult to emulate with model systems. Here we use the physical architecture of substrates consisting of arrays of micropillars to systematically control the behavior of supported lipid bilayers - an important step in engineering model lipid membrane systems with well-defined functionalities. Competition between attractive interactions of supported lipid bilayers with the underlying substrate versus the energy cost associated with membrane bending at pillar edges can be systematically investigated as functions of pillar height and pitch, chemical functionalization of the microstructured substrate, and the type of unilamellar vesicles used for assembling the supported bilayer. Confocal fluorescent imaging and AFM measurements highlight correlations that exist between topological and mechanical properties of lipid bilayers and lateral lipid mobility in these confined environments. This study provides a baseline for future investigations into lipid domain reorganization on structured solid surfaces and scaffolds for cell growth.

  11. Long term performance degradation analysis and optimization of anode supported solid oxide fuel cell stacks

    International Nuclear Information System (INIS)

    Parhizkar, Tarannom; Roshandel, Ramin

    2017-01-01

    Highlights: • A degradation based optimization framework is developed. • The cost of electricity based on degradation of solid oxide fuel cells is minimized. • The effects of operating conditions on degradation mechanisms are investigated. • Results show 7.12% lower cost of electricity in comparison with base case. • Degradation based optimization is a beneficial concept for long term analysis. - Abstract: The main objective of this work is minimizing the cost of electricity of solid oxide fuel cell stacks by decelerating degradation mechanisms rate in long term operation for stationary power generation applications. The degradation mechanisms in solid oxide fuel cells are caused by microstructural changes, reactions between lanthanum strontium manganite and electrolyte, poisoning by chromium, carburization on nickel particles, formation of nickel sulfide, nickel coarsening, nickel oxidation, loss of conductivity and crack formation in the electrolyte. The rate of degradation mechanisms depends on the cell operating conditions (cell voltage and fuel utilization). In this study, the degradation based optimization framework is developed which determines optimum operating conditions to achieve a minimum cost of electricity. To show the effectiveness of the developed framework, optimization results are compared with the case that system operates at its design point. Results illustrate optimum operating conditions decrease the cost of electricity by 7.12%. The performed study indicates that degradation based optimization is a beneficial concept for long term performance degradation analysis of energy conversion systems.

  12. A new approach to the treatment of recurrent aphthous stomatitis with bioadhesive gels containing cyclosporine A solid lipid nanoparticles: in vivo/in vitro examinations

    Directory of Open Access Journals (Sweden)

    Karavana SY

    2012-11-01

    Full Text Available Sinem Yaprak Karavana,1 Evren Homan Gökçe,1 Seda Rençber,1 Seda Özbal,2 Çetin Pekçetin,2 Pelin Güneri,3 Gökhan Ertan11Department of Pharmaceutical Technology, Faculty of Pharmacy, Ege University, Bornova-Izmir, 2Department of Histology and Embryology, School of Medicine, Dokuz Eylul University, Inciralti, Izmir, 3Department of Oral Diagnosis and Radiology, Faculty of Dentistry, Ege University, Bornova-Izmir, TurkeyAim: To develop a suitable buccal bioadhesive gel formulation containing cyclosporine A solid lipid nanoparticles (CsA SLNs for the treatment of recurrent aphthous stomatitis.Methods: The suitability of the prepared formulations for buccal application was assessed by means of rheological studies, textural profile analysis, and ex vivo drug-release studies. Plastic flows, typical gel-like spectra, and suitable mechanical properties were obtained from prepared formulations. The retention time was explored in in vivo distribution studies and the effect of the gel containing CsA SLNs on the healing of oral mucosal ulceration was investigated in an animal model. In vivo distribution studies are a very important indicator of the retention time of formulations at the application site.Results: Distribution studies showed that 64.76% ± 8.35% of the formulation coded "F8+SLN" remained on the buccal mucosa 6 hours after application. For the second part of the in vivo experiments, 36 rabbits were separated into three groups: the first group was treated with the gel formulation without the active agent; the second group with the gel formulation containing CsA SLNs; and the third group, used as the control group, received no treatment. Wound healing was established by scoring of the rate of wound healing on Days 3, 6, 9, and 12. Histological observations were made on the same days as the scoring studies. The bioadhesive gel formulation that included CsA SLNs increased the rate of mucosal repair significantly.Conclusion: This study has shown

  13. Solid-supported synthesis: From pharmacologically relevant heterocycles to biologically active surfaces

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V.

    for solid-phase synthesis, methods for on - and off-bead screening of combinatorial libraries and their applic ation to various biological targets. The first part of the thesis is dedicated to the development of methodology for the synthesis of structurally diverse heterocyclic scaffolds via N...... methods for the controlled organo-functionalization of titanium, one of the most prominent materials in medicinal device industry, have been suggested . Initial acidic and oxidative treatment s of the metal surface genera te reactive hydroxyl moieties , which are subsequently modified with synthetically...... versatile amine -containing reagents. Subsequent applications in antimicrobial peptide synthesis, metal -catalysis, release from the surface, and polymer grafti ng, are also presented....

  14. Metronomic Chemotherapy vs Best Supportive Care in Progressive Pediatric Solid Malignant Tumors: A Randomized Clinical Trial.

    Science.gov (United States)

    Pramanik, Raja; Agarwala, Sandeep; Gupta, Yogendra Kumar; Thulkar, Sanjay; Vishnubhatla, Sreenivas; Batra, Atul; Dhawan, Deepa; Bakhshi, Sameer

    2017-09-01

    Although oral metronomic chemotherapy is often used in progressive pediatric solid malignant tumors, a literature review reveals that only small single-arm retrospective or phase 1 and 2 studies have been performed. Skepticism abounds because of the lack of level 1 evidence. To compare the effect of metronomic chemotherapy on progression-free survival (PFS) with that of placebo in pediatric patients with primary extracranial, nonhematopoietic solid malignant tumors that progress after at least 2 lines of chemotherapy. A double-blinded, placebo-controlled randomized clinical trial was conducted from October 1, 2013, through December 31, 2015, at the cancer center at All India Institute of Medical Sciences in children aged 5 to 18 years with primary extracranial, nonhematopoietic solid malignant tumors that progressed after at least 2 lines of chemotherapy and had no further curative options. One arm received a 4-drug oral metronomic regimen of daily celecoxib and thalidomide with alternating periods of etoposide and cyclophosphamide, whereas the other arm received placebo. Disease status was assessed at baseline, 9 weeks, 18 weeks, and 27 weeks or at clinical progression. The primary end point was PFS as defined by the proportion of patients without disease progression at 6 months, and PFS duration and overall survival (OS) were secondary end points. A total of 108 of the 123 patients screened were enrolled, with 52 randomized to the placebo group (median age, 15 years; 40 male [76.9%]) and 56 to the metronomic chemotherapy group (median age, 13 years; 42 male [75.0%]). At a median follow-up of 2.9 months, 100% of the patients had disease progression by 6 months in the placebo group vs 96.4% in the metronomic chemotherapy group (P = .24). Median PFS and OS in the 2 groups was similar (hazard ratio [HR], 0.69; 95% CI, 0.47-1.03 [P = .07] for PFS; and HR, 0.74; 95% CI, 0.50-1.09 [P = .13] for OS). In post hoc subgroup analysis, cohorts receiving more than

  15. Towards High Power Density Metal Supported Solid Oxide Fuel Cell for Mobile Applications

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Persson, Åsa Helen; Muhl, Thuy

    2017-01-01

    For use of metal supported SOFC in mobile applications it is important to reduce the thermal mass to enable fast start up, increase stack power density in terms of weight and volume and reduce costs. In the present study, we report on the effect of reducing the support layer thickness of 313 μm...

  16. Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts

    Directory of Open Access Journals (Sweden)

    Ernő E. Kiss

    2012-12-01

    Full Text Available Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

  17. Fabrication and Characterization of Graded Anodes for Anode-Supported Solid Oxide Fuel Cells by Tape Casting and Lamination

    DEFF Research Database (Denmark)

    Beltran-Lopez, J.F.; Laguna-Bercero, M.A.; Gurauskis, Jonas

    2014-01-01

    Graded anodes for anode-supported solid oxide fuel cells (SOFCs) are fabricated by tape casting and subsequent cold lamination of plates using different compositions. Rheological parameters are adjusted to obtain stable suspensions for tape casting. The conditions for the tape casting and laminat......Graded anodes for anode-supported solid oxide fuel cells (SOFCs) are fabricated by tape casting and subsequent cold lamination of plates using different compositions. Rheological parameters are adjusted to obtain stable suspensions for tape casting. The conditions for the tape casting...... and lamination will be described. Flexural strength of the reduced cermets measured using three-point bending configuration is 468±37MPa. The graded anode supports are characterized by scanning electron microscope observations, mercury porosimetry intrusion, and resistivity measurements, showing an adequate...... of tapes at room temperature without using plasticizers. This is made by the combination of two different binders with varying Tg (glass transition temperature) which resulted in plastic deformation at room temperature. Those results indicate that the proposed process is a cost-effective method...

  18. Preparation and application of zirconium sulfate supported on SAPO-34 molecular sieve as solid acid catalyst for esterification

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dongyan, E-mail: xdy0156@sina.com; Ma, Hong; Cheng, Fei

    2014-05-01

    Graphical abstract: - Highlights: • SAPO-34 supported zirconium sulfate solid acid catalyst was prepared. • Esterification of acetic acid with ethanol can be catalyzed by ZS/SAPO-34. • The hydration of ZS is vital to the acidic property and catalytic performance. • The ZS/SAPO-34 catalyst treated at 200 °C shows good reusability. - Abstract: Zirconium sulfate (ZS) was supported on SAPO-34 molecular sieve by using an incipient wetness impregnation method with zirconium sulfate as the precursor. The as-prepared catalysts were used as solid acid catalyst for esterification reaction of acetic acid with ethanol. The influence of calcination temperature on the acidic property, catalytic activity, and reusability of ZS/SAPO-34 catalysts were mainly investigated. FT-IR, SEM, EDS and TG analysis have been carried out to demonstrate the characteristics of ZS/SAPO-34 catalysts. It was found that the 30 wt%ZS/SAPO-34 catalysts display the property of superacid irrespective of calcination temperature. The ZS/SAPO-34 catalyst treated at 200 °C can enhance the interaction between the supported ZS and SAPO-34 and keep the catalyst remaining substantially active after several reaction cycles. However, further increasing calcination temperature will cause the transfer of ZS from hydrate to anhydrous phase, and thus the decrease of activity.

  19. Preparation and application of zirconium sulfate supported on SAPO-34 molecular sieve as solid acid catalyst for esterification

    International Nuclear Information System (INIS)

    Xu, Dongyan; Ma, Hong; Cheng, Fei

    2014-01-01

    Graphical abstract: - Highlights: • SAPO-34 supported zirconium sulfate solid acid catalyst was prepared. • Esterification of acetic acid with ethanol can be catalyzed by ZS/SAPO-34. • The hydration of ZS is vital to the acidic property and catalytic performance. • The ZS/SAPO-34 catalyst treated at 200 °C shows good reusability. - Abstract: Zirconium sulfate (ZS) was supported on SAPO-34 molecular sieve by using an incipient wetness impregnation method with zirconium sulfate as the precursor. The as-prepared catalysts were used as solid acid catalyst for esterification reaction of acetic acid with ethanol. The influence of calcination temperature on the acidic property, catalytic activity, and reusability of ZS/SAPO-34 catalysts were mainly investigated. FT-IR, SEM, EDS and TG analysis have been carried out to demonstrate the characteristics of ZS/SAPO-34 catalysts. It was found that the 30 wt%ZS/SAPO-34 catalysts display the property of superacid irrespective of calcination temperature. The ZS/SAPO-34 catalyst treated at 200 °C can enhance the interaction between the supported ZS and SAPO-34 and keep the catalyst remaining substantially active after several reaction cycles. However, further increasing calcination temperature will cause the transfer of ZS from hydrate to anhydrous phase, and thus the decrease of activity

  20. Development of layered anode structures supported over Apatite-type Solid Electrolytes

    Directory of Open Access Journals (Sweden)

    Pandis P.

    2016-01-01

    Full Text Available Apatite-type lanthanum silicates (ATLS materials have attracted interest in recent literature as solid electrolytes for SOFCs. The fabrication of an ATLS based fuel cell with the state-of-art electrodes (NiO/YSZ as anode and LSCF or LSM as cathode can show degradation after long operation hours due to Si diffusion mainly towards the anode. In this work, we report a “layer-by-layer anodic electrodes” fabrication by means of spin coating and physical spraying. The overall aim of this work is the successful fabrication of such a layered structure including suitable blocking layers towards the inhibition of Si interdiffusion from the apatite electrolyte to the anode. The results showed that the deposition of 3 layers of LFSO/GDC (3μm, NiO/GDC (4μm and the final NiO/YSZ anode layer provided a stable half-cell, with no solid state reaction occurring among the electrodes and no Si diffusion observed towards the anode after thermal treatment at 800°C for 120h.

  1. Solid-supported enzymatic synthesis of pectic oligogalacturonides and their analysis by MALDI-TOF mass spectrometry

    DEFF Research Database (Denmark)

    Guillaumie, Fanny; Sterling, J.D.; Jensen, K.J.

    2003-01-01

    Solid-phase biosynthetic reactions, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF), was used to gain insight into the biosynthesis of pectin oligomers. Sepharose supports bearing long pectic oligogalacturonides (OGAs) anchored through...... into the liquid phases by MALDI-TOF mass spectrometry. In time course studies conducted with an immobilized (alpha-D-GalA)(14) and limiting amounts of the glycosyl donor, the predominant product was an OGA extended by one GalA residue at the non-reducing end (i.e., (GalA)(15)). When UDP-GalA was added...

  2. Mechanistic modelling of a cathode-supported solid oxide fuel cell. Paper no. IGEC-1-103

    International Nuclear Information System (INIS)

    Suwanwarangkul, R.; Croiset, E.; Pritzker, M.D.; Fowler, M.W.; Douglas, P.L.; Entchev, E.

    2005-01-01

    A model for a cathode-supported tubular solid oxide fuel cell operating with humidified H 2 has been developed. Momentum-, mass-, energy- and charge-transport equations coupled with electrochemical reactions (H 2 oxidation and O 2 reduction) are considered in the model. The model also takes into account the radiative heat transfer between the cell and air-preheating tube. The model is validated against published experimental data ands shows a good agreement. The distributions of temperature, current density, reversible cell voltage, overpotential and species mole fractions within the cell are discussed in detail. (author)

  3. Transport of Eu3+ through a Bis(2-ethylhexyl)-phosphoric acid, n-dodecane solid supported liquid membrane

    International Nuclear Information System (INIS)

    Danesi, P.R.; Horwitz, E.P.; Rickert, P.

    1982-01-01

    The coupled transpot of Eu 3 + and H + ions througn a solid supported liquid membrane consisting of a porous polypropylene film immobilizing an HDEHP solution in n-dodecane has been studied as a function of the membrane area, stirring speed of the aqueous solutions, membrane composition, and acidity of the feed solution. The experimental results are in agreement with predictions derived from a theoretical permeability coefficient equation which assumes that membrane diffusion and aqueous film diffusion are the only rate-controlling factors

  4. Microwave Assisted Solvent Free Synthesis of Azomethines from Aryl Aldehydes on Melamin Formaldehyde as Solid Support

    Directory of Open Access Journals (Sweden)

    Ramin Rezaei

    2011-01-01

    Full Text Available Various aryl aldehydes underwent prompt one pot conversion into the corresponding azomethines in high yields by reacting with hydroxylamine hydrochloride supported on melamine formaldehyde under microwave irradiation.

  5. A New Miniaturized Inkjet Printed Solid State Electrolyte Sensor for Applications in Life Support Systems - First Results

    Science.gov (United States)

    Hill, Christine; Stefanos Fasoulas, -; Eberhart, Martin; Berndt, Felix

    New generations of integrated closed loop systems will combine life support systems (incl. biological components) and energy systems such as fuel cell and electrolysis systems. Those systems and their test beds also contain complex safety sensor monitoring systems. Especially in fuel cells and electrolysis systems, the hydrogen and oxygen flows and exchange into other areas due to diffusion processes or leaks need to be monitored. Knowledge of predominant gas concentrations at all times is essential to avoid explosive gas mixtures. Solid state electrolyte sensors are promising for use as safety sensors. They have already been developed and produced at various institutes, but the power consumption for heating an existing solid state electrolyte sensor element still lies between 1 to 1.5 W and the operational readiness still takes about 20 to 30 s. This is partially due to the current manufacturing process for the solid state electrolyte sensor elements that is based on screen printing technology. However this technology has strong limitations in flexibility of the layout and re-designs. It is therefore suitable for mass production, but not for a flexible development and the production of specific individual sensors, e.g. for space applications. Moreover a disadvantage is the relatively high material consumption, especially in combination with the sensors need of expensive noble metal and ceramic pastes, which leads to a high sensor unit price. The Inkjet technology however opens up completely new possibilities in terms of dimensions, geometries, structures, morphologies and materials of sensors. This new approach is capable of printing finer high-resolution layers without the necessity of meshes or masks for patterning. Using the Inkjet technology a design change is possible at any time on the CAD screen. Moreover the ink is only deposited where it is needed. Custom made sensors, as they are currently demanded in space sensor applications, are thus realized simply

  6. Development status of solid polymer electrolyte water electrolysis for manned spacecraft life support systems

    Science.gov (United States)

    Nuttall, L. J.; Titterington, W. A.

    1974-01-01

    Details of the design and system verification test results are presented for a six-man-rated oxygen generation system. The system configuration incorporates components and instrumentation for computer-controlled operation with automatic start-up/shutdown sequencing, fault detection and isolation, and with self-contained sensors and controls for automatic safe emergency shutdown. All fluid and electrical components, sensors, and electronic controls are designed to be easily maintainable under zero-gravity conditions. On-board component spares are utilized in the system concept to sustain long-term operation (six months minimum) in a manned spacecraft application. The system is centered on a 27-cell solid polymer electrolyte water electrolysis module which, combined with the associated system components and controls, forms a total system envelope 40 in. high, 40 in. wide, and 30 in. deep.

  7. Supporting Innovation in Organic Agriculture: A European Perspective Using Experience from the SOLID Project

    DEFF Research Database (Denmark)

    Padel, Susanne; Vaarst, Mette; Zaralis, K.

    2015-01-01

    quality forage is vitally important, but farmers showed a lack of confidence in the reliability of forage production both in quantity and quality. We conclude that the systems framework improves the understanding of innovation processes in organic agriculture. Farmer-led research is an effective way......Organic farming is recognized as one source for innovation helping agriculture to develop sustainably. However, the understanding of innovation in agriculture is characterized by technical optimism, relying mainly on new inputs and technologies originating from research. The paper uses...... the alternative framework of innovation systems describing innovation as the outcome of stakeholder interaction and examples from the SOLID (Sustainable Organic Low-Input Dairying) project to discuss the role of farmers, researchers and knowledge exchange for innovation. We used a farmer-led participatory...

  8. Investigation of Novel Electrocatalysts for Metal Supported Solid Oxide Fuel Cells - Ru:GDC

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Thydén, Karl Tor Sune

    2015-01-01

    Even though solid oxide fuel cells (SOFCs) have a high potential with respect to efficiency and fuel flexibility they are not yet competitive in terms of cost and durability with conventional chemical energy conversion technologies. The potential cost reduction can be achieved through...... in tolerating the vibrations, transient loads, thermal and redox cycling [1-2]. The DTU MS-SOFC design based on ferritic stainless steel requires incorporation of electrocatalyst into the anode functional layer by infiltration methods [3]. Previously, the preferred electrocatalyst has been gadolinium doped...... and microstructure of the infiltrated electrocatalyst layer was characterized using high-resolution electron microscopy. The electrochemical characterization involved polarization curves and electrochemical impedance spectroscopy (EIS) in the temperature range of 650-750ºC. The polarization curve for Ru...

  9. New methodology of preparation support for solid oxide fuel cells using different pore forming agent

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, Raigenis da P.; Guedes, Bruna C.F.; Silva, Marcos A. da; Carvalho, Luiz F.V. de; Boaventura, Jaime S. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica; Pontes, Luiz A.M. [Universidade Federal da Bahia (EP/UFBA), Salvador, BA (Brazil). Escola Politecnica. Programa de Pos-Graduacao em Engenharia Quimica

    2008-07-01

    The development of environment-friendly energy sources has been of the most important scientific and technological area. Solid oxide fuel cells (SOFC) are very promising alternative for their ability to handle renewable fuels with low emissions and high efficiency. However, this device requires massive improvement before commercial application. This work studies the pore formation in the cell anode and cathode with NaHCO{sub 3} or citric acid, comparing to graphite. The three agents make pore with similar features, but the use of NaHCO{sub 3} and citric acid considerably improves the adhesion of the electrode-electrolyte interface, critical characteristic for good cell efficiency. The prepared anode-electrolyte-cathode structure was studied by SEM technique. The SOFC prepared using citric acid was tested with gaseous ethanol, natural gas and hydrogen. For all these three fuels the SOFC shows virtually no overpotential, indicating the good ionic conductance of the electrodes-electrolyte interface.. (author)

  10. Preliminary Electrochemical Characterization of Anode Supported Solid Oxide Cell (AS-SOC) Produced in the Institute of Power Engineering Operated in Electrolysis Mode (SOEC)

    Science.gov (United States)

    Kupecki, Jakub; Motyliński, Konrad; Skrzypkiewicz, Marek; Wierzbicki, Michał; Naumovich, Yevgeniy

    2017-12-01

    The article discusses the operation of solid oxide electrochemical cells (SOC) developed in the Institute of Power Engineering as prospective key components of power-to-gas systems. The fundamentals of the solid oxide cells operated as fuel cells (SOFC - solid oxide fuel cells) and electrolysers (SOEC - solid oxide fuel cells) are given. The experimental technique used for electrochemical characterization of cells is presented. The results obtained for planar cell with anodic support are given and discussed. Based on the results, the applicability of the cells in power-to-gas systems (P2G) is evaluated.

  11. Identifying a compound modifying a cellular response, comprises attaching cells having a reporter system onto solid supports, releasing a library member, screening and identifying target cells

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to methods for identifying compounds capable of modulating a cellular response. The methods involve attaching living cells to solid supports comprising a library of test compounds. Test compounds modulating a cellular response, for example via a cell surface molecule...... may be identified by selecting solid supports comprising cells, wherein the cellular response of interest has been modulated. The cellular response may for example be changes in signal transduction pathways modulated by a cell surface molecule....

  12. Modified fly ash from municipal solid waste incineration as catalyst support for Mn-Ce composite oxides

    Science.gov (United States)

    Chen, Xiongbo; Liu, Ying; Yang, Ying; Ren, Tingyan; Pan, Lang; Fang, Ping; Chen, Dingsheng; Cen, Chaoping

    2017-08-01

    Fly ash from municipal solid waste incineration was modified by hydrothermal treatment and used as catalyst support for Mn-Ce composite oxides. The prepared catalyst showed good activity for the selective catalytic reduction (SCR) of NO by NH3. A NO conversion of 93% could be achieved at 300 °C under a GHSV of 32857 h-1. With the help of characterizations including XRD, BET, SEM, TEM, XPS and TPR, it was found that hydrothermal treatment brought a large surface area and abundant mesoporous to the modified fly ash, and Mn-Ce composite oxides were highly dispersed on the surface of the support. These physical and chemical properties were the intrinsic reasons for the good SCR activity. This work transformed fly ash into high value-added products, providing a new approach to the resource utilization and pollution control of fly ash.

  13. Testing of a cathode fabricated by painting with a brush pen for anode-supported tubular solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Renzhu; Zhao, Chunhua; Li, Junliang; Wang, Shaorong; Wen, Zhaoyin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

    2010-01-15

    We have studied the properties of a cathode fabricated by painting with a brush pen for use with anode-supported tubular solid oxide fuel cells (SOFCs). The porous cathode connects well with the electrolyte. A preliminary examination of a single tubular cell, consisting of a Ni-YSZ anode support tube, a Ni-ScSZ anode functional layer, a ScSZ electrolyte film, and a LSM-ScSZ cathode fabricated by painting with a brush pen, has been carried out, and an improved performance is obtained. The ohmic resistance of the cathode side clearly decreases, falling to a value only 37% of that of the comparable cathode made by dip-coating at 850 C. The single cell with the painted cathode generates a maximum power density of 405 mW cm{sup -2} at 850 C, when operating with humidified hydrogen. (author)

  14. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    Energy Technology Data Exchange (ETDEWEB)

    Anantachaisilp, Suranan; Smith, Siwaporn Meejoo [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400 (Thailand); Treetong, Alongkot; Ruktanonchai, Uracha Rungsardthong [National Nanotechnology Center, National Science and Technology Development Agency, 111 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Pratontep, Sirapat [College of KMITL Nanotechnology, King Mongkut' s Institute of Technology Ladkrabang, Bangkok (Thailand); Puttipipatkhachorn, Satit, E-mail: uracha@nanotec.or.th [Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400 (Thailand)

    2010-03-26

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of {gamma}-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812 as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the {gamma}-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance ({sup 1}H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the {sup 1}H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of {gamma}-oryzanol inside the lipid nanoparticles, the {sup 1}H-NMR revealed that the chemical shifts of the liquid lipid in {gamma}-oryzanol loaded systems were found at rather higher field than those in {gamma}-oryzanol free systems, suggesting incorporation of {gamma}-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of {gamma}-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models

  15. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    Science.gov (United States)

    Anantachaisilp, Suranan; Meejoo Smith, Siwaporn; Treetong, Alongkot; Pratontep, Sirapat; Puttipipatkhachorn, Satit; Rungsardthong Ruktanonchai, Uracha

    2010-03-01

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of γ-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812® as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the γ-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance (1H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the 1H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of γ-oryzanol inside the lipid nanoparticles, the 1H-NMR revealed that the chemical shifts of the liquid lipid in γ-oryzanol loaded systems were found at rather higher field than those in γ-oryzanol free systems, suggesting incorporation of γ-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of γ-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of γ-oryzanol and

  16. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    International Nuclear Information System (INIS)

    Anantachaisilp, Suranan; Smith, Siwaporn Meejoo; Treetong, Alongkot; Ruktanonchai, Uracha Rungsardthong; Pratontep, Sirapat; Puttipipatkhachorn, Satit

    2010-01-01

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of γ-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812 as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the γ-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance ( 1 H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the 1 H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of γ-oryzanol inside the lipid nanoparticles, the 1 H-NMR revealed that the chemical shifts of the liquid lipid in γ-oryzanol loaded systems were found at rather higher field than those in γ-oryzanol free systems, suggesting incorporation of γ-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of γ-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of γ-oryzanol and

  17. Solid-support Electron Paramagnetic Resonance (EPR) Studies of Aβ40 Monomers Reveal a Structured State with Three Ordered Segments*

    Science.gov (United States)

    Gu, Lei; Ngo, Sam; Guo, Zhefeng

    2012-01-01

    Alzheimer disease is associated with the pathological accumulation of amyloid-β peptide (Aβ) in the brain. Soluble Aβ oligomers formed during early aggregation process are believed to be neurotoxins and causative agents in Alzheimer disease. Aβ monomer is the building block for amyloid assemblies. A comprehensive understanding of the structural features of Aβ monomer is crucial for delineating the mechanism of Aβ oligomerization. Here we investigated the structures of Aβ40 monomer using a solid-support approach, in which Aβ40 monomers are tethered on the solid support via an N-terminal His tag to prevent further aggregation. EPR spectra of tethered Aβ40 with spin labels at 18 different positions show that Aβ40 monomers adopt a completely disordered structure under denaturing conditions. Under native conditions, however, EPR spectra suggest that Aβ40 monomers adopt both a disordered state and a structured state. The structured state of Aβ40 monomer has three more ordered segments at 14–18, 29–30, and 38–40. Interactions between these segments may stabilize the structured state, which likely plays an important role in Aβ aggregation. PMID:22277652

  18. Spinel-based coatings for metal supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Stefan, Elena; Neagu, Dragos; Blennow Tullmar, Peter

    2017-01-01

    Metal supports and metal supported half cells developed at DTU are used for the study of a solution infiltration approach to form protective coatings on porous metal scaffolds. The metal particles in the anode layer, and sometimes even in the support may undergo oxidation in realistic operating...... conditions leading to severe cell degradation. Here, a controlled oxidation of the porous metal substrate and infiltration of Mn and/or Ce nitrate solutions are applied for in situ formation of protective coatings. Our approach consists of scavenging the FeCr oxides formed during the controlled oxidation...... into a continuous and well adhered coating. The effectiveness of coatings is the result of composition and structure, but also of the microstructure and surface characteristics of the metal scaffolds....

  19. Micromechanical Modeling of Solid Oxide Fuel Cell Anode Supports based on Three-dimensional Reconstructions

    DEFF Research Database (Denmark)

    Kwok, Kawai; Jørgensen, Peter Stanley; Frandsen, Henrik Lund

    2014-01-01

    Ni-3YSZ in the operating temperature through numerical micromechanical modeling. Three-dimensional microstructures of Ni-3YSZ anode supports are reconstructed from a two-dimensional image stack obtained via focused ion beam tomography. Time-dependent stress distributions in the microscopic scale...... are computed by the finite element method. The macroscopic creep response of the porous anode support is determined based on homogenization theory. It is shown that micromechanical modeling provides an effective tool to study the effect of microstructures on the macroscopic properties....

  20. Calcium Oxide Supported on Monoclinic Zirconia as a Highly Active Solid Base Catalyst

    NARCIS (Netherlands)

    Frey, A.M.; Haasterecht, van T.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Calcium oxide supported on ZrO2 is a highly active catalyst for base-catalyzed reactions such as aldol-type reactions and transesterification reactions. The role of key parameters during preparation, that is, impregnation versus precipitation, heat treatment, and metal oxide loading on the basicity

  1. High temperature mechanical properties of zirconia tapes used for electrolyte supported solid oxide fuel cells

    Science.gov (United States)

    Fleischhauer, Felix; Bermejo, Raul; Danzer, Robert; Mai, Andreas; Graule, Thomas; Kuebler, Jakob

    2015-01-01

    Solid-Oxide-Fuel-Cell systems are efficient devices to convert the chemical energy stored in fuels into electricity. The functionality of the cell is related to the structural integrity of the ceramic electrolyte, since its failure can lead to drastic performance losses. The mechanical property which is of most interest is the strength distribution at all relevant temperatures and how it is affected with time due to the environment. This study investigates the impact of the temperature on the strength and the fracture toughness of different zirconia electrolytes as well as the change of the elastic constants. 3YSZ and 6ScSZ materials are characterised regarding the influence of sub critical crack growth (SCCG) as one of the main lifetime limiting effects for ceramics at elevated temperatures. In addition, the reliability of different zirconia tapes is assessed with respect to temperature and SCCG. It was found that the strength is only influenced by temperature through the change in fracture toughness. SCCG has a large influence on the strength and the lifetime for intermediate temperature, while its impact becomes limited at temperatures higher than 650 °C. In this context the tetragonal 3YSZ and 6ScSZ behave quite different than the cubic 10Sc1CeSZ, so that at 850 °C it can be regarded as competitive compared to the tetragonal compounds.

  2. NiO-YSZ cermets supported low temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinge; Robertson, Mark; Deces-Petit, Cyrille; Xie, Yongsong; Hui, Rob; Yick, Sing; Styles, Edward; Roller, Justin; Kesler, Olivera; Maric, Radenka; Ghosh, Dave [Institute for Fuel Cell Innovation, National Research Council Canada, 3250 East Mall, Vancouver, BC (Canada V6T 1W5)

    2006-10-20

    Solid oxide fuel cells with thin electrolyte of two types, Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} (SDC) (15{mu}m) single-layer and 8mol% Yttria stabilized zirconia (YSZ) (5{mu}m)+SDC (15{mu}m) bi-layer on NiO-YSZ cermet substrates were fabricated by screen printing and co-firing. A Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3} cathode was printed, and in situ sintered during a cell performance test. The SDC single-layer electrolyte cell showed high electrochemical performance at low temperature, with a 1180mWcm{sup -2} peak power density at 650{sup o}C. The YSZ+SDC bi-layer electrolyte cell generated 340mWcm{sup -2} peak power density at 650{sup o}C, and showed good performance at 700-800{sup o}C, with an open circuit voltage close to theoretical value. Many high Zr-content micro-islands were found on the SDC electrolyte surface prior to the cathode preparation. The influence of co-firing temperature and thin film preparation methods on the Zr-islands' appearance was investigated. (author)

  3. Mechanistic modelling of a cathode-supported tubular solid oxide fuel cell

    Science.gov (United States)

    Suwanwarangkul, R.; Croiset, E.; Pritzker, M. D.; Fowler, M. W.; Douglas, P. L.; Entchev, E.

    A two-dimensional mechanistic model of a tubular solid oxide fuel cell (SOFC) considering momentum, energy, mass and charge transport is developed. The model geometry of a single cell comprises an air-preheating tube, air channel, fuel channel, anode, cathode and electrolyte layers. The heat radiation between cell and air-preheating tube is also incorporated into the model. This allows the model to predict heat transfer between the cell and air-preheating tube accurately. The model is validated and shows good agreement with literature data. It is anticipated that this model can be used to help develop efficient fuel cell designs and set operating variables under practical conditions. The transport phenomena inside the cell, including gas flow behaviour, temperature, overpotential, current density and species concentration, are analysed and discussed in detail. Fuel and air velocities are found to vary along flow passages depending on the local temperature and species concentrations. This model demonstrates the importance of incorporating heat radiation into a tubular SOFC model. Furthermore, the model shows that the overall cell performance is limited by O 2 diffusion through the thick porous cathode and points to the development of new cathode materials and designs being important avenues to enhance cell performance.

  4. Fabrication and electrochemical properties of cathode-supported solid oxide fuel cells via slurry spin coating

    International Nuclear Information System (INIS)

    Chen Min; Luo Jingli; Chuang, Karl T.; Sanger, Alan R.

    2012-01-01

    Highlights: ► LSM cathode-supported cell prepared by slurry spin coating. ► Optimizing porosity in CFL resulting in power density of 0.58 W cm −2 at 850 °C. ► Activation polarization govern the impedance arcs measured under the OCV condition. ► Concentration polarization can induce the change of activation polarization. ► Four kinds of polarizations of our cells are separated and investigated. - Abstract: A cathode-supported SOFC consisting of LSM (La 0.8 Sr 0.2 MnO 3−δ ) cathode supporter, LSM–Sm 0.2 Ce 0.8 O 2−δ (SDC) cathode functional layer (CFL), yttria stabilized zirconia (YSZ)/SDC bi-layered electrolyte and Ni-YSZ anode layer was fabricated by a slurry spin coating technique. The influence of the porosity in both the CFL and cathode supporter on the electrochemical properties of the cells has been investigated. It was found that properly controlling the porosity in the CFL would improve the performance of the cells using O 2 in the cathode side (O 2 -cells), with a maximum power density (MPD) value achieving as high as 0.58 W cm −2 at 850 °C. However, this improvement is not so evident for the cells using air in the cathode side (air-cells). When increasing the porosity in the cathode-supporter, a significant increase of the power density for the air cells due to the decreasing R conc,c (cathode concentration polarization to the cell resistance) can be ascertained. In terms of our analysis on various electrochemical parameters, the R act (activation polarization to the cell resistance) is assumed to be mainly responsible for the impedance arcs measured under the OCV condition, with a negligible R conc,c value being able to be detected in our impedances. In this case, a significant decreasing size of the impedance arcs due to the increasing porosity in the cathode supporter would correspond to a decrease of the R act values, which was proved to be induced by the decreasing R conc,c .

  5. Performance of Electrolyte Supported Solid Oxide Fuel Cells with STN Anodes

    DEFF Research Database (Denmark)

    Veltzé, Sune; Reddy Sudireddy, Bhaskar; Jørgensen, Peter Stanley

    2013-01-01

    In order to replace the state of the art Ni-cermet as SOFC anode, electrolyte supported cells comprising CGO/Ni infiltrated Nbdoped SrTiO3 anodes, and LSM/YSZ cathodes have been developed and tested as single 5 x 5 cm2 cells. The initial performance reached 0.4 W/cm2 at 850 C. Further tests under...

  6. A tosyl-activated magnetic bead cellulose as solid support for sensitive protein detection

    Czech Academy of Sciences Publication Activity Database

    Yan, J.; Horák, Daniel; Lenfeld, Jiří; Hammond, M.; Kamali-Moghaddam, M.

    2013-01-01

    Roč. 167, č. 3 (2013), s. 235-240 ISSN 0168-1656 R&D Projects: GA ČR GAP503/10/0664; GA MŠk 7E12054 EU Projects: European Commission(XE) 259796 - DIATOOLS Institutional support: RVO:61389013 Keywords : bead cellulose * magnetic * protein detection Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.884, year: 2013

  7. Effects of solid-state fermentation with two filamentous fungi on the total phenolic contents, flavonoids, antioxidant activities and lipid fractions of plum fruit (Prunus domestica L.) by-products.

    Science.gov (United States)

    Dulf, Francisc Vasile; Vodnar, Dan Cristian; Socaciu, Carmen

    2016-10-15

    Evolutions of phenolic contents and antioxidant activities during solid-state fermentation (SSF) of plum pomaces (from the juice industry) and brandy distillery wastes with Aspergillus niger and Rhizopus oligosporus were investigated. The effect of fermentation time on the oil content and major lipid classes in the plum kernels was also studied. Results showed that total phenolic (TP) amounts increased by over 30% for SSF with Rhizopus oligosporus and by >21% for SSF with A. niger. The total flavonoid contents presented similar tendencies to those of the TPs. The free radical scavenging activities of methanolic extracts were also significantly enhanced. The HPLC-MS analysis showed that quercetin-3-glucoside was the major phenolic compound in both fermented plum by-products. The results also demonstrated that SSF not only helped to achieve higher lipid recovery from plum kernels, but also resulted in oils with better quality attributes (high sterol ester and n-3 PUFA-rich polar lipid contents). Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Solid polymer electrolyte water electrolysis preprototype subsystem. [oxygen production for life support systems on space stations

    Science.gov (United States)

    1979-01-01

    Hardware and controls developed for an electrolysis demonstration unit for use with the life sciences payload program and in NASA's regenerative life support evaluation program are described. Components discussed include: the electrolysis module; power conditioner; phase separator-pump and hydrogen differential regulator; pressure regulation of O2, He, and N2; air-cooled heat exchanger; water accumulator; fluid flow sight gage assembly; catalytic O2/H2 sensor; gas flow sensors; low voltage power supply; 100 Amp DC contactor assembly; and the water purifier design.

  9. Anode Supported Solid Oxide Fuel Cells - Deconvolution of Degradation into Cathode and Anode Contributions

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

    2007-01-01

    The degradation of anode supported cells was studied over 1500 h as function of cell polarization either in air or oxygen on the cathode. Based on impedance analysis, contributions of anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2); they were significantly smaller when testing in oxygen compared to air. Microstructural analysis of the cathode/electrolyte interface of a not-tested reference cell carried out after removal of the cathode showed sharp craters on the electrolyte surface where...

  10. N-Confused Porphyrin Immobilized on Solid Supports: Synthesis and Metal Ions Sensing Efficacy

    Directory of Open Access Journals (Sweden)

    Sara R. D. Gamelas

    2018-04-01

    Full Text Available In this work, the N-confused porphyrin 5,10,15,20-tetraphenyl-2-aza-21-carbaporphyrin (NCTPP was immobilized on neutral or cationic supports based on silica and on Merrifield resin. The new materials were characterized by appropriate techniques (UV-Vis spectroscopy, SEM, and zeta potential analysis. Piezoelectric quartz crystal gold electrodes were coated with the different hybrids and their ability to interact with heavy metals was evaluated. The preliminary results obtained showed that the new materials can be explored for metal cations detection and the modification of the material surface is a key factor in tuning the metal selectivity.

  11. L-tryptophan-induced electron transport across supported lipid bilayers: an alkyl-chain tilt-angle, and bilayer-symmetry dependence.

    Science.gov (United States)

    Sarangi, Nirod Kumar; Patnaik, Archita

    2012-12-21

    Molecular orientation-dependent electron transport across supported 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayers (SLBs) on semiconducting indium tin oxide (ITO) is reported with an aim towards potential nanobiotechnological applications. A bifunctional strategy is adopted to form symmetric and asymmetric bilayers of DPPC that interact with L-tryptophan, and are analyzed by surface manometry and atomic force microscopy. Polarization-dependent real-time Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS) analysis of these SLBs reveals electrostatic, hydrogen-bonding, and cation-π interactions between the polar head groups of the lipid and the indole side chains. Consequently, a molecular tilt arises from the effective interface dipole, facilitating electron transport across the ITO-anchored SLBs in the presence of an internal Fe(CN)(6)(4-/3-) redox probe. The incorporation of tryptophan enhances the voltammetric features of the SLBs. The estimated electron-transfer rate constants for symmetric and asymmetric bilayers (k(s) = 2.0×10(-2) and 2.8×10(-2) s(-1)) across the two-dimensional (2D) ordered DPPC/tryptophan SLBs are higher compared to pure DPPC SLBs (k(s) = 3.2×10(-3) and 3.9×10(-3) s(-1)). In addition, they are molecular tilt-dependent, as it is the case with the standard apparent rate constants k(app)(0), estimated from electrochemical impedance spectroscopy and bipotentiostatic experiments with a Pt ultramicroelectrode. Lower magnitudes of k(s) and k(app)(0) imply that electrochemical reactions across the ITO-SLB electrodes are kinetically limited and consequently governed by electron tunneling across the SLBs. Standard theoretical rate constants (k(th)(0)) accrued upon electron tunneling comply with the potential-independent electron-tunneling coefficient β = 0.15 Å(-1). Insulator-semiconductor transitions moving from a liquid-expanded to a condensed 2D-phase state of the SLBs are noted, adding a new dimension

  12. Fabrication and characterization of anode-supported micro-tubular solide oxide fuel cell by phase inversion method

    Science.gov (United States)

    Ren, Cong

    Nowadays, the micro-tubular solid oxide fuel cells (MT-SOFCs), especially the anode supported MT-SOFCs have been extensively developed to be applied for SOFC stacks designation, which can be potentially used for portable power sources and vehicle power supply. To prepare MT-SOFCs with high electrochemical performance, one of the main strategies is to optimize the microstructure of the anode support. Recently, a novel phase inversion method has been applied to prepare the anode support with a unique asymmetrical microstructure, which can improve the electrochemical performance of the MT-SOFCs. Since several process parameters of the phase inversion method can influence the pore formation mechanism and final microstructure, it is essential and necessary to systematically investigate the relationship between phase inversion process parameters and final microstructure of the anode supports. The objective of this study is aiming at correlating the process parameters and microstructure and further preparing MT-SOFCs with enhanced electrochemical performance. Non-solvent, which is used to trigger the phase separation process, can significantly influence the microstructure of the anode support fabricated by phase inversion method. To investigate the mechanism of non-solvent affecting the microstructure, water and ethanol/water mixture were selected for the NiO-YSZ anode supports fabrication. The presence of ethanol in non-solvent can inhibit the growth of the finger-like pores in the tubes. With the increasing of the ethanol concentration in the non-solvent, a relatively dense layer can be observed both in the outside and inside of the tubes. The mechanism of pores growth and morphology obtained by using non-solvent with high concentration ethanol was explained based on the inter-diffusivity between solvent and non-solvent. Solvent and non-solvent pair with larger Dm value is benefit for the growth of finger-like pores. Three cells with different anode geometries was

  13. Laboratory Studies of Solid CO2 Ices at Different Temperatures and Annealing Times in Support of Spitzer Space Telescope Observations

    Science.gov (United States)

    White, Douglas; Gerakines, P. A.

    2007-12-01

    The infrared absorption features of solid carbon dioxide have been detected by space observatories in nearly all lines of sight probing the dense interstellar medium (ISM). It has also been shown that the absorption feature of solid CO2 near 658 cm-1 (15.2 μm) should be a sensitive indicator of the physical conditions of the ice (e.g., temperature and composition). However, the profile structure of this feature is not well understood, and previous laboratory studies have concentrated on a limited range of temperatures and compositions for comparisons to observed spectra from both the Infrared Space Observatory and the Spitzer Space Telescope. In the laboratory study described here, the infrared spectra of ices bearing H2O, CH3OH, and CO2 have been measured with systematically varying compositions and temperatures that span the range of the values expected in the interstellar medium. The mid-infrared spectra (λ = 2.5-25 µm) were measured for 47 different ice compositions at temperatures ranging from 5 K to evaporation (at 5 K intervals). Additionally, annealing experiments of some of these ice compositions have been investigated. These data may be used to determine thermal histories of interstellar ices. This research was supported by NASA award NNG05GE44G under the Astronomy and Physics Research & Analysis Program (APRA).

  14. Assessment of the cathode contribution to the degradation of anode-supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

    2008-01-01

    The degradation of anode-supported cells was studied over 1500 h as a function of cell polarization either in air or oxygen on the cathode side. Based on impedance analysis, contributions of the anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2). Microstructural analysis of the cathode/electrolyte interface carried out after removal of the cathode showed craters on the electrolyte surface where the lanthanum strontium manganite (LSM) particles had been located. The changes of shape and size...... of these craters observed after testing correlated with the cell voltage degradation rates. The results can be interpreted in terms of element redistribution at the cathode/electrolyte interface and formation of foreign phases giving rise to a weakening of local contact points of the LSM cathode and yttria...

  15. An optics-based variable-temperature assay system for characterizing thermodynamics of biomolecular reactions on solid support

    Energy Technology Data Exchange (ETDEWEB)

    Fei, Yiyan; Landry, James P.; Zhu, X. D., E-mail: xdzhu@physics.ucdavis.edu [Department of Physics, University of California, One Shields Avenue, Davis, California 95616 (United States); Li, Yanhong; Yu, Hai; Lau, Kam; Huang, Shengshu; Chokhawala, Harshal A.; Chen, Xi [Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616 (United States)

    2013-11-15

    A biological state is equilibrium of multiple concurrent biomolecular reactions. The relative importance of these reactions depends on physiological temperature typically between 10 °C and 50 °C. Experimentally the temperature dependence of binding reaction constants reveals thermodynamics and thus details of these biomolecular processes. We developed a variable-temperature opto-fluidic system for real-time measurement of multiple (400–10 000) biomolecular binding reactions on solid supports from 10 °C to 60 °C within ±0.1 °C. We illustrate the performance of this system with investigation of binding reactions of plant lectins (carbohydrate-binding proteins) with 24 synthetic glycans (i.e., carbohydrates). We found that the lectin-glycan reactions in general can be enthalpy-driven, entropy-driven, or both, and water molecules play critical roles in the thermodynamics of these reactions.

  16. Mechanical Properties of Supports and Half‐Cells for Solid Oxide Electrolysis Influenced by Alumina‐Zirconia Composites

    DEFF Research Database (Denmark)

    Charlas, Benoit; Ni, De Wei; Frandsen, Henrik Lund

    2017-01-01

    In order to improve the durability and robustness of solid oxide electrolysis cells (SOEC) and stacks, it is necessary to improve the strength of its components. In cathode supported SOEC, the main structural component is the Ni(O)- YSZ support. But the strength of the half-cell or cell is also...... determined by the strength of other weaker components and by the residual stress state induced by the thermal expansion mismatch. In this study, the mechanical properties of Ni(O)-3YSZ supports with a reference composition and with substitution of 3YSZ by 20A3YSZ (3YSZ with 20 wt.% Al2O3) have been tested...... and compared. The initial interest of this substitution are a decrease of the coefficient of thermal expansion (CTE) mismatch within the half-cell and the fact that 20A3YSZ is stronger than 3YSZ. The influence of the process on the composition, strength, elastic properties and electrical conductivity...

  17. Feasible way of Human Solid and Liquid Wastes' Inclusion Into Intersystem Mass Exchange of Biological-Technical Life Support Systems

    Science.gov (United States)

    Ushakova, Sofya; Tikhomirov, Alexander A.; Tikhomirova, Natalia; Kudenko, Yurii; Griboskaya, Illiada; Gros, Jean-Bernard; Lasseur, Christophe

    The basic objective arising at use of mineralized human solid and liquid wastes serving as the source of mineral elements for plants cultivation in biological-technical life support systems appears to be NaCl presence in them. The given work is aimed at feasibility study of mineralized human metabolites' utilization for nutrient solutions' preparation for their further employment at a long-term cultivation of uneven-aged wheat and Salicornia europaea L. cenosis in a conveyer regime. Human solid and liquid wastes were mineralized by the "wet incineration" method developed by Yu. Kudenko. On their base the solutions were prepared which were used for cultivation of 5-aged wheat conveyer with the time step-interval of 14 days. Wheat was cultivated by hydroponics method on expanded clay aggregate. For partial demineralization of nutrient solution every two weeks after regular wheat harvesting 12 L of solution was withdrawn from the wheat irrigation tank and used for Salicornia europaea cultivation by the water culture method in a conveyer regime. The Salicornia europaea conveyer was represented by 2 ages with the time step-interval of 14 days. Resulting from repeating withdrawal of the solution used for wheat cultivation, sodium concentration in the wheat irrigation solution did not exceed 400 mg/l, and mineral elements contained in the taken solution were used for Salicornia europaea cultivation. The experiment lasted 7 months. Total wheat biomass productivity averaged 30.1 g*m-2*day-1 at harvest index equal to 36.8The work was carried out under support of SB RAS grant 132 and INTAS 05-1000008-8010

  18. Perceived social support and health-related quality of life (HRQoL) in Tehranian adults: Tehran lipid and glucose study.

    Science.gov (United States)

    Jalali-Farahani, Sara; Amiri, Parisa; Karimi, Mehrdad; Vahedi-Notash, Golnaz; Amirshekari, Golshan; Azizi, Fereidoun

    2018-05-10

    Several studies have demonstrated the positive association between perceived social support and health-related quality of life (HRQoL) in certain groups; however, few studies have assessed this relationship in general population and between genders. This study aimed to investigate associations between socio-demographic factors, perceived social support and HRQoL among an urban Iranian population. The study population were 1036 adults who had participated in Tehran Lipid and Glucose Study (TLGS). Data on socio-demographic information, perceived social support and HRQoL were collected using standard questionnaires by trained interviewers. Perceived social support and HRQoL were assessed using Iranian versions of the Multidimensional Scale of Perceived Social Support (MSPSS) and Short-Form 12-Item Health Survey version 2 (SF-12v2) respectively. Data on sets of associations among socio-demographic factors, perceived social support and quality of life were analyzed using Structural Equation Modeling (SEM) with IBM SPSS AMOS software. Mean ages were 50.3 ± 16.3 and 49.6 ± 14.0 years in men and women respectively and 40.9% of participants were male. In terms of perceived social support scores, except for family subscale scores (p = 0.003), there were no significant differences between men and women. However, men had significantly higher HRQoL scores, compared to women in all subscales. The findings of SEM analysis demonstrated that being married in both genders (p social support. In terms of physical HRQoL, being single and higher perceived social support in both genders and lower age and not having any chronic diseases, only in women were associated with higher physical HRQoL. However, for mental HRQoL, age and perceived social support had significant direct associations with mental HRQoL in both genders (p social support was found to be both directly and indirectly associated with physical and mental aspects of HRQoL in both genders. Current

  19. A comprehensive CFD model of anode-supported solid oxide fuel cells

    International Nuclear Information System (INIS)

    Jeon, Dong Hyup

    2009-01-01

    The two-dimensional comprehensive CFD model of anode-supported SOFCs operating at intermediate temperature has been presented. This model provides transport phenomena of gas species with electrochemical characteristics and micro-structural properties, and predicts SOFC performance. The mathematical model solves conservation of electrons and ions, continuity equation, conservation of momentum, conservation of mass, and conservation of energy. A continuum micro-scale model based on statistical properties together with a mole-based conservation model was employed. CFD technique was used to solve the set of governing equations. The cell performance was decomposed with contributions of each overpotential and was presented at several operating temperatures with analysis of effective diffusivity. It was found that the contribution of potential gain due to temperature rising was considerably high. However it became non-significant at high operating temperature due to decreasing of effective diffusivity in AFL. These results showed that the performance and the distributions of current density, overpotentials, and mole fractions of gas species have a strong dependence upon temperature. From these results, it was concluded that the conservation of energy should be accommodated in comprehensive SOFC model. Also the useful information for the effect of parameters on cell performance and transport phenomena was provided

  20. Solid-phase synthesis of protein-polymers on reversible immobilization supports.

    Science.gov (United States)

    Murata, Hironobu; Carmali, Sheiliza; Baker, Stefanie L; Matyjaszewski, Krzysztof; Russell, Alan J

    2018-02-27

    Facile automated biomacromolecule synthesis is at the heart of blending synthetic and biologic worlds. Full access to abiotic/biotic synthetic diversity first occurred when chemistry was developed to grow nucleic acids and peptides from reversibly immobilized precursors. Protein-polymer conjugates, however, have always been synthesized in solution in multi-step, multi-day processes that couple innovative chemistry with challenging purification. Here we report the generation of protein-polymer hybrids synthesized by protein-ATRP on reversible immobilization supports (PARIS). We utilized modified agarose beads to covalently and reversibly couple to proteins in amino-specific reactions. We then modified reversibly immobilized proteins with protein-reactive ATRP initiators and, after ATRP, we released and analyzed the protein polymers. The activity and stability of PARIS-synthesized and solution-synthesized conjugates demonstrated that PARIS was an effective, rapid, and simple method to generate protein-polymer conjugates. Automation of PARIS significantly reduced synthesis/purification timelines, thereby opening a path to changing how to generate protein-polymer conjugates.

  1. Real-time monitoring of melittin-induced pore and tubule formation from supported lipid bilayers and its physiological relevance

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Miszta, Adam; Hermens, W.; Hof, Martin

    2010-01-01

    Roč. 163, č. 2 (2010), s. 200-206 ISSN 0009-3084 R&D Projects: GA MŠk(CZ) LC06063; GA AV ČR GEMEM/09/E006 Institutional research plan: CEZ:AV0Z40400503 Keywords : antimicrobiological peptides * support phospholipid builayers * ellipsometry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.861, year: 2010

  2. Coupling of lipid membrane elasticity and in-plane dynamics

    Science.gov (United States)

    Tsang, Kuan-Yu; Lai, Yei-Chen; Chiang, Yun-Wei; Chen, Yi-Fan

    2017-07-01

    Biomembranes exhibit liquid and solid features concomitantly with their in-plane fluidity and elasticity tightly regulated by cells. Here, we present experimental evidence supporting the existence of the dynamics-elasticity correlations for lipid membranes and propose a mechanism involving molecular packing densities to explain them. This paper thereby unifies, at the molecular level, the aspects of the continuum mechanics long used to model the two membrane features. This ultimately may elucidate the universal physical principles governing the cellular phenomena involving biomembranes.

  3. Chemistry by nanocatalysis: First example of a solid-supported RAPTA complex for organic reactions in aqueous medium

    KAUST Repository

    García-Garrido, Sergio E.

    2010-11-18

    A ruthenium-arene-PTA (RAPTA) complex has been supported for the first time on an inorganic solid, that is, silica-coated ferrite nanoparticles. The resulting magnetic material proved to be a general, very efficient and easily reusable catalyst for three synthetically useful organic transformations; selective nitrile hydration, redox isomerization of allylic alcohols, and heteroannulation of (Z)-enynols. The use of low metal concentration, environmentally friendly water as a reaction medium, with no use at all of organic solvent during or after the reactions, and microwaves as an alternative energy source renders the synthetic processes reported herein "truly" green and sustainable. RAPTA\\'s delight: A nano-RAPTA complex supported on silica-coated ferrite nanoparticles proved to be a general, very efficient and easily reusable catalyst for three synthetically useful organic transformations; selective nitrile hydration, redox isomerization of allylic alcohols, and heteroannulation of (Z)-enynols. The use of low metal concentrations, water as a reaction medium, and microwaves as an energy source renders these processes green and sustainable. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Polyoxotungstate nanoclusters supported on silica as an efficient solid-phase microextraction fiber of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Abolghasemi, Mir Mahdi; Yousefi, Vahid; Rafiee, Ezzat

    2014-01-01

    A highly porous silica-supported tungstophosphoric acid (PW) nanocluster was prepared for use in solid-phase microextraction (SPME) of polycyclic aromatic hydrocarbons (PAHs). The PWs represent a class of discrete transition metal-oxide nanoclusters and their structures resemble discrete fragments of metal-oxide structures of definite size and shape. Transition metal-oxide nanoclusters display large structural diversity, and their monodisperse sizes can be tuned from several Ångstroms up to 10 nm. The highly porous silica-supported tungstophosphoric acid nanocluster material is found to be capable of efficiently extracting PAHs from aqueous sample solutions. The nanomaterial was immobilized on a stainless steel wire for fabrication of the SPME fiber. Following thermal desorption, the PAHs were quantified by GC-MS. Analytical merits include limits of detection that range from 0.02 to 0.1 pg mL −1 and a dynamic range as wide as from 0.001 to 100 ng mL −1 . Under optimum conditions, the repeatability for one fiber (n = 3), expressed as the relative standard deviation, is between 4.3 % and 8.6 %. The method is simple, rapid, and inexpensive. The thermal stability of the fiber and the high relative recovery make this method superior to conventional methods of extraction. (author)

  5. Modeling and Predicting the Electrical Conductivity of Composite Cathode for Solid Oxide Fuel Cell by Using Support Vector Regression

    Science.gov (United States)

    Tang, J. L.; Cai, C. Z.; Xiao, T. T.; Huang, S. J.

    2012-07-01

    The electrical conductivity of solid oxide fuel cell (SOFC) cathode is one of the most important indices affecting the efficiency of SOFC. In order to improve the performance of fuel cell system, it is advantageous to have accurate model with which one can predict the electrical conductivity. In this paper, a model utilizing support vector regression (SVR) approach combined with particle swarm optimization (PSO) algorithm for its parameter optimization was established to modeling and predicting the electrical conductivity of Ba0.5Sr0.5Co0.8Fe0.2 O3-δ-xSm0.5Sr0.5CoO3-δ (BSCF-xSSC) composite cathode under two influence factors, including operating temperature (T) and SSC content (x) in BSCF-xSSC composite cathode. The leave-one-out cross validation (LOOCV) test result by SVR strongly supports that the generalization ability of SVR model is high enough. The absolute percentage error (APE) of 27 samples does not exceed 0.05%. The mean absolute percentage error (MAPE) of all 30 samples is only 0.09% and the correlation coefficient (R2) as high as 0.999. This investigation suggests that the hybrid PSO-SVR approach may be not only a promising and practical methodology to simulate the properties of fuel cell system, but also a powerful tool to be used for optimal designing or controlling the operating process of a SOFC system.

  6. Stir-bar supported micro-solid-phase extraction for the determination of polychlorinated biphenyl congeners in serum samples.

    Science.gov (United States)

    Sajid, Muhammad; Basheer, Chanbasha

    2016-07-15

    In present work, a new configuration of micro-solid phase extraction was introduced and termed as stir-bar supported micro-solid-phase extraction (SB-μ-SPE). A tiny stir-bar was packed inside the porous polypropylene membrane along with sorbent material and the edges of membrane sheet were heat sealed to secure the contents. The packing of stir-bar inside the μ-SPE device does not allow the device to stick with the wall or any corner of the sample vial during extraction, which is, however, a frequent observation in routine μ-SPE. Moreover, it enhances effective surface area of the sorbent exposed to sample solution through continuous agitation (motion and rotation). It also completely immerses the SB-μ-SPE device in the sample solution even for non-polar sorbents. Polychlorinated biphenyls (PCBs) were selected as model compounds and the method performance was evaluated in human serum samples. After extraction, samples were analyzed by gas chromatography mass spectrometry (GC-MS). The factors that affect extraction efficiency of SB-μ-SPE were optimized. Under optimum conditions, a good linearity (0.1-100ngmL(-1)) with coefficients of determinations ranging from 0.9868 to 0.9992 was obtained. Limits of detections were ranged between 0.003 and 0.047ngmL(-1). Acceptable values for inter-day (3.2-9.1%) and intra-day (3.1-7.2%) relative standard deviations were obtained. The optimized method was successfully applied to determine the concentration of PCB congeners in human serum samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Control of anode supported SOFCs (solid oxide fuel cells): Part I. mathematical modeling and state estimation within one cell

    International Nuclear Information System (INIS)

    Amedi, Hamid Reza; Bazooyar, Bahamin; Pishvaie, Mahmoud Reza

    2015-01-01

    In this paper, a 3-dimensional mathematical model for one cell of an anode-supported SOFC (solid oxide fuel cells) is presented. The model is derived from the partial differential equations representing the conservation laws of ionic and electronic charges, mass, energy, and momentum. The model is implemented to fully characterize the steady state operation of the cell with countercurrent flow pattern of fuel and air. The model is also used for the comparison of countercurrent with concurrent flow patterns in terms of thermal stress (temperature distribution) and quality of operation (current density). Results reveal that the steady-state cell performance curve and output of simulations qualitatively match experimental data of the literature. Results also demonstrate that countercurrent flow pattern leads to an even distribution of temperature, more uniform current density along the cell and thus is more enduring and superior to the concurrent flow pattern. Afterward, the thorough 3-dimensional model is used for state estimation instead of a real cell. To estimate states, the model is simplified and changed to a 1-dimensional model along flow streams. This simplified model includes uncertainty (because of simplifying assumptions of the model), noise, and disturbance (because of measurements). The behaviors of extended and ensemble Kalman filter as an observer are evaluated in terms of estimating the states and filtering the noises. Results demonstrate that, like extended Kalman filter, ensemble Kalman filter properly estimates the states with 20 sets. - Highlights: • A 3-dimensional model for one cell of SOFC (solid oxide fuel cells) is presented. • Higher voltages and thermal stress in countercurrent than concurrent flow pattern. • State estimation of the cell is examined by ensemble and extended Kalman filters. • Ensemble with 20 sets is as good as extended Kalman filter.

  8. Internal reforming characteristics of cermet supported solid oxide fuel cell using yttria stabilized zirconia fed with partially reformed methane

    Energy Technology Data Exchange (ETDEWEB)

    Momma, Akihiko; Takano, Kiyonami; Tanaka, Yohei; Negishi, Akira; Kato, Ken; Nozaki, Ken; Kato, Tohru [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono Tsukuba Ibaraki, 305-8568 (Japan); Ichigi, Takenori; Matsuda, Kazuyuki; Ryu, Takashi [Application Development Project, Corporate R and D, NGK Insulators, Ltd., 2-56 Suda-cho Mizuho-ku Nagoya-shi Aichi, 467-8530 (Japan)

    2009-08-01

    In order to investigate the internal reforming characteristics in a cermet supported solid oxide fuel cell (SOFC) using YSZ as the electrolyte, the concentration profiles of the gaseous species along the gas flow direction in the anode were measured. Partially reformed methane using a pre-reformer kept at a constant temperature is supplied to the center of the cell which is operated with a seal-less structure at the gas outlet. The anode gas is sucked in via silica capillaries to the initially evacuated gas tanks. The process is simultaneously carried out using five sampling ports. The sampled gas is analyzed by a gas chromatograph. Most of the measurements are made at the cell temperature (T{sub cell}) of 750 C and at various temperatures of the pre-reformer (T{sub ref}) with various fuel utilizations (U{sub f}) of the cell. The composition of the fuel at the inlet of the anode was confirmed to be almost the same as that theoretically calculated assuming equilibrium at the temperature of the pre-reformer. The effect of internal reforming in the anode is clearly observed as a steady decrease in the methane concentration along the flow axis. The effect of the water-gas shift reaction is also observed as a decrease in the CO{sub 2} concentration and an increase of CO concentration around the gas inlet region, as the water-gas shift reaction inversely proceeds when T{sub cell} is higher than T{sub ref}. The diffusion of nitrogen from the seal-less outermost edge is observed, and the diffusion is confirmed to be more significant as U{sub f} decreases. The observations are compared with the results obtained by the SOFC supported by lanthanum gallate electrolyte. With respect to the internal reforming performance, the cell investigated here is found to be more effective when compared to the previously reported electrolyte supported cell. (author)

  9. Internal reforming characteristics of cermet supported solid oxide fuel cell using yttria stabilized zirconia fed with partially reformed methane

    Science.gov (United States)

    Momma, Akihiko; Takano, Kiyonami; Tanaka, Yohei; Negishi, Akira; Kato, Ken; Nozaki, Ken; Kato, Tohru; Ichigi, Takenori; Matsuda, Kazuyuki; Ryu, Takashi

    In order to investigate the internal reforming characteristics in a cermet supported solid oxide fuel cell (SOFC) using YSZ as the electrolyte, the concentration profiles of the gaseous species along the gas flow direction in the anode were measured. Partially reformed methane using a pre-reformer kept at a constant temperature is supplied to the center of the cell which is operated with a seal-less structure at the gas outlet. The anode gas is sucked in via silica capillaries to the initially evacuated gas tanks. The process is simultaneously carried out using five sampling ports. The sampled gas is analyzed by a gas chromatograph. Most of the measurements are made at the cell temperature (T cell) of 750 °C and at various temperatures of the pre-reformer (T ref) with various fuel utilizations (U f) of the cell. The composition of the fuel at the inlet of the anode was confirmed to be almost the same as that theoretically calculated assuming equilibrium at the temperature of the pre-reformer. The effect of internal reforming in the anode is clearly observed as a steady decrease in the methane concentration along the flow axis. The effect of the water-gas shift reaction is also observed as a decrease in the CO 2 concentration and an increase of CO concentration around the gas inlet region, as the water-gas shift reaction inversely proceeds when T cell is higher than T ref. The diffusion of nitrogen from the seal-less outermost edge is observed, and the diffusion is confirmed to be more significant as U f decreases. The observations are compared with the results obtained by the SOFC supported by lanthanum gallate electrolyte. With respect to the internal reforming performance, the cell investigated here is found to be more effective when compared to the previously reported electrolyte supported cell.

  10. Medium chain acylcarnitines dominate the metabolite pattern in humans under moderate intensity exercise and support lipid oxidation.

    Directory of Open Access Journals (Sweden)

    Rainer Lehmann

    Full Text Available BACKGROUND: Exercise is an extreme physiological challenge for skeletal muscle energy metabolism and has notable health benefits. We aimed to identify and characterize metabolites, which are components of the regulatory network mediating the beneficial metabolic adaptation to exercise. METHODOLOGY AND PRINCIPAL FINDINGS: First, we investigated plasma from healthy human subjects who completed two independent running studies under moderate, predominantly aerobic conditions. Samples obtained prior to and immediately after running and then 3 and 24 h into the recovery phase were analyzed by a non-targeted (NT- metabolomics approach applying liquid chromatography-qTOF-mass spectrometry. Under these conditions medium and long chain acylcarnitines were found to be the most discriminant plasma biomarkers of moderately intense exercise. Immediately after a 60 min (at 93% V(IAT or a 120 min run (at 70% V(IAT a pronounced, transient increase dominated by octanoyl-, decanoyl-, and dodecanoyl-carnitine was observed. The release of acylcarnitines as intermediates of partial beta-oxidation was verified in skeletal muscle cell culture experiments by probing (13C-palmitate metabolism. Further investigations in primary human myotubes and mouse muscle tissue revealed that octanoyl-, decanoyl-, and dodecanoyl-carnitine were able to support the oxidation of palmitate, proving more effective than L-carnitine. CONCLUSIONS: Medium chain acylcarnitines were identified and characterized by a functional metabolomics approach as the dominating biomarkers during a moderately intense exercise bout possessing the power to support fat oxidation. This physiological production and efflux of acylcarnitines might exert beneficial biological functions in muscle tissue.

  11. Synthesis of quinoxaline 1,4-di-n-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

    International Nuclear Information System (INIS)

    Gomez-Caro, Lilia C.; Sanchez-Sanchez, Mario; Bocanegra-Garcia, Virgilio; Rivera, Gildardo; Monge, Antonio

    2011-01-01

    We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield. (author)

  12. Synthesis of quinoxaline 1,4-di-n-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Caro, Lilia C.; Sanchez-Sanchez, Mario; Bocanegra-Garcia, Virgilio; Rivera, Gildardo [Universidad Autonoma de Tamaulipas, Reynosa (Mexico). Dept. de Farmacia y Quimica Medicinal; Monge, Antonio [Universidad de Navarra, Pamplona (Spain). Centro de Investigacion en Farmacobiologia Aplicada. Unidad de Investigacion y Desarrollo de Medicamentos

    2011-07-01

    We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield. (author)

  13. Complete doping in solid-state by silica-supported perchloric acid as dopant solid acid: Synthesis and characterization of the novel chiral composite of poly [(±)-2-(sec-butyl) aniline

    Energy Technology Data Exchange (ETDEWEB)

    Farrokhzadeh, Abdolkarim; Modarresi-Alam, Ali Reza, E-mail: modaresi@chem.usb.ac.ir

    2016-05-15

    Poly [(±)-2-(sec-butyl) aniline]/silica-supported perchloric acid composites were synthesized by combination of poly[(±)-2-sec-butylaniline] base (PSBA) and the silica-supported perchloric acid (SSPA) as dopant solid acid in solid-state. The X-ray photoelectron spectroscopy (XPS) and CHNS results confirm nigraniline oxidation state and complete doping for composites (about 75%) and non-complete for the PSBA·HCl salt (about 49%). The conductivity of samples was (≈0.07 S/cm) in agreement with the percent of doping obtained of the XPS analysis. Also, contact resistance was determined by circular-TLM measurement. The morphology of samples by the scanning electron microscopy (SEM) and their coating were investigated by XPS, SEM-map and energy-dispersive X-ray spectroscopy (EDX). The key benefits of this work are the preparation of conductive chiral composite with the delocalized polaron structure under green chemistry and solid-state condition, the improvement of the processability by inclusion of the 2-sec-butyl group and the use of dopant solid acid (SSPA) as dopant. - Highlights: • The solid-state synthesis of the novel chiral composites of poly[(±)-2-(sec-butyl)aniline] (PSBA) and silica-supported perchloric acid (SSPA). • It takes 120 h for complete deprotonation of PSBA.HCl salt. • Use of SSPA as dopant solid acid for the first time to attain the complete doping of PSBA. • The coating of silica surface with PSBA.

  14. Synthesis, activity, and structure--activity relationship studies of novel cationic lipids for DNA transfer.

    Science.gov (United States)

    Byk, G; Dubertret, C; Escriou, V; Frederic, M; Jaslin, G; Rangara, R; Pitard, B; Crouzet, J; Wils, P; Schwartz, B; Scherman, D

    1998-01-15

    We have designed and synthesized original cationic lipids for gene delivery. A synthetic method on solid support allowed easy access to unsymmetrically monofunctionalized polyamine building blocks of variable geometries. These polyamine building blocks were introduced into cationic lipids. To optimize the transfection efficiency in the novel series, we have carried out structure-activity relationship studies by introduction of variable-length lipids, of variable-length linkers between lipid and cationic moiety, and of substituted linkers. We introduce the concept of using the linkers within cationic lipids molecules as carriers of side groups harboring various functionalities (side chain entity), as assessed by the introduction of a library composed of cationic entities, additional lipid chains, targeting groups, and finally the molecular probes rhodamine and biotin for cellular traffic studies. The transfection activity of the products was assayed in vitro on Hela carcinoma, on NIH3T3, and on CV1 fibroblasts and in vivo on the Lewis Lung carcinoma model. Products from the series displayed high transfection activities. Results indicated that the introduction of a targeting side chain moiety into the cationic lipid is permitted. A primary physicochemical characterization of the DNA/lipid complexes was demonstrated with this leading compound. Selected products from the series are currently being developed for preclinical studies, and the labeled lipopolyamines can be used to study the intracellular traffic of DNA/cationic lipid complexes.

  15. Development and testing of anode-supported solid oxide fuel cells with slurry-coated electrolyte and cathode

    Energy Technology Data Exchange (ETDEWEB)

    Muccillo, R.; Muccillo, E.N.S.; Fonseca, F.C.; Franca, Y.V.; Porfirio, T.C. [Centro de Ciencia e Tecnologia de Materiais, Instituto de Pesquisas Energeticas e Nucleares, C.P. 11049, Pinheiros, S. Paulo, SP 05422-970 (Brazil); de Florio, D.Z. [Instituto de Quimica, UNESP, R. Prof. Francisco Degni s/n, Araraquara, SP 14801-970 (Brazil); Berton, M.A.C.; Garcia, C.M. [Instituto de Tecnologia para o Desenvolvimento, DPMA, C.P. 19067, Curitiba, PR 81531-980 (Brazil)

    2006-06-01

    A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). The whole project consisted of the preparation of the component materials: anode, cathode and electrolyte, and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Several anode-supported single SOFCs of the type (ZrO{sub 2}:Y{sub 2}O{sub 3}+NiO) thick anode/(ZrO{sub 2}:Y{sub 2}O{sub 3}) thin electrolyte/(La{sub 0.65}Sr{sub 0.35}MnO{sub 3}+ZrO{sub 2}:Y{sub 2}O{sub 3}) thin cathode have been prepared and tested at 700 and 800{sup o}C after in situ H{sub 2} anode reduction. The main results show that the slurry-coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (author)

  16. Graphite Carbon-Supported Mo2C Nanocomposites by a Single-Step Solid State Reaction for Electrochemical Oxygen Reduction.

    Science.gov (United States)

    Huang, K; Bi, K; Liang, C; Lin, S; Wang, W J; Yang, T Z; Liu, J; Zhang, R; Fan, D Y; Wang, Y G; Lei, M

    2015-01-01

    Novel graphite-molybdenum carbide nanocomposites (G-Mo2C) are synthesized by a typical solid state reaction with melamine and MoO3 as precursors under inert atmosphere. The characterization results indicate that G-Mo2C composites are composed of high crystallization and purity of Mo2C and few layers of graphite carbon. Mo2C nanoparticles with sizes ranging from 5 to 50 nm are uniformly supported by surrounding graphite layers. It is believed that Mo atom resulting from the reduction of MoO3 is beneficial to the immobilization of graphite carbon. Moreover, the electrocatalytic performances of G-Mo2C for ORR in alkaline medium are investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test with 3M methanol. The results show that G-Mo2C has a considerable catalytic activity and superior methanol tolerance performance for the oxygen reduction reaction (ORR) benefiting from the chemical interaction between the carbide nanoparticles and graphite carbon.

  17. LONG-TERM PERFORMANCE OF SOLID OXIDE STACKS WITH ELECTRODE-SUPPORTED CELLS OPERATING IN THE STEAM ELECTROLYSIS MODE

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; R. C. O' Brien; X. Zhang; G. Tao; B. J. Butler

    2011-11-01

    Performance characterization and durability testing have been completed on two five-cell high-temperature electrolysis stacks constructed with advanced cell and stack technologies. The solid oxide cells incorporate a negative-electrode-supported multi-layer design with nickel-zirconia cermet negative electrodes, thin-film yttria-stabilized zirconia electrolytes, and multi-layer lanthanum ferrite-based positive electrodes. The per-cell active area is 100 cm2. The stack is internally manifolded with compliant mica-glass seals. Treated metallic interconnects with integral flow channels separate the cells. Stack compression is accomplished by means of a custom spring-loaded test fixture. Initial stack performance characterization was determined through a series of DC potential sweeps in both fuel cell and electrolysis modes of operation. Results of these sweeps indicated very good initial performance, with area-specific resistance values less than 0.5 ?.cm2. Long-term durability testing was performed with A test duration of 1000 hours. Overall performance degradation was less than 10% over the 1000-hour period. Final stack performance characterization was again determined by a series of DC potential sweeps at the same flow conditions as the initial sweeps in both electrolysis and fuel cell modes of operation. A final sweep in the fuel cell mode indicated a power density of 0.356 W/cm2, with average per-cell voltage of 0.71 V at a current of 50 A.

  18. Application of La-Doped SrTiO3 in Advanced Metal-Supported Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sabrina Presto

    2018-03-01

    Full Text Available Composite materials frequently allow the drawbacks of single components to be overcome thanks to a synergistic combination of material- and structure-specific features, leading to enhanced and also new properties. This is the case of a metallic-ceramic composite, a nickel-chromium-aluminum (NiCrAl foam impregnated with La-doped Strontium Titanate (LST. This particular cermet has very interesting properties that can be used in different fields of application, namely: mechanical robustness provided by the metal foam; and chemical stability in harsh conditions of temperature and atmosphere by promotion of a thin protective layer of alumina (Al2O3; high electronic conductivity given by a percolating ceramic conducting phase, i.e., La-doped Strontium Titanate. In this paper, its application as a current collector in a metal-supported Solid Oxide Fuel Cells (SOFC was studied. Firstly, the electronic properties of different compositions, stoichiometric and under stoichiometric, of LST were analyzed to choose the best one in terms of conductivity and phase purity. Then, LST chemical stability was studied in the presence of Al2O3 at different temperatures, gas compositions and aging times. Finally, stability and conductivity of LST-impregnated NiCrAl foam composite materials were measured, and LST was found to be fully compatible with the NiCrAl foam, as no reactions were detected in oxidizing and reducing atmosphere after up to 300 h operation at 750 °C and 900 °C between the Al2O3 layer and LST. Results showed that the composite is suitable as a current collector in innovative designs of metal-supported SOFC, like the Evolve cell, in which the metallic part is supposed not only to provide the structural stability to the cell, but also to play the role of current collector due to the impregnation of ceramic material.

  19. Preparation of functional layers for anode-supported solid oxide fuel cells by the reverse roll coating process

    Science.gov (United States)

    Mücke, R.; Büchler, O.; Bram, M.; Leonide, A.; Ivers-Tiffée, E.; Buchkremer, H. P.

    The roll coating technique represents a novel method for applying functional layers to solid oxide fuel cells (SOFCs). This fast process is already used for mass production in other branches of industry and offers a high degree of automation. It was utilized for coating specially developed anode (NiO + 8YSZ, 8YSZ: 8 mol% yttria-stabilized zirconia) and electrolyte (8YSZ) suspensions on green and pre-sintered tape-cast anode supports (NiO + 8YSZ). The layers formed were co-fired in a single step at 1400 °C for 5 h. As a result, the electrolyte exhibited a thickness of 14-18 μm and sufficient gas tightness. Complete cells with a screen-printed and sintered La 0.65Sr 0.3MnO 3- δ (LSM)/8YSZ cathode yielded a current density of 0.9-1.1 A cm -2 at 800 °C and 0.7 V, which is lower than the performance of non-co-fired slip-cast or screen-printed Jülich standard cells with thinner anode and electrolyte layers. The contribution of the cell components to the total area-specific resistance (ASR) was calculated by analyzing the distribution function of the relaxation times (DRTs) of measured electrochemical impedance spectra (EIS) and indicates the potential improvement in the cell performance achievable by reducing the thickness of the roll-coated layers. The results show that the anode-supported planar half-cells can be fabricated cost-effectively by combining roll coating with subsequent co-firing.

  20. Solid Matter

    CERN Document Server

    Angelo, Joseph A

    2011-01-01

    Supported by a generous quantity of full-color illustrations and interesting sidebars, Solid Matter introduces the basic characteristics and properties of solid matter. It briefly describes the cosmic connection of the elements, leading readers through several key events in human pre-history that resulted in more advanced uses of matter in the solid state. Chapters include:. -Solid Matter: An Initial Perspective. -Physical Behavior of Matter. -The Gravity of Matter. -Fundamentals of Materials Science. -Rocks and Minerals. -Metals. -Building Materials. -Carbon Earth's Most Versatile Element. -S

  1. Pharmacogenetics of lipid diseases

    Directory of Open Access Journals (Sweden)

    Ordovas Jose M

    2004-01-01

    Full Text Available Abstract The genetic basis for most of the rare lipid monogenic disorders have been elucidated, but the challenge remains in determining the combination of genes that contribute to the genetic variability in lipid levels in the general population; this has been estimated to be in the range of 40-60 per cent of the total variability. Therefore, the effect of common polymorphisms on lipid phenotypes will be greatly modulated by gene-gene and gene-environment interactions. This approach can also be used to characterise the individuality of the response to lipid-lowering therapies, whether using drugs (pharmacogenetics or dietary interventions (nutrigenetics. In this regard, multiple studies have already described significant interactions between candidate genes for lipid and drug metabolism that modulate therapeutic response--although the outcomes of these studies have been controversial and call for more rigorous experimental design and analytical approaches. Once solid evidence about the predictive value of genetic panels is obtained, risk and therapeutic algorithms can begin to be generated that should provide an accurate measure of genetic predisposition, as well as targeted behavioural modifications or drugs of choice and personalised dosages of these drugs.

  2. Consumption of a solid fat rich in lauric acid results in a more favorable serum lipid profile in healthy men and women than consumption of a solid fat rich in trans-fatty acids

    NARCIS (Netherlands)

    Roos, de N.M.; Schouten, E.G.; Katan, M.B.

    2001-01-01

    Solid fats are used in food manufacturing to provide texture and firmness to foods. Such fats are rich in either saturated or trans-fatty acids, both of which increase the risk of coronary heart disease. Epidemiological and experimental studies suggest that trans-fatty acids increase risk more than

  3. Solid-State NMR and DFT Studies on the Formation of Well-Defined Silica-Supported Tantallaaziridines: From Synthesis to Catalytic Application

    KAUST Repository

    Hamzaoui, Bilel; Pelletier, Jeremie; Abou-Hamad, Edy; Chen, Yin; El Eter, Mohamad; Chermak, Edrisse; Cavallo, Luigi; Basset, Jean-Marie

    2016-01-01

    spectroscopy, elemental analysis, and 1H,13C HETCOR and DQ TQ solid-state (SS) NMR spectroscopy. The formation mechanism, by β-H abstraction, was investigated by SS NMR spectroscopy and supported by DFT calculations. The C-H activation of the dimethylamide

  4. TrackArt: the user friendly interface for single molecule tracking data analysis and simulation applied to complex diffusion in mica supported lipid bilayers.

    Science.gov (United States)

    Matysik, Artur; Kraut, Rachel S

    2014-05-01

    Single molecule tracking (SMT) analysis of fluorescently tagged lipid and protein probes is an attractive alternative to ensemble averaged methods such as fluorescence correlation spectroscopy (FCS) or fluorescence recovery after photobleaching (FRAP) for measuring diffusion in artificial and plasma membranes. The meaningful estimation of diffusion coefficients and their errors is however not straightforward, and is heavily dependent on sample type, acquisition method, and equipment used. Many approaches require advanced computing and programming skills for their implementation. Here we present TrackArt software, an accessible graphic interface for simulation and complex analysis of multiple particle paths. Imported trajectories can be filtered to eliminate spurious or corrupted tracks, and are then analyzed using several previously described methodologies, to yield single or multiple diffusion coefficients, their population fractions, and estimated errors. We use TrackArt to analyze the single-molecule diffusion behavior of a sphingolipid analog SM-Atto647N, in mica supported DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) bilayers. Fitting with a two-component diffusion model confirms the existence of two separate populations of diffusing particles in these bilayers on mica. As a demonstration of the TrackArt workflow, we characterize and discuss the effective activation energies required to increase the diffusion rates of these populations, obtained from Arrhenius plots of temperature-dependent diffusion. Finally, TrackArt provides a simulation module, allowing the user to generate models with multiple particle trajectories, diffusing with different characteristics. Maps of domains, acting as impermeable or permeable obstacles for particles diffusing with given rate constants and diffusion coefficients, can be simulated or imported from an image. Importantly, this allows one to use simulated data with a known diffusion behavior as a comparison for results

  5. Second-harmonic generation of Lamb modes in a solid layer supported by a semi-infinite substrate

    International Nuclear Information System (INIS)

    Deng Mingxi

    2004-01-01

    Using a second-order perturbation approximation and a modal expansion analysis approach, this study develops an effective technique for studying the generation of second harmonics of Lamb modes propagating in the composite structure consisting of a solid layer supported by a semi-infinite substrate. The nonlinearity in the elastic wave motion process can result in the generation of second harmonics of primary Lamb mode propagation in the composite structure, and this nonlinearity may be treated as a second-order perturbation of the elastic response of the primary waves. There are second-order bulk and surface/interface driving sources in the composite structure wherever the primary Lamb modes propagate. These driving sources can be thought of as the forcing functions of a finite series of double-frequency Lamb modes (DFLMs) in terms of the approach of modal expansion analysis for waveguide excitation. The fields of the second harmonics of the primary Lamb modes can be regarded as superpositions of the fields of a finite series of DFLMs. Although Lamb modes are dispersive, the field of one DFLM component can have a cumulative growth effect when its phase velocity exactly or approximately equals that of a primary Lamb mode. The formal solutions for the second harmonics of Lamb modes have been obtained. The numerical simulations clearly show the physical process of the generation of second harmonics of Lamb modes in the composite structure. The complicated problems of second-harmonic generation of Lamb modes have been exactly determined within the second-order perturbation approximation

  6. Phase I study of OM-174, a lipid A analogue, with assessment of immunological response, in patients with refractory solid tumors

    International Nuclear Information System (INIS)

    Isambert, Nicolas; Bardou, Marc; Fumoleau, Pierre; Paul, Catherine; Ferrand, Christophe; Zanetta, Sylvie; Bauer, Jacques; Ragot, Kevin; Lizard, Gérard; Jeannin, Jean-François

    2013-01-01

    Lipids A, the lipophilic partial structure of lipopolysaccharides, induce regression of several tumor types in animal models. Rather than exerting direct cytotoxic effect, these compounds trigger the immune system which in turn stimulates secretion of cytokines, and activates the inducible nitric oxide synthase, as well as immune cell infiltration of tumors. OM-174 is an analogue of lipid A with dual action on Toll-like receptors 2 and 4. In an experimental model of peritoneal carcinomatosis induced in BDIX rats by intraperitoneal injection of syngeneic PROb colon cancer cells, it induced a complete regression of tumors. The present phase I trial was conducted to determine the maximum tolerated dose, the recommended phase II dose and biological response associated with OM-174 administered as intravenous infusion. Patients received OM-174 twice weekly for a total of 5, 10 or 15 injections of either 600, 800 or 1000 μg/m 2 . Blood samples for pharmacokinetic analysis and cytokine dosages were collected. NK cells activity and Toll-like receptors 4 polymorphism analysis were also performed. Seventeen patients were included. The highest dose administered was 1000 μg/m 2 repeated in 15 injections. The most common toxicities were a chills, fever, nausea/vomiting, diarrhea, fatigue and headache. No patient experienced haematological side effects. As no dose limiting toxicity was observed, despite a grade 3 respiratory complication, the maximal tolerated dose and recommended dose were not established. Three patients exhibited disease stabilization with a mean duration of 4 months. Pharmacokinetic profile of OM-174 was characterized by a low distribution volume and clearance. Analysis of TLR 4 polymorphysm showed that most (16/17) patients carried the wild type alleles. A progressive increase in NK cell number and activity was observed only in patients receiving 1000 μg/m 2 of OM-174. A peak of IL-8 and IL-10 concentrations were observed after each OM-174 injection. Peaks

  7. High throughput measurement of high temperature strength of ceramics in controlled atmosphere and its use on solid oxide fuel cell anode supports

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Curran, Declan; Rasmussen, Steffen

    2014-01-01

    In the development of structural and functional ceramics for high temperature electrochemical conversion devices such as solid oxide fuel cells, their mechanical properties must be tested at operational conditions, i.e. at high temperature and controlled atmospheres. Furthermore, characterization...... for testing multiple samples at operational conditions providing a high throughput and thus the possibility achieve high reliability. Optical methods are used to measure deformations contactless, frictionless load measuring is achieved, and multiple samples are handled in one heat up. The methodology...... is validated at room temperature, and exemplified by measurement of the strength of solid oxide fuel cell anode supports at 800 C. © 2014 Elsevier B.V. All rights reserved....

  8. Transport parameters of thin, supported cathode layers in solid oxide fuel cells (SOFCs); Transportparameter duenner, getraegerter Kathodenschichten der oxidkeramischen Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Wedershoven, Christian

    2010-12-22

    The aim of this work was to determine the transport properties of thin cathode layers, which are part of the composite layer of a fabricated anode-supported solid oxide fuel cell (SOFC). The transport properties of the anode and cathode have a significant influence on the electrochemical performance of a fuel cell stack and therefore represent an important parameter when designing fuel cell stacks. In order to determine the transport parameters of the cathode layers in a fabricated SOFC, it is necessary to permeate the thin cathode layer deposited on the gas-tight electrolyte with a defined gas transport. These thin cathode layers cannot be fabricated as mechanically stable single layers and cannot therefore be investigated in the diffusion and permeation experiments usually used to determine transport parameters. The setup of these experiments - particularly the sample holder - was therefore altered in this work. The result of this altered setup was a three-dimensional flow configuration. Compared to the conventional setup, it was no longer possible to describe the gas transport in the experiments with an analytical one-dimensional solution. A numerical solution process had to be used to evaluate the measurements. The new setup permitted a sufficiently symmetrical gas distribution and thus allowed the description of the transport to be reduced to a two-dimensional description, which significantly reduced the computational effort required to evaluate the measurements. For pressure-induced transport, a parametrized coherent expression of transport could be derived. This expression is equivalent to the analytical description of the transport in conventional measurement setups, with the exception of parameters that describe the geometry of the gas diffusion. In this case, a numerical process is not necessary for the evaluation. Using the transport parameters of mechanically stable anode substrates, which can be measured both in the old and the new setups, the old and

  9. How synthetic membrane systems contribute to the understanding of lipid-driven endocytosis.

    Science.gov (United States)

    Schubert, Thomas; Römer, Winfried

    2015-11-01

    Synthetic membrane systems, such as giant unilamellar vesicles and solid supported lipid bilayers, have widened our understanding of biological processes occurring at or through membranes. Artificial systems are particularly suited to study the inherent properties of membranes with regard to their components and characteristics. This review critically reflects the emerging molecular mechanism of lipid-driven endocytosis and the impact of model membrane systems in elucidating the complex interplay of biomolecules within this process. Lipid receptor clustering induced by binding of several toxins, viruses and bacteria to the plasma membrane leads to local membrane bending and formation of tubular membrane invaginations. Here, lipid shape, and protein structure and valency are the essential parameters in membrane deformation. Combining observations of complex cellular processes and their reconstitution on minimal systems seems to be a promising future approach to resolve basic underlying mechanisms. This article is part of a Special Issue entitled: Mechanobiology. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. A New Nano Silica Gel Supported by Thionyl Chloride as a Solid Acid for the Efficient Diazotization of Aniline Derivatives: Application and Synthesis of Azo Dyes

    Directory of Open Access Journals (Sweden)

    Mohammad Mirjalili

    2012-01-01

    Full Text Available A new nano silicagel supported by thionyl chloride as a solid acid was synthesized and used as a increasing the production yield of dye to affect the efficient diazotization of arylamines. The diazonium salts thus obtained were coupled, using standard experimental procedures, to anilines and naphthols to afford the requisite azo dyes in good yield. The diazotization and subsequent azo-coupling generated the related azo dyes at low temperature in short reaction times with a simple experimental procedure.

  11. Application of an Activated Carbon-Based Support for Magnetic Solid Phase Extraction Followed by Spectrophotometric Determination of Tartrazine in Commercial Beverages

    OpenAIRE

    Rodr?guez, Jos? A.; Escamilla-Lara, Karen A.; Guevara-Lara, Alfredo; Miranda, Jose M.; P?ez-Hern?ndez, Ma. Elena

    2015-01-01

    A method is presented for magnetic solid phase extraction of tartrazine from nonalcoholic beverages. The method involves the extraction and clean-up by activated carbon covered with magnetite dispersed in the sample, followed by the magnetic isolation and desorption of the analyte by basified methanol. The tartrazine eluted from the magnetic support was determined by spectrophotometry. Under optimal conditions, the linear range of the calibration curve ranges from 3 to 30?mg?L?1, with a limit...

  12. Lipid Nanotechnology

    Directory of Open Access Journals (Sweden)

    Gijsje Koenderink

    2013-02-01

    Full Text Available Nanotechnology is a multidisciplinary field that covers a vast and diverse array of devices and machines derived from engineering, physics, materials science, chemistry and biology. These devices have found applications in biomedical sciences, such as targeted drug delivery, bio-imaging, sensing and diagnosis of pathologies at early stages. In these applications, nano-devices typically interface with the plasma membrane of cells. On the other hand, naturally occurring nanostructures in biology have been a source of inspiration for new nanotechnological designs and hybrid nanostructures made of biological and non-biological, organic and inorganic building blocks. Lipids, with their amphiphilicity, diversity of head and tail chemistry, and antifouling properties that block nonspecific binding to lipid-coated surfaces, provide a powerful toolbox for nanotechnology. This review discusses the progress in the emerging field of lipid nanotechnology.

  13. Hairy foam" : carbon nanofibers grown on solid foam. A fully accessible, high surface area, graphitic catalyst support

    NARCIS (Netherlands)

    Wenmakers, P.W.A.M.; Schaaf, van der J.; Kuster, B.F.M.; Schouten, J.C.

    2008-01-01

    This paper describes the synthesis of carbon nanofibers (CNFs) on solid carbon foam ("Hairy Foam") by catalytic decompn. of ethylene. The effect of nickel loading on fiber diam. and morphol., CNF coverage, and fiber layer thickness is studied using SEM and N2/Kr-physisorption. The surface area

  14. Using Dark Field X-Ray Microscopy To Study In-Operando Yttria Stabilized Zirconia Electrolyte Supported Solid Oxide Cell

    DEFF Research Database (Denmark)

    Sierra, J. X.; Poulsen, H. F.; Jørgensen, P. S.

    Dark Field X-Ray Microscopy is a promising technique to study the structure of materials in nanometer length scale. In combination with x-ray diffraction technique, the microstructure evolution of Yttria Stabilized Zirconia electrolyte based solid oxide cell was studied running at extreme operating...

  15. Comparison of TEVAR resin beads, PAN fibers, and ePTFE membranes as a solid support for Aliquat-336 in immobilized liquid extraction chromatography for separation of actinides

    International Nuclear Information System (INIS)

    Joe Dauner; Steve Workman

    2012-01-01

    The following paper covers a comparison of two new systems to traditional TEVA R resin systems for the analytical separation of actinides by immobilized liquid-liquid extraction using Aliquat-336. The new systems are using expanded polytetrafluroethane (ePTFE) membrane or polyacrylonitrile (PAN) fibers as the solid support. The systems are compared in two ways. First in how much Aliquat-336 they contain with the Vs, ratio of volume of Aliquat-336 to volume of polymeric support, being 0.158, 0.483, and 0.590 for the TEVA R resin, PAN fibers, and the ePTFE systems, respectively. The second comparison is in their performance capacity of extraction of uranyl chloride anion complex. The fiber and resins systems show similar capacities, and the membrane system being an order of magnitude less than the other systems. A cost comparison demonstrates the savings advantages of using a fiber based support compared with resin and membrane support systems. (author)

  16. Lipid Panel

    Science.gov (United States)

    ... A routine cardiac risk assessment typically includes a fasting lipid panel. Beyond that, research continues into the usefulness of other non-traditional markers of cardiac risk, such as Lp-PLA 2 . A health practitioner may choose to evaluate one or more ...

  17. Microemulsion extrusion technique : a new method to produce lipid nanoparticles

    NARCIS (Netherlands)

    de Jesus, Marcelo Bispo; Radaic, Allan; Zuhorn, Inge S.; de Paula, Eneida

    2013-01-01

    Solid lipid nanoparticles (SLN) and nano-structured lipid carriers (NLC) have been intensively investigated for different applications, including their use as drug and gene delivery systems. Different techniques have been employed to produce lipid nanoparticles, of which high pressure homogenization

  18. LipidPedia: a comprehensive lipid knowledgebase.

    Science.gov (United States)

    Kuo, Tien-Chueh; Tseng, Yufeng Jane

    2018-04-10

    Lipids are divided into fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, sterols, prenol lipids and polyketides. Fatty acyls and glycerolipids are commonly used as energy storage, whereas glycerophospholipids, sphingolipids, sterols and saccharolipids are common used as components of cell membranes. Lipids in fatty acyls, glycerophospholipids, sphingolipids and sterols classes play important roles in signaling. Although more than 36 million lipids can be identified or computationally generated, no single lipid database provides comprehensive information on lipids. Furthermore, the complex systematic or common names of lipids make the discovery of related information challenging. Here, we present LipidPedia, a comprehensive lipid knowledgebase. The content of this database is derived from integrating annotation data with full-text mining of 3,923 lipids and more than 400,000 annotations of associated diseases, pathways, functions, and locations that are essential for interpreting lipid functions and mechanisms from over 1,400,000 scientific publications. Each lipid in LipidPedia also has its own entry containing a text summary curated from the most frequently cited diseases, pathways, genes, locations, functions, lipids and experimental models in the biomedical literature. LipidPedia aims to provide an overall synopsis of lipids to summarize lipid annotations and provide a detailed listing of references for understanding complex lipid functions and mechanisms. LipidPedia is available at http://lipidpedia.cmdm.tw. yjtseng@csie.ntu.edu.tw. Supplementary data are available at Bioinformatics online.

  19. Calcium-dependent hydrolysis of supported planar lipids was triggered by honey bee venom phospholipase A2 with the right orientation at the interface.

    Science.gov (United States)

    Kai, Siqi; Li, Xu; Li, Bolin; Han, Xiaofeng; Lu, Xiaolin

    2017-12-20

    Hydrolysis of planar phospholipids catalyzed by honey bee venom phospholipase A 2 (bvPLA 2 ) was studied. Experiments demonstrated that Ca 2+ ions mediated between the lipids and bvPLA 2 , induced reorientation of bvPLA 2 , and activated hydrolysis. One of the hydrolysis products, fatty acids, was desorbed, and the other one, lysophospholipids, self-organized at the interface.

  20. Supported liquid membrane based removal of lead(II) and cadmium(II) from mixed feed: Conversion to solid waste by precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Bhatluri, Kamal Kumar; Manna, Mriganka Sekhar; Ghoshal, Aloke Kumar; Saha, Prabirkumar, E-mail: p.saha@iitg.ac.in

    2015-12-15

    Highlights: • Simultaneous removal of two heavy metals lead and cadmium. • Conversion of liquid waste to solid precipitation. • Precipitation facilitates the metals transportation through LM. • Solidification of liquid waste minimizes the final removal of waste. - Abstract: Simultaneous removal of two heavy metals, lead(II) and cadmium(II), from mixed feed using supported liquid membrane (SLM) based technique is investigated in this work. The carrier-solvent combination of “sodium salt of Di-2-ethylhexylphosphoric acid (D2EHPA) (4% w/w) in environmentally benign coconut oil” was immobilized into the pores of solid polymeric polyvinylidene fluoride (PVDF) support. Sodium carbonate (Na{sub 2}CO{sub 3}) was used as the stripping agent. Carbonate salts of lead(II) and cadmium(II) were formed in the stripping side interface and they were insoluble in water leading to precipitation inside the stripping solution. The transportation of solute is positively affected due to the precipitation. Lead(II) removal was found to be preferential due to its favorable electronic configuration. The conversion of the liquid waste to the solid one was added advantage for the final removal of hazardous heavy metals.

  1. Use of computerized, 3-dimensional solids modeling and data base management to support radiation mapping and ALARA planning

    International Nuclear Information System (INIS)

    Schauss, R.D.; Slobodien, M.S.

    1986-01-01

    The RADiation Mapping and ALARA Planning System (RADMAPS) under development by GPU Nuclear Corporation in conjunction with Construction Systems Associates, Inc., integrates computerized solids modeling and data base management to provide an automated, integrated systems solution to the problems associated with acquiring, managing, and communicating plant radiological data at nuclear facilities. This presentation describes the status of the RADMAPS development and outlines plans for future expansion

  2. Peptide Macrocycles Featuring a Backbone Secondary Amine: A Convenient Strategy for the Synthesis of Lipidated Cyclic and Bicyclic Peptides on Solid Support

    DEFF Research Database (Denmark)

    Oddo, Alberto; Münzker, Lena; Hansen, Paul Robert

    2015-01-01

    A convenient strategy for the on-resin synthesis of macrocyclic peptides (3- to 13-mers) via intramolecular halide substitution by a diamino acid is described. The method is compatible with standard Fmoc/tBu SPPS and affords a tail-to-side-chain macrocyclic peptide featuring an endocyclic secondary...

  3. International and domestic uses of solid biofuels under different renewable energy support scenarios in the European Union

    International Nuclear Information System (INIS)

    Hoefnagels, Ric; Resch, Gustav; Junginger, Martin; Faaij, André

    2014-01-01

    Highlights: • A GIS based intermodal biomass transport model was developed for the European Union. • It was linked to the renewable energy model Green-X updated with biomass trade. • Scenarios of renewable energy deployment in the EU27 to 2020 were assessed. • Domestic biomass resources will remain the largest source of bioenergy (over 90%). • But increasing amounts of solid biomass will be traded (up to 506 PJ in 2020). - Abstract: This article describes the development of a geographic information systems (GIS) ba