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Sample records for hemoglobin-containing liposome vesicles

  1. Automatic labeling method for injectable {sup 15}O-oxygen using hemoglobin-containing liposome vesicles and its application for measurement of brain oxygen consumption by PET

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    Tiwari, Vijay Narayan [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan)], E-mail: tiwaridr@u-fukui.ac.jp; Kiyono, Yasushi; Kobayashi, Masato; Mori, Tetsuya; Kudo, Takashi [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Okazawa, Hidehiko [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Research and Education Program for Life Science, University of Fukui, Fukui (Japan); Fujibayashi, Yasuhisa [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Research and Education Program for Life Science, University of Fukui, Fukui (Japan)], E-mail: yfuji@u-fukui.ac.jp

    2010-01-15

    Introduction: The aim of this study was to develop an injectable {sup 15}O-O{sub 2} system using hemoglobin-containing vesicles (HbV), a type of artificial red blood cell, and to investigate the feasibility of {sup 15}O{sub 2}-labeled HbV ({sup 15}O{sub 2}-HbV) to measure cerebral metabolic rate of oxygen (CMRO{sub 2}) in rats. Methods: The direct bubbling method was combined with vortexing to enhance labeling efficiency of HbV with {sup 15}O-O{sub 2} gas. L-Cysteine was added as a reductant to protect hemoglobin molecules in HbV from oxidation at different concentrations, and labeling efficiencies were also compared. Measurement of cerebral blood flow (CBF) and CMRO{sub 2} in five normal rats was performed using a small animal PET scanner after the injection of H{sub 2}{sup 15}O and {sup 15}O{sub 2}-HbV to evaluate the precision of hemodynamic parameters quantitatively. Results: The labeling efficiency of HbV was significantly increased when vortexing and bubbling were combined compared with the simple bubbling method (P<.05). The most efficient method for labeling was bubbling of {sup 15}O-O{sub 2} combined with vortexing and the addition of 2.8 mM L-cysteine in HbV solution. The mean radioactivity of 214.4{+-}7.8 MBq/mL HbV was obtained using this method. PET scans using {sup 15}O{sub 2}-HbV and H{sub 2}{sup 15}O yielded a mean CMRO{sub 2} value of 6.8{+-}1.4 (mL/min per 100 g) in rats with normal CBF of 51.4{+-}7.9 (mL/min per 100 g). Conclusion: Addition of L-cysteine to HbV and simple direct bubbling of {sup 15}O-O{sub 2} gas combined with vortexing was the most efficient method for preparation of {sup 15}O{sub 2}-HbV. The present injectable system using {sup 15}O{sub 2}-HbV was successfully utilized to measure CMRO{sub 2} in rats, indicating that this new method could be useful for animal models to measure oxygen metabolism in the brain.

  2. Mechanisms of Slower Nitric Oxide Uptake by Red Blood Cells and Other Hemoglobin-containing Vesicles*

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    Azarov, Ivan; Liu, Chen; Reynolds, Hannah; Tsekouras, Zaharo; Lee, Janet S.; Gladwin, Mark T.; Kim-Shapiro, Daniel B.

    2011-01-01

    Nitric oxide (NO) acts as a smooth muscle relaxation factor and plays a crucial role in maintaining vascular homeostasis. NO is scavenged rapidly by hemoglobin (Hb). However, under normal physiological conditions, the encapsulation of Hb inside red blood cells (RBCs) significantly retards NO scavenging, permitting NO to reach the smooth muscle. The rate-limiting factors (diffusion of NO to the RBC surface, through the RBC membrane or inside of the RBC) responsible for this retardation have been the subject of much debate. Knowing the relative contribution of each of these factors is important for several reasons including optimization of the development of blood substitutes where Hb is contained within phospholipid vesicles. We have thus performed experiments of NO uptake by erythrocytes and microparticles derived from erythrocytes and conducted simulations of these data as well as that of others. We have included extracellular diffusion (that is, diffusion of the NO to the membrane) and membrane permeability, in addition to intracellular diffusion of NO, in our computational models. We find that all these mechanisms may modulate NO uptake by membrane-encapsulated Hb and that extracellular diffusion is the main rate-limiting factor for phospholipid vesicles and erythrocytes. In the case of red cell microparticles, we find a major role for membrane permeability. These results are consistent with prior studies indicating that extracellular diffusion of several gas ligands is also rate-limiting for erythrocytes, with some contribution of a low membrane permeability. PMID:21808057

  3. IN-VITRO FUSION OF RETICULOCYTE ENDOCYTIC VESICLES WITH LIPOSOMES

    NARCIS (Netherlands)

    VIDAL, M; HOEKSTRA, D

    1995-01-01

    Since reticulocytes have a high demand for iron, which is required for heme biosynthesis, these cells are highly specialized in the endocytosis of the iron carrier transferrin (Tf). From the resulting endocytic vesicles (EVs), iron is released and the vesicles rapidly return to the cell membrane

  4. Sulfanilamide in solution and liposome vesicles; in vitro release and UV-stability studies

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    Sanja Petrović

    2017-12-01

    Full Text Available The main goal of this study was to develop a liposome formulation with sulfanilamide and to investigate the liposomes impact on its release and stability to the UV-A/UV-B and UV-C irradiation. Liposome dispersions with incorporated sulfanilamide were prepared by thin-film hydration method and liposomes role to the sulfanilamide release was investigated by using a dialysis method. Comparatively, sulfanilamide in phosphate buffer solution was subject to release study as well to the UV irradiation providing for the possibilities of kinetics analysis. In vitro drug release study demonstrated that 20% of sulfanilamide was released from liposomes within 1 h that is approximately twice as slower as in the case of dissolved sulfanilamide in phosphate buffer solution. The kinetic release process can be described by Korsmeyer–Peppas model and according to the value of diffusion release exponent it can be concluded that drug release mechanism is based on the phenomenon of diffusion. The sulfanilamide degradation in phosphate buffer solution and liposomes is related to the formation of UV-induced degradation products that are identified by UHPLC/MS analysis as: sulfanilic acid, aniline and benzidine. The UV-induced sulfanilamide degradation in the phosphate buffer solution and liposome vesicles fits the first- order kinetic model. The degradation rate constants are dependent on the involved UV photons energy input as well as sulfanilamide microenvironment. Liposome microenvironment provides better irradiation sulfanilamide stability. The obtained results suggest that liposomes might be promising carriers for delayed sulfanilamide delivery and may serve as a basis for further research.

  5. Block liposomes vesicles of charged lipids with distinctly shaped nanoscale sphere-, pear-, tube-, or rod-segments.

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    Zidovska, Alexandra; Ewert, Kai K; Quispe, Joel; Carragher, Bridget; Potter, Clinton S; Safinya, Cyrus R

    2009-01-01

    We describe the preparation and characterization of block liposomes, a new class of liquid (chain-melted) vesicles, from mixtures of the highly charged (+16 e) multivalent cationic lipid MVLBG2 and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC). Block liposomes (BLs) consist of distinct spherical, tubular vesicles, and cylindrical micelles that remain connected, forming a single liposome. This is in contrast to typical liposome systems, where distinctly shaped liposomes are macroscopically separated. In a narrow composition range (8-10 mol% MVLBG2), an abundance of micrometer-scale BLs (typically sphere-tube-sphere triblocks) is observed. Cryo-TEM reveals that BLs are also present at the nanometer scale, where the blocks consist of distinctly shaped nanoscale spheres, pears, tubes, or rods. Pear-tube diblock and pear-tube-pear triblock liposomes contain nanotubes with inner lumen diameter 10-50 nm. In addition, sphere-rod diblock liposomes are present, containing rigid micellar nanorods approximately 4 nm in diameter and several microm in length. Block liposomes may find a range of applications in chemical and nucleic acid delivery and as building blocks in the design of templates for hierarchical structures.

  6. Liposomes for topical use: a physico-chemical comparison of vesicles prepared from egg or soy lecithin.

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    Budai, Lívia; Kaszás, Nóra; Gróf, Pál; Lenti, Katalin; Maghami, Katayoon; Antal, István; Klebovich, Imre; Petrikovics, Ilona; Budai, Marianna

    2013-01-01

    Developments in nanotechnology and in the formulation of liposomal systems provide the opportunity for cosmetic dermatology to design novel delivery systems. Determination of their physico-chemical parameters has importance when developing a nano-delivery system. The present study highlights some technological aspects/characteristics of liposomes formulated from egg or soy lecithins for topical use. Alterations in the pH, viscosity, surface tension, and microscopic/macroscopic appearance of these vesicular systems were investigated. The chemical composition of the two types of lecithin was checked by mass spectrometry. Caffeine, as a model molecule, was encapsulated into multilamellar vesicles prepared from the two types of lecithin: then zeta potential, membrane fluidity, and encapsulation efficiency were compared. According to our observations, samples prepared from the two lecithins altered the pH in opposite directions: egg lecithin increased it while soy lecithin decreased it with increased lipid concentration. Our EPR spectroscopic results showed that the binding of caffeine did not change the membrane fluidity in the temperature range of possible topical use (measured between 2 and 50 °C). Combining our results on encapsulation efficiency for caffeine (about 30% for both lecithins) with those on membrane fluidity data, we concluded that the interaction of caffeine with the liposomal membrane does not change the rotational motion of the lipid molecules close to the head group region. In conclusion, topical use of egg lecithin for liposomal formulations can be preferred if there are no differences in the physico-chemical properties due to the encapsulated drugs, because the physiological effects of egg lecithin vesicles on skin are significantly better than that of soy lecithin liposomes.

  7. Cholesterol-peptide hybrids to form liposome-like vesicles for gene delivery.

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    Qiong Tang

    Full Text Available In this paper, four amphiphilic cholesterol-peptide conjugates (Ch-R5H5, Ch-R3H3, Ch-R5 and Ch-R5 were designed and synthesized, and their properties in gene delivery were evaluated in vitro with an aim of developing more efficient gene delivery carriers. These amphiphilic cholesterol-peptide conjugates are composed of hydrophobic cholesterol and positively charged peptides. They were able to self-assemble into micelles at low concentrations and their critical micelle concentrations in phosphate buffered saline (pH 7.4 are ≤85 µg/mL. Amphiphilic cholesterol-peptide conjugates condensed DNA more efficiently than a hydrophilic cationic oligoarginine (R10 peptide with no hydrophobic segment. Their transfection efficiencies were at least two orders of magnitude greater than that of R10 peptide in HEK-293 cells. Moreover, the introduction of histidine residues in cholesterol-peptide conjugates led to higher gene expression efficiency compared with cholesterol-peptides without histidine (Ch-R5 and Ch-R3, and the luciferase expression level was comparable or even higher than that induced by PEI at its optimal N/P ratio. In particular, Ch-R5H5 condensed DNA into smaller nanoparticles than Ch-R3H3 at higher N/P ratios, and the minimum size of Ch-R5H5/DNA complexes was 180 nm with zeta potential of 23 mV, achieved at the N/P ratio of 30. This liposome-like vesicle may be a promising gene delivery carrier for intravenous therapy.

  8. Liposomes.

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    Posner, Robert

    2002-09-01

    Robert Posner has 40 years of experience in skin care bench chemistry, product development, and sales and marketing. Working closely with dermatologists and plastic surgeons, Posner is a former member of the NY State Hospital Pharmacists Association, the American Pharmaceutical Association, and the American Association of Hospital Pharmacists. Currently, Posner sits on the Board of Directors of EMDA (Esthetic Manufacturers and Distributors Association). Posner has written numerous articles for Les Nouvelles Esthetiques Magazine, is presently a consultant for Day Spa Magazine, and had been one of only two non-dermatologists on a consultant basis with Cosmetic Dermatology Journal. Posner's company--ABBE Cosmetic Group International in Farmingdale, NY--formulates and manufactures skin care products for many well-known companies in the beauty industry. For many years, both the bench chemist and the dermatologist have been concerned with developing an ideal base for deliverance of 'actives' to the human epidermis. As is common knowledge, the skin is a protective organ which allows very few materials to penetrate. Some bases are unable to work effectively because of their relative inability to penetrate the stratum corneum; for example, some notable actives such as collagen and elastin are molecules too large to penetrate effectively. With the liposome at our command however, we can carry and then release an active into several layers of epidermis. We can release both oil- and water-soluble actives, and at the same time control the feel and effectiveness of a topical application. This article will examine the liposome: what it is, how it works, and how products made with liposomes can benefit dermatology.

  9. Combining gas-phase electrophoretic mobility molecular analysis (GEMMA), light scattering, field flow fractionation and cryo electron microscopy in a multidimensional approach to characterize liposomal carrier vesicles.

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    Urey, Carlos; Weiss, Victor U; Gondikas, Andreas; von der Kammer, Frank; Hofmann, Thilo; Marchetti-Deschmann, Martina; Allmaier, Günter; Marko-Varga, György; Andersson, Roland

    2016-11-20

    For drug delivery, characterization of liposomes regarding size, particle number concentrations, occurrence of low-sized liposome artefacts and drug encapsulation are of importance to understand their pharmacodynamic properties. In our study, we aimed to demonstrate the applicability of nano Electrospray Gas-Phase Electrophoretic Mobility Molecular Analyser (nES GEMMA) as a suitable technique for analyzing these parameters. We measured number-based particle concentrations, identified differences in size between nominally identical liposomal samples, and detected the presence of low-diameter material which yielded bimodal particle size distributions. Subsequently, we compared these findings to dynamic light scattering (DLS) data and results from light scattering experiments coupled to Asymmetric Flow-Field Flow Fractionation (AF4), the latter improving the detectability of smaller particles in polydisperse samples due to a size separation step prior detection. However, the bimodal size distribution could not be detected due to method inherent limitations. In contrast, cryo transmission electron microscopy corroborated nES GEMMA results. Hence, gas-phase electrophoresis proved to be a versatile tool for liposome characterization as it could analyze both vesicle size and size distribution. Finally, a correlation of nES GEMMA results with cell viability experiments was carried out to demonstrate the importance of liposome batch-to-batch control as low-sized sample components possibly impact cell viability. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Liposomes for Topical Use: A Physico-Chemical Comparison of Vesicles Prepared from Egg or Soy Lecithin

    OpenAIRE

    Budai, Lívia; Kaszás, Nóra; Gróf, Pál; Lenti, Katalin; Maghami, Katayoon; Antal, István; Klebovich, Imre; Petrikovics, Ilona; Budai, Marianna

    2013-01-01

    Developments in nanotechnology and in the formulation of liposomal systems provide the opportunity for cosmetic dermatology to design novel delivery systems. Determination of their physico-chemical parameters has importance when developing a nano-delivery system. The present study highlights some technological aspects/characteristics of liposomes formulated from egg or soy lecithins for topical use. Alterations in the pH, viscosity, surface tension, and microscopic/macroscopic appearance of t...

  11. Liposome-encapsulated hemoglobin (hemoglobin-vesicle) is not transferred from mother to fetus at the late stage of pregnancy in the rat model.

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    Kaga, Maiko; Li, Heng; Ohta, Hidenobu; Taguchi, Kazuaki; Ogaki, Shigeru; Izumi, Hitomi; Inagaki, Masumi; Tsuchiya, Shigeru; Okamura, Kunihiro; Otagiri, Masaki; Sakai, Hiromi; Yaegashi, Nobuo

    2012-10-05

    Liposome-encapsulated hemoglobin (hemoglobin vesicles: HbV; diameter 250 nm) is reconstructed from human hemoglobin and developed as an artificial oxygen carrier for use as a transfusion alternative. Previous studies using rodent models closely investigated the safety of daily repeated infusions (DRI) of HbV and reported that the reticuloendothelial system was physiologically capable of degrading HbV to maintain plasma clinical chemistry within normal ranges. The present study examined the effect of DRI of HbV on the pregnant rat mother and fetal development, focusing on placental transfer of HbV in pregnancy. Pregnant rats intravenously received HbV bolus injections at 2 ml/kg/day for the last 7 consecutive days till term. The cumulative infusion volume (14 ml/kg) was equal to 25% of the whole blood volume (56 ml/kg). Maternal DRI of HbV had no obvious side effects on the pregnant mother or on fetal development. Maternal vital signs, plasma clinical chemistry, and blood gas parameters were overall normal after DRI of HbV. In addition, maternal/fetal transfer of HbV was limited to the placenta and HbV did not reach the fetus. Histopathological examination with human hemoglobin antibody detected HbV accumulation in the maternal spleen, liver, kidney, and placenta, but not in the fetuses. These results were also confirmed by a pharmacokinetic study using (125)I-labeled HbV. This safety study of HbV use in the pregnant mother and fetus will contribute to a possible application of HbV as a potential treatment for fetal hypoxia by supplying oxygen through the placenta. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  12. Preparation of large monodisperse vesicles.

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    Ting F Zhu

    Full Text Available Preparation of monodisperse vesicles is important both for research purposes and for practical applications. While the extrusion of vesicles through small pores (approximately 100 nm in diameter results in relatively uniform populations of vesicles, extrusion to larger sizes results in very heterogeneous populations of vesicles. Here we report a simple method for preparing large monodisperse multilamellar vesicles through a combination of extrusion and large-pore dialysis. For example, extrusion of polydisperse vesicles through 5-microm-diameter pores eliminates vesicles larger than 5 microm in diameter. Dialysis of extruded vesicles against 3-microm-pore-size polycarbonate membranes eliminates vesicles smaller than 3 microm in diameter, leaving behind a population of monodisperse vesicles with a mean diameter of approximately 4 microm. The simplicity of this method makes it an effective tool for laboratory vesicle preparation with potential applications in preparing large monodisperse liposomes for drug delivery.

  13. Liposome: classification, preparation, and applications

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    Akbarzadeh, Abolfazl; Rezaei-Sadabady, Rogaie; Davaran, Soodabeh; Joo, Sang Woo; Zarghami, Nosratollah; Hanifehpour, Younes; Samiei, Mohammad; Kouhi, Mohammad; Nejati-Koshki, Kazem

    2013-02-01

    Liposomes, sphere-shaped vesicles consisting of one or more phospholipid bilayers, were first described in the mid-60s. Today, they are a very useful reproduction, reagent, and tool in various scientific disciplines, including mathematics and theoretical physics, biophysics, chemistry, colloid science, biochemistry, and biology. Since then, liposomes have made their way to the market. Among several talented new drug delivery systems, liposomes characterize an advanced technology to deliver active molecules to the site of action, and at present, several formulations are in clinical use. Research on liposome technology has progressed from conventional vesicles to `second-generation liposomes', in which long-circulating liposomes are obtained by modulating the lipid composition, size, and charge of the vesicle. Liposomes with modified surfaces have also been developed using several molecules, such as glycolipids or sialic acid. This paper summarizes exclusively scalable techniques and focuses on strengths, respectively, limitations in respect to industrial applicability and regulatory requirements concerning liposomal drug formulations based on FDA and EMEA documents.

  14. Physicochemical characteristics of liposomes are decisive for their antirestenosis efficacy following local delivery.

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    Haeri, Azadeh; Sadeghian, Saeed; Rabbani, Shahram; Shirani, Shapour; Anvari, Maryam Sotoudeh; Dadashzadeh, Simin

    2017-01-01

    To develop an ameliorated sirolimus (SIR) liposome for intramural delivery, the effects of various carrier physicochemical parameters on the antirestenosis efficacy were evaluated. Different liposomes were prepared, characterized and administered to balloon injured rats (12 animal groups). Their efficacies were investigated using morphometric, immunohistochemical and in vivo computed tomography imaging analyses. The antirestenosis efficacy of SIR liposomes decreased in the following order: cationic 100 nm vesicles ≥ cationic 60 nm vesicles > neutral 100 nm vesicles ≥ stealth 100 nm vesicles > anionic 100 nm vesicles. The 100 µg SIR loaded in cationic liposomes showed almost no artery stenosis. Appropriate modulation of physicochemical characteristics makes it possible to optimize the liposomes for local delivery.

  15. Microfluidic-enabled liposomes elucidate size-dependent transdermal transport.

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    Renee R Hood

    Full Text Available Microfluidic synthesis of small and nearly-monodisperse liposomes is used to investigate the size-dependent passive transdermal transport of nanoscale lipid vesicles. While large liposomes with diameters above 105 nm are found to be excluded from deeper skin layers past the stratum corneum, the primary barrier to nanoparticle transport, liposomes with mean diameters between 31-41 nm exhibit significantly enhanced penetration. Furthermore, multicolor fluorescence imaging reveals that the smaller liposomes pass rapidly through the stratum corneum without vesicle rupture. These findings reveal that nanoscale liposomes with well-controlled size and minimal size variance are excellent vehicles for transdermal delivery of functional nanoparticle drugs.

  16. Temoporfin-loaded liposomes

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Freisleben, Ines; Steiniger, Frank

    2010-01-01

    Temoporfin (mTHPC) is a potent but highly hydrophobic second-generation photosensitizer and has been approved for the palliative treatment of patients with advanced head and neck cancer by photodynamic therapy. Liposome formulations have been evaluated as carrier system for this drug to overcome ...... investigations indicate the presence of micellar structures in addition to vesicles. Lyophilization and reconstitution led to an alteration in the morphology but had overall no distinct influence on the colloidal stability....... calorimetry and cryo-electron microscopy. Incorporation of temoporfin resulted in a distinct concentration dependent decrease of the main phase transition of the liposomes. In case of liposomes based on dipalmitoylphosphatidylcholine/-glycerol, phase transition was close or even below body temperature...

  17. On the use of liposome controls in studies investigating the clinical potential of extracellular vesicle-based drug delivery systems - A commentary

    DEFF Research Database (Denmark)

    Johnsen, Kasper Bendix; Gudbergsson, Johann Mar; Duroux, Meg

    2018-01-01

    The field of extracellular vesicle (EV)-based drug delivery systems has evolved significantly through the recent years, and numerous studies suggest that these endogenous nanoparticles can function as efficient drug delivery vehicles in a variety of diseases. Many characteristics of these EV...

  18. Penetration of tamoxifen citrate loaded ethosomes and liposomes across human skin: a comparative study with confocal laser scanning microscopy.

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    Sarwa, Khomendra K; Suresh, Preeti K; Rudrapal, Mithun; Verma, Vinod K

    2014-01-01

    In the present study, ethosomal and liposomal formulations containing tamoxifen citrate were prepared and evaluated for their penetration properties in human cadaver skin using Franz diffusion cell and confocal laser scanning microscope (CLSM). The results clearly revealed that ethosomal vesicles showed a better drug permeation profile than that of liposomal vesicles. In addition, low fluorescence intensity in CLSM was recorded with liposomes as compared to ethosomes, indicating lower cumulative amount of drug permeation from liposomal vesicles. Furthermore, CLSM showed uniform fluorescence intensity across the entire depth of skin in ethosomal treatment, indicating high penetrability of ethosomal vesicles through human cadaver skin. In contrast, low penetrability of conventional liposomal vesicles was recorded as penetration was limited to the 7(th) section (i.e. upper epidermis layer) of skin as evident from visualization of intact liposomal vesicles in CLSM.

  19. Biological Responsiveness and Metabolic Performance of Liposome-Encapsulated Hemoglobin (Hemoglobin-Vesicles) in Apolipoprotein E-Deficient Mice after Massive Intravenous Injection.

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    Taguchi, Kazuaki; Nagao, Saori; Yamasaki, Keishi; Sakai, Hiromi; Seo, Hakaru; Maruyama, Toru; Otagiri, Masaki

    2015-01-01

    The hemoglobin-vesicle (HbV), a vesicle in which a concentrated human hemoglobin solution is encapsulated, was developed as an artificial oxygen carrier. Although HbV has a favorable safety, metabolic, and excretion performance in healthy animals, the effect of a massive amount of HbV, which also contains a large amount of a lipid component including cholesterol, on physiological response and metabolic performance under hyperlipidemic conditions is unclear. The aim of this study was to evaluate whether administration of HbV causes toxicity in apolipoprotein E-deficient mice (hyperlipidemic model mice). Apolipoprotein E-deficient mice were given a single injection of HbV (2000 mg hemoglobin/kg), and physiological responses and metabolic profiles were monitored for 14 d thereafter. All the mice tolerated the massive amount of HbV and survived, and adequate biocompatibility was observed. Serum biochemical parameters indicate that liver and kidney function were not remarkably affected, and morphological changes in the liver and spleen were negligible. Lipid parameters in serum were significantly increased until 3 d after HbV administration, but recovered within 7 d after the administration. In a pharmacokinetic study, HbV was mainly found distributed in the liver and spleen, and disappeared from the body within 14 d. In conclusion, even under conditions of hyperlipidemia, a massive dose of HbV and its components resulted in favorable biological compatibility, metabolic, and excretion profiles. These findings provide further support for the safety of HbV for clinical use.

  20. Potential Effect of Liposomes and Liposome-Encapsulated Botulinum Toxin and Tacrolimus in the Treatment of Bladder Dysfunction

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    Joseph J. Janicki

    2016-03-01

    Full Text Available Bladder drug delivery via catheter instillation is a widely used treatment for recurrence of superficial bladder cancer. Intravesical instillation of liposomal botulinum toxin has recently shown promise in the treatment of overactive bladder and interstitial cystitis/bladder pain syndrome, and studies of liposomal tacrolimus instillations show promise in the treatment of hemorrhagic cystitis. Liposomes are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core that can encapsulate hydrophilic and hydrophobic drug molecules to be delivered to cells via endocytosis. This review will present new developments on instillations of liposomes and liposome-encapsulated drugs into the urinary bladder for treating lower urinary tract dysfunction.

  1. Propylene glycol liposomes as a topical delivery system for miconazole nitrate: comparison with conventional liposomes.

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    Elmoslemany, Riham M; Abdallah, Ossama Y; El-Khordagui, Labiba K; Khalafallah, Nawal M

    2012-06-01

    Propylene glycol (PG)-phospholipid vesicles have been advocated as flexible lipid vesicles for enhanced skin delivery of drugs. To further characterize the performance of these vesicles and to address some relevant pharmaceutical issues, miconazole nitrate(MN)-loaded PG nanoliposomes were prepared and characterized for vesicle size, entrapment efficiency, in vitro release, and vesicle stability. An issue of pharmaceutical importance is the time-dependent, dilution-driven diffusion of propylene glycol out of the vesicles. This was addressed by assessing propylene glycol using gas chromatography in the separated vesicles and monitoring its buildup in the medium after repeated dispersion of separated vesicles in fresh medium. Further, the antifungal activity of liposomal formulations under study was assessed using Candida albicans, and their in vitro skin permeation and retention were studied using human skin. At all instances, blank and drug-loaded conventional liposomes were included for comparison. The results provided evidence of controlled MN delivery, constant percent PG uptake in the vesicles (≈45.5%) in the PG concentration range 2.5 to 10%, improved vesicle stability, and enhanced skin deposition of MN with minimum skin permeation. These are key issues for different formulation and performance aspects of propylene glycol-phospholipid vesicles.

  2. Recent advances and perspectives in liposomes for cutaneous drug delivery.

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    Caritá, Amanda C; Eloy, Josimar O; Chorilli, Marlus; Lee, Robert J; Leonardi, Gislaine Ricci

    2017-10-09

    The cutaneous route is attractive for the delivery of drugs in the treatment of a wide variety of diseases. However the stratum corneum (SC) is an effective barrier that hampers skin penetration. Within this context, liposomes emerge as a potential carrier for improving topical delivery of therapeutic agents. In this review, we aimed to discuss key aspects for the topical delivery by drug-loaded liposomes. Phospholipid type and phase transition temperature have been shown to affect liposomal topical delivery. The effect of surface charge is subject to considerable variation depending on drug and composition. In addition, modified vesicles with the presence of components for permeation enhancement, such as surfactants and solvents, have been shown to have a considerable effect. These liposomes include: Transfersomes, Niosomes, Ethosomes, Transethosomes, Invasomes, coated liposomes, penetration enhancer containing vesicles (PEVs), fatty acids vesicles, Archaeosomes and Marinosomes. Furthermore, adding polymeric coating onto liposome surface could influence cutaneous delivery. Mechanisms of delivery include intact vesicular skin penetration, free drug diffusion, permeation enhancement, vesicle adsorption to and/or fusion with the SC, trans-appendageal penetration, among others. Finally, several skin conditions, including acne, melasma, skin aging, fungal infections and skin cancer, have benefited from liposomal topical delivery of drugs, with promising in vitro and in vivo results. However, despite the existence of some clinical trials, more studies are needed to be conducted in order to explore the potential of liposomes in the dermatological field. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Filter-extruded liposomes revisited

    DEFF Research Database (Denmark)

    Hinna, Askell; Steiniger, Frank; Hupfeld, Stefan

    2016-01-01

    (pore-size, number of filter passages, and flow-rate), flow field-flow fractionation in conjunction with multi-angle laser light scattering (AF4-MALLS, Wyatt Technology Corp., Santa Barbara, CA) was employed. Liposome size-distributions determined by AF4-MALLS were compared with those of dynamic light...... scattering and correlated with cryo-transmission electron microscopy and 31P-NMR-analysis of lamellarity. Both the mean size of liposome and the width of size distribution were found to decrease with sequential extrusion through smaller pore size filters, starting at a size range of &70–415nm upon repeated...... extrusion through 400nm pore-filters, eventually ending with a size range from &30 to 85nm upon extrusion through 30nm pore size filters. While for small pores sizes (50 nm), increased flow rates resulted in smaller vesicles, no significant influence of flow rate on mean vesicle size was seen with larger...

  4. Reconstitution of lipid vesicles associated with HVJ (Sendai virus) sikes. Purification and some properties of vesicles containing nontoxic fragment A of diphtheria toxin

    Science.gov (United States)

    1979-01-01

    A mixture of HVJ (Sendai virus) spike proteins, the nontoxic fragment A of diphtheria toxin, lecithin, and cholesterol was solubilized in sucrose solution containing a nonionic neutral detergent. The liposomal vesicles which formed on removal of the detergent by dialysis were purified by gel filtration and centrifugation on a sucrose gradient. The resulting purified vesicles had hemagglutinating activity, hemolytic activity and, after solubilization, the enzymic activity of fragment A. The vesicles had no cell fusion activity. Electron microscopy showed that both the outside and inside of membranes of the vesicles were associated with the spikes. When the vesicles were freeze- fractured, no large aggregates of particles were seen on either face. Such fragment A-containing lipid vesicles (liposomes) with HVJ spikes bound to mamalian cell membrane and released their fragment A into the cytoplasm causing cell death. Neither fragment A-containing liposomes without spikes nor empty liposomes with spikes were toxic. PMID:217880

  5. Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography

    DEFF Research Database (Denmark)

    Franzen, Ulrik; Østergaard, Jesper

    2012-01-01

    of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the characterization......Liposomes are self-assembled phospholipid vesicles and have numerous research and therapeutic applications. In the pharmaceutical and biomedical sciences liposomes find use as models of biological membranes, partitioning medium and as drug carriers. The present review addresses the use of capillary...... of liposome drug delivery systems, e.g., for the investigation of encapsulation efficiency and drug leakage. The well-known characteristics of capillary electrophoresis, i.e., low sample volume requirement, high separation efficiency in aqueous media without a stationary phase, minimal sample preparation...

  6. Real-time observation of liposome bursting induced by acetonitrile.

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    Yoshida, Kazunari; Horii, Keitaro; Fujii, Yasuhiro; Nishio, Izumi

    2014-10-06

    We show the bursting process of dioleoylphosphatidylcholine (DOPC) liposomes in response to the addition of acetonitrile, a small toxic molecule widely used in the fields of chemistry and industry. The percentage of destroyed liposomes is reduced upon decreasing the acetonitrile fraction in the aqueous solution and vesicle bursting is not observed at volume ratios of 4:6 and below. This indicates that a high fraction of acetonitrile causes the bursting of liposomes, and it is proposed that this occurs through insertion of the molecules into outer leaflet of the lipid bilayer. The elapsed time between initial addition of acetonitrile and liposome bursting at each vesicle is also measured and demonstrated to be dependent on the volume fraction of acetonitrile and the vesicle size. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Vesicle Photonics

    Science.gov (United States)

    Vasdekis, A. E.; Scott, E. A.; Roke, S.; Hubbell, J. A.; Psaltis, D.

    2013-07-01

    Amphiphiles, under appropriate conditions, can self-assemble into nanoscale thin membrane vessels (vesicles) that encapsulate and hence protect and transport molecular payloads. Vesicles assemble naturally within cells but can also be artificially synthesized. In this article, we review the mechanisms and applications of light-field interactions with vesicles. By being associated with light-emitting entities (e.g., dyes, fluorescent proteins, or quantum dots), vesicles can act as imaging agents in addition to cargo carriers. Vesicles can also be optically probed on the basis of their nonlinear response, typically from the vesicle membrane. Light fields can be employed to transport vesicles by using optical tweezers (photon momentum) or can directly perturb the stability of vesicles and hence trigger the delivery of the encapsulated payload (photon energy). We conclude with emerging vesicle applications in biology and photochemical microreactors.

  8. Ethosomes and liposomes as topical vehicles for azelaic acid: a preformulation study.

    Science.gov (United States)

    Esposito, Elisabetta; Menegatti, Enea; Cortesi, Rita

    2004-01-01

    The basic properties and the in vitro release rate kinetics of azelaic acid (AA), alternatively vehiculated in different phospholipid-based vesicles such as ethosomes or liposomes, were investigated. Ethosomes were produced by a simple method based on addition of an aqueous phase to an ethanol solution (comprised between 20\\% and 45%, v/v) of soy phosphatidyl choline (5%, w/w) and AA (0.2%, w/w) under mechanical stirring. Liposomes were obtained by the same composition in the absence of ethanol with the reverse-phase evaporation method. Vesicle size was measured by photon correlation spectroscopy (PCS), evidencing smaller mean diameters and narrower dimensional distributions in the case of ethosomes with respect to liposomes. In order to obtain homogeneously sized vesicles, both ethosomal and liposomal dispersions were extruded through polycarbonate membranes with pores of calibrated diameter (400 nm and 200 nm). Vesicle morphology was characterized by freeze-fracture scanning electron microscopy (SEM) showing the presence of unilamellar vesicles both in liposome- and in ethosome-based dispersions. Free energy measurements of the vesicle bilayers were conducted by differential scanning calorimetry (DSC). AA diffusion from ethosomal or liposomal dispersions and from ethosomes and liposomes incorporated in a viscous gel was investigated by a Franz cell assembled with synthetic membranes. The release rate was more rapid from ethosomal systems than from liposomal systems. In particular, ethosomes produced by the highest ethanol concentration released AA more rapidly, and the same trend was found using viscous forms.

  9. Amyloglucosidase enzymatic reactivity inside lipid vesicles

    Directory of Open Access Journals (Sweden)

    Kim Jin-Woo

    2007-10-01

    Full Text Available Abstract Efficient functioning of enzymes inside liposomes would open new avenues for applications in biocatalysis and bioanalytical tools. In this study, the entrapment of amyloglucosidase (AMG (EC 3.2.1.3 from Aspergillus niger into dipalmitoylphosphatidylcholine (DPPC multilamellar vesicles (MLVs and large unilamellar vesicles (LUVs was investigated. Negative-stain, freeze-fracture, and cryo-transmission electron microscopy images verified vesicle formation in the presence of AMG. Vesicles with entrapped AMG were isolated from the solution by centrifugation, and vesicle lamellarity was identified using fluorescence laser confocal microscopy. The kinetics of starch hydrolysis by AMG was modeled for two different systems, free enzyme in aqueous solution and entrapped enzyme within vesicles in aqueous suspension. For the free enzyme system, intrinsic kinetics were described by a Michaelis-Menten kinetic model with product inhibition. The kinetic constants, Vmax and Km, were determined by initial velocity measurements, and Ki was obtained by fitting the model to experimental data of glucose concentration-time curves. Predicted concentration-time curves using these kinetic constants were in good agreement with experimental measurements. In the case of the vesicles, the time-dependence of product (glucose formation was experimentally determined and simulated by considering the kinetic behavior of the enzyme and the permeation of substrate into the vesicle. Experimental results demonstrated that entrapped enzymes were much more stable than free enyzme. The entrapped enzyme could be recycled with retention of 60% activity after 3 cycles. These methodologies can be useful in evaluating other liposomal catalysis operations.

  10. Unilamellar liposomes with enhanced boron content.

    Science.gov (United States)

    Li, Tiejun; Hamdi, Julie; Hawthorne, M Frederick

    2006-01-01

    A new type of boron-rich, DSPC-free, unilamellar liposomes was formed using the novel dual-chain, ionic, nido-carborane lipid, K[nido-7-(C16H33OCH2)2CHOCH2-7,8-C2B9H11] (DAC-16), and cholesterol for encapsulation of an aqueous buffer core. Since DSPC was not necessary for the formation of stable DAC-16 liposomes, the boron concentration of these vesicles was increased dramatically to approximately 8.8 wt % in the dry lipid; these liposomes had a high bilayer boron incorporation efficiency of 98%. DSPC-free liposomes exhibited a size distribution pattern of 40-60 nm, which was in the range normally associated with selective tumor uptake. This size distribution was maintained throughout storage at room temperature for several months. Additionally, optimized liposome formulations incorporating DAC-16, DSPC, and cholesterol were identified having stable size distribution patterns after storage for more than two months at a variety of temperatures. Although animal studies indicate that DAC-16 liposomes are toxic, this new ionic nido-carborane lipid allows the formation of liposomes of high boron content for in vitro applications that require the delivery of large amounts of boron.

  11. Morphological and topological transformations of lipid bilayer vesicles

    Science.gov (United States)

    Nomura, Fumimasa; Honda, Makoto; Takeda, Shuichi; Umeda, Tamiki; Takiguchi, Kingo; Hotani, Hirokazu

    2000-06-01

    Liposomes are the micro compartments made of lipid bilayer membrane of which characteristics are quite similar to those of biological membrane. To form artificial cell-like structure, we made liposomes that contained subunit of cytoskeletons: tubulin or actin. Spherical liposomes were transformed into bipolar or cell-like shape by mechanical force generated by the polymerization of encapsulated subunits of microtubules. Disk or dumbbell shape was generated by the polymerization of encapsulated action. Dynamic processes of morphological transformations of liposomes were visualized by the high intensity dark-field light microscopy. Topological changes such as fusion and division of membrane vesicles also play an essential role in cellular activities. We investigated the mechanism of these topological transformations by visualizing their real-time processes. A variety of novel topological transformations were found, including the opening-up of liposomes and the direct expulsion of inner vesicles. .

  12. Stimuli-Responsive Liposomes for Controlled Drug Delivery

    KAUST Repository

    Li, Wengang

    2014-09-01

    Liposomes are promising drug delivery vesicles due to their biodegradibility, large volume and biocompatibility towards both hydrophilic and hydrophobic drugs. They suffer, however, from poor stability which limits their use in controlled delivery applications. Herein, a novel method was devised for modification of liposomes with small molecules, polymers or nanoparticles to afford stimuli responsive systems that release on demand and stay relatively stable in the absence of the trigger.. This dissertation discusses thermosensitive, pH sensitive, light sensitive and magnetically triggered liposomes that have been prepared for controlled drug delivery application. RAFT polymerization was utilized for the preparation of thermosensitive liposomes (Cholesterol-PNIPAm) and acid-labile liposomes (DOPE-PAA). With low Mw Cholesterol-PNIPAm, the thermosensitive liposomes proved to be effective for controlled release and decreased the cytotoxicity of PNIPAm by eliciting the polymer doses. By crosslinking the DOPE-PAA on liposome surface with acid-labile diamine linkers, DOPE-PAA liposomes were verified to be sensitive at low pH. The effects of polymer structures (linear or hyperbranched) have also been studied for the stability and release properties of liposomes. Finally, a dual-responsive Au@SPIO embedded liposome hybrid (ALHs) was prepared with light-induced “on-and-off” function by photo-thermal process (visible light) and instant release properties triggered by alternating magnetic field, respectively. The ALH system would be further applied into the cellular imaging field as MRI contrast agent.

  13. Factors affecting liposomes particle size prepared by ethanol injection method.

    Science.gov (United States)

    Shaker, Sherif; Gardouh, Ahmed Rifaat; Ghorab, Mamdouh Mostafa

    2017-10-01

    Ethanol injection is one of the techniques frequently used to produce liposomes which favors both simplicity and safety. In this process, an ethanolic solution of lipids is rapidly injected into an aqueous medium through a needle, dispersing the phospholipids throughout the medium and promoting the vesicle formation. Being a critical parameter that determines the fate of liposome and its distribution, we studied different factors affecting the particle size of liposomes including different phospholipid (Phosal® 53 MCT) and cholesterol concentrations and the use of different types of non-ionic surfactants at fixed Phosal® 53 MCT concentration of 50 mg per formulation. Both Phosal® 53 MCT and cholesterol concentration had direct effect on liposomes particle size. Non-ionic surfactants produced liposomes of smaller particle size when compared to conventional liposomes formed using Phosal® 53 MCT 300 mg per formulation only, whereas this effect was diminished when higher Phosal® 53 MCT to cholesterol ratios were used that obviously increased liposomes size. Smaller liposomes sizes were obtained upon using non-ionic surfactants of lower hydrophilic/hydrophobic balance (HLB) as both Tween 80 and Cremophor RH 40 produced liposomes of smaller particle size compared to Poloxamer 407. The smallest liposomes particle size was successfully obtained in the formulation comprising 300 mg Phosal® MCT, 150 mg cholesterol and 50 mg Tween 80.

  14. Bladder uptake of liposomes after intravesical administration occurs by endocytosis.

    Directory of Open Access Journals (Sweden)

    Bharathi Raja Rajaganapathy

    Full Text Available Liposomes have been used therapeutically and as a local drug delivery system in the bladder. However, the exact mechanism for the uptake of liposomes by bladder cells is unclear. In the present study, we investigated the role of endocytosis in the uptake of liposomes by cultured human UROtsa cells of urothelium and rat bladder. UROtsa cells were incubated in serum-free media with liposomes containing colloidal gold particles for 2 h either at 37°C or at 4°C. Transmission Electron Microscopy (TEM images of cells incubated at 37°C found endocytic vesicles containing gold inside the cells. In contrast, only extracellular binding was noticed in cells incubated with liposomes at 4°C. Absence of liposome internalization at 4°C indicates the need of energy dependent endocytosis as the primary mechanism of entry of liposomes into the urothelium. Flow cytometry analysis revealed that the uptake of liposomes at 37°C occurs via clathrin mediated endocytosis. Based on these observations, we propose that clathrin mediated endocytosis is the main route of entry for liposomes into the urothelial layer of the bladder and the findings here support the usefulness of liposomes in intravesical drug delivery.

  15. Evaluation of the physicochemical properties of liposomes as potential carriers of anticancer drugs: spectroscopic study

    Science.gov (United States)

    Pentak, Danuta

    2016-05-01

    Vesicle size and composition are a critical parameter for determining the circulation half-life of liposomes. Size influences the degree of drug encapsulation in liposomes. The geometry, size, and properties of liposomes in an aqueous environment have to be described to enable potential applications of liposome systems as drug carriers. The characteristics of multiple thermotropic phase transitions are also an important consideration in liposomes used for analytical and bioanalytical purposes. The aim of this study was to evaluate the physicochemical properties of liposomes which accommodate hydrophilic and amphiphilic drugs used in cancer therapy. The studied liposomes were prepared with the involvement of the modified reverse-phase evaporation method (mREV). The prepared liposomes had a diameter of 70-150 nm. The analyzed compounds were 1-β- d-arabinofuranosylcytosine, cyclophosphamide, and ifosfamide. In literature, there is no information about simultaneous incorporation of cytarabine, ifosfamide, and cyclophosphamide, in spite of the fact that these drugs have been used for more than 30 years. A combination of the examined drugs is used in CODOX-M/IVAC therapy. CODOX-M/IVAC (cyclophosphamide, doxorubicin, high-dose methotrexate/ifosfamide, etoposide, and high-dose cytarabine) is one of the currently preferred intensive-dose chemotherapy regimens for Burkitt lymphoma (BL). The present research demonstrates the pioneering studies of incorporation of ifosfamide into liposome vesicles, location of and competition between the analyzed drugs and liposome vesicles. The applied methods were nuclear magnetic resonance (NMR), atomic force microscopy (AFM), differential scanning calorimetry (DSC).

  16. Placing and shaping liposomes with reconfigurable DNA nanocages

    Science.gov (United States)

    Zhang, Zhao; Yang, Yang; Pincet, Frederic; C. Llaguno, Marc; Lin, Chenxiang

    2017-07-01

    The diverse structure and regulated deformation of lipid bilayer membranes are among a cell's most fascinating features. Artificial membrane-bound vesicles, known as liposomes, are versatile tools for modelling biological membranes and delivering foreign objects to cells. To fully mimic the complexity of cell membranes and optimize the efficiency of delivery vesicles, controlling liposome shape (both statically and dynamically) is of utmost importance. Here we report the assembly, arrangement and remodelling of liposomes with designer geometry: all of which are exquisitely controlled by a set of modular, reconfigurable DNA nanocages. Tubular and toroid shapes, among others, are transcribed from DNA cages to liposomes with high fidelity, giving rise to membrane curvatures present in cells yet previously difficult to construct in vitro. Moreover, the conformational changes of DNA cages drive membrane fusion and bending with predictable outcomes, opening up opportunities for the systematic study of membrane mechanics.

  17. Plasmon resonant liposomes for controlled drug delivery

    Science.gov (United States)

    Knights-Mitchell, Shellie S.; Romanowski, Marek

    2015-03-01

    Nanotechnology use in drug delivery promotes a reduction in systemic toxicity, improved pharmacokinetics, and better drug bioavailability. Liposomes continue to be extensively researched as drug delivery systems (DDS) with formulations such as Doxil® and Ambisome® approved by FDA and successfully marketed in the United States. However, the limited ability to precisely control release of active ingredients from these vesicles continues to challenge the broad implementation of this technology. Moreover, the full potential of the carrier to sequester drugs until it can reach its intended target has yet to be realized. Here, we describe a liposomal DDS that releases therapeutic doses of an anticancer drug in response to external stimulus. Earlier, we introduced degradable plasmon resonant liposomes. These constructs, obtained by reducing gold on the liposome surface, facilitate spatial and temporal release of drugs upon laser light illumination that ultimately induces an increase in temperature. In this work, plasmon resonant liposomes have been developed to stably encapsulate and retain doxorubicin at physiological conditions represented by isotonic saline at 37o C and pH 7.4. Subsequently, they are stimulated to release contents either by a 5o C increase in temperature or by laser illumination (760 nm and 88 mW/cm2 power density). Successful development of degradable plasmon resonant liposomes responsive to near-infrared light or moderate hyperthermia can provide a new delivery method for multiple lipophilic and hydrophilic drugs with pharmacokinetic profiles that limit clinical utility.

  18. Liposomes- and ethosomes-associated distamycins: a comparative study.

    Science.gov (United States)

    Cortesi, Rita; Romagnoli, Romeo; Drechsler, Markus; Menegatti, Enea; Zaid, Abdel N; Ravani, Laura; Esposito, Elisabetta

    2010-12-01

    The present article describes a comparative study of the performances of liposomes and ethosomes as specialized delivery systems for distamycin A (DA) and two of its derivatives. Liposomes and ethosomes were prepared by classical methods, extruded through polycarbonate filters, and characterized in terms of dimensions, morphology, and encapsulation efficiency. It was found that DA was associated with vesicles (either liposomes or ethosomes) by around 16.0%, while both derivatives of DA showed a percentage of association around 80% in the case of liposomes and around 50% in the case of ethosomes. In vitro antiproliferative activity experiments performed on cultured human and mouse leukemic cells demonstrated that vesicles were able to increase the activity of both derivatives of DA. In addition, it was demonstrated that the aging of both liposomes- and ethosomes-associated distamycin suspensions did not heavily influence the vesicle size, while all samples showed a relevant drug leakage with time. Moreover, according to the different physicochemical characteristics of DA and its derivatives (i.e., log P), vesicle-associated DA showed the highest loss of drug with respect to both its derivatives. In conclusion, the enhancement of drug activity expressed by these specialized delivery systems-associated DD could be interesting to obtain an efficient therapeutic effect aimed at reducing or minimizing toxic effects occurring with distamycins administration.

  19. The impact of metal complex lipids on viscosity and curvature of hybrid liposomes.

    Science.gov (United States)

    Ohtani, Ryo; Tokita, Tsukasa; Takaya, Tomohisa; Iwata, Koichi; Kinoshita, Masanao; Matsumori, Nobuaki; Nakamura, Masaaki; Lindoy, Leonard F; Hayami, Shinya

    2017-12-12

    A morphology transformation of hybrid liposomes was shown to occur from spherical vesicles to tubular micelles when increasing the ratio of the metal complex lipid present. Phase transition temperatures increased while viscosities decreased, indicating that the hybrids exhibit stronger interaction between heads but weaker interaction between alkyl chains than occurs in pristine liposomes.

  20. Rupture Pathway of Phosphatidylcholine Liposomes on Silicon Dioxide

    Directory of Open Access Journals (Sweden)

    Fredrik Höök

    2009-04-01

    Full Text Available We have investigated the pathway by which unilamellar POPC liposomes upon adsorption undergo rupture and form a supported lipid bilayer (SLB on a SiO2 surface. Biotinylated lipids were selectively incorporated in the outer monolayer of POPC liposomes to create liposomes with asymmetric lipid compositions in the outer and inner leaflets. The specific binding of neutravidin and anti-biotin to SLBs formed by liposome fusion, prior to and after equilibrated flip-flop between the upper and lower monolayers in the SLB, were then investigated. It was concluded that the lipids in the outer monolayer of the vesicle predominantly end up on the SLB side facing the SiO2 substrate, as demonstrated by having maximum 30-40% of lipids in the liposome outer monolayer orienting towards the bulk after forming the SLB.

  1. Liposomal Formulations in Clinical Use: An Updated Review

    Directory of Open Access Journals (Sweden)

    Upendra Bulbake

    2017-03-01

    Full Text Available Liposomes are the first nano drug delivery systems that have been successfully translated into real-time clinical applications. These closed bilayer phospholipid vesicles have witnessed many technical advances in recent years since their first development in 1965. Delivery of therapeutics by liposomes alters their biodistribution profile, which further enhances the therapeutic index of various drugs. Extensive research is being carried out using these nano drug delivery systems in diverse areas including the delivery of anti-cancer, anti-fungal, anti-inflammatory drugs and therapeutic genes. The significant contribution of liposomes as drug delivery systems in the healthcare sector is known by many clinical products, e.g., Doxil®, Ambisome®, DepoDur™, etc. This review provides a detailed update on liposomal technologies e.g., DepoFoam™ Technology, Stealth technology, etc., the formulation aspects of clinically used products and ongoing clinical trials on liposomes.

  2. Deformable liposomes and ethosomes: mechanism of enhanced skin delivery.

    Science.gov (United States)

    Elsayed, Mustafa M A; Abdallah, Ossama Y; Naggar, Viviane F; Khalafallah, Nawal M

    2006-09-28

    Despite intensive research, the mechanisms by which vesicular systems deliver drugs into intact skin are not yet fully understood. In the current study, possible mechanisms by which deformable liposomes and ethosomes improve skin delivery of ketotifen under non-occlusive conditions were investigated. In vitro permeation and skin deposition behavior of deformable liposomes and ethosomes, having ketotifen both inside and outside the vesicles (no separation of free ketotifen), having ketotifen only inside the vesicles (free ketotifen separated) and having ketotifen only outside the vesicles (ketotifen solution added to empty vesicles), was studied using rabbit pinna skin. Results suggested that both the penetration enhancing effect and the intact vesicle permeation into the stratum corneum might play a role in improving skin delivery of drugs by deformable liposomes, under non-occlusive conditions, and that the penetration enhancing effect was of greater importance in case of ketotifen. Regarding ethosomes, results indicated that ketotifen should be incorporated in ethosomal vesicles for optimum skin delivery. Ethosomes were not able to improve skin delivery of non-entrapped ketotifen.

  3. Hybrid, Nanoscale Phospholipid/Block Copolymer Vesicles

    Directory of Open Access Journals (Sweden)

    Bo Liedberg

    2013-09-01

    Full Text Available Hybrid phospholipid/block copolymer vesicles, in which the polymeric membrane is blended with phospholipids, display interesting self-assembly behavior, incorporating the robustness and chemical versatility of polymersomes with the softness and biocompatibility of liposomes. Such structures can be conveniently characterized by preparing giant unilamellar vesicles (GUVs via electroformation. Here, we are interested in exploring the self-assembly and properties of the analogous nanoscale hybrid vesicles (ca. 100 nm in diameter of the same composition prepared by film-hydration and extrusion. We show that the self-assembly and content-release behavior of nanoscale polybutadiene-b-poly(ethylene oxide (PB-PEO/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC hybrid phospholipid/block copolymer vesicles can be tuned by the mixing ratio of the amphiphiles. In brief, these hybrids may provide alternative tools for drug delivery purposes and molecular imaging/sensing applications and clearly open up new avenues for further investigation.

  4. A liposome-based size calibration method for measuring microvesicles by flow cytometry.

    Science.gov (United States)

    Simonsen, J B

    2016-01-01

    ESSENTIALS: A gold standard to determine the sizes of microvesicles by flow cytometry is needed. We used fluorescently labeled liposomes to estimate the size of microvesicles with flow cytometry. We suggest that liposomes are more accurate size calibrators than the commonly used polystyrene beads. The liposome-based size calibrators improve the size assessment of microvesicle made with flow cytometry. During the past years, the need for a gold standard to determine the sizes of extracellular vesicles including microvesicles by flow cytometry has been emphasized. This work suggests that artificial vesicles can be used as calibrators to estimate the size of microvesicles from the side scattering (SSC) measured with flow cytometry. We prepared fluorescently labeled liposomes with different maximum sizes defined by the pore size (200, 400, 800, and 1000 nm) of the membrane used for the extrusion. The fluorescence strengths from the largest liposomes pertaining to each pore size enabled us to verify the correlation between the SSC from a liposome and the corresponding size. This study indicates that artificial vesicles are more accurate size calibrators compared to the commonly used polystyrene calibrator beads illustrated by the SSC from 110 nm polystyrene beads corresponds to the scattering from ~400 nm vesicle-like particles. We also show that this method of size assessment based on SSC has a low resolution that is roughly estimated to be between 60 and 200 nm, dependent on the vesicle size. © 2015 International Society on Thrombosis and Haemostasis.

  5. Development of risperidone liposomes for brain targeting through intranasal route.

    Science.gov (United States)

    Narayan, Reema; Singh, Mohan; Ranjan, OmPrakash; Nayak, Yogendra; Garg, Sanjay; Shavi, Gopal V; Nayak, Usha Y

    2016-10-15

    The present paper is aimed at development of functionalized risperidone liposomes for brain targeting through nasal route for effective therapeutic management of schizophrenia. The risperidone liposomes were prepared by thin film hydration method. Various parameters such as lipid ratio and lipid to drug ratio were optimized by using Design-Expert(®) Software to obtain high entrapment with minimum vesicle size. The surface of the optimized liposomes was modified by coating stearylamine and MPEG-DSPE for enhanced penetration to the brain. The formulations were evaluated for vesicle size, zeta potential, and entrapment efficiency. The morphology was studied by Transmission Electron Microscopy (TEM). In vivo efficacy was assessed by performing pharmacokinetic study in Wistar albino rats following intranasal administration of the formulations in comparison to intravenous bolus administration of pure drug. The mean vesicle size of optimized liposomes ranged from 90 to 100nm with low polydispersity index (risperidone into the brain than plasma. High brain targeting efficiency index for LP-16 indicating preferential transport of the drug to brain. The study demonstrated successful formulation of surface modified risperidone liposomes for nasal delivery with brain targeting potential. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Effective Retinal Penetration of Lipophilic and Lipid-Conjugated Hydrophilic Agents Delivered by Engineered Liposomes.

    Science.gov (United States)

    Lee, Junsung; Goh, Unbyeol; Lee, Hyoung-Jin; Kim, Jiyoung; Jeong, Moonkyoung; Park, Ji-Ho

    2017-02-06

    Efficient delivery of drugs to the retina is critical but difficult to achieve with current methods. There have been a number of attempts to use intravitreal injection of liposomes, artificial vesicles composed of a phospholipid bilayer, to overcome the limitations of conventional intravitreal injection (short retention time, toxicity, poor penetration, etc.). Here, we report an optimal liposomal formulation that can diffuse through the vitreous humor, deliver the incorporated agents to all retinal layers effectively, and maintain them for a relatively long time. We first delivered lipophilic compounds and phospholipid-conjugated hydrophilic agents to the inner limiting membrane using engineered liposomes. Subsequently, the agents penetrated the retina deeply, presumably via extracellular vesicles, nanoscale vesicles secreted from retinal-associated cells. These results suggest that this engineered liposomal formulation can leverage the biological transport system for effective retinal penetration of lipophilic and lipid-conjugated agents.

  7. Amphotericin B Liposomal Injection

    Science.gov (United States)

    Amphotericin B liposomal injection is used to treat fungal infections such as cryptococcal meningitis (a fungal infection of the ... infections in people who cannot receive conventional amphotericin B therapy. Amphotericin B liposomal injection is in a ...

  8. Avanafil Liposomes as Transdermal Drug Delivery for Erectile ...

    African Journals Online (AJOL)

    Purpose: To formulate avanafil, a recently approved phosphodiesterase-5 enzyme inhibitor, in liposomal form for enhanced transdermal permeation and bioavailability. Methods: Two preparation procedures were employed, leading to the formation of multilamellar vesicles (MLVs) and reverse-phase evaporation unilamellar ...

  9. Interaction of spermine with dimyristoyl-L-alpha-phosphatidyl-DL-glycerol multilamellar liposomes.

    Science.gov (United States)

    Stevanato, R; Wisniewska, A; Momo, F

    1997-10-15

    Polycationic spermine interacts with the negative phosphate group of dimyristoylphosphatidylglycerol multilamellar liposomes, forming a positively charged shell around the vesicle surface. An association constant of (2.15+/-0.45) x 10(3) M(-1) between spermine and the phospholipid groups in liposomes has been evaluated by a new and rapid enzymatic method. ESR spectra show that the effects of this polycation on liposomes are substantially different from those of cations like Ca2+ and Mg2+ and confirm the ability of spermine to induce liposome aggregation and not fusion.

  10. Influence of the Flexible Liposomes on the Skin Deposition of a Hydrophilic Model Drug, Carboxyfluorescein: Dependency on Their Composition

    Directory of Open Access Journals (Sweden)

    Mohamed Badran

    2012-01-01

    Full Text Available This study focuses on the effect of different flexible liposomes containing sodium cholate, Tween 80, or cineol on skin deposition of carboxyfluorescein (CF. Size distribution, morphology, zeta potential, and stability of the prepared vesicles were evaluated. The influence of these systems on the skin deposition of CF utilizing rat skin as membrane model was investigated. Results showed that all of the investigated liposomes had almost spherical shapes with low polydispersity (PDI < 0.3 and particles size range from 83 to 175 nm. All liposomal formulations exhibited negative zeta potential, good drug entrapment efficiency, and stability. In vitro skin deposition data showed that flexible liposomes gave significant deposition of CF on the skin compared to conventional liposomes and drug solutions. This study revealed that flexible liposomes, containing cineole, were able to deliver higher amount of CF suggesting that the hydrophilic drugs delivery to the skin was strictly correlated to the vesicle composition.

  11. Atmospheric-pressure guided streamers for liposomal membrane disruption

    Energy Technology Data Exchange (ETDEWEB)

    Svarnas, P.; Aleiferis, Sp. [High Voltage Laboratory, Department of Electrical and Computer Engineering, University of Patras, Rion 26504 (Greece); Matrali, S. H. [Pharmaceutical Technology Laboratory, Department of Pharmacy, University of Patras, Rion 26504 (Greece); Gazeli, K. [High Voltage Laboratory, Department of Electrical and Computer Engineering, University of Patras, Rion 26504 (Greece); IPREM-LCABIE, Plasmas et Applications, UPPA, 64000 Pau (France); Clement, F. [IPREM-LCABIE, Plasmas et Applications, UPPA, 64000 Pau (France); Antimisiaris, S. G. [Pharmaceutical Technology Laboratory, Department of Pharmacy, University of Patras, Rion 26504 (Greece); Institute of Chemical Engineering Sciences (ICES)-FORTH, Rion 26504 (Greece)

    2012-12-24

    The potential to use liposomes (LIPs) as a cellular model in order to study interactions of cold atmospheric-pressure plasma with cells is herein investigated. Cold atmospheric-pressure plasma is formed by a dielectric-barrier discharge reactor. Large multilamellar vesicle liposomes, consisted of phosphatidylcholine and cholesterol, are prepared by the thin film hydration technique, to encapsulate a small hydrophilic dye, i.e., calcein. The plasma-induced release of calcein from liposomes is then used as a measure of liposome membrane integrity and, consequently, interaction between the cold atmospheric plasma and lipid bilayers. Physical mechanisms leading to membrane disruption are suggested, based on the plasma characterization including gas temperature calculation.

  12. Current Status of Ethosomes and Elastic Liposomes in Dermal and Transdermal Drug Delivery.

    Science.gov (United States)

    Ita, Kevin

    2016-01-01

    It is still not clear whether intact lipid vesicles can cross the human skin. Some reports in the literature indicate that transfersomes® can cross the skin. Other reports suggest that intact liposomes cannot cross the skin. Of course, the composition of the various formulations has to be taken into consideration before making such assertions. The present review examines the use of vesicles- elastic liposomes and ethosomes- for transdermal drug delivery. Liposomes are micro- or nano-structures formed from a bilayer of lipid surrounding an aqueous core. Elastic liposomes differ from conventional liposomes because they contain edge activators (surfactants) which impart elasticity and deformability. Ethosomes are efficient in facilitating percutaneous drug penetration. They are structurally similar to conventional liposomes in the sense that they are prepared from phospholipids but different because they contain a high concentration of ethanol. Both elastic liposomes and ethosomes are increasingly being used for delivering low and high molecular weight drugs. In this review, several reports are presented showing the usefulness of these vesicles and mechanistic insight sought as to why they may be effective in certain cases.

  13. Block liposomes from curvature-stabilizing lipids: connected nanotubes, -rods, or -spheres.

    Science.gov (United States)

    Zidovska, Alexandra; Ewert, Kai K; Quispe, Joel; Carragher, Bridget; Potter, Clinton S; Safinya, Cyrus R

    2009-03-03

    We report on the discovery of block liposomes, a new class of chain-melted (liquid) vesicles, with membranes comprised of mixtures of the membrane-curvature-stabilizing multivalent lipid MVLBG2 of colossal charge +16 e and neutral 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC). In a narrow MVLBG2 composition range (8-10 mol%), cryo-TEM revealed block liposomes consisting of distinctly shaped, yet connected, nanoscale spheres, pears, tubes, or rods. Unlike typical liposome systems, where spherical vesicles, tubular vesicles, and cylindrical micelles are separated on the macroscopic scale, within a block liposome, shapes are separated on the nanometer scale. Diblock (pear-tube) and triblock (pear-tube-pear) liposomes contain nanotubes with inner lumen diameter of 10-50 nm. Diblock (sphere-rod) liposomes were found to contain micellar nanorods approximately 4 nm in diameter and several micrometers in length, analogous to cytoskeletal filaments of eukaryotic cells. Block liposomes may find a range of applications in chemical and nucleic acid delivery and as building blocks in the design of templates for hierarchical structures.

  14. A new method for liposome preparation using a membrane contactor.

    Science.gov (United States)

    Jaafar-Maalej, Chiraz; Charcosset, Catherine; Fessi, Hatem

    2011-09-01

    In this article, we present a novel, scalable liposomal preparation technique suitable for the entrapment of pharmaceutical agents into liposomes. This new method is based on the ethanol-injection technique and uses a membrane contactor module, specifically designed for colloidal system preparation. In order to investigate the process, the influence of key parameters on liposome characteristics was studied. It has been established that vesicle-size distribution decreased with a decrease of the organic-phase pressure, an increase of the aqueous-phase flow rate, and a decrease of the phospholipid concentration. Additionally, special attention was paid on reproducibility and long-term stability of lipid vesicles, confirming the robustness of the membrane contactor-based technique. On the other hand, drug-loaded liposomes were prepared and filled with two hydrophobic drug models. High entrapment-efficiency values were successfully achieved for indomethacin (63%) and beclomethasone dipropionate (98%). Transmission electron microscopy images revealed nanometric quasispherical-shaped multilamellar vesicles (size ranging from 50 to 160 nm).

  15. Radiation induced oxidative damage modification by cholesterol in liposomal membrane

    Science.gov (United States)

    Pandey, B. N.; Mishra, K. P.

    1999-05-01

    Ionizing radiation induced structural and chemical alterations in egg lecithin liposomal membrane have been studied by measurements of lipid peroxides, conjugated diene and fluorescence polarization. Predominantly unilamellar phospholipid vesicles prepared by sonication procedure were subjected to radiation doses of γ-rays from Co-60 in aerated, buffered aqueous suspensions. The oxidative damage in irradiated lipid molecules of liposomes has been determined spectrophotometrically by diene conjugate formation and thiobarbituric acid reactive (TBAR) method as a function of radiation dose. A correlation was found between the radiation dose applied (0.1-1 kGy) and the consequent lipid oxidation. The damage produced in irradiated liposomal membrane was measured by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence decay and polarization. The observed decrease in DPH fluorescence and increase in polarization was found dependent on the radiation dose suggesting alterations in rigidity or organizational order in phospholipid bilayer after irradiation. Furthermore, irradiated liposome vesicles composed of cholesterol showed marked reduction in observed radiation mediated peroxide formation and significantly affected the DPH fluorescence parameters. The magnitude of these modifying effects were found dependent on the mole fraction of cholesterol. It is concluded that modulation of structural order in unilamellar vesicle membrane by variations in basic molecular components controlled the magnitude of lipid peroxidation and diene conjugate formation. These observations contribute to our understanding of mechanism of radical reaction mediated damage caused by ionizing radiation in phospholipid membrane.

  16. Radiation induced oxidative damage modification by cholesterol in liposomal membrane

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.N. [Radiation Biology and Biochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Mishra, K.P. [Radiation Biology and Biochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India)

    1999-05-01

    Ionizing radiation induced structural and chemical alterations in egg lecithin liposomal membrane have been studied by measurements of lipid peroxides, conjugated diene and fluorescence polarization. Predominantly unilamellar phospholipid vesicles prepared by sonication procedure were subjected to radiation doses of {gamma}-rays from Co-60 in aerated, buffered aqueous suspensions. The oxidative damage in irradiated lipid molecules of liposomes has been determined spectrophotometrically by diene conjugate formation and thiobarbituric acid reactive (TBAR) method as a function of radiation dose. A correlation was found between the radiation dose applied (0.1-1 kGy) and the consequent lipid oxidation. The damage produced in irradiated liposomal membrane was measured by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence decay and polarization. The observed decrease in DPH fluorescence and increase in polarization was found dependent on the radiation dose suggesting alterations in rigidity or organizational order in phospholipid bilayer after irradiation. Furthermore, irradiated liposome vesicles composed of cholesterol showed marked reduction in observed radiation mediated peroxide formation and significantly affected the DPH fluorescence parameters. The magnitude of these modifying effects were found dependent on the mole fraction of cholesterol. It is concluded that modulation of structural order in unilamellar vesicle membrane by variations in basic molecular components controlled the magnitude of lipid peroxidation and diene conjugate formation. These observations contribute to our understanding of mechanism of radical reaction mediated damage caused by ionizing radiation in phospholipid membrane.

  17. Evaluation of the physicochemical properties of liposomes as potential carriers of anticancer drugs: spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Pentak, Danuta, E-mail: danuta.pentak@us.edu.pl [University of Silesia, Department of Materials Chemistry and Chemical Technology, Institute of Chemistry (Poland)

    2016-05-15

    Vesicle size and composition are a critical parameter for determining the circulation half-life of liposomes. Size influences the degree of drug encapsulation in liposomes. The geometry, size, and properties of liposomes in an aqueous environment have to be described to enable potential applications of liposome systems as drug carriers. The characteristics of multiple thermotropic phase transitions are also an important consideration in liposomes used for analytical and bioanalytical purposes. The aim of this study was to evaluate the physicochemical properties of liposomes which accommodate hydrophilic and amphiphilic drugs used in cancer therapy. The studied liposomes were prepared with the involvement of the modified reverse-phase evaporation method (mREV). The prepared liposomes had a diameter of 70–150 nm. The analyzed compounds were 1-β-d-arabinofuranosylcytosine, cyclophosphamide, and ifosfamide. In literature, there is no information about simultaneous incorporation of cytarabine, ifosfamide, and cyclophosphamide, in spite of the fact that these drugs have been used for more than 30 years. A combination of the examined drugs is used in CODOX-M/IVAC therapy. CODOX-M/IVAC (cyclophosphamide, doxorubicin, high-dose methotrexate/ifosfamide, etoposide, and high-dose cytarabine) is one of the currently preferred intensive-dose chemotherapy regimens for Burkitt lymphoma (BL). The present research demonstrates the pioneering studies of incorporation of ifosfamide into liposome vesicles, location of and competition between the analyzed drugs and liposome vesicles. The applied methods were nuclear magnetic resonance (NMR), atomic force microscopy (AFM), differential scanning calorimetry (DSC).Graphical Abstract.

  18. Carriers for skin delivery of trihexyphenidyl HCl: ethosomes vs. liposomes.

    Science.gov (United States)

    Dayan, N; Touitou, E

    2000-09-01

    The purpose of this work was to characterize a novel ethosomal carrier containing trihexyphenidyl HCl (THP) and to investigate the delivery of THP from ethosomes versus classic liposomes. THP-ethosomal systems were shown by electron microscopy to contain small, phospholipid vesicles. As the THP concentration was increased from 0 to 3%, the size of the vesicles decreased from 154 to 90 nm. This is most likely due to the surface activity of THP (critical micelle concentration of 5.9 mg/ml), as measured in this work. In addition, the ethosome zeta potential value increased as a function of THP concentration, from -4.5 to +10.4 when the THP concentration was increased from 0 to 3%. In contrast, THP liposomes were much larger and their charge was not affected by THP. When compared with standard liposomes, ethosomes had a higher entrapment capacity and a greater ability to deliver entrapped fluorescent probe to the deeper layers of skin. The flux of THP through nude mouse skin from THP ethosomes (0.21 mg/cm2 h) was 87, 51 and 4.5 times higher than from liposomes, phosphate buffer and hydroethanolic solution, respectively (p ethosomal system than from liposomes or a control hydroethanolic solution. Our results indicate that the ethosomal THP system may be a promising candidate for transdermal delivery of THP.

  19. Liposomal formulations of prilocaine, lidocaine and mepivacaine prolong analgesic duration.

    Science.gov (United States)

    Cereda, Cíntia Maria Saia; Brunetto, Giovana Bruschini; de Araújo, Daniele Ribeiro; de Paula, Eneida

    2006-11-01

    A laboratory investigation was undertaken to compare the in vivo antinociceptive effects of 2% liposomal formulations of prilocaine (PLC), lidocaine (LDC) and mepivacaine (MVC) compared to plain solutions of each of these three local anesthetics. Large unilamellar vesicles were prepared by extrusion (400 nm), at pH 7.4. The membrane/water partition coefficients were obtained from encapsulation efficiency values, after incorporation of each local anesthetic to the vesicles. The anesthetic effect of each liposomal formulation was compared to the respective local anesthetic solution in water, using the infraorbital nerve-blockade test, in rats. The partition coefficients were: 57 for PLC, 114 for LDC and 93 for MVC. In vivo results showed that local anesthetic-free liposomes, used as control, had no analgesic effect. In contrast, the encapsulated formulations induced increased intensities of total anesthetic effect (35.3%, 26.1% and 57.1%) and time for recovery (percentage increases of 30%, 23.1% and 56%), respectively, for PLC, LDC and MVC when compared to the plain solutions (P < 0.01). These results indicate that liposomes provide effective drug-delivery systems for intermediate-duration local anesthetics. Mepivacaine was affected to the greatest extent, while LDC benefited least from liposome encapsulation, possibly due to greater vasodilatory properties of LDC.

  20. Cold field emission gun-scanning electron microscopy: a new tool for morphological and ultrastructural analysis of liposomes.

    Science.gov (United States)

    De Rosa, G; De Stefano, M; Ungaro, F; La Rotonda, M I

    2008-10-01

    Liposomes are lipid vesicles largely investigated in the past 30 years as pharmaceutical carriers. In the development of new liposome-based formulations, the study of liposome surface properties remains a crucial step. For this purpose, microscopy techniques can provide useful information, although each such technique suffers from some limitations. Here, we have used cold field emission gun-scanning electron microscopy (cFEG-SEM) to acquire detailed images of liposome surface. In particular, we observed PEGylated and non-PEGylated liposomes in different size ranges. In the case of nanosized liposomes (mean diameter about 200 nm), a morphological evaluation of the whole preparation was obtained. On the other hand, in the case of giant liposomes (mean diameter about 2 microm), it was possible to observe the different surface ultrastructures of the two formulations. In particular, a regular and only slightly wrinkled surface was observed in the case of non-PEGylated liposomes, while a very irregular surface ultrastructure was visible in the case of PEGylated liposomes. This study shows, for the first time, the potential of cFEG-SEM as a new and powerful tool to obtain information on liposome morphology and, at least in the case of giant liposomes, on ultrastructure of the liposome surface.

  1. Tuning the Extent and Depth of Penetration of Flexible Liposomes in Human Skin.

    Science.gov (United States)

    Franzé, Silvia; Donadoni, Giulia; Podestà, Alessandro; Procacci, Patrizia; Orioli, Marica; Carini, Marina; Minghetti, Paola; Cilurzo, Francesco

    2017-06-05

    In this work we made an attempt to assess the effect of drug-induced changes of flexibility on the penetration of deformable vesicles into the human skin. Eight cationic liposomes with different degrees of flexibility were obtained by entrapping unfractionated heparin, enoxaparin, and nadroparin. The deformability was studied by a novel, facile, and reliable extrusion assay appositely developed and validated by means of quantitative nanoscale mechanical AFM measurements of vesicle elastic modulus (log10(YM)). The proposed extrusion assay, determining the forces involved in vesicles deformation, resulted very sensitive to evidence of minimal changes in bilayer rigidity (σ) and vesicle deformation (K). The drug loading caused a reduction of liposome flexibility with respect to the reference plain liposomes and in accordance to the heparin type, drug to cationic lipid (DOTAP) ratio, and drug distribution within the vesicles. Interestingly, the σ and log10(YM) values perfectly correlated (R(2) = 0.935), demonstrating the reliability of the deformability data obtained with both approaches. The combination of TEM and LC-MS/MS spectrometry allowed the pattern of the penetration of the entire vesicles into the skin to be followed. In all cases, intact liposomes in the epidermis layers were observed and a relationship between the depth of penetration and the liposome flexibility was found, supporting the hypothesis of the whole vesicle penetration mechanism. Moreover, the results of the extent (R24) of vesicle penetration in the human skin samples showed a direct relation to the flexibility values (σ1 = 0.65 ± 0.10 MPa → R24 = 3.33 ± 0.02 μg/mg; σ2 = 0.95 ± 0.04 MPa → R24 = 1.18 ± 0.26 μg/mg; σ3 = 1.89 ± 0.30 MPa → R24 = 0.53 ± 0.33 μg/mg).

  2. Silica-Coated Liposomes for Insulin Delivery

    Directory of Open Access Journals (Sweden)

    Neelam Dwivedi

    2010-01-01

    Full Text Available Liposomes coated with silica were explored as protein delivery vehicles for their enhanced stability and improved encapsulation efficiency. Insulin was encapsulated within the fluidic phosphatidylcholine lipid vesicles by thin film hydration at pH 2.5, and layer of silica was formed above lipid bilayer by acid catalysis. The presence of silica coating and encapsulated insulin was identified using confocal and electron microscopy. The native state of insulin present in the formulation was evident from Confocal Micro-Raman spectroscopy. Silica coat enhances the stability of insulin-loaded delivery vehicles. In vivo study shows that these silica coated formulations were biologically active in reducing glucose levels.

  3. Analysis of individual lipoproteins and liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, D.L.; Keller, R.A.; Nolan, J.P. [and others

    1997-08-01

    We describe the application of single molecule detection (SMD) technologies for the analysis of natural (serum lipoproteins) and synthetic (liposomes) transport systems. The need for advanced analytical procedures of these complex and important systems is presented with the specific enhancements afforded by SMD with flowing sample streams. In contrast to bulk measurements which yield only average values, measurement of individual species allows creation of population histograms from heterogeneous samples. The data are acquired in minutes and the analysis requires relatively small sample quantities. Preliminary data are presented from the analysis of low density lipoprotein, and multilamellar and unilamellar vesicles.

  4. Physical Immobilization Liposomes in Uniform Zwitterionic Microgel Particles Fabricated in Microcapillary Device

    Science.gov (United States)

    Jeong, Eun Seon; Byun, Aram; Kim, Jin Woong

    2014-03-01

    Lipid molecules have both hydrophilic and hydrophobic properties. Since their packing parameter ranges from 0.5 to 1, they self-assemble to form a vesicle structure, liposome. Thanks to the vesicle structure, liposome is able to encapsulate both hydrophilic and hydrophobic active ingredients, thus widening its applicability to pharmaceutical, cosmetic, and food industry. However, its vesicular structure is readily transferred to micelle in the presence of amphiphilic additives with low packing parameters. Therefore, it is critical to developing a technique to overcome this drawback. This study introduces a microfluidic approach to physically immobilize liposome in microgel particles. For this, we generate a uniform liposome-in-oil-in-water emulsion in a capillary-based microfluidic device. Basically, we observe how the flows in micro-channels affect generation of embryo emulsion drops. Then, the uniform emulsion is solidified by using photo-polymerization. Finally, we characterize the particle morphology, membrane fluidity, and mesh property, encapsulation efficiency and releasing.

  5. Liposomes as siRNA delivery vectors.

    Science.gov (United States)

    Bochicchio, Sabrina; Dalmoro, Annalisa; Barba, Anna Angela; Grassi, Gabriele; Lamberti, Gaetano

    2014-01-01

    Nucleic Acid Based Drugs (NABDs) constitute a class of promising and powerful therapeutic new agents with limited side effects, potentially useable against a wide range of diseases, including cancer. Among them, the short interfering RNAs (siRNAs), represent very effective molecules. Despite their in vitro efficacy, the major drawback that limits siRNAs usage consists in a difficult delivery due to their very low stability in physiological fluids, and to their limited membrane-permeability through physiological barriers. On the other hand, the liposomes (lipid bilayers closed in vesicles of various sizes) represent interesting drug delivery systems (DDSs) which can be tailored in order to get the best performance in terms of load, vesicle size and transfection yield. In this work, the current state of study in these two fields, and the connections between them, are briefly summarized.

  6. Liposome preparation using a hollow fiber membrane contactor--application to spironolactone encapsulation.

    Science.gov (United States)

    Laouini, A; Jaafar-Maalej, C; Sfar, S; Charcosset, C; Fessi, H

    2011-08-30

    In this study, we present a novel liposome preparation technique suitable for the entrapment of pharmaceutical and cosmetic agents. This new method uses a membrane contactor in a hollow fiber configuration. In order to investigate the process, key parameters influence on the liposome characteristics was studied. It has been established that the vesicle size distribution decreased with the organic phase pressure decrease, the phospholipid concentration decreases and the aqueous to organic phase volume ratio increases. Liposomes were filled with a hydrophobic drug model, spironolactone that could be used for a paediatric medication. The mean size of drug-free and drug-loaded liposomes was, respectively, 113 ± 4 nm and 123 ± 3 nm. The zeta potential of drug-free and drug-loaded liposomes was, respectively, -43 ± 0.7 mV and -23 ± 0.6 mV. High entrapment efficiency values were successfully achieved (93 ± 1.12%). Transmission electron microscopy images revealed nanometric sized and spherical shaped oligo-lamellar vesicles. The release profile showed a rapid and complete release within about 5h. Additionally, special attention was paid on process reproducibility and long term lipid vesicles stability. Results confirmed the robustness of the hollow fiber module based technique. Moreover, the technique is simple, fast and has a potential for continuous production of nanosized liposome suspensions at large scale. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Skin penetration behaviour of liposomes as a function of their composition.

    Science.gov (United States)

    Gillet, A; Lecomte, F; Hubert, P; Ducat, E; Evrard, B; Piel, G

    2011-09-01

    Deformable liposomes have been developed and evaluated as a novel topical and transdermal delivery system. Their mechanism of drug transport into and through the skin has been investigated but remains a much debated question. The present study concerns ex vivo diffusion experiments using pig ear skin in order to explain the penetration mechanism of classical and deformable liposomes. Classical and deformable vesicles containing betamethasone in the aqueous compartment through the use of cyclodextrin inclusion complexes were compared to vesicles encapsulating betamethasone in their lipid bilayer. Deformable liposomes contained sodium deoxycholate as the edge activator. Liposomes were characterised by their diameter, encapsulation efficiency, deformability, stability (in terms of change in diameter) and release of encapsulated drug. Ex vivo diffusion studies using Franz diffusion cells were performed. Confocal microscopy was performed to visualise the penetration of fluorescently labelled liposomes into the skin. This study showed that liposomes do not stay intact when they penetrate the deepest layers of the skin. Betamethasone is released from the vesicles after which free drug molecules can diffuse through the stratum corneum and partition into the viable skin tissue. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Silica-based monolithic capillary columns modified by liposomes for characterization of analyte-liposome interactions by capillary liquid chromatography.

    Science.gov (United States)

    Moravcová, Dana; Planeta, Josef; Wiedmer, Susanne K

    2013-11-22

    This study introduces a silica-based monolith in a capillary format (0.1 mm × 100 mm) as a support for immobilization of liposomes and its characterization in immobilized liposome chromatography. Silica-based monolithic capillary columns prepared by acidic hydrolysis of tetramethoxysilane in the presence of polyethylene glycol and urea were modified by (3-aminopropyl)trimethoxysilane, whereby amino groups were introduced to the monolithic surface. These groups undergo reaction with glutaraldehyde to form an iminoaldehyde, allowing covalent binding of pre-formed liposomes containing primary amino groups. Two types of phospholipid vesicles were used for column modification; these were 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphatidyl choline with and without 1,2-diacyl-sn-glycero-3-phospho-L-serine. The prepared columns were evaluated under isocratic separation conditions employing 20mM phosphate buffer at pH 7.4 as a mobile phase and a set of unrelated drugs as model analytes. The liposome layer on the synthesized columns significantly changed the column selectivity compared to the aminopropylsilylated monolithic stationary phase. Monolithic columns modified by liposomes were stable under the separation conditions, which proved the applicability of the suggested preparation procedure for the synthesis of capillary columns dedicated to study analyte-liposome interactions. The column efficiency originating from the silica monolith was preserved and reached, e.g., more than 120,000 theoretical plates/m for caffeine as a solute. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Lipossomas: a bala mágica acertou? Liposomes: has the magic bullet hit the target?

    Directory of Open Access Journals (Sweden)

    Nuno C. Santos

    2002-12-01

    Full Text Available Efficient drug delivery systems are as important as drug themselves. A powerful drug unable to reach the target cell is useless in practice. Ehrlich's Magic Bullet was the first carrier system to be proposed. The evolution in this domain has been quite slow as the natural mechanisms of mammals against foreign products are hard to overcome. However, lipid-based systems (liposomes and related vesicles have attained reasonable success. The basic preparations and structural features of liposomes and related vesicles as well as their applications are addressed from the chemist's and biochemist's point of view.

  10. pH sensitive coiled coils: a strategy for enhanced liposomal drug delivery

    Science.gov (United States)

    Reja, Rahi M.; Khan, Mohsina; Singh, Sumeet K.; Misra, Rajkumar; Shiras, Anjali; Gopi, Hosahudya N.

    2016-02-01

    Stimuli responsive controlled release from liposome based vesicles is a promising strategy for the site specific delivery of drugs. Herein, we report the design of pH sensitive coiled coils and their incorporation into the liposome as triggers for the controlled release of encapsulated drugs. The designed coiled coil peptides with the incorporation of environment sensitive fluorescent amino acids were found to be stable at physiological pH and unstructured while changing the pH of the environment to either acidic or basic. This pH dependent conformational switch of the coiled-coil polypeptides was exploited as triggers for the enhanced release of the encapsulated drug molecules from liposomes. The SEM, DLS and TEM analysis revealed the uniform morphology of the peptide liposome hybrid vesicles. Further, the drug encapsulated liposome internalization experiments with cancer cells revealed the enhanced release and accumulation of drugs in the acidic lysosomal compartments in comparison with liposomes without coiled coils.Stimuli responsive controlled release from liposome based vesicles is a promising strategy for the site specific delivery of drugs. Herein, we report the design of pH sensitive coiled coils and their incorporation into the liposome as triggers for the controlled release of encapsulated drugs. The designed coiled coil peptides with the incorporation of environment sensitive fluorescent amino acids were found to be stable at physiological pH and unstructured while changing the pH of the environment to either acidic or basic. This pH dependent conformational switch of the coiled-coil polypeptides was exploited as triggers for the enhanced release of the encapsulated drug molecules from liposomes. The SEM, DLS and TEM analysis revealed the uniform morphology of the peptide liposome hybrid vesicles. Further, the drug encapsulated liposome internalization experiments with cancer cells revealed the enhanced release and accumulation of drugs in the acidic

  11. Cell-penetrating peptide-based intelligent liposomal systems for enhanced drug delivery.

    Science.gov (United States)

    Gao, Huile; Zhang, Qianyu; Yu, Zhiqiang; He, Qin

    2014-01-01

    Liposomes are widely used as drug delivery systems and several liposome-based nanomedicines have been approved for clinical use. Cell penetrating peptides (CPPs) have been decorated onto nanoparticulated vesicle such as liposomes to further improve the intracellular delivery efficiency. However, the poor selectivity of CPPs hindered their application, especially in the in vivo application. To resolve this issue, several strategies have been developed, including shielding and environment-triggered deshielding of CPPs as well as designing of environment-responsive CPPs and specific- targeting CPPs and last but not least, combination strategy. In this review, the abovementioned strategies were discussed.

  12. Role of liposome in treatment of overactive bladder and interstitial cystitis

    Directory of Open Access Journals (Sweden)

    Shih-Ya Hung

    2015-03-01

    Full Text Available Intravesical (local therapy of agents has been effective in delaying or preventing recurrence of superficial bladder cancer. This route of drug administration has also shown tremendous promise in the treatment of interstitial cystitis/painful bladder syndrome (IC/PBS and overactive bladder without systemic side effects. Liposomes are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core. They can incorporate drug molecules, both hydrophilic and hydrophobic, and show greater uptake into cells via endocytosis. Intravesical liposomes have therapeutic effects on IC/PBS patients, mainly because of their ability to form a protective lipid film on the urothelial surface. Recent studies have shown the sustained efficacy and safety of intravesical instillation of botulinum toxin formulated with liposomes (lipo-BoNT for the treatment of refractory overactive bladder This review considers the current status of intravesical liposomes or liposomal mediated drug delivery for the treatment of IC/PBS and overactive bladder.

  13. Lyoprotective Effect of Alkyl Sulfobetaines for Freeze-drying 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine Liposomes.

    Science.gov (United States)

    Aikawa, Tatsuo; Sato, Kanta; Okado, Hiroki; Takahashi, Yukako; Kondo, Takeshi; Yuasa, Makoto

    2017-11-01

    A liposome is a molecular assembly in the form of a vesicle comprised of a phospholipid bilayer. Liposomes can be used as molecular containers in various fields such as pharmaceutical, cosmetic, and food industries. It is difficult to maintain the original structure of liposomes in an aqueous medium. Phospholipids, which are components of liposomes, are susceptible to hydrolysis, which causes disruption of the liposomal structure and dysfunction of the molecular container. In this context, freeze-drying liposomes is a preferable method to improve the shelf life of liposomes. However, when freeze-drying liposomes, a lyoprotective agent is required to preserve their original structure. In this study, we investigate whether alkyl sulfobetaines (SBn, n: number of carbons in the alkyl chain, n = 1-18) can be used as lyoprotectants for 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes. The results indicated that the length of the alkyl chain of the SBn was an important factor to prevent liposome disruption during the freeze-drying and subsequent rehydration processes. The use of SBn with an alkyl chain of intermediate length (n = 6-10) could prevent liposome disruption and remarkably reduce the gel-to-liquid crystal phase transition temperature (Tm) of the freeze-dried liposomes. This indicates that these SBn could intercalate in the dried bilayer and reduce intermolecular interaction between DPPC in the bilayer. The Tm reduction of the freeze-dried liposomes should contribute to prevention of the gel-to-liquid phase transition of the liposomes during the rehydration process, which has been known to be a main cause of liposome disruption. We expect that the results from this study will provide an insight into the influence of zwitterionic additives on freeze-dried lipid bilayers and the lyoprotective effect, which should be useful in many biochemical and biomedical fields.

  14. Novel methods for the encapsulation of meglumine antimoniate into liposomes

    Directory of Open Access Journals (Sweden)

    F. Frézard

    2000-07-01

    Full Text Available The antimonial drug, meglumine antimoniate, was successfully encapsulated in dehydration-rehydration vesicles and in freeze-dried empty liposomes (FDELs. High encapsulation efficiencies (from 28 to 58% and low weight ratios of lipids to encapsulated antimony (from 1:0.15 to 1:0.3 were achieved. These formulations, contrary to those obtained by conventional methods, can be stored as intermediate lyophilized forms and reconstituted just before use. The efficacy of FDEL-encapsulated meglumine antimoniate was evaluated in hamsters experimentally infected with Leishmania chagasi. A significant reduction of liver parasite burdens was observed in animals treated with this preparation, when compared to control animals treated with empty liposomes. In contrast, free meglumine antimoniate was found to be inefficient when administered at a comparable dose of antimony. This novel liposome-based meglumine antimoniate formulation appears to be promising as a pharmaceutical product for the treatment of visceral leishmaniasis.

  15. Liposomal paclitaxel formulations.

    Science.gov (United States)

    Koudelka, Stěpán; Turánek, Jaroslav

    2012-11-10

    Over the past three decades, taxanes represent one of the most important new classes of drugs approved in oncology. Paclitaxel (PTX), the prototype of this class, is an anti-cancer drug approved for the treatment of breast and ovarian cancer. However, notwithstanding a suitable premedication, present-day chemotherapy employing a commercial preparation of PTX (Taxol®) is associated with serious side effects and hypersensitivity reactions. Liposomes represent advanced and versatile delivery systems for drugs. Generally, both in vivo mice tumor models and human clinical trials demonstrated that liposomal PTX formulations significantly increase a maximum tolerated dose (MTD) of PTX which outperform that for Taxol®. Liposomal PTX formulations are in various stages of clinical trials. LEP-ETU (NeoPharm) and EndoTAG®-1 (Medigene) have reached the phase II of the clinical trials; Lipusu® (Luye Pharma Group) has already been commercialized. Present achievements in the preparation of various liposomal formulations of PTX, the development of targeted liposomal PTX systems and the progress in clinical testing of liposomal PTX are discussed in this review summarizing about 30 years of liposomal PTX development. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Characterization and In Vitro Skin Permeation of Meloxicam-Loaded Liposomes versus Transfersomes

    Directory of Open Access Journals (Sweden)

    Sureewan Duangjit

    2011-01-01

    Full Text Available The goal of this study was to develop and evaluate the potential use of liposome and transfersome vesicles in the transdermal drug delivery of meloxicam (MX. MX-loaded vesicles were prepared and evaluated for particle size, zeta potential, entrapment efficiency (%EE, loading efficiency, stability, and in vitro skin permeation. The vesicles were spherical in structure, 90 to 140 nm in size, and negatively charged (−23 to −43 mV. The %EE of MX in the vesicles ranged from 40 to 70%. Transfersomes provided a significantly higher skin permeation of MX compared to liposomes. Fourier Transform Infrared Spectroscopy (FT-IR and Differential Scanning Calorimetry (DSC analysis indicated that the application of transfersomes significantly disrupted the stratum corneum lipid. Our research suggests that MX-loaded transfersomes can be potentially used as a transdermal drug delivery system.

  17. A pulse radiolysis study of the dynamics of ascorbic acid free radicals within a liposomal environment.

    Science.gov (United States)

    Kobayashi, Kazuo; Seike, Yumiko; Saeki, Akinori; Kozawa, Takahiro; Takeuchi, Fusako; Tsubaki, Motonari

    2014-10-06

    The dynamics of free-radical species in a model cellular system are examined by measuring the formation and decay of ascorbate radicals within a liposome with pulse radiolysis techniques. Upon pulse radiolysis of an N2O-saturated aqueous solution containing ascorbate-loaded liposome vesicles, ascorbate radicals are formed by the reaction of OH(·) radicals with ascorbate in unilamellar vesicles exclusively, irrespective of the presence of vesicle lipids. The radicals are found to decay rapidly compared with the decay kinetics in an aqueous solution. The distinct radical reaction kinetics in the vesicles and in bulk solution are characterized, and the kinetic data are analyzed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Lipid Vesicles for the Skin Delivery of Diclofenac: Cerosomes vs. Other Lipid Suspensions

    OpenAIRE

    Anahita Fathi-Azarbayjani; Kai Xin Ng; Yew Weng Chan; Sui Yung Chan

    2015-01-01

    Purpose: Lipid suspensions as drug carriers, including conventional liposomes, ethosomes, transferosomes, proniosomes, niosomes, PEG-PPG-PEG niosomes and stratum corneum liposomes (cerosomes), were formulated and compared. Methods: Lipid vesicles were formulated and assessed with regards to enhancement of skin permeation of diclofenac and stability profiles of the formulations. Formulation-induced changes of the biophysical structure of excised human skin were monitored using the Fourier t...

  19. Microfluidics based manufacture of liposomes simultaneously entrapping hydrophilic and lipophilic drugs.

    Science.gov (United States)

    Joshi, Sameer; Hussain, Maryam T; Roces, Carla B; Anderluzzi, Giulia; Kastner, Elisabeth; Salmaso, Stefano; Kirby, Daniel J; Perrie, Yvonne

    2016-11-30

    Despite the substantial body of research investigating the use of liposomes, niosomes and other bilayer vesicles for drug delivery, the translation of these systems into licensed products remains limited. Indeed, recent shortages in the supply of liposomal products demonstrate the need for new scalable production methods for liposomes. Therefore, the aim of our research has been to consider the application of microfluidics in the manufacture of liposomes containing either or both a water soluble and a lipid soluble drug to promote co-delivery of drugs. For the first time, we demonstrate the entrapment of a hydrophilic and a lipophilic drug (metformin and glipizide respectively) both individually, and in combination, using a scalable microfluidics manufacturing system. In terms of the operating parameters, the choice of solvents, lipid concentration and aqueous:solvent ratio all impact on liposome size with vesicle diameter ranging from ∼90 to 300nm. In terms of drug loading, microfluidics production promoted high loading within ∼100nm vesicles for both the water soluble drug (20-25% of initial amount added) and the bilayer embedded drug (40-42% of initial amount added) with co-loading of the drugs making no impact on entrapment efficacy. However, co-loading of glipizide and metformin within the same liposome formulation did impact on the drug release profiles; in both instances the presence of both drugs in the one formulation promoted faster (up to 2 fold) release compared to liposomes containing a single drug alone. Overall, these results demonstrate the application of microfluidics to prepare liposomal systems incorporating either or both an aqueous soluble drug and a bilayer loaded drug. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. In vitro spectroscopic study of piperine-encapsulated nanosize liposomes.

    Science.gov (United States)

    Pentak, Danuta

    2016-03-01

    Black pepper is a source of effective antioxidants. It contains several powerful antioxidants and is thus one of the most important spices for preventing and curtailing oxidative stress. There is considerable interest in the development of a drug-delivery systems that would result in the selective delivery of antioxidants to tissues in sufficient concentrations to ameliorate oxidant-induced tissue injuries. Liposomes are biocompatible, biodegradable and nontoxic artificial phospholipid vesicles that offer the possibility of carrying hydrophilic, hydrophobic and amphiphilic molecules. This article focuses on the use of liposomes for the delivery of antioxidants in the prevention or treatment of pathological conditions related to oxidative stress. Liposome formulations of piperine were analyzed with various spectroscopic methods. The formulation with the highest entrapment efficiency (90.5%) was formulated with an L-α-phosphatidylcholine dipalmitoyl (DPPC):piperine, 30:1 molar ratio, and total lipid count of 19.47 mg/ml in the final liposomal preparation. The liposome formulation was found to be stable after storage at 4 °C, protected from light, for a minimum of 3 weeks. The incremental process of piperine penetration through the phospholipid membrane was analyzed using the FT-IR, UV-Vis and NMR methods. Temperature stability studies carried out at 37 °C showed the highest percentage of piperine release in the first 3 h of incubation.

  1. Extracellular vesicles: fundamentals and clinical relevance

    Directory of Open Access Journals (Sweden)

    Wael Nassar

    2015-01-01

    Full Text Available All types of cells of eukaryotic organisms produce and release small nanovesicles into their extracellular environment. Early studies have described these vesicles as ′garbage bags′ only to remove obsolete cellular molecules. Valadi and colleagues, in 2007, were the first to discover the capability of circulating extracellular vesicles (EVs to horizontally transfer functioning gene information between cells. These extracellular vesicles express components responsible for angiogenesis promotion, stromal remodeling, chemoresistance, genetic exchange, and signaling pathway activation through growth factor/receptor transfer. EVs represent an important mode of intercellular communication by serving as vehicles for transfer between cells of membrane and cytosolic proteins, lipids, signaling proteins, and RNAs. They contribute to physiology and pathology, and they have a myriad of potential clinical applications in health and disease. Moreover, vesicles can pass the blood-brain barrier and may perhaps even be considered as naturally occurring liposomes. These cell-derived EVs not only represent a central mediator of the disease microenvironment, but their presence in the peripheral circulation may serve as a surrogate for disease biopsies, enabling real-time diagnosis and disease monitoring. In this review, we′ll be addressing the characteristics of different types of extracellular EVs, as well as their clinical relevance and potential as diagnostic markers, and also define therapeutic options.

  2. Compartmentalization and Transport in Synthetic Vesicles

    Directory of Open Access Journals (Sweden)

    Christine eSchmitt

    2016-02-01

    Full Text Available Nano-scale vesicles have become a popular tool in life sciences. Besides liposomes that are generated from phospholipids of natural origin, polymersomes fabricated of synthetic block copolymers enjoy increasing popularity, as they represent more versatile membrane building blocks that can be selected based on their specific physicochemical properties, like permeability, stability or chemical reactivity.In this review, we focus on the application of simple and nested artificial vesicles in synthetic biology. First, we provide an introduction into the utilization of multi-compartmented vesosomes as compartmentalized nano-scale bioreactors. In the bottom-up development of protocells from vesicular nano-reactors, the specific exchange of pathway intermediates across compartment boundaries represents a bottleneck for future studies. To date, most compartmented bioreactors rely on unspecific exchange of substrates and products. This is either based on changes in permeability of the coblock polymer shell by physicochemical triggers or by the incorporation of unspecific porin proteins into the vesicle membrane. Since the incorporation of membrane transport proteins into simple and nested artificial vesicles offers the potential for specific exchange of substances between subcompartments, it opens new vistas in the design of protocells. Therefore we devote the main part of the review to summarize the technical advances in the use of phospholipids and block copolymers for the reconstitution of membrane proteins.

  3. Delivery of fluorescent-labeled cyclodextrin by liposomes: role of transferrin modification and phosphatidylcholine composition.

    Science.gov (United States)

    Chen, Jun; Yao, Junhong; Ma, Zhuyue; Peng, Pei; Lu, Shanshan; Hu, Yudong; Xu, Fei; Yang, Yang; Yang, Xixiong

    2017-03-01

    Drug-in-CD-in-liposome (DCL) systems which encapsulate the drug/CD inclusion complexes into inner aqueous phase of liposomes have been applied as a novel strategy to improve efficacy of lipophilic antitumor drugs. The aim of this work was to assess the role of transferrin (Tf) modification and phosphatidylcholine (PC) composition on the properties of liposomes containing hydroxypropyl-β-cyclodextrin (HP-β-CD). Fluorescence dye, FITC, was conjugated with HP-β-CD to facilitate the analysis. The resulting FITC-HP-β-CD was further encapsulated into liposomes and then the liposomes were modified with Tf. The FITC-HP-β-CD-loaded liposomes with different PC compositions were compared in terms of particle size, zeta potential, FITC content, FITC-HP-β-CD leakage, phase transition temperature (Tm) and cellular uptake. The apparent partition coefficient values of different PCs were also determined. Compared to PEGylated liposomes, FITC-HP-β-CD-loaded liposomes modified with Tf had been proved to significantly increase vesicle stability and specific cellular uptake. Moreover, PC composition affected the properties of liposomes. Soybean phosphatidylcholine (SPC) liposomes modified with Tf were found to be more easily internalized into tumor cells than 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and hydrogenated soybean phosphatidylcholine (HSPC) while Tf density on the liposomal surface was similar. And the lipophilicity of SPC was found to be much higher than DPPC and HSPC. Collectively, by the optimization of PC composition, the development of DCL modified with Tf might represent a potential strategy for the antitumor application of lipophilic drugs.

  4. Effects of various spacers between biotin and the phospholipid headgroup on immobilization and sedimentation of biotinylated phospholipid-containing liposomes facilitated by avidin-biotin interactions.

    Science.gov (United States)

    Sakamoto, Yasuhisa; Kikuchi, Koji; Umeda, Kazuaki; Nakanishi, Hiroyuki

    2017-09-01

    Immobilization and sedimentation of liposomes (lipid vesicles) are used in liposome-protein binding assays, facilitated by avidin/streptavidin/NeutrAvidin and biotinylated phospholipid-containing liposomes. Here, we examined the effects of three spacers [six-carbon (X), polyethylene glycol (PEG) 180 (molecular weight 180) and PEG2000 (molecular weight 2,000)] between biotin and the phospholipid headgroup on the immobilization and sedimentation of small unilamellar liposomes/vesicles (SUVs). PEG180 and PEG2000 showed more efficient immobilization of biotinylated SUVs on NeutrAvidin-coated plates than X, but X and PEG180 showed more efficient sedimentation of biotinylated SUVs upon NeutrAvidin addition than PEG2000. Thus, the most appropriate spacers differed between immobilization and sedimentation. A spacer for biotinylated SUVs must be selected according to the particular liposome-protein binding assays examined. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  5. Stability of marine lipid based-liposomes under Acid conditions. Influence of xanthan gum.

    Science.gov (United States)

    Cansell, M; Moussaoui, N; Lefrançois, C

    2001-01-01

    Liposomes are potential candidates in Human nutrition to supplement diets in essential lipo- and hydro-soluble nutriments. In this context, marine lipid based-vesicles, rich in polyunsaturated fatty acids, and containing vitamin B1 (thiamine) were prepared. Two methods were envisaged for vitamin trapping, passive encapsulation and active loading through the use of a transmembrane pH gradient. These methods were compared in terms of thiamine trapping efficiency. Influence of xanthan addition was also studied. Although, the active loading yielded to higher encapsulation ratios than the passive method, encapsulation efficiency was markedly increased, in both cases, as soon as the hydrocolloid was added after the lipid hydration phase. Liposome stability was assayed by microscopy observation and membrane permeability to thiamine in a medium that mimic that faced by the structures administrated by the oral route, i.e., an acid pH medium, as in the Human stomach. Low pH value led to an instantaneous vesicle aggregation. Thiamine was totally released from liposomes prepared without xanthan after 24 h storage in a neutral medium. This time was shortened to 1 h at pH 1.5. However, thiamine retention was significantly improved when liposomes were prepared in presence of the hydrocolloid, whatever the encapsulation method used. On the whole, these results were interpreted in terms of xanthan coating around the liposome surface that would result from lipid-hydrocolloid interactions occurring during the centrifugation steps of liposome preparation.

  6. Deformable liposomes and ethosomes as carriers for skin delivery of ketotifen.

    Science.gov (United States)

    Elsayed, M M A; Abdallah, O Y; Naggar, V F; Khalafallah, N M

    2007-02-01

    Deformable liposomes and ethosomes were investigated as carriers for skin delivery of ketotifen (KT) in terms of vesicle size, entrapment efficiency, stability, in vitro permeation and skin deposition properties. Phosphatidylcholine (PC) from soybean lecithin was used in the preparation of all vesicles. Sodium cholate, sodium deoxycholate and Tween 80 were investigated as edge activators in preparation of KT deformable liposomes. KT ethosomes were prepared in two PC concentrations, 2% and 4.25% w/v, in 30% v/v ethanol. KT deformable liposomes showed improved entrapment efficiency over KT ethosomes. KT deformable liposomes with Tween 80 as an edge activator were more stable upon storage at 5 +/- 1 degree C than those prepared using sodium cholate or sodium deoxycholate and were more stable than KT ethosomes. In vitro permeation and skin deposition studies employed only deformable liposomes with Tween 80 as an edge activator and ethosomes with 4.25% w/v PC concentration. Both of them improved skin delivery of KT over controls and over traditional liposomes, with greater improvement of KT skin deposition than KT skin permeation, hence are more useful for dermal than for transdermal delivery of KT.

  7. Interaction of insulin, cholesterol-derivatized mannan, and carboxymethyl chitin with liposomes: A differential scanning calorimetry study

    OpenAIRE

    M. Tabbakhian; Rogers, J.A.

    2012-01-01

    The interaction of drugs and polymers used to incorporate in or surface modify/coat the liposomes can affect the phase transition, fluidity and other physical properties as well as in vivo fate of vesicles. In this study, differential scanning calorimetry (DSC) was used to investigate changes in the temperature and the enthalpy of phase transition of liposomes of various electrical charges following interaction with carboxymethyl chitin (CM-chitin) as a hydrophilic polymer, cholesterol-deriva...

  8. Salt, shake, fuse--giant hybrid polymer/lipid vesicles through mechanically activated fusion.

    Science.gov (United States)

    Henderson, Ian M; Paxton, Walter F

    2014-03-24

    Large (200 nm) poly(ethylene oxide)-b-poly(butadiene) polymer vesicles fuse into giant (>1 μm) vesicles with mild agitation in dilute aqueous NaCl solutions. This unusual effect is attributed to the salt-induced contraction of the poly(ethylene oxide) corona, reducing steric resistance between vesicles and, with agitation, increasing the probability of contact between the hydrophobic cores of adjacent membranes. In addition, NaCl and agitation facilitated the creation of giant hybrid vesicles from much smaller homogeneous polymersomes and liposomes. Whereas lipid vesicles do not readily fuse with each other under the same circumstances, they did fuse with polymersomes to produce hybrid polymer/lipid vesicles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The Vesicle Priming Factor CAPS Functions as a Homodimer via C2 Domain Interactions to Promote Regulated Vesicle Exocytosis.

    Science.gov (United States)

    Petrie, Matt; Esquibel, Joseph; Kabachinski, Greg; Maciuba, Stephanie; Takahashi, Hirohide; Edwardson, J Michael; Martin, Thomas F J

    2016-09-30

    Neurotransmitters and peptide hormones are secreted by regulated vesicle exocytosis. CAPS (also known as CADPS) is a 145-kDa cytosolic and peripheral membrane protein required for vesicle docking and priming steps that precede Ca 2+ -triggered vesicle exocytosis. CAPS binds phosphatidylinositol 4,5-bisphosphate (PI(4,5)P 2 ) and SNARE proteins and is proposed to promote SNARE protein complex assembly for vesicle docking and priming. We characterized purified soluble CAPS as mainly monomer in equilibrium with small amounts of dimer. However, the active form of CAPS bound to PC12 cell membranes or to liposomes containing PI(4,5)P 2 and Q-SNARE proteins was mainly dimer. CAPS dimer formation required its C2 domain based on mutation or deletion studies. Moreover, C2 domain mutations or deletions resulted in a loss of CAPS function in regulated vesicle exocytosis, indicating that dimerization is essential for CAPS function. Comparison of the CAPS C2 domain to a structurally defined Munc13-1 C2A domain dimer revealed conserved residues involved in CAPS dimerization. We conclude that CAPS functions as a C2 domain-mediated dimer in regulated vesicle exocytosis. The unique tandem C2-PH domain of CAPS may serve as a PI(4,5)P 2 -triggered switch for dimerization. CAPS dimerization may be coupled to oligomeric SNARE complex assembly for vesicle docking and priming. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Liposome-encapsulated chemotherapy

    DEFF Research Database (Denmark)

    Børresen, B.; Hansen, A. E.; Kjær, A.

    2018-01-01

    in a canine cancer patient was published shortly thereafter. Regardless, no general application for liposomal cytotoxic drugs has been established in veterinary oncology till now. Due to the popularity of canines as experimental models for pharmacokinetic analyses and toxicity studies, multiple publications...... exist describing various liposomal drugs in healthy dogs. Also, some evidence for its use in veterinary cancer patients exists, especially in canine lymphoma, canine splenic hemangiosarcoma and feline soft tissue sarcoma, however, the results have not been overwhelming. Reasons for this may be related...

  11. Influence of the Flexible Liposomes on the Skin Deposition of a Hydrophilic Model Drug, Carboxyfluorescein: Dependency on Their Composition

    Science.gov (United States)

    Badran, Mohamed; Shalaby, Khaled; Al-Omrani, Abdullah

    2012-01-01

    This study focuses on the effect of different flexible liposomes containing sodium cholate, Tween 80, or cineol on skin deposition of carboxyfluorescein (CF). Size distribution, morphology, zeta potential, and stability of the prepared vesicles were evaluated. The influence of these systems on the skin deposition of CF utilizing rat skin as membrane model was investigated. Results showed that all of the investigated liposomes had almost spherical shapes with low polydispersity (PDI cineole, were able to deliver higher amount of CF suggesting that the hydrophilic drugs delivery to the skin was strictly correlated to the vesicle composition. PMID:22536120

  12. Characterization of novel multifunctional cationic polymeric liposomes formed from octadecyl quaternized carboxymethyl chitosan/cholesterol and drug encapsulation.

    Science.gov (United States)

    Liang, Xiao F; Wang, Han J; Luo, Hao; Tian, Hui; Zhang, Bing B; Hao, Li J; Teng, Jon I; Chang, Jin

    2008-07-15

    The design and construction of effective delivery vectors for drugs is very important. We have discovered that octadecyl quaternized carboxymethyl chitosan (OQCMC) in combination with cholesterol (Chol) could form stable vesicles with structure similar to that of conventional liposomes prepared from phosphatidylcholine/cholesterol (PC/Chol). Compared to conventional liposomes, our polymeric liposomes formed by OQCMC/Chol have many excellent features, such as good physical and thermal stability, excellent solubility in water, and high effectiveness in drug encapsulation. Trans-activating transcriptional activator protein (TAT peptide) could be connected on the surface of cationic polymeric liposomes by using cross-linking reagent N-hydroxysuccinimidyl-3-(2-pyridyldithio) propionate (SPDP). Also, oil-soluble magnetic nanoparticles were used to verify the bilayer structure of the polymeric liposomes and their ability to solublize hydrophobic materials. Using different preparation methods, OQCMC/Chol could easily be made into nanoscale particles by encapsulating both hydrophilic and hydrophobic components. We have successfully prepared polymeric liposomes encapsulating quantum dots (QDs), superparamagnetic nanoparticles, or both. Vincristine was also encapsulated in the polymeric liposomes with high drug encapsulation efficiency (90.1%). Vincristine-loaded magnetic polymeric liposomes were stable in aqueous solution and exhibited slow, steady release action over 2 weeks under physiologic pH (7.4). This allows the use of multifunctional cationic polymeric liposomes, such as those developed here from modified chitosan, in various applications such as cancer diagnosis and treatment.

  13. A liposome-based size calibration method for measuring microvesicles by flow cytometry

    DEFF Research Database (Denmark)

    Simonsen, Jens Bæk

    2016-01-01

    BACKGROUND: Over the last years the need for a gold standard to determine the sizes of extracellular vesicles including microvesicles by flow cytometry has been emphasized. METHODS: This work suggests to use artificial vesicles as calibrators to ascertain the size of microvesicles from the side...... to verify the correlation between the SSC from a liposome and the corresponding size. CONCLUSIONS: We show that artificial vesicles are more accurate size calibrators compared to the commonly used polystyrene calibrator beads illustrated by the SSC from 110 nm polystyrene beads corresponds to the scattering...... from ~400 nm sized vesicle-like particles. We also show that this method of size assessment based on SSC has a low resolution that is roughly estimated to be between 60 to 200 nm dependent on the vesicle size. This article is protected by copyright. All rights reserved....

  14. Tumor uptake of /sup 67/Ga-carrying liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Ogihara, Izumi; Kojima, Shuji; Kubodera, Akiko; Jay, M.

    1986-02-01

    The in vivo distribution, excretion, and tumor localization of liposome-encapsulated /sup 67/Ga in normal and Ehrlich tumor (solid form)-bearing mice were studied. In normal mice, multilamellar vesicles (MLVs) were taken up mainly be the liver and spleen, whereas small, unilamellar vesicles (SUVs) exhibited a broader tissue distribution. When /sup 67/Ga was encapsulated in MLVs or SUVs, the excretion of the radiotracer in the urine and feces was less than that observed for free tracer at 72 h after i.v. administration. In tumor-bearing mice, SUVs were formed to accumulate preferentially in tumors. The tumor uptake of neutral, positive, and negative SUVs was 10%-13% of the administered dose per gram of tumor tissue at 24 h after their injection. These values were about three times higher than those found for free /sup 67/Ga-nitrilotriacetic acid trisodium salt (NTA) or /sup 67/Ga-citrate. Significant differences in tumor uptake due to different surface charges of liposomes were not observed. Enhanced tumor-to-blood and tumor-to-muscle ratios were also observed at 24 h after injection. These results suggest that /sup 67/Ga-carrying liposomes may be a useful for tumor imaging.

  15. Liposome and niosome preparation using a membrane contactor for scale-up.

    Science.gov (United States)

    Pham, Thi Thuy; Jaafar-Maalej, Chiraz; Charcosset, Catherine; Fessi, Hatem

    2012-06-01

    The scaling-up ability of liposome and niosome production, from laboratory scale using a syringe-pump device to a pilot scale using the membrane contactor module, was investigated. For this aim, an ethanol injection-based method was applied for liposome and niosome preparation. The syringe-pump device was used for laboratory scale batches production (30 ml for liposomes, 20 ml for niosomes) then a pilot scale (750 ml for liposomes, 1000 ml for niosomes) were obtained using the SPG membrane contactor. Resulted nanovesicles were characterized in terms of mean vesicles size, polydispersity index (PdI) and zeta potential. The drug encapsulation efficiency (E.E.%) was evaluated using two drug-models: caffeine and spironolactone, a hydrophilic and a lipophilic molecule, respectively. As results, nanovectors mean size using the syringe-pump device was comprised between 82 nm and 95 nm for liposomes and between 83 nm and 127 nm for niosomes. The optimal E.E. of caffeine within niosomes, was found around 9.7% whereas the spironolactone E.E. reached 95.6% which may be attributed to its lipophilic properties. For liposomes these values were about 9.7% and 86.4%, respectively. It can be clearly seen that the spironolactone E.E. was slightly higher within niosomes than liposomes. Optimized formulations, which offered smaller size and higher E.E., were selected for pilot scale production using the SPG membrane. It has been found that vesicles characteristics (size and E.E.%) were reproducible using the membrane contactor module. Thus, the current study demonstrated the usefulness of the membrane contactor as a device for scaling-up both liposome and niosome preparations with small mean sizes. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Uniport of monoanionic L-malate in membrane vesicles from Leuconostoc oenos

    NARCIS (Netherlands)

    SALEMA, M; POOLMAN, B; LOLKEMA, JS; DIAS, MCL; KONINGS, WN

    1994-01-01

    L-malate transport was studied in membrane vesicles from Leuconostoc oenos MLE(-) (mutant lacking malolactic enzyme) which were fused with liposomes containing beef heart cytochrome c oxidase as a proton-motive-force-generating system. In these hybrid membranes, accumulation of L-malate was observed

  17. Transport of Basic Amino Acids by Membrane Vesicles of Lactococcus lactis

    NARCIS (Netherlands)

    Driessen, Arnold J.M.; Leeuwen, Cornelis van; Konings, Wilhelmus

    The uptake of the basic amino acids arginine, ornithine, and lysine was studied in membrane vesicles derived from cells of Lactococcus lactis which were fused with liposomes in which beef heart mitochondrial cytochrome c oxidase was incorporated as a proton motive force (PMF)-generating system. In

  18. trimethylammoniumpropane-based Liposomes

    African Journals Online (AJOL)

    Kongmuang S. Ultrastructural characterisation of liposomes using transmission electron microscope. Adv. Mater Res 2008; 55(57): 709-711. 15. Zetasizer Nano Series. Malvern Instruments, England. 2005, User Manual Issue 2.2. 16. Office International des Epizooties (OIE) (World. Organization of Animal Health). 2004.

  19. Effects of lipid segregation and lysolipid dissociation on drug release from thermosensitive liposomes.

    Science.gov (United States)

    Sandström, Maria C; Ickenstein, Ludger M; Mayer, Lawrence D; Edwards, Katarina

    2005-09-20

    Lysolipid-containing thermosensitive liposomes (LTSL) release their contents instantly when heated to temperatures close to their gel to liquid-crystalline phase transition temperature (TC). We have recently shown that during the melting transition these liposomes undergo major morphology changes, including the formation of open liposomes, bilayer discs, and pore-like defects. The hyperthermia-induced release of liposomal contents appears to depend on the presence and accumulation of membrane additives in grain boundaries, which enhance packing defects and, in the case of micelle-forming membrane additives, stabilize the bilayer rim of open liposome structures and transient membrane pores. In the present study, we used the fluorescent label 1-pyrenehexadecanoicacid (PHDA) and a radiolabelled lysolipid as markers for lysolipid membrane distribution and retention, respectively. PHDA dimer formation indicated local PHDA accumulation in cholesterol-free liposomes but not in cholesterol-containing liposomes. When LTSL were incubated at a temperature of 37 degrees C together with egg-phosphatidylcholine (EPC) multilamellar vesicles (MLVs) approximately 50% of the lysolipids transferred rapidly from LTSL to EPC MLVs. This transfer led to a significant reduction in the amount of carboxyfluorescein released from LTSL upon heating. Our results imply that poor retention of lysolipids in the LTSL membrane could also affect drug release characteristics of LTSL in vivo.

  20. Development of a DNA-liposome complex for gene delivery applications.

    Science.gov (United States)

    Rasoulianboroujeni, M; Kupgan, G; Moghadam, F; Tahriri, M; Boughdachi, A; Khoshkenar, P; Ambrose, J J; Kiaie, N; Vashaee, D; Ramsey, J D; Tayebi, L

    2017-06-01

    The association structures formed by cationic liposomes and DNA (Deoxyribonucleic acid)-liposome have been effectively utilized as gene carriers in transfection assays. In this research study, cationic liposomes were prepared using a modified lipid film hydration method consisting of a lyophilization step for gene delivery applications. The obtained results demonstrated that the mean particle size had no significant change while the polydispersity (PDI) increased after lyophilization. The mean particle size slightly reduced after lyophilization (520±12nm to 464±25nm) while the PDI increased after lyophilization (0.094±0.017 to 0.220±0.004). In addition. The mean particle size of vesicles increases when DNA is incorporated to the liposomes (673±27nm). According to the Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) images, the spherical shape of liposomes confirmed their successful preservation and reconstitution from the powder. It was found that liposomal formulation has enhanced transfection considerably compared to the naked DNA as negative control. Finally, liposomal formulation in this research had a better function than Lipofectamine® 2000 as a commercialized product because the cellular activity (cellular protein) was higher in the prepared lipoplex than Lipofectamine® 2000. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Coupling of Ligands to the Liposome Surface by Click Chemistry.

    Science.gov (United States)

    Spanedda, Maria Vittoria; De Giorgi, Marcella; Hassane, Fatouma Saïd; Schuber, Francis; Bourel-Bonnet, Line; Frisch, Benoît

    2017-01-01

    Click chemistry represents a new bioconjugation strategy that can be used to conveniently attach various ligands to the surface of preformed liposomes. This efficient and chemoselective reaction involves a Cu(I)-catalyzed azide-alkyne cycloaddition which can be performed under mild experimental conditions in aqueous media. Here we describe the application of a model click reaction to the conjugation, in a single step, of unprotected α-1-thiomannosyl ligands, functionalized with an azide group, to liposomes containing a terminal alkyne-functionalized lipid anchor. Excellent coupling yields have been obtained in the presence of bathophenanthroline disulfonate, a water soluble copper-ion chelator, acting as a catalyst. No vesicle leakage is triggered by this conjugation reaction and the coupled mannose ligands are exposed at the surface of the liposomes. The major limitation of Cu(I)-catalyzed click reactions is that this conjugation is restricted to liposomes made of saturated (phospho)lipids. To circumvent that constraint, an example of alternative copper-free azide-alkyne click reaction has been developed. Molecular tools and results are presented here.

  2. Pore formation by T3SS translocators: liposome leakage assay.

    Science.gov (United States)

    Faudry, Eric; Perdu, Caroline; Attrée, Ina

    2013-01-01

    Gram-negative bacteria utilize a dedicated membrane-embedded apparatus, the type III secretion system (T3SS), to inject proteins into host cells. The passage of the proteins across the target membrane is accomplished by a proteinaceous pore-the translocon-formed within the host-cell cytoplasmic membrane. Translocators bound to their chaperones can be expressed in Escherichia coli and subsequently dissociated from the chaperone by guanidine treatment. The pore formation properties of the translocators can then be studied by an in-vitro liposome leakage assay. Sulforhodamine-B is encapsulated within lipid vesicles during liposome preparation. At high concentration, this fluorochrome exhibits self-quenching limiting fluorescence emission. Upon pore formation, liposome leakage leads to the dilution of Sulforhodamine-B in the medium and fluorescence emission increases. Alternatively, fluorochromes coupled to large dextran molecules can be encapsulated in order to estimate pore dimensions. Here we describe protein expression and purification, dye-liposome preparation, and leakage assay conditions.

  3. Lipid Vesicles for the Skin Delivery of Diclofenac: Cerosomes vs. Other Lipid Suspensions

    Directory of Open Access Journals (Sweden)

    Anahita Fathi-Azarbayjani

    2015-03-01

    Full Text Available Purpose: Lipid suspensions as drug carriers, including conventional liposomes, ethosomes, transferosomes, proniosomes, niosomes, PEG-PPG-PEG niosomes and stratum corneum liposomes (cerosomes, were formulated and compared. Methods: Lipid vesicles were formulated and assessed with regards to enhancement of skin permeation of diclofenac and stability profiles of the formulations. Formulation-induced changes of the biophysical structure of excised human skin were monitored using the Fourier transform infrared spectroscopy. Results: The stability profiles of these suspensions over 12 weeks did not show any significant drug leakage from the vesicles of interest (p > 0.05. FTIR observations indicated that the vesicles increased stratum corneum (SC lipid fluidization and altered protein conformation. Skin permeability experiments showed that the free unencapsulated drug in the cerosomal formulations caused significant increase in drug permeation across the skin (p < 0.01. Low skin permeability of drug from the other lipid suspensions could be due to the entrapment of diclofenac within these vesicles which decreased the solubility of the hydrophilic drug in the skin lipids and the partition coefficient of the drug from these vesicles into the SC. Conclusion: Optimal drug entrapment in vesicles or alteration of the skin structure may not necessarily enhance the permeation of hydrophilic drugs across the human skin. These lipid vesicles may be further developed into carriers of both hydrophilic and hydrophobic drugs for topical and transdermal delivery, respectively.

  4. Utilization of thin film method for preparation of celecoxib loaded liposomes

    Directory of Open Access Journals (Sweden)

    Eskandar Moghimipour

    2012-06-01

    Full Text Available Purpose: Celecoxib is nonsteroiddal anti-inflammatory drug that has been used extensively to treat patients with arthritis. The aim of the present study was to formulate and characterize liposomal vesicles loaded with celecoxib. Methods: Liposomes were prepared by thin film method using soya lecithin and cholesterol. The release of drug was determined using a dialysis membrane method. Liposomes were characterized by Differential Scanning Calorimetery (DSC, Transmission Electron Microscopy (TEM and their particle size was also determined. Results: The results showed that the drug encapsulation efficiency was 67.34% and there was 67.16% release after 0.5, 1, 2, 3, 4, 5, 6, 7, 8 and 24 h. Results of particle size determination showed a mean size of 677nm and nanoparticles were spherical as shown by TEM. The DSC curve of lecithin, cholesterol and celecoxib were different from celecoxib containing liposome. Conclusion: The results of characterization of the vesicles indicated the potential application of celecoxib loaded liposome as carrier system.

  5. Boronated liposome development and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, M.F. [Univ. of California, Los Angeles, CA (United States)

    1995-11-01

    The boronated liposome development and evaluation effort consists of two separate tasks. The first is the development of new boron compounds and the synthesis of known boron species with BNCT potential. These compounds are then encapsulated within liposomes for the second task, biodistribution testing in tumor-bearing mice, which examines the potential for the liposomes and their contents to concentrate boron in cancerous tissues.

  6. Design of peptide-targeted liposomes containing nucleic acids.

    Science.gov (United States)

    Santos, Adriana O; da Silva, Lígia C Gomes; Bimbo, Luís M; de Lima, Maria C Pedroso; Simões, Sérgio; Moreira, João N

    2010-03-01

    Anticancer systemic gene silencing therapy has been so far limited by the inexistence of adequate carrier systems that ultimately provide an efficient intracellular delivery into target tumor cells. In this respect, one promising strategy involves the covalent attachment of internalizing-targeting ligands at the extremity of PEG chains grafted onto liposomes. Therefore, the present work aims at designing targeted liposomes containing nucleic acids, with small size, high encapsulation efficiency and able to be actively internalized by SCLC cells, using a hexapeptide (antagonist G) as a targeting ligand. For this purpose, the effect of the liposomal preparation method, loading material (ODN versus siRNA) and peptide-coupling procedure (direct coupling versus post-insertion) on each of the above-mentioned parameters was assessed. Post-insertion of DSPE-PEG-antagonist G conjugates into preformed liposomes herein named as stabilized lipid particles, resulted in targeted vesicles with a mean size of about 130 nm, encapsulation efficiency close to 100%, and a loading capacity of approximately 5 nmol siRNA/mumol of total lipid. In addition, the developed targeted vesicles showed increased internalization in SCLC cells, as well as in other tumor cells and HMEC-1 microvascular endothelial cells. The improved cellular association, however, did not correlate with enhanced downregulation of the target protein (Bcl-2) in SCLC cells. These results indicate that additional improvements need to be performed in the future, namely by ameliorating the access of the nucleic acids to the cytoplasm of the tumor cells following receptor-mediated endocytosis. Copyright 2009 Elsevier B.V. All rights reserved.

  7. Liposome Biodistribution via Europium Complexes.

    Science.gov (United States)

    Mignet, Nathalie; Scherman, Daniel

    2017-01-01

    The drug delivery field needs tools to follow vector biodistribution. Radioactive tracers and conventional fluorophores are widely used. We propose here to use europium complexes. Use of pulsed light source time-resolved fluorimetry takes into account the fluorescence decay time of the lanthanide chelates to gain sensitivity in biological media. The method was developed to follow liposome biodistribution. Octadecyl-DTPA.Eu compound has been prepared and incorporated into liposomes without alteration of its fluorescence signal. The method has been validated by comparison with fluorophore-labeled liposomes. The way to proceed to use this method for liposomes or other vectors is detailed.

  8. Use of solid-state nanopores for sensing co-translocational deformation of nano-liposomes.

    Science.gov (United States)

    Goyal, Gaurav; Darvish, Armin; Kim, Min Jun

    2015-07-21

    Membrane deformation of nano-vesicles is crucial in many cellular processes such as virus entry into the host cell, membrane fusion, and endo- and exocytosis; however, studying the deformation of sub-100 nm soft vesicles is very challenging using the conventional techniques. In this paper, we report detecting co-translocational deformation of individual 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) nano-liposomes using solid-state nanopores. Electrokinetic translocation through the nanopore caused the soft DOPC liposomes (85 nm diameter) to change their shape, which we attribute to the strong electric field strength and physical confinement inside the pore. The experiments were performed at varying transmembrane voltages and the deformation was observed to mount up with increasing applied voltage and followed an exponential trend. Numerical simulations were performed to simulate the concentrated electric field strength inside the nanopore and a field strength of 14 kV cm(-1) (at 600 mV applied voltage) was achieved at the pore center. The electric field strength inside the nanopore is much higher than the field strength known to cause deformation of 15-30 μm giant membrane vesicles. As a control, we also performed experiments with rigid polystyrene beads that did not show any deformation during translocation events, which further established our hypothesis of co-translocational deformation of liposomes. Our technique presents an innovative and high throughput means for investigating deformation behavior of soft nano-vesicles.

  9. Complement activation as a bioequivalence issue relevant to the development of generic liposomes and other nanoparticulate drugs

    Energy Technology Data Exchange (ETDEWEB)

    Szebeni, Janos, E-mail: jszebeni2@gmail.com [Nanomedicine Research and Education Center, Semmelweis University, Budapest & SeroScience Ltd, Budapest (Hungary); Storm, Gert [Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht (Netherlands)

    2015-12-18

    Liposomes are known to activate the complement (C) system, which can lead in vivo to a hypersensitivity syndrome called C activation-related pseudoallergy (CARPA). CARPA has been getting increasing attention as a safety risk of i.v. therapy with liposomes, whose testing is now recommended in bioequivalence evaluations of generic liposomal drug candidates. This review highlights the adverse consequences of C activation, the unique symptoms of CARPA triggered by essentially all i.v. administered liposomal drugs, and the various features of vesicles influencing this adverse immune effect. For the case of Doxil, we also address the mechanism of C activation and the opsonization vs. long circulation (stealth) paradox. In reviewing the methods of assessing C activation and CARPA, we delineate the most sensitive porcine model and an algorithm for stepwise evaluation of the CARPA risk of i.v. liposomes, which are proposed for standardization for preclinical toxicology evaluation of liposomal and other nanoparticulate drug candidates. - Highlights: • Outlining of difficulties in generic development of liposomal drugs. • New regulatory requirements to evaluate CARPA in preclinical studies. • Review of complement activation by liposomes and its adverse consequences (CARPA). • Assays of C activation in vitro and CARPA in vivo, with the porcine test in focus. • Decision tree how to handle the risk of CARPA assessed by a battery of tests.

  10. The gastro-intestinal absorption of griseofulvin can be enhanced by encapsulation into liposomes.

    Science.gov (United States)

    Sue, M S; Liu, K M; Yu, H S

    1993-01-01

    Liposomes are microscopic structures consisting of one or more lipid bilayers enclosing a definite aqueous space. They are widely used as a drug carrier and for the delivery of drugs through membranes. Drugs can be encapsulated into the inner water phase or lipidic wall, depending on their own hydro- or lipophilicity. The characteristics of the vesicles is fusion with cells and natural endocytosis uptake. We applied the properties of liposomes to overcome the poor gastro-intestinal (GI) absorption of griseofulvin and compared results with the traditional dosage form. In this experiment, the maximum plasma concentration obtained from griseofulvin liposomes was about 2.6 times than that from griseofulvin suspension. We used the lipids to prepare liposomes that consisted of phosphatidycholine, cholesterol, and dicetylphosphate in the molar ratio, 1:1.6:0.2, which is similar to the membrane composition of red blood cells. We examined some factors affecting the encapsulation ratin (E.R.%) and physicochemical properties of liposomes. When the lipid-to-griseofulvin weight ratio approached 38:1, the encapsulation ratio reached 94%. The different lipid/aqueous ratio (19/1 48/1 96/1) appeared to have little effect on E.R. value. The stability of griseofulvin liposomes in terms of leakage of griseofulvin was negligible over a period of 18 days at 4 degrees C. The sedimentation of vesicles bearing negative charges exhibited the best flocculation state. The plasma level-time profile of griseofulvin obtained from ingestion of liposomal dosage form showed itself to be significantly higher (P<0.01) Cmax, AUC, Ka, and t1/2 than that from suspension.

  11. Synaptic Vesicle Endocytosis

    Science.gov (United States)

    Saheki, Yasunori; De Camilli, Pietro

    2012-01-01

    Neurons can sustain high rates of synaptic transmission without exhausting their supply of synaptic vesicles. This property relies on a highly efficient local endocytic recycling of synaptic vesicle membranes, which can be reused for hundreds, possibly thousands, of exo-endocytic cycles. Morphological, physiological, molecular, and genetic studies over the last four decades have provided insight into the membrane traffic reactions that govern this recycling and its regulation. These studies have shown that synaptic vesicle endocytosis capitalizes on fundamental and general endocytic mechanisms but also involves neuron-specific adaptations of such mechanisms. Thus, investigations of these processes have advanced not only the field of synaptic transmission but also, more generally, the field of endocytosis. This article summarizes current information on synaptic vesicle endocytosis with an emphasis on the underlying molecular mechanisms and with a special focus on clathrin-mediated endocytosis, the predominant pathway of synaptic vesicle protein internalization. PMID:22763746

  12. Targeting of small molecule anticancer drugs to the tumour and its vasculature using cationic liposomes: lessons from gene therapy

    Directory of Open Access Journals (Sweden)

    Choong Peter FM

    2006-06-01

    Full Text Available Abstract Cationic (positively charged liposomes have been tested in various gene therapy clinical trials for neoplastic and other diseases. They have demonstrated selectivity for tumour vascular endothelial cells raising hopes for both antiangiogenic and antivascular therapies. They are also capable of being selectively delivered to the lungs and liver when administered intravenously. These vesicles are being targeted to the tumour in various parts of the body by using advanced liposomal systems such as ligand-receptor and antibody-antigen combinations. At present, the transferrin receptor is commonly used for cancer-targeted drug delivery systems including cationic liposomes. This review looks at the growing utility of these vesicles for delivery of small molecule anticancer drugs.

  13. Physicochemical characterizations of functional hybrid liposomal nanocarriers formed using photo-sensitive lipids

    Science.gov (United States)

    Kumar Pramanik, Sumit; Losada-Pérez, Patricia; Reekmans, Gunter; Carleer, Robert; D'Olieslaeger, Marc; Vanderzande, Dirk; Adriaensens, Peter; Ethirajan, Anitha

    2017-04-01

    With recent advances in the field of diagnostics and theranostics, liposomal technology has secured a fortified position as a potential nanocarrier. Specifically, radiation/photo-sensitive liposomes containing photo-polymerizable cross-linking lipids are intriguing as they can impart the vesicles with highly interesting properties such as response to stimulus and improved shell stability. In this work, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphoethanolamine (DTPE) is used as a photo-polymerizable lipid to form functional hybrid-liposomes as it can form intermolecular cross-linking through the diacetylenic groups. Hybrid-liposomes were formulated using mixtures of DTPE and saturated lipids of different chain lengths (dipalmitoylphosphatidylcholine (DPPC) and dimirystoilphosphatidylcholine (DMPC)) at different molar ratios. The physico-chemical characteristics of the liposomes has been studied before and after UV irradiation using a combination of techniques: DSC, QCM-D and solid-state NMR. The results signify the importance of a subtle modification in alkyl chain length on the phase behavior of the hybrid-liposomes and on the degree of crosslinking in the shell.

  14. Preparation and Characterization of Escherichia coli Liposomes as a New Drug Delivery System to Colon Cancer

    Directory of Open Access Journals (Sweden)

    Mohammad Kargar

    2016-06-01

    Full Text Available Introduction: Liposomes are spherical vesicles composed of concentric phospholipid bilayers that can entrap hydrophilic, hydrophobic drugs. Liposomes can be prepared from natural phospholipids, synthetic lipids or bacterial lipids. The aim of this study was to formulate liposome from bacterial lipids and evaluate physicochemical properties. Materials and methods: This study was performed experimentally on E.coli. The lipids were extracted from E.coli. using chloroform and methanol. Film method was used for preparing nano-systems and methylene blue was used as a drug model. Then their particle sizes were determined using particle sizer. The release methylene blue was carried out using dialysis membrane. Also, trailing them in cancer cells was evaluated by using carboxyfluorescein. Results: The average particle size of E.coli. liposomal was 338 nm. Encapsulation efficiency was 53.33 ± 2.88% and the value of release after 24 h was 97.54% ± 0.00. Liposomes could deliver the carboxyfluorescein to cancer cells. Discussion and conclusion: The results of this study demonstrated that bacterial liposome has probably a suitable nano-particle such as particle size and desirable loading and it is possible to use them as drug delivery system.

  15. Lipid Vesicles for the Skin Delivery of Diclofenac: Cerosomes vs. Other Lipid Suspensions

    Science.gov (United States)

    Fathi-Azarbayjani, Anahita; Ng, Kai Xin; Chan, Yew Weng; Chan, Sui Yung

    2015-01-01

    Purpose: Lipid suspensions as drug carriers, including conventional liposomes, ethosomes, transferosomes, proniosomes, niosomes, PEG-PPG-PEG niosomes and stratum corneum liposomes (cerosomes), were formulated and compared. Methods: Lipid vesicles were formulated and assessed with regards to enhancement of skin permeation of diclofenac and stability profiles of the formulations. Formulation-induced changes of the biophysical structure of excised human skin were monitored using the Fourier transform infrared spectroscopy. Results: The stability profiles of these suspensions over 12 weeks did not show any significant drug leakage from the vesicles of interest (p > 0.05). FTIR observations indicated that the vesicles increased stratum corneum (SC) lipid fluidization and altered protein conformation. Skin permeability experiments showed that the free unencapsulated drug in the cerosomal formulations caused significant increase in drug permeation across the skin (p hydrophilic drug in the skin lipids and the partition coefficient of the drug from these vesicles into the SC. Conclusion: Optimal drug entrapment in vesicles or alteration of the skin structure may not necessarily enhance the permeation of hydrophilic drugs across the human skin. These lipid vesicles may be further developed into carriers of both hydrophilic and hydrophobic drugs for topical and transdermal delivery, respectively. PMID:25789216

  16. Fusion of Nonionic Vesicles

    DEFF Research Database (Denmark)

    Bulut, Sanja; Oskolkova, M. Z.; Schweins, R.

    2010-01-01

    We present an experimental study of vesicle fusion using light and neutron scattering to monitor fusion events. Vesicles are reproducibly formed with an extrusion procedure using an single amphiphile triethylene glycol mono-n-decyl ether in water. They show long-term stability for temperatures ar...... a barrier to fusion changing from 15 k(B)T at T = 26 degrees C to 10k(H) T at T = 35 degrees C. These results are compatible with the theoretical predictions using the stalk model of vesicle fusion....

  17. Compressibilities and Volume Fluctuations of Archaeal Tetraether Liposomes

    Science.gov (United States)

    Chong, Parkson Lee-Gau; Sulc, Michael; Winter, Roland

    2010-01-01

    Bipolar tetraether lipids (BTLs) are abundant in crenarchaeota, which thrive in both thermophilic and nonthermophilic environments, with wide-ranging growth temperatures (4–108°C). BTL liposomes can serve as membrane models to explore the role of BTLs in the thermal stability of the plasma membrane of crenarchaeota. In this study, we focus on the liposomes made of the polar lipid fraction E (PLFE). PLFE is one of the main BTLs isolated from the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius. Using molecular acoustics (ultrasound velocimetry and densimetry), pressure perturbation calorimetry, and differential scanning calorimetry, we have determined partial specific adiabatic and isothermal compressibility, their respective compressibility coefficients, partial specific volume, and relative volume fluctuations of PLFE large unilamellar vesicles (LUVs) over a wide range of temperatures (20–85°C). The results are compared with those obtained from liposomes made of dipalmitoyl-L-α-phosphatidylcholine (DPPC), a conventional monopolar diester lipid. We found that, in the entire temperature range examined, compressibilities of PLFE LUVs are low, comparable to those found in gel state of DPPC. Relative volume fluctuations of PLFE LUVs at any given temperature examined are 1.6–2.2 times more damped than those found in DPPC LUVs. Both compressibilities and relative volume fluctuations in PLFE LUVs are much less temperature-sensitive than those in DPPC liposomes. The isothermal compressibility coefficient (βTlipid) of PLFE LUVs changes from 3.59 × 10−10 Pa−1 at 25°C to 4.08 × 10−10 Pa−1 at 78°C. Volume fluctuations of PLFE LUVs change only 0.25% from 30°C to 80°C. The highly damped volume fluctuations and their low temperature sensitivity, echo that PLFE liposomes are rigid and tightly packed. To our knowledge, the data provide a deeper understanding of lipid packing in PLFE liposomes than has been previously reported, as well as a molecular

  18. iGUVs: Preparing Giant Unilamellar Vesicles with a Smartphone and Lipids Easily Extracted from Chicken Eggs

    Science.gov (United States)

    Almendro Vedia, Víctor G.; Natale, Paolo; Chen, Su; Monroy, Francisco; Rosilio, Veronique; López-Montero, Ivan

    2017-01-01

    Since the first report of electroformed micrometer-sized liposomes in the 1980s, giant unilamellar vesicles (GUVs) have generated a lot of interest in the biophysical and biochemical communities. However, their penetration rate in high school or at the undergraduate level is still limited because of the requirement of specialized materials for…

  19. A renewal model for the emergence of anomalous solute crowding in liposomes.

    Science.gov (United States)

    Paradisi, Paolo; Allegrini, Paolo; Chiarugi, Davide

    2015-01-01

    A fundamental evolutionary step in the onset of living cells is thought to be the spontaneous formation of lipid vesicles (liposomes) in the pre-biotic mixture. Even though it is well known that hydrophobic forces drive spontaneous liposome formation in aqueous solutions, how the components of the earliest biochemical pathways were trapped and concentrated in the forming vesicles is an issue that still needs to be clarified. In recent years, some authors carried out a set of experiments where a unexpectedly high amount of solutes were found in a small number of liposomes, spontaneously formed in aqueous solution. A great number of empty liposomes were found in the same experiments and the global observed behavior was that of a distribution of solute particles into liposomes in agreement with a inverse power-law function rather than with the expected Poisson distribution. The chemical and physical mechanisms leading to the observed "anomalous solute crowding" are still unclear, but the non-Poisson power-law behavior is associated with some cooperative behavior with strong non-linear interactions in the biochemical processes occurring in the solution. For tackling this issue we propose a model grounding on the Cox's theory of renewal point processes, which many authors consider to play a central role in the description of complex cooperative systems. Starting from two very basic hypotheses and the renewal assumption, we derive a model reproducing the behavior outlined above. In particular, we show that the assumption of a "cooperative" interaction between the solute molecules and the forming liposomes is sufficient for the emergence of the observed power-law behavior. Even though our approach does not provide experimental evidences of the chemical and physical bases of the solute crowding, it suggests promising directions for experimental research and it also provide a first theoretical prediction that could possibly be tested in future experimental investigations.

  20. Experimental Aspects of Colloidal Interactions in Mixed Systems of Liposome and Inorganic Nanoparticle and Their Applications

    Directory of Open Access Journals (Sweden)

    Michael Gradzielski

    2012-09-01

    Full Text Available In the past few years, growing attention has been devoted to the study of the interactions taking place in mixed systems of phospholipid membranes (for instance in the form of vesicles and hard nanoparticles (NPs. In this context liposomes (vesicles may serve as versatile carriers or as a model system for biological membranes. Research on these systems has led to the observation of novel hybrid structures whose morphology strongly depends on the charge, composition and size of the interacting colloidal species as well as on the nature (pH, ionic strength of their dispersing medium. A central role is played by the phase behaviour of phospholipid bilayers which have a tremendous influence on the liposome properties. Another central aspect is the incorporation of nanoparticles into vesicles, which is intimately linked to the conditions required for transporting a nanoparticle through a membrane. Herein, we review recent progress made on the investigations of the interactions in liposome/nanoparticle systems focusing on the particularly interesting structures that are formed in these hybrid systems as well as their potential applications.

  1. Liposome based radiosensitizer cancer therapy

    DEFF Research Database (Denmark)

    Pourhassan, Houman

    Liposome-encapsulated chemotherapeutics have been used in the treatment of a variety of cancers and are feasible for use as mono-therapeutics as well as for combination therapy in conjunction with other modalities. Despite widespread use of liposomal drugs in cancer patient care, insufficient drug...... in tumor-bearing mice.The safety and efficacy of sPLA2-sensitive liposomal L-OHP was assessed in sPLA2-deficient FaDu hypopharyngeal squamous cell carcinoma and sPLA2-expressing Colo205 colorectal adenocarcinoma. Also, the feasibility of multimodal cancer therapy employing L-OHP encapsulated in MMP....... And may thereby improve therapeutic outcome. Two types of enzymes commonly overexpressed in solid cancers and exploited for liposomal drug delivery purposes, are secretory phospholipase A2 (sPLA2) and matrix metalloproteinases (MMPs).Furthermore, as platinum-based chemotherapeutic compounds are renowned...

  2. Polymeric vesicles: from drug carriers to nanoreactors and artificial organelles.

    Science.gov (United States)

    Tanner, Pascal; Baumann, Patric; Enea, Ramona; Onaca, Ozana; Palivan, Cornelia; Meier, Wolfgang

    2011-10-18

    One strategy in modern medicine is the development of new platforms that combine multifunctional compounds with stable, safe carriers in patient-oriented therapeutic strategies. The simultaneous detection and treatment of pathological events through interactions manipulated at the molecular level offer treatment strategies that can decrease side effects resulting from conventional therapeutic approaches. Several types of nanocarriers have been proposed for biomedical purposes, including inorganic nanoparticles, lipid aggregates, including liposomes, and synthetic polymeric systems, such as vesicles, micelles, or nanotubes. Polymeric vesicles--structures similar to lipid vesicles but created using synthetic block copolymers--represent an excellent candidate for new nanocarriers for medical applications. These structures are more stable than liposomes but retain their low immunogenicity. Significant efforts have been made to improve the size, membrane flexibility, and permeability of polymeric vesicles and to enhance their target specificity. The optimization of these properties will allow researchers to design smart compartments that can co-encapsulate sensitive molecules, such as RNA, enzymes, and proteins, and their membranes allow insertion of membrane proteins rather than simply serving as passive carriers. In this Account, we illustrate the advances that are shifting these molecular systems from simple polymeric carriers to smart-complex protein-polymer assemblies, such as nanoreactors or synthetic organelles. Polymeric vesicles generated by the self-assembly of amphiphilic copolymers (polymersomes) offer the advantage of simultaneous encapsulation of hydrophilic compounds in their aqueous cavities and the insertion of fragile, hydrophobic compounds in their membranes. This strategy has permitted us and others to design and develop new systems such as nanoreactors and artificial organelles in which active compounds are simultaneously protected and allowed to

  3. Influence of different sugar cryoprotectants on the stability and physico-chemical characteristics of freeze-dried 5-fluorouracil plurilamellar vesicles

    Directory of Open Access Journals (Sweden)

    Mohamed Mahmoud Nounou

    2005-07-01

    Full Text Available Lyophilization increases the shelf-life of liposomes by preserving it in a dry form as lyophilized cake to be reconstituted with water immediately prior to administration. Aiming at increasing stability and availability of 5-Fluorouracil liposomal products, 5-Fluorouacil Stable Plurilamellar Vesicles were prepared. Freeze dried liposomal dispersions were prepared with or without cryoprotectants. The cryoprotectants used were glucose, mannitol or trehalose in 1, 2 and 4 grams per gram phospholipids. The results showed that lyophilized cake of liposomes without cryoprotectants was compact and difficult to reconstitute, in comparison with fluffy cakes which reconstituted easily and quickly when using cryoprotectants. The percentage of 5-Fluorouracil retained in liposomes freeze-dried without cryoprotectants was 18.29% ± 0.96% and the percentage of 5-Fluorouracil retained in stable plurilamellar vesicles was 31.22% ± 0.62% using 4 grams trehalose as cryoprotectant per gram of lipid. Physico-chemical and release stability studies showed superior potentials of the lyophilized product after reconstitution in comparison to dispersion product. It may be concluded that all tested sugars have cryoprotectant effects that stabilized liposomes in the freeze dried state, where trehalose offered the most superior cryoprotectant effect for freeze dried 5-fluorouracil liposomes.

  4. EXPERIMENTAL LIPOSOMAL VIRAL VACCINE SAFETY

    Directory of Open Access Journals (Sweden)

    Romanova OA

    2016-12-01

    Full Text Available Introduction. With the transport links development there is rather important issue respiratory viral infections spread, especially influenza. The only method controlling influenza is vaccination. Search and development effective and safe vaccines is important. Material and methods. In base SO "Mechnikov Institute Microbiology and Immunology National Ukrainian Academy Medical Sciences" in the scientific theme "Developing new approaches to creating viral vaccines and study specific activity depending of type and degree component`s modification" was created several experimental influenza vaccine with subsequent component`s modification for selecting the most optimal pattern of safety and immunogenicity. In assessing the influenza vaccine safety is using a few criteria, including, reactivity, as measured by the frequency of local and systemic adverse (negative effects, which due to its introduction, and for lipid content drugs, ability to influence oxidation processes. At present study phase was determined: a systemic reaction and local reaction of delayed-type hypersensitivity (foot pad swelling assay;b lipids and proteins peroxidation processes after administration officinal and experimental vaccines (content protein’s carbonyl groups, lipid’s hydroperoxides, activity of glutathione-peroxidase.Study objects were trivalent seasonal influenza vaccine, "Vaxigrip" (Sanofi Pasteur, S.A., France, "Inflexal V" (Biotech Ltd. Berne, Switzerland and experimental vaccine samples. Highest immunogenicity vaccines had undergone improvements and modifications using adjuvant systems and acylation influenza proteins. Liposomes 2 – the experimental influenza vaccine with a liposome negative charge and antigenic composition like split vaccines "Vaksihryp". Liposomes 2.1 - the adjuvantexperimental influenza vaccine with modifications liposomal components (etoniy and chlorophyllipt molecules embedded in liposomal membrane. Liposomes 2.2 - the adjuvant

  5. The effects of lyophilization on the stability of liposomes containing 5-FU.

    Science.gov (United States)

    Glavas-Dodov, M; Fredro-Kumbaradzi, E; Goracinova, K; Simonoska, M; Calis, S; Trajkovic-Jolevska, S; Hincal, A A

    2005-03-03

    Multilamellar liposomes containing 5-fluorouracil (5-FU) were prepared by modified lipid film hydration method and were lyophilized with or without saccharose as cryoprotectant. The effect of lyophilization on the stability of liposomes was evaluated by comparing the vesicle size, encapsulation efficiency and the drug release rate before and after lyophilization/rehydration. The process of lyophilization, without cryoprotectant, resulted in particle size increase and significant content leakage. By the addition of saccharose, the lipid bilayers become more stable and less permeable to the encapsulated drug, saccharose imparted 5-FU retention of about 80% after lyophilization/rehydration. Freeze-drying did not affect the particle size of liposomes containing saccharose as cryoprotectant. The drug release profiles of rehydrated liposomes followed Higuchi's square root model. Also, the obtained release profiles were all biphasic: a rapid initial drug release phase (burst release of the portion of the drug that leaked out of liposomes during the lyophilization) was followed by a slower, approximately constant drug release phase (zero-order kinetics).

  6. Process Variables and Design of Experiments in Liposome and Nanoliposome Research.

    Science.gov (United States)

    Zoghi, Alaleh; Khosravi-Darani, Kianoush; Omri, Abdelwahab

    2018-01-01

    Liposomes vesicles consisting of one or more phospholipid bilayers are microcarriers used in numerous scientific disciplines. During the last decade, nanostructured liposomes, or nanoliposomes, have been utilized in biomedical investigations due to their unique characteristics including nanoscale size, sustained release, biocompatibility, and biodegradability. The extensive literature covering the field of liposomology is an indication of increasing interests and applications in many areas, especially as carriers of active substances in nanomedicine, agriculture, food technology, and cosmetics. Nanoliposomes application as drug carriers resulted in more effective treatment of such diseases as cancers, atherosclerosis, infectious diseases and ocular disorders. In this communication, we will introduce commonly used methods for the preparation of liposome, pointing the therapeutic report of liposomes, and explaining the common process variables in liposome encapsulations. We will also review different screening methods and full and fractional factorial designs that impact independent variables in certain applications and the end-user response. We will review such key factors as encapsulation efficiency, loading capacity, particles' biologic, structural and physicochemical properties, and lipid composition in an effort to provide a comprehensive guide for liposomologists in different fields of interest. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. Preparation and Characterization of Naringenin-Loaded Elastic Liposomes for Topical Application.

    Directory of Open Access Journals (Sweden)

    Ming-Jun Tsai

    Full Text Available Excessive production of radical oxygen species in skin is a contributor to a variety of skin pathologies. Naringenin is a potent antioxidant. The purpose of the present study was to develop elastic liposomes for naringenin topical application. Naringenin-loaded elastic liposomes containing different amounts of Tween 80 and cholesterol were prepared. The physicochemical properties including vesicle size, surface charge, encapsulation efficiency, and permeability capacity were determined to evaluate the effect of components. The stability of formulation and skin irritation caused by drug-loaded elastic liposomes were also evaluated for assessment of the clinical utility of elastic liposomes. Saturated aqueous solution of naringenin and naringenin dissolved in 10% Tween 80 solution (5 mg/mL were used as the control group. The result showed that in using elastic liposomes as carrier, the deposition amounts in the skin of naringenin were significantly increased about 7.3~11.8-fold and 1.2~1.9-fold respectively, when compared with the saturated aqueous solution and Tween 80 solution-treated groups. The level of drug was more than 98.89±3.90% after 3 months of storage at 4℃. In a skin irritation test, the result showed experimental formulation exhibit considerably less irritating than the positive control (paraformaldehyde-treated group, suggesting its potential therapeutic application.

  8. OBTAINING AND CHARACTERISTIC OF CURCUMIN LIPOSOMAL FORM

    Directory of Open Access Journals (Sweden)

    Shulga S. M.

    2014-10-01

    Full Text Available Creation of liposomal forms of curcumin (diferuloilmetane was investegated in the work. The methods of preparation and determination of the obtained liposomes sizes and percentage of curcumin in liposomes are given. Soybean phospholipids, egg yolk phospholipids and sunflower phospholipids were selected for preparation of “empty” liposomes and liposomes loaded curcumin: C-SPC-L (curcumin encapsulated in SPC liposomes, C-EPC-L (curcumin encapsulated in EPC liposomes and C-SFPC-L (curcumin encapsulated in liposomes SFPC. Physical properties of different liposomes such as average size (Dl and encapsulation efficiency (EE were studed. Using photon correlation spectroscopy, the average size of three types of curcumin-loaded liposomes were found as Dl = 111 ± 3 nm for C-SPC-L, Dl = 98 ± 5 nm for C-EPC-L and Dl = 109 ± 5 nm for C-SFPC-L. Encapsulation efficiency showed the following values: EEC-SPC-L = 83 ± 4%, EEC-EPC-L = 82 ± 3%, and EEC-SFPC-L = 85 ± 4%. We determined that by using the methods of freezing and thawing or sonication it was possible to isolate liposomes sized in the range 100– 120 nm. Upon that the obtained liposomal form of curcumin was stable and freeze-thaw method was optimal for liposomal form and provides a relatively high level (more than 80% of curcumin inclusion.

  9. In vitro determination of the efficacy of scorpion venoms as anti-cancer agents against colorectal cancer cells: a nano-liposomal delivery approach

    Science.gov (United States)

    Al-Asmari, Abdulrahman K; Ullah, Zabih; Al Balowi, Ali; Islam, Mozaffarul

    2017-01-01

    The use of liposomes in biological and medicinal sciences is a relatively new approach. The liposomal strategy greatly depends on the technological advancement in the formation of vesicles of various sizes and properties. In the current study, we encapsulated the venoms obtained from medically important scorpions such as Androctonus bicolor (AB), Androctonus crassicauda (AC), and Leiurus quinquestriatus (LQ). To begin with, our first and foremost aim was to prepare biocompatible and biodegradable nanovesicles. Additionally, we intended to enhance the anti-cancer potential of these encapsulated venoms. The liposomal venoms were prepared by rehydration and dehydration methods. Morphology, particle size, and size distribution of the liposomes were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), and Zetasizer. We found that the prepared liposomes had a smooth surface and a spherical/ovoid shape and existed mainly as single unilamellar vesicles (SUVs). Furthermore, the liposomal formulation of all three venoms exhibited excellent stability and good encapsulation efficiency (EE). Additionally, the anti-cancer potential of the encapsulated venoms was also evaluated on a colorectal cancer cell line (HCT-8). The venom-loaded liposomes showed elevated anti-cancer properties such as low rate of cell survival, higher reactive oxygen species (ROS) generation, and enhancement in the number of apoptotic cells. In addition to this, cell cycle analysis revealed G0/G1 enrichment upon venom treatment. The effect of treatment was more pronounced when venom–liposome was used as compared to free venom on the HCT-8 cell line. Furthermore, we did not observe any interference of liposomal lipids used in these preparations on the progression of cancer cells. Considering these findings, we can conclude that the encapsulated scorpion venoms exhibit better efficacy and act more vigorously as an anti-cancer agent on the colorectal cancer cell line when

  10. Development of liposomal anticancer drugs.

    Science.gov (United States)

    Hyodo, Kenji; Yamamoto, Eiichi; Suzuki, Takuya; Kikuchi, Hiroshi; Asano, Makoto; Ishihara, Hiroshi

    2013-01-01

    Liposomes are drug delivery systems that can alter the pharmacokinetic properties of compounds. The adverse effects of anticancer agents are a limiting factor for cancer chemotherapy, therefore, liposomal formulations have the potential to improve the therapeutic efficacy of anticancer agents by enhancing their accumulation in tumors and reducing non-selective distribution to normal tissues, which is known as the enhanced permeability and retention effect. To develop a liposomal anticancer agent as a drug product, its formulation must be designed to ensure its quality until it is administered to patients and to exert maximum potency in clinical use rather than in animal experiments. The chemical stability and physicochemical stability of the ingredients are key factors in the design of liposomal formulations. Drug release rates are critical factors in the therapeutic efficacy of liposomal drug products because the encapsulated drug has no pharmacological activity, and only released drug can exert antitumor/toxic activities. Liposomes should maintain the drug in a stable state in the circulation and then promptly release it after accumulation in the target tissue in order to achieve a sufficient drug concentration. To understand the profile of the formulation and to guarantee the quality of drug product, a reliable analytical method that can determine the released and encapsulated drugs in biological fluids is required. Simple online solid phase extractions of the released and encapsulated drugs using a column-switching HPLC system meet the requirements and this system enables accurate in vitro release testing and in vivo pharmacokinetic evaluation. This review introduces the process of liposomal drug product development from various viewpoints.

  11. Characteristics and behaviour of liposomes when incubated with natural bile salt extract: implications for their use as oral drug delivery systems.

    Science.gov (United States)

    Hermida, Laura G; Sabés-Xamaní, Manuel; Barnadas-Rodríguez, Ramon

    2014-09-21

    The use of liposomes for oral administration of drugs and for food applications is based on their ability to preserve entrapped substances and to increase their bioavailability. Bile salts are one of the agents that affect the liposome structure during intestinal digestion and the main reported studies on liposome/bile salt systems used only one bile salt. The aim of this work is to characterise the interaction of liposomes with a natural bile salt extract (BSE) at physiological pH and temperature. Three types of liposomes (fluid, gel-state and liquid-ordered bilayers) were studied. Phase diagrams were obtained and a very different behaviour was found. Fluid bilayers were completely permeable to an entrapped dye with partial or complete disruption of vesicles (final size 10 nm). Gel-state bilayers released their content but BSE led to the formation of large mixed structures (2000 nm). Liquid-ordered bilayers formed mixed vesicles (1000 nm) and, surprisingly, retained a high percentage of their aqueous content (about 50%). As a consequence, each type of liposome offers singular features to be used in oral applications due to their specific interaction with bile salts.

  12. Liposomal preparation by supercritical fluids technology | Zhong ...

    African Journals Online (AJOL)

    From 1970s, supercritical fluids technology (SCF) has been utilized in liposomal preparation because of its friendliness, nontoxicity to the environment and its possibility to achieve solvent-free liposomes and industrial-scale of liposome production under the conditions of current good manufacturing practice (cGMP).

  13. The targeting of phospholipid liposomes to bacteria.

    Science.gov (United States)

    Jones, M N; Kaszuba, M; Reboiras, M D; Lyle, I G; Hill, K J; Song, Y H; Wilmot, S W; Creeth, J E

    1994-11-23

    Phospholipid liposomes have been prepared from phospholipid mixtures including dipalmitoylphosphatidylcholine/phosphatidylinositol (DPPC/PI) and DPPC/dipalmitoylphosphatidylglycerol (DPPC/DPPG) mixtures and targeted to adsorbed biofilms of the skin-associated bacteria Staphylococcus epidermidis and Proteus vulgaris and the oral bacterium Streptococcus sanguis. The effects of time, liposome concentration and density of bacteria in the biofilm have been studied in detail for Staphylococcus epidermidis. The targeting (as assessed by the apparent monolayer coverage of the biofilms by liposomes) to the biofilms was found to be sensitive to the mol% of PI and DPPG in the liposomes and optimum levels of PI were found for targeting to each bacterium. The use of PI and DPPG-containing liposomes for the delivery of the bactericide, Triclosan, to biofilms of Staphylococcus epidermidis was studied as a function of the amount of Triclosan carried by the liposomes. All the liposome systems tested inhibited the growth of bacteria from the biofilms after brief (2 min) exposure to Triclosan-carrying liposomes. At low Triclosan levels bacterial growth inhibition by Triclosan-carrying liposomes exceeded that by an equivalent level of free Triclosan. After short periods (min) of exposure of biofilms to Triclosan-carrying liposomes the bactericide was shown to preferentially concentrate in the biofilms relative to its liposomal lipid carrier. The results suggest that phospholipid liposomes with appropriately chosen lipid composition have potential for the targeting and delivery of bactericide to bacteria.

  14. Aerosol Performance and Stability of Liposomes Containing Ciprofloxacin Nanocrystals

    Science.gov (United States)

    Wu, Huiying; Gonda, Igor; Chan, Hak-Kim

    2015-01-01

    Abstract Background: Previously we showed that the release properties of a liposomal ciprofloxacin (CFI) formulation could be attenuated by incorporation of drug nanocrystals within the vesicles. Rather than forming these drug nanocrystals during drug loading, they were created post manufacture simply by freezing and thawing the formulation. The addition of surfactant to CFI, either polysorbate 20 or Brij 30, provided an additional means to modify the release profile or incorporate an immediate-release or ‘burst’ component as well. The goal of this study was to develop a CFI formulation that retained its nanocrystalline morphology and attenuated release profile after delivery as an inhaled aerosol. Methods: Preparations of 12.5 mg/mL CFI containing 90 mg/mL sucrose and 0.1% polysorbate 20 were formulated between pH 4.6 to 5.9, stored frozen, and thawed prior to use. These thawed formulations, before and after mesh nebulization, and after subsequent refrigerated storage for up to 6 weeks, were characterized in terms of liposome structure by cryogenic transmission electron microscopy (cryo-TEM) imaging, vesicle size by dynamic light scattering, pH, drug encapsulation by centrifugation-filtration, and in vitro release (IVR) performance. Results: Within the narrower pH range of 4.9 to 5.3, these 12.5 mg/mL liposomal ciprofloxacin formulations containing 90 mg/mL sucrose and 0.1% polysorbate 20 retained their physicochemical stability for an additional 3 months refrigerated storage post freeze-thaw, were robust to mesh nebulization maintaining their vesicular form containing nanocrystalline drug and an associated slower release profile, and formed respirable aerosols with a mass median aerodynamic diameter (MMAD) of ∼3.9 μm and a geometric standard deviation (GSD) of ∼1.5. Conclusions: This study demonstrates that an attenuated release liposomal ciprofloxacin formulation can be created through incorporation of drug nanocrystals in response to freeze

  15. Environment-responsive multifunctional liposomes.

    Science.gov (United States)

    Kale, Amit A; Torchilin, Vladimir P

    2010-01-01

    Liposomal nanocarriers anchored with a cell-penetrating peptide and a pH-sensitive PEG-shield where later has ability to provide simultaneously better systemic circulation and site-specific exposure of cell penetrating peptide. PEG chains were incorporated into the liposome membrane via the PEG-attached phosphatidylethanolamine (PE) residue with PEG and PE being conjugated with the lowered pH-degradable hydrazone bond (PEG-HZ-PE), while cell-penetrating peptide (TATp) was added as TATp-PEG-PE conjugate. Under normal conditions, liposome-grafted PEG "shielded" liposome-attached TATp moieties, since the PEG spacer for TATp attachment (PEG(1000)) was shorter than protective PEG(2000). PEGylated liposomes accumulate in targets via the EPR effect, but inside the "acidified" tumor or ischemic tissues lose their PEG coating because of the lowered pH-induced hydrolysis of HZ and penetrate inside cells via the now-exposed TATp moieties. pH-responsive behavior of these constructs is successfully tested in cell cultures in vitro as well as in tumors in experimental mice in vivo. These nanocarriers also showed enhanced pGFP transfection efficiency upon intratumoral administration in mice, compared to control pH nonsensitive counterpart. These results can be considered as an important step in the development of tumor-specific stimuli-sensitive drug and gene delivery systems.

  16. Inhibition of skin inflammation in mice by diclofenac in vesicular carriers: liposomes, ethosomes and PEVs.

    Science.gov (United States)

    Caddeo, Carla; Sales, Octavio Diez; Valenti, Donatella; Saurí, Amparo Ruiz; Fadda, Anna Maria; Manconi, Maria

    2013-02-25

    Diclofenac-loaded phospholipid vesicles, namely conventional liposomes, ethosomes and PEVs (penetration enhancer-containing vesicles) were developed and their efficacy in TPA (phorbol ester) induced skin inflammation was examined. Vesicles were made from a cheap and unpurified mixture of phospholipids and diclofenac sodium; Transcutol P and propylene glycol were added to obtain PEVs, and ethanol to produce ethosomes. The structure and lamellar organization of the vesicle bilayer were investigated by transmission electron microscopy and small and wide angle X-ray scattering, as well as the main physico-chemical features. The formulations, along with a diclofenac solution and commercial Voltaren Emulgel, were tested in a comparative trial for anti-inflammatory efficacy on TPA-treated mice dorsal skin. Vesicles were around 100 nm, negatively charged, able to encapsulate diclofenac in good yields, and disclosed different lamellarity, as a function of the formulation composition. Vesicular formulations promoted drug accumulation and reduced the permeation. Administration of vesicular diclofenac on TPA-inflamed skin resulted in marked attenuation of oedema and leucocyte infiltration, especially using PEVs. Histology confirmed the effectiveness of vesicles, since they provided an amelioration of the tissual damage induced by TPA. The proposed approach based on vesicular nanocarriers may hold promising therapeutic value for treating a variety of inflammatory skin disorders. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Interaction of insulin, cholesterol-derivatized mannan, and carboxymethyl chitin with liposomes: A differential scanning calorimetry study.

    Science.gov (United States)

    Tabbakhian, M; Rogers, J A

    2012-01-01

    The interaction of drugs and polymers used to incorporate in or surface modify/coat the liposomes can affect the phase transition, fluidity and other physical properties as well as in vivo fate of vesicles. In this study, differential scanning calorimetry (DSC) was used to investigate changes in the temperature and the enthalpy of phase transition of liposomes of various electrical charges following interaction with carboxymethyl chitin (CM-chitin) as a hydrophilic polymer, cholesterol-derivatized mannan (CHM) as a hydrophilic polymer bearing a hydrophobic moiety, and insulin as a model peptide. The results indicated that insulin incorporation or polymers caused no significant change in the phase transition temperature (T(m)) of liposomes. However, reduction in the enthalpy of the transition (ΔH°) following coating with CHM supports an anchoring mechanism to the bilayer by the polymer, whereas no change or little increase in the ΔH° after coating with carboxymethyl chitin suggests no significant interaction or electrostatic weak interactions of polymer with liposomes. The DSC data of liposome-polymer interaction may be suggestive of changes in membrane fluidity, drug release, and possibly the behavior of liposomes in biological milieu.

  18. Uji Aktivitas Antiproliferasi Formula Liposom Ekstrak Etanol Kunyit (Curcuma domestica Terhadap Sel Kanker Payudara T47D

    Directory of Open Access Journals (Sweden)

    Gabriella Pasaribu

    2016-04-01

    Full Text Available Breast cancer is one of deadliest diseases in the world. Turmeric extract was known to have antiproliferative activity. To minimize its toxicity, turmeric extract was encapsulated with liposome, a vesicle lipid bilayer that was functioned as cancer drug carrier in body. This research aimed to determine encapsulation effect of turmeric extract against antiproliferative activity in T47D breast cancer cells through in vitro assay. Liposomes was made using thin layer method and particle size was reduced by extrusion. Materials that was used phosphatidylcholine, cholesterol, and turmeric extract. Optimization of liposomes was made in three formulations with different extract concentrations. The most optimal formulation was formulation with less extract and physical parameters which have smallest precipitates and longest settling time. Evaluation liposome particle size and zeta potential were used DLS, morphology was used TEM, and entrapment efficiency was used dialysis. The most optimal formulation was tested their antiproliferative activity compared with not encapsulated extracts used 3-(4,5-dimethylazole-2-yl-2,5-diphenyltetrazolium bromide (MTT method. The result showed that there was antiproliferative activity in encapsulated extracts. IC50 encapsulated extracts was 45.762 μg/ml and IC50 extracts was 36.399 μg/ml. Liposome particle size was below 445 nm. Zeta potential was -7.51 mV. Morphology was LUV and MVV. Entrapment efficiency was 63.80%. It could be concluded that encapsulation of turmeric extract into liposome could reduce its toxicity against cancer cells.

  19. In vivo Stability of Ester- and Ether-Linked Phospholipid-Containing Liposomes as Measured by Perturbed Angular Correlation Spectroscopy

    Science.gov (United States)

    Derksen, Johannes T.; Baldeschwieler, John D.; Scherphof, Gerrit L.

    1988-12-01

    To evaluate liposome formulations for use as intracellular sustained-release drug depots, we have compared the uptake and degradation in rat liver and spleen of liposomes of various compositions, containing as their bulk phospholipid an ether-linked phospholipid or one of several ester-linked phospholipids, by perturbed angular correlation spectroscopy. Multilamellar and small unilamellar vesicles (MLVs and SUVs), composed of egg phosphatidylcholine, sphingomyelin, distearoyl phosphatidylcholine (DSPC), dipalmitoyl phosphatidylcholine (DPPC) or its analog dihexadecylglycerophosphorylcholine (DHPC), and cholesterol plus phosphatidylserine, and containing 111In complexed to nitrilotriacetic acid, were injected intravenously in rats. Recovery of 111In-labeled liposomes in blood, liver, and spleen was assessed at specific time points after injection and the percentage of liposomes still intact in liver and spleen was determined by measurement of the time-integrated angular perturbation factor 111In of the [G22(∞ )] label. We found that MLVs but not SUVs, having DHPC as their bulk phospholipid, showed an increased resistance against lysosomal degradation as compared to other phospholipid-containing liposomes. The use of diacyl phospholipids with a high gel/liquid-crystalline phase-transition temperature, such as DPPC and DSPC, also retarded degradation of MLV, but not of SUV in the dose range tested, while the rate of uptake of these liposomes by the liver was lower.

  20. How pure are your vesicles?

    Science.gov (United States)

    Webber, Jason; Clayton, Aled

    2013-01-01

    We propose a straightforward method to estimate the purity of vesicle preparations by comparing the ratio of nano-vesicle counts to protein concentration, using tools such as the increasingly available NanoSight platform and a colorimetric protein assay such as the BCA-assay. Such an approach is simple enough to apply to every vesicle preparation within a given laboratory, assisting researchers as a routine quality control step. Also, the approach may aid in comparing/standardising vesicle purity across diverse studies, and may be of particular importance in evaluating vesicular biomarkers. We herein propose some criteria to aid in the definition of pure vesicles. PMID:24009896

  1. Development and characterization of nanopore system for nano-vesicle analysis

    Science.gov (United States)

    Goyal, Gaurav

    Nano-vesicles have recently attracted a lot of attention in research and medical communities and are very promising next-generation drug delivery vehicles. This is due to their biocompatibility, biodegradability and their ability to protect drug cargo and deliver it to site-specific locations, while maintaining the desired pharmacokinetic profile. The interaction of these drug loaded vesicles with the recipient cells via adsorption, endocytosis or receptor mediated internalization involve significant bending and deformation and is governed by mechanical properties of the nano-vesicles. Currently, the mechanical characteristics of nano-vesicles are left unexplored because of the difficulties associated with vesicle analysis at sub-100 nm length scale. The need for a complete understanding of nano-vesicle interaction with each other and the recipient cells warrants development of an analytical tool capable of mechanical investigation of individual vesicles at sub-100 nm scale. This dissertation presents investigation of nano-vesicle deformability using resistive pulse sensing and solid-state nanopore devices. The dissertation is divided into four chapters. Chapter 1 discusses the motivation, specific aims and presents an overview of nanoparticle characterization techniques, resistive pulse sensing background and principles, techniques for fabricating solid-state nanopores, as well the deformation behavior of giant vesicles when placed in electric field. Chapter 2 is dedicated to understanding of the scientific principles governing transport of sub-100 nm particles in dilute solutions. We investigated the translocation of rigid nanoparticles through nanopores at salt concentrations behavior of liposomes was compared to the rigid polystyrene particles which maintained their shape and did not exhibit any deformation. Chapter 4 extends the vesicle deformation analysis to exosomes derived from human breast cancer cell line. Exosomes also exhibit co

  2. Biological reference materials for extracellular vesicle studies.

    Science.gov (United States)

    Valkonen, S; van der Pol, E; Böing, A; Yuana, Y; Yliperttula, M; Nieuwland, R; Laitinen, S; Siljander, P R M

    2017-02-15

    Extracellular vesicles (EVs) mediate normal physiological homeostasis and pathological processes by facilitating intercellular communication. Research of EVs in basic science and clinical settings requires both methodological standardization and development of reference materials (RM). Here, we show insights and results of biological RM development for EV studies. We used a three-step approach to find and develop a biological RM. First, a literature search was done to find candidates for biological RMs. Second, a questionnaire was sent to EV researchers querying the preferences for RM and their use. Third, a biological RM was selected, developed, characterized, and evaluated. The responses to the survey demonstrated a clear and recognized need for RM optimized for the calibration of EV measurements. Based on the literature, naturally occurring and produced biological RM, such as virus particles and liposomes, were proposed as RM. However, none of these candidate RMs have properties completely matching those of EVs, such as size and refractive index distribution. Therefore, we evaluated the use of nanoerythrosomes (NanoE), vesicles produced from erythrocytes, as a potential biological RM. The strength of NanoE is their resemblance to EVs. Compared to the erythrocyte-derived EVs (eryEVs), NanoE have similar morphology, a similar refractive index (1.37), larger diameter (70% of the NanoE are over 200nm), and increased positive staining for CD235a and lipids (Di-8-ANEPPS) (58% and 67% in NanoE vs. 21% and 45% in eryEVs, respectively). Altogether, our results highlight the general need to develop and validate new RM with similar physical and biochemical properties as EVs to standardize EV measurements between instruments and laboratories. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Lipossomas: propriedades físico-químicas e farmacológicas, aplicações na quimioterapia à base de antimônio Liposomes: physicochemical and pharmacological properties, applications in antimony-based chemotherapy

    Directory of Open Access Journals (Sweden)

    Frédéric Frézard

    2005-06-01

    Full Text Available The use of organoantimonial complexes in the therapeutic of leishmaniasis and schistosomiasis has been limited mainly by the need for daily parenteral administration, their adverse side-effects and the appearance of drug resistance. Liposome encapsulation has been so far the most effective means to improve the efficacy of pentavalent antimonials against visceral leishmaniasis. Pharmacologically- and pharmaceutically-acceptable liposomal compositions are still being investigated through manipulation of preparation method, lipid composition and vesicle size. Recently, the encapsulation of a trivalent antimonial within "stealth" liposomes was found to reduce its acute toxicity and effectively deliver this compound to the parasite in experimental schistosomiasis.

  4. Role of B-1 cells in the immune response against an antigen encapsulated into phosphatidylcholine-containing liposomes.

    Science.gov (United States)

    Cruz-Leal, Yoelys; Machado, Yoan; López-Requena, Alejandro; Canet, Liem; Laborde, Rady; Álvares, Anuska Marcelino; Lucatelli Laurindo, María F; Santo Tomas, Julio F; Alonso, María E; Alvarez, Carlos; Mortara, Renato A; Popi, Ana F; Mariano, Mario; Pérez, Rolando; Lanio, María E

    2014-08-01

    B-1 lymphocytes comprise a unique subset of B cells that differ phenotypically, ontogenetically and functionally from conventional B-2 cells. A frequent specificity of the antibody repertoire of peritoneal B-1 cells is phosphatidylcholine. Liposomes containing phosphatidylcholine have been studied as adjuvants and their interaction with dendritic cells and macrophages has been demonstrated. However, the role of B-1 cells in the adjuvanticity of liposomes composed of phosphatidylcholine has not been explored. In the present work, we studied the contribution of B-1 cells to the humoral response against ovalbumin (OVA) encapsulated into dipalmitoylphosphatidylcholine (DPPC) and cholesterol-containing liposomes. BALB/X-linked immunodeficient (xid) mice, which are deficient in B-1 cells, showed quantitative and qualitative differences in the anti-OVA antibody response compared with wild-type animals after immunization with these liposomes. The OVA-specific immune response was significantly increased in the BALB/xid mice when reconstituted with B-1 cells from naive BALB/c mice. Our results indicate the internalization of DPPC-containing liposomes by these cells and their migration from the peritoneal cavity to the spleen. Phosphatidylcholine significantly contributed to the immunogenicity of liposomes, as DPPC-containing liposomes more effectively stimulated the anti-OVA response compared with vesicles composed of dipalmitoylphosphatidylglycerol. In conclusion, we present evidence for a cognate interaction between B-1 cells and phosphatidylcholine liposomes, modulating the immune response to encapsulated antigens. This provides a novel targeting approach to assess the role of B-1 cells in humoral immunity. © The Japanese Society for Immunology. 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Comparison of ethosomes and liposomes for skin delivery of psoralen for psoriasis therapy.

    Science.gov (United States)

    Zhang, Yong-Tai; Shen, Li-Na; Wu, Zhong-Hua; Zhao, Ji-Hui; Feng, Nian-Ping

    2014-08-25

    Recent reports have indicated that psoriasis may be caused by malfunctioning dermal immune cells, and psoralen ultraviolet A (PUVA) is an effective treatment for this chronic disease. However, conventional topical formulations achieve poor drug delivery across patches of psoriasis to their target sites. The present study describes the development of a novel psoralen transdermal delivery system employing ethosomes, flexible vesicles that can penetrate the stratum corneum and target deep skin layers. An in vitro skin permeation study showed that the permeability of psoralen-loaded ethosomes was superior to that of liposomes. Using ethosomes, psoralen transdermal flux and skin deposition were 38.89±0.32 μg/cm(2)/h and 3.87±1.74 μg/cm(2), respectively, 3.50 and 2.15 times those achieved using liposomes, respectively. The ethosomes and liposomes were found to be safe following daily application to rat skin in vivo, for 7 days. The ethosomes showed better biocompatibility with human embryonic skin fibroblasts than did an equivalent ethanol solution, indicating that the phosphatidylcholine present in ethosome vesicles improved their biocompatibility. These findings indicated that ethosomes could potentially improve the dermal and transdermal delivery of psoralen and possibly of other drugs requiring deep skin delivery. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Rapid Single-step Formation of Liposomes by Flow Assisted Stationary Phase Interdiffusion.

    Science.gov (United States)

    Has, Chandra; Phapal, Sopan M; Sunthar, P

    2018-01-17

    Laboratory preparation of unilamellar liposomes often involves multiple steps carried out over several hours to achieve a monodisperse size distribution. Here we present a methodology, based on a recently introduced lipid self-assembly principle-stationary phase interdiffusion (SPI)-to prepare large unilamellar vesicles (LUVs) of a monodisperse population in a short period of about 10min. The stationary interface between a lipid-ethanol phase and an aqueous phase is created by a density difference induced convective flow in a horizontal capillary. The average size of the liposomes, as expected from the SPI principle, is modulated only by the temperature and the type of lipids. Lipid concentration, ethanol content, pH of the aqueous phase, and the time duration of the experiment have little influence on the mean diameter of the vesicles. This simple methodology can be easily carried out with a capillary and a micro-needled syringe, and provides a rapid production tool for researchers requiring reproducible liposome suspensions. Refined natural lipids, based on soy and egg lecithin mixtures, yield LUVs in the range 100-200 nm, suitable for drug delivery applications. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Bilayer properties of giant magnetic liposomes formed by cationic pyridine amphiphile and probed by active deformation under magnetic forces.

    Science.gov (United States)

    Petrichenko, O; Erglis, K; Cēbers, A; Plotniece, A; Pajuste, K; Béalle, G; Ménager, Ch; Dubois, E; Perzynski, R

    2013-01-01

    We synthesize giant magnetic liposomes by a reverse-phase evaporation method (REV) using a new self-assembling Cationic Pyridine Amphiphile (CPA) derived from 1,4-dihydropyridine as liposome-forming agent and a magnetic ferrofluid based on γ-Fe(2)O(3) nanoparticles. Having in view the potential interest of CPA in targeted transport by magnetic forces, the mechanical elastic properties of such bilayers are here directly investigated in vesicles loaded with magnetic nanoparticles. Bending elastic modulus K(b) ∼ 0.2 to 5k(B)T and pre-stress τ ∼ 3.2 to 12.10(-6) erg/cm(2) are deduced from the under-field deformations of the giant magnetic liposomes. The obtained K(b) values are discussed in terms of A. Wurgers's theory.

  8. Intravesical liposome drug delivery and IC/BPS.

    Science.gov (United States)

    Janicki, Joseph J; Gruber, Michele A; Chancellor, Michael B

    2015-10-01

    Intravesical therapy has previously shown to be effective in delaying or preventing recurrence of superficial bladder cancer. This local route of drug administration is now demonstrating promise in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) with the benefit of minimal systemic side effects. Liposomes (LPs) are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core. They can incorporate drug molecules, both hydrophobic and hydrophilic, and vastly improve cellular uptake of these drug molecules via endocytosis. Intravesical LPs have therapeutic effects on IC/BPS patients, mainly due to their ability to form a protective lipid film on the urothelial surface and repair the damaged urothelium. This review considers the current status of intravesical LPs and LP mediated drug delivery for the treatment of IC/BPS.

  9. Liposomes: from a clinically established drug delivery system to a nanoparticle platform for theranostic nanomedicine.

    Science.gov (United States)

    Al-Jamal, Wafa' T; Kostarelos, Kostas

    2011-10-18

    For decades, clinicians have used liposomes, self-assembled lipid vesicles, as nanoscale systems to deliver encapsulated anthracycline molecules for cancer treatment. The more recent proposition to combine liposomes with nanoparticles remains at the preclinical development stages; however, such hybrid constructs present great opportunities to engineer theranostic nanoscale delivery systems, which can combine simultaneous therapeutic and imaging functions. Many novel nanoparticles of varying chemical compositions are being developed in nanotechnology laboratories, but further chemical modification is often required to make these structures compatible with the biological milieu in vitro and in vivo. Such nanoparticles have shown promise as diagnostic and therapeutic tools and generally offer a large surface area that allows covalent and non-covalent surface functionalization with hydrophilic polymers, therapeutic moieties, and targeting ligands. In most cases, such surface manipulation diminishes the theranostic properties of nanoparticles and makes them less stable. From our perspective, liposomes offer structural features that can make nanoparticles biocompatible and present a clinically proven, versatile platform for further enhancement of the pharmacological and diagnostic efficacy of nanoparticles. In this Account, we describe two examples of liposome-nanoparticle hybrids developed as theranostics: liposome-quantum dot hybrids loaded with a cytotoxic drug (doxorubicin) and artificially enveloped adenoviruses. We incorporated quantum dots into lipid bilayers, which rendered them dispersible in physiological conditions. This overall vesicular structure allowed them to be loaded with doxorubicin molecules. These structures exhibited cytotoxic activity and labeled cells both in vitro and in vivo. In an alternative design, lipid bilayers assembled around non-enveloped viral nanoparticles and altered their infection tropism in vitro and in vivo with no chemical or

  10. Application of Coiled Coil Peptides in Liposomal Anticancer Drug Delivery Using a Zebrafish Xenograft Model.

    Science.gov (United States)

    Yang, Jian; Shimada, Yasuhito; Olsthoorn, René C L; Snaar-Jagalska, B Ewa; Spaink, Herman P; Kros, Alexander

    2016-08-23

    The complementary coiled coil forming peptides E4 [(EIAALEK)4] and K4 [(KIAALKE)4] are known to trigger liposomal membrane fusion when tethered to lipid vesicles in the form of lipopeptides. In this study, we examined whether these coiled coil forming peptides can be used for drug delivery applications. First, we prepared E4 peptide modified liposomes containing the far-red fluorescent dye TO-PRO-3 iodide (E4-Lipo-TP3) and confirmed that E4-liposomes could deliver TP3 into HeLa cells expressing K4 peptide on the membrane (HeLa-K) under cell culture conditions in a selective manner. Next, we prepared doxorubicin-containing E4-liposomes (E4-Lipo-DOX) and confirmed that E4-liposomes could also deliver DOX into HeLa-K cells. Moreover, E4-Lipo-DOX showed enhanced cytotoxicity toward HeLa-K cells compared to free doxorubicin. To prove the suitability of E4/K4 coiled coil formation for in vivo drug delivery, we injected E4-Lipo-TP3 or E4-Lipo-DOX into zebrafish xenografts of HeLa-K. As a result, E4-liposomes delivered TP3 to the implanted HeLa-K cells, and E4-Lipo-DOX could suppress cancer proliferation in the xenograft when compared to nontargeted conditions (i.e., zebrafish xenograft with free DOX injection). These data demonstrate that coiled coil formation enables drug selectivity and efficacy in vivo. It is envisaged that these findings are a step forward toward biorthogonal targeting systems as a tool for clinical drug delivery.

  11. Transbilayer movement and net flux of cholesterol and cholesterol sulfate between liposomal membranes.

    Science.gov (United States)

    Rodrigueza, W V; Wheeler, J J; Klimuk, S K; Kitson, C N; Hope, M J

    1995-05-09

    The kinetics of cholesterol and cholesterol sulfate (CS) movement between vesicles have been investigated. CS is widely distributed in cell membranes, plasma and skin and is similar in structure to cholesterol, but possesses an ionizable sulfate moiety at the 3 beta-position which imparts a negative charge at physiological pHs. Donor vesicles of various sizes ranging from 40 to 250 nm, composed of egg phosphatidylcholine (EPC)/sterol/N-palmitoyldihydrolactosylcerebroside (75:10:15 mole ratio) containing trace amounts of [3H]sterol, were used to monitor sterol transfer into a 10-fold excess of large unilamellar vesicles (LUV) composed of EPC with a diameter of 100 nm. The two populations of vesicles were separated by centrifugation following the addition of a lectin which caused the aggregation of donor vesicles. Both cholesterol and CS exhibited biphasic kinetics of exchange. The rate constants for efflux and transbilayer diffusion for both sterol molecules were determined after fitting kinetic data, using numerical integration, to a three-compartment model, which includes the inner and outer monolayers of donor vesicles and the acceptor bilayer. The rate of intermembrane exchange for CS was approximately 10-fold faster than for cholesterol in all liposomes tested. Using the kinetic model, a rate of transbilayer movement for cholesterol and CS was estimated. In both cases, it was found to be slower than the rate of efflux from the surface of vesicles. For vesicles containing CS, the surface charge was monitored to demonstrate that the slowly exchanging pool was located in the inner monolayer, and the rapidly exchanging pool in the outer half of the bilayer. For cholesterol, it was not possible to distinguish between this model and one where lateral domains of cholesterol within the plane of the bilayer may influence the kinetics of exchange.

  12. Thermophoretic migration of vesicles depends on mean temperature and head group chemistry

    Science.gov (United States)

    Talbot, Emma L.; Kotar, Jurij; Parolini, Lucia; di Michele, Lorenzo; Cicuta, Pietro

    2017-05-01

    A number of colloidal systems, including polymers, proteins, micelles and hard spheres, have been studied in thermal gradients to observe and characterize their driven motion. Here we show experimentally the thermophoretic behaviour of unilamellar lipid vesicles, finding that mobility depends on the mean local temperature of the suspension and on the structure of the exposed polar lipid head groups. By tuning the temperature, vesicles can be directed towards hot or cold, forming a highly concentrated region. Binary mixtures of vesicles composed of different lipids can be segregated using thermophoresis, according to their head group. Our results demonstrate that thermophoresis enables robust and chemically specific directed motion of liposomes, which can be exploited in driven processes.

  13. Self-assembly of mixed lipids into bicelles and vesicles: molecular dynamics simulations

    Science.gov (United States)

    Sharma, Hari; Wang, Zilu; Dormidontova, Elena

    Formation of complex supramolecular nanostructures, such as micelles, bicelles, vesicles (liposomes) etc. via self-assembly of simple molecules has provided a new pathway for the design and development of effective drug carriers. Solid nanoparticles or functional biopolymers, such as RNA, DNA, peptides can be encapsulated into these carriers for controlled delivery or selective targeting. We performed coarse grained molecular dynamics simulation using the MARTINI force field to study the self-assembly of a binary surfactant mixture composed of long and short phospholipids, DPPC and DHPC, in the ratio 3:1. We found that at low temperature lipids self-assemble into a bicelle (nanodisc) with the longer lipid mainly forming the interior and short lipid the rim of the bicelle. At higher temperature the nanodisc transforms into a vesicle with homogeneously distributed lipids. The structural changes of these nanodiscs and vesicles imposed by gold nanoparticle encapsulation and pegylation will be addressed.

  14. Clove essential oil-in-cyclodextrin-in-liposomes in the aqueous and lyophilized states: From laboratory to large scale using a membrane contactor.

    Science.gov (United States)

    Sebaaly, Carine; Charcosset, Catherine; Stainmesse, Serge; Fessi, Hatem; Greige-Gerges, Hélène

    2016-03-15

    This work is dedicated to prepare liposomal dry powder formulations of inclusion complexes of clove essential oil (CEO) and its main component eugenol (Eug). Ethanol injection method and membrane contactor were applied to prepare liposomes at laboratory and large scale, respectively. Various liposomal formulations were tested: (1) free hydroxypropyl-β-cyclodextrin loaded liposomes; (2) drug in hydroxypropyl-β-cyclodextrin in liposomes (DCL); (3) DCL2 obtained by double loading technique, where the drug is added in the organic phase and the inclusion complex in the aqueous phase. Liposomes were characterized for their particle size, polydispersity index, Zeta potential, morphology, encapsulation efficiency of CEO components and Eug loading rate. Reproducible results were obtained with both injection devices. Compared to Eug-loaded liposomes, DCL and DCL2 improved the loading rate of Eug and possessed smaller vesicles size. The DPPH(•) scavenging activity of Eug and CEO was maintained upon incorporation of Eug and CEO into DCL and DCL2. Contrary to DCL2, DCL formulations were stable after 1 month of storage at 4°C and upon reconstitution of the dried lyophilized cakes. Hence, DCL in aqueous and lyophilized forms, are considered as a promising carrier system to preserve volatile and hydrophobic drugs enlarging their application in cosmetic, pharmaceutical and food industries. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. THE PREPARATION OF LIPOSOMES DERIVED FROM MIXED MICELLES OF LECITHIN ADDED BY SODIUM CHOLATE, FOLLOWED BY DIALYSING USING HEMOFLOW HIGH FLUX F60S

    Directory of Open Access Journals (Sweden)

    Rolf Schubert

    2004-12-01

    Full Text Available Liposomes are used for drug carriers meaning that drugs are incorporated in the membrane or the vesicle of the liposomes. In this study, liposomes were prepared from mixed micelles, consisting of phosphatidylcholine, without or with cholesterol and sodium cholate was added in several ratios namely 0.44; 0.55; 0.63; 0.70; 0.90 and 1.10. After the preparation, the sodium cholate has been removed by a dialysis membrane, using the Hemoflow High Flux, which is generally used for haemodialysis. The Hemoflow High Flux is a tool in an effort to obtain a simple, quick, effective method for removing sodium cholate in the process of preparing liposomes. The effectiveness of this tool was proved by the particle size of the liposome which was measured by the Malvern Particle Sizer. The particle size of the liposome consisting of phosphatidylcholine (PC without cholesterol and with cholesterol was 63-68 nm at all ratios and approximately 125 nm at the ratio of 0.55; 0.63; 0.70, respectively. The particle size of the liposome tended to be smaller after dialyzing, although the concentration of lipids tended to increase. However, a large amount of buffer solution has to be used with this method.

  16. Optimization of formulation variables of benzocaine liposomes using experimental design.

    Science.gov (United States)

    Mura, Paola; Capasso, Gaetano; Maestrelli, Francesca; Furlanetto, Sandra

    2008-01-01

    This study aimed to optimize, by means of an experimental design multivariate strategy, a liposomal formulation for topical delivery of the local anaesthetic agent benzocaine. The formulation variables for the vesicle lipid phase uses potassium glycyrrhizinate (KG) as an alternative to cholesterol and the addition of a cationic (stearylamine) or anionic (dicethylphosphate) surfactant (qualitative factors); the percents of ethanol and the total volume of the hydration phase (quantitative factors) were the variables for the hydrophilic phase. The combined influence of these factors on the considered responses (encapsulation efficiency (EE%) and percent drug permeated at 180 min (P%)) was evaluated by means of a D-optimal design strategy. Graphic analysis of the effects indicated that maximization of the selected responses requested opposite levels of the considered factors: For example, KG and stearylamine were better for increasing EE%, and cholesterol and dicethylphosphate for increasing P%. In the second step, the Doehlert design, applied for the response-surface study of the quantitative factors, pointed out a negative interaction between percent ethanol and volume of the hydration phase and allowed prediction of the best formulation for maximizing drug permeation rate. Experimental P% data of the optimized formulation were inside the confidence interval (P < 0.05) calculated around the predicted value of the response. This proved the suitability of the proposed approach for optimizing the composition of liposomal formulations and predicting the effects of formulation variables on the considered experimental response. Moreover, the optimized formulation enabled a significant improvement (P < 0.05) of the drug anaesthetic effect with respect to the starting reference liposomal formulation, thus demonstrating its actually better therapeutic effectiveness.

  17. Mechanics of Biomimetic Liposomes Encapsulating an Actin Shell

    Science.gov (United States)

    Guevorkian, Karine; Manzi, John; Pontani, Léa-Lætitia; Brochard-Wyart, Françoise; Sykes, Cécile

    2015-01-01

    Cell-shape changes are insured by a thin, dynamic, cortical layer of cytoskeleton underneath the plasma membrane. How this thin cortical structure impacts the mechanical properties of the whole cell is not fully understood. Here, we study the mechanics of liposomes or giant unilamellar vesicles, when a biomimetic actin cortex is grown at the inner layer of the lipid membrane via actin-nucleation-promoting factors. Using a hydrodynamic tube-pulling technique, we show that tube dynamics is clearly affected by the presence of an actin shell anchored to the lipid bilayer. The same force pulls much shorter tubes in the presence of the actin shell compared to bare membranes. However, in both cases, we observe that the dynamics of tube extrusion has two distinct features characteristic of viscoelastic materials: rapid elastic elongation, followed by a slower elongation phase at a constant rate. We interpret the initial elastic regime by an increase of membrane tension due to the loss of lipids into the tube. Tube length is considerably shorter for cortex liposomes at comparable pulling forces, resulting in a higher spring constant. The presence of the actin shell seems to restrict lipid mobility, as is observed in the corral effect in cells. The viscous regime for bare liposomes corresponds to a leakout of the internal liquid at constant membrane tension. The presence of the actin shell leads to a larger friction coefficient. As the tube is pulled from a patchy surface, membrane tension increases locally, leading to a Marangoni flow of lipids. As a conclusion, the presence of an actin shell is revealed by its action that alters membrane mechanics. PMID:26682806

  18. Liposomal Antioxidants for Protection against Oxidant-Induced Damage

    Directory of Open Access Journals (Sweden)

    Zacharias E. Suntres

    2011-01-01

    Full Text Available Reactive oxygen species (ROS, including superoxide anion, hydrogen peroxide, and hydroxyl radical, can be formed as normal products of aerobic metabolism and can be produced at elevated rates under pathophysiological conditions. Overproduction and/or insufficient removal of ROS result in significant damage to cell structure and functions. In vitro studies showed that antioxidants, when applied directly and at relatively high concentrations to cellular systems, are effective in conferring protection against the damaging actions of ROS, but results from animal and human studies showed that several antioxidants provide only modest benefit and even possible harm. Antioxidants have yet to be rendered into reliable and safe therapies because of their poor solubility, inability to cross membrane barriers, extensive first-pass metabolism, and rapid clearance from cells. There is considerable interest towards the development of drug-delivery systems that would result in the selective delivery of antioxidants to tissues in sufficient concentrations to ameliorate oxidant-induced tissue injuries. Liposomes are biocompatible, biodegradable, and nontoxic artificial phospholipid vesicles that offer the possibility of carrying hydrophilic, hydrophobic, and amphiphilic molecules. This paper focus on the use of liposomes for the delivery of antioxidants in the prevention or treatment of pathological conditions related to oxidative stress.

  19. Reduction-sensitive liposomes from a multifunctional lipid conjugate and natural phospholipids: reduction and release kinetics and cellular uptake.

    Science.gov (United States)

    Goldenbogen, Björn; Brodersen, Nicolai; Gramatica, Andrea; Loew, Martin; Liebscher, Jürgen; Herrmann, Andreas; Egger, Holger; Budde, Bastian; Arbuzova, Anna

    2011-09-06

    The development of targeted and triggerable delivery systems is of high relevance for anticancer therapies. We report here on reduction-sensitive liposomes composed of a novel multifunctional lipidlike conjugate, containing a disulfide bond and a biotin moiety, and natural phospholipids. The incorporation of the disulfide conjugate into vesicles and the kinetics of their reduction were studied using dansyl-labeled conjugate 1 in using the dansyl fluorescence environmental sensitivity and the Förster resonance energy transfer from dansyl to rhodamine-labeled phospholipids. Cleavage of the disulfide bridge (e.g., by tris(2-carboxyethyl)phosphine (TCEP), dithiothreitol (DTT), l-cysteine, or glutathione (GSH)) removed the hydrophilic headgroup of the conjugate and thus changed the membrane organization leading to the release of entrapped molecules. Upon nonspecific uptake of vesicles by macrophages, calcein release from reduction-sensitive liposomes consisting of the disulfide conjugate and phospholipids was more efficient than from reduction-insensitive liposomes composed only of phospholipids. The binding of streptavidin to the conjugates did not interfere with either the subsequent reduction of the disulfide bond of the conjugate or the release of entrapped molecules. Breast cancer cell line BT-474, overexpressing the HER2 receptor, showed a high uptake of the reduction-sensitive doxorubicin-loaded liposomes functionalized with the biotin-tagged anti-HER2 antibody. The release of the entrapped cargo inside the cells was observed, implying the potential of using our system for active targeting and delivery. © 2011 American Chemical Society

  20. Durable vesicles for reconstitution of membrane proteins in biotechnology.

    Science.gov (United States)

    Beales, Paul A; Khan, Sanobar; Muench, Stephen P; Jeuken, Lars J C

    2017-02-08

    The application of membrane proteins in biotechnology requires robust, durable reconstitution systems that enhance their stability and support their functionality in a range of working environments. Vesicular architectures are highly desirable to provide the compartmentalisation to utilise the functional transmembrane transport and signalling properties of membrane proteins. Proteoliposomes provide a native-like membrane environment to support membrane protein function, but can lack the required chemical and physical stability. Amphiphilic block copolymers can also self-assemble into polymersomes: tough vesicles with improved stability compared with liposomes. This review discusses the reconstitution of membrane proteins into polymersomes and the more recent development of hybrid vesicles, which blend the robust nature of block copolymers with the biofunctionality of lipids. These novel synthetic vesicles hold great promise for enabling membrane proteins within biotechnologies by supporting their enhanced in vitro performance and could also contribute to fundamental biochemical and biophysical research by improving the stability of membrane proteins that are challenging to work with. © 2017 The Author(s).

  1. Charged copolypeptide vesicles with controlled size for intracellular drug delivery

    Science.gov (United States)

    Holowka, Eric Peter

    Much focus has been given to the synthesis of polypeptidic based materials due to their unique structural features. These polypeptides commonly are amphiphilic in character that benefit from secondary structural features associated with one of the polymer blocks. These features, such as alpha-helix and beta-sheet conformations, allow for control over nanoscale ordering through self-assembly for use in biological sensors and therapeutic drug delivery. We report the preparation and characterization of charged amphiphilic block copolypeptide vesicle formers using transition metal mediated living ring-opening polymerization of N-carboxyanhydrides (NCAs). The vesicle membranes show fluidic properties suggested by dynamic physical behavior allowing for fine size adjustments using liposomal extrusion methods. This extrusion also allows for a facile mode of encapsulation of biomolecules for drug delivery. Modification of the charged residues has shown vesicle stability under osmotic and thermal stress, in pH buffers, and serum cell media, as well as the ability for lipid interaction and cellular interactions.

  2. Capacious and programmable multi-liposomal carriers

    Science.gov (United States)

    Yaroslavov, Alexander A.; Sybachin, Andrey V.; Zaborova, Olga V.; Migulin, Vasiliy A.; Samoshin, Vyacheslav V.; Ballauff, Matthias; Kesselman, Ellina; Schmidt, Judith; Talmon, Yeshayahu; Menger, Fredric M.

    2015-01-01

    Spherical polycationic brushes (SPBs) were synthesized by grafting polycationic chains onto 100 nm polystyrene particles. These particles were exposed to unilamellar egg-lecithin (EL) liposomes with a mean diameter of 40 nm that had been rendered anionic via the presence of 10 molar% of phosphatidylserine (PS1-). The liposomes also contained 30 mole% of a morpholinocyclohexanol-based lipid (MOCH) that undergoes a conformational flip when the pH is decreased from 7.0 to 5.0. Mixtures of SPBs and liposomes at pH 7 gave an electrostatically-driven complex possessing, on average, about 40 liposomes for each SPB particle. It was found that the bound liposomes rapidly release much of their contents when the pH is reduced from 7.0 to 5.0 owing mostly to a MOCH conformational change that creates defects in the bilayer membrane. The drop in pH does not, however, induce a separation of the liposomes from the SPBs. Around 50-60% of the liposome contents escape before, it is reasoned, lateral and transmembrane motion of the membrane components heals the defects and prevents further release. Remarkably, the liposomes complexed with SPB release their cargo much faster than the identical but non-complexed liposomes.Spherical polycationic brushes (SPBs) were synthesized by grafting polycationic chains onto 100 nm polystyrene particles. These particles were exposed to unilamellar egg-lecithin (EL) liposomes with a mean diameter of 40 nm that had been rendered anionic via the presence of 10 molar% of phosphatidylserine (PS1-). The liposomes also contained 30 mole% of a morpholinocyclohexanol-based lipid (MOCH) that undergoes a conformational flip when the pH is decreased from 7.0 to 5.0. Mixtures of SPBs and liposomes at pH 7 gave an electrostatically-driven complex possessing, on average, about 40 liposomes for each SPB particle. It was found that the bound liposomes rapidly release much of their contents when the pH is reduced from 7.0 to 5.0 owing mostly to a MOCH conformational

  3. Characterization of the physicochemical properties of phospholipid vesicles prepared in CO2/water systems at high pressure.

    Science.gov (United States)

    Nakamura, Hidemi; Taguchi, Shogo; Suga, Keishi; Hayashi, Keita; Jung, Ho-Sup; Umakoshi, Hiroshi

    2015-09-21

    Phospholipid vesicles were prepared by the nonsolvent method using high-pressure CO2/water systems. The membrane properties of vesicles prepared at different pressures and temperatures were mainly characterized based on analysis of the membrane fluidity and membrane polarity, using the fluorescent probes 1,6-diphenyl-1,3,5-hexatriene and 6-dodecanoyl-N,N-dimethyl-2-naphthylamine, respectively. The CO2(liquid)/water(liquid) and the CO2(supercritical)/water(liquid) two-phase (heterogeneous) systems resulted in the formation of vesicles with high yield (ca. 85%-88%). The membrane fluidity and polarity of the vesicles were similar to those of liposomes prepared by the conventional method. It is suggested that high-pressure CO2 can be used to form an appropriate hydrophobic-hydrophilic interface where phospholipid molecules as a self-assembled membrane.

  4. The toolbox of vesicle sidedness determination

    NARCIS (Netherlands)

    Meszaros, Peter; Hoekstra, Dick; Kok, Jan Willem

    2012-01-01

    Vesicles prepared from cellular plasma membranes are widely used in science for different purposes. The outer membrane leaflet differs from the inner membrane leaflet of the vesicle, and during vesicle preparation procedures two types of vesicles will be generated: right-side-out vesicles, of which

  5. Biodegradable liposome-encapsulated hydrogels for biomedical applications: a marriage of convenience.

    Science.gov (United States)

    Grijalvo, Santiago; Mayr, Judith; Eritja, Ramon; Díaz, David Díaz

    2016-04-01

    Hydrogels are hydrophilic three-dimensional networks with demonstrated potential for medical and pharmaceutical applications. Specifically, biopolymer-based hydrogels offer certain advantages over synthetic polymers in terms of biocompatibility and biodegradability. Because of their inherent properties, hydrogels are able to efficiently encapsulate and liberate in a controlled release manner, different hydrophobic and hydrophilic therapeutic molecules, including nucleic acids, proteins and antibodies. Several strategies have been reported in the literature to minimize the potential burst release of encapsulated drugs, thus preventing their local accumulation and consequent toxic responses. Within this context, liposomes embedded in hydrogels have emerged as an attractive strategy to reduce this undesirable effect. This tutorial review covers a selection of the most promising cationic, neutral and anionic biopolymer-based hydrogels containing liposomes, niosomes or vesicles for drug delivery or tissue engineering applications.

  6. The Effectiveness of Raloxifene-Loaded Liposomes and Cochleates in Breast Cancer Therapy.

    Science.gov (United States)

    Ağardan, N Başaran Mutlu; Değim, Zelihagül; Yılmaz, Şükran; Altıntaş, Levent; Topal, Turgut

    2016-08-01

    Liposome (spherical vesicles) and cochleate (multilayer crystalline, spiral structure) formulations containing raloxifene have been developed having dimethyl-β-cyclodextrin (DM-β-CD) or sodium taurocholate (NaTC). Raloxifene was approved initially for the treatment of osteoporosis but it is also effective on breast tissue and endometrial cells. Raloxifene inhibits matrix metalloproteinase-2 (MMP-2) enzyme, which is known to be responsible for tumor invasion and the initiation of angiogenesis during the tumor growth. Therefore, raloxifene was selected as a model drug. A series of raloxifene-loaded liposome and cochleate formulations were prepared. In vitro release studies and in vivo tests were performed. Breast cancer cell lines (MCF-7) were also used to find the most effective formulation. Highest antitumor activity was observed, and MMP-2 enzyme was also found to be inhibited with raloxifene-loaded cochleates containing DM-β-CD. These developed formulations can be helpful for further treatment alternatives and new strategies for cancer therapy.

  7. LIPOSOMES AND NANOSOMES: STRUCTURE, PROPERTIES, PRODUCTION

    Directory of Open Access Journals (Sweden)

    S. M. Shulga

    2013-10-01

    Full Text Available Liposomes are hollow particles which content is limited to a lipid membrane. They belong to a large family of vesicular (bubble structures formed by amphiphilic molecules. Liposomes consisting of one or more phospholipid bilayers were first described in the mid 60s. In a relatively short period liposomes transformed from a simple model that mimics the cell membrane into the object of active research and variety of practical applications. Currently a large number of laboratory techniques create liposomes and relatively small number of technologies used in the industry are available. However, most of ones have limitations in conditions of the biologically active substances inclusion in liposomes due to their sensitivity to mechanical and/or chemical damage. In reviews the liposomes structure, properties and methods for creating and scaling in industrial production are described.

  8. The adjuvant mechanism of cationic dimethyldioctadecylammonium liposomes

    DEFF Research Database (Denmark)

    Korsholm, Karen Smith; Agger, Else Marie; Foged, Camilla

    2007-01-01

    Cationic liposomes are being used increasingly as efficient adjuvants for subunit vaccines but their precise mechanism of action is still unknown. Here, we investigated the adjuvant mechanism of cationic liposomes based on the synthetic amphiphile dimethyldioctadecylammonium (DDA). The liposomes...... concentrations. This efficient adsorption onto the liposomes led to an enhanced uptake of OVA by BM-DCs as assessed by flow cytometry and confocal fluorescence laser-scanning microscopy. This was an active process, which was arrested at 4 degrees and by an inhibitor of actin-dependent endocytosis, cytochalasin D....... In vivo studies confirmed the observed effect because adsorption of OVA onto DDA liposomes enhanced the uptake of the antigen by peritoneal exudate cells after intraperitoneal injection. The liposomes targeted antigen preferentially to antigen-presenting cells because we only observed a minimal uptake...

  9. Vesicles and vesicle gels - structure and dynamics of formation

    CERN Document Server

    Gradzielski, M

    2003-01-01

    Vesicles constitute an interesting morphology formed by self-aggregating amphiphilic molecules. They exhibit a rich structural variety and are of interest both from a fundamental point of view (for studying closed bilayer systems) and from a practical point of view (whenever one is interested in the encapsulation of active molecules). In many circumstances vesicular structures have to be formed by external forces, but of great interest are amphiphilic systems, where they form spontaneously. Here the question arises of whether this means that they are also thermodynamically stable structures, which at least in some systems appears to be the case. If such vesicles are well defined in size, it is possible to pack them densely and thereby form vesicle gels that possess highly elastic properties even for relatively low volume fractions of amphiphile. Conditions for the formation and the microstructure of such vesicle gels have been studied in some detail for the case of unilamellar vesicles. Another important and ...

  10. Evaluation of Extrusion Technique for Nanosizing Liposomes

    Directory of Open Access Journals (Sweden)

    Sandy Gim Ming Ong

    2016-12-01

    Full Text Available The aim of the present study was to study the efficiency of different techniques used for nanosizing liposomes. Further, the aim was also to evaluate the effect of process parameters of extrusion techniques used for nanosizing liposomes on the size and size distribution of the resultant liposomes. To compare the efficiency of different nanosizing techniques, the following techniques were used to nanosize the liposomes: extrusion, ultrasonication, freeze-thaw sonication (FTS, sonication and homogenization. The extrusion technique was found to be the most efficient, followed by FTS, ultrasonication, sonication and homogenization. The extruder used in the present study was fabricated using readily available and relatively inexpensive apparatus. Process parameters were varied in extrusion technique to study their effect on the size and size distribution of extruded liposomes. The results obtained indicated that increase in the flow rate of the extrusion process decreased the size of extruded liposomes however the size homogeneity was negatively impacted. Furthermore, the liposome size and distribution was found to decline with decreasing membrane pore size. It was found that by extruding through a filter with a pore size of 0.2 µm and above, the liposomes produced were smaller than the pore size, whereas, when they were extruded through a filter with a pore size of less than 0.2 µm the resultant liposomes were slightly bigger than the nominal pore size. Besides that, increment of extrusion temperature above transition temperature of the pro-liposome had no effect on the size and size distribution of the extruded liposomes. In conclusion, the extrusion technique was reproducible and effective among all the methods evaluated. Furthermore, processing parameters used in extrusion technique would affect the size and size distribution of liposomes. Therefore, the process parameters need to be optimized to obtain a desirable size range and homogeneity

  11. Preeclampsia and Extracellular Vesicles.

    Science.gov (United States)

    Gilani, Sarwat I; Weissgerber, Tracey L; Garovic, Vesna D; Jayachandran, Muthuvel

    2016-09-01

    Preeclampsia is a hypertensive pregnancy disorder characterized by development of hypertension and proteinuria after 20 weeks of gestation that remains a leading cause of maternal and neonatal morbidity and mortality. While preeclampsia is believed to result from complex interactions between maternal and placental factors, the proximate pathophysiology of this syndrome remains elusive. Cell-to-cell communication is a critical signaling mechanism for feto-placental development in normal pregnancies. One mechanism of cellular communication relates to activated cell-derived sealed membrane vesicles called extracellular vesicles (EVs). The concentrations and contents of EVs in biological fluids depend upon their cells of origin and the stimuli which trigger their production. Research on EVs in preeclampsia has focused on EVs derived from the maternal vasculature (endothelium, vascular smooth muscle) and blood (erythrocytes, leukocytes, and platelets), as well as placental syncytiotrophoblasts. Changes in the concentrations and contents of these EVs may contribute to the pathophysiology of preeclampsia by accentuating the pro-inflammatory and pro-coagulatory states of pregnancy. This review focuses on possible interactions among placental- and maternal-derived EVs and their contents in the initiation and progression of the pathogenesis of preeclampsia. Understanding the contributions of EVs in the pathogenesis of preeclampsia may facilitate their use as diagnostic and prognostic biomarkers.

  12. Complement activation-related pseudoallergy in dogs following intravenous administration of a liposomal formulation of meglumine antimoniate

    Directory of Open Access Journals (Sweden)

    Raul R. Ribeiro

    2013-08-01

    Full Text Available The increasing use of nanotechnologies in advanced therapies has allowed the observation of specific adverse reactions related to nanostructures. The toxicity of a novel liposome formulation of meglumine antimoniate in dogs with visceral leishmaniasis after single dose has been investigated. Groups of 12 animals received by the intravenous route a single dose of liposomal meglumine antimoniate (group I [GI], 6.5 mg Sb/kg, empty liposomes (GII or isotonic saline (GIII. Evaluation of hematological and biochemical parameters showed no significant changes 4 days after administration. No undesired effects were registered in the GIII. However, adverse reactions were observed in 67.7% of dogs from both groups that received liposomal formulations. The side effects began moments after bolus administration and disappeared during the first 15 minutes after treatment. Prostation, sialorrhea and defecation were the most frequent clinical signs, registered in 33.3% and 41.6 % of animals from the groups GI and GII, respectively. Tachypnea, mydriasis, miosis, vomiting and cyanosis were also registered in both groups. The adverse reactions observed in this study were attributed to the activation of the complement system by lipid vesicles in a phenomenon known as Complement Activation-Related Pseudoallergy (CARPA. The influence of the physical-chemical characteristics of liposomal formulation in the triggering of CARPA is discussed.

  13. A general method, employing arsenazo III in liposomes, for study of calcium ionophores: results with A23187 and prostaglandins.

    Science.gov (United States)

    Weissmann, G; Anderson, P; Serhan, C; Samuelsson, E; Goodman, E

    1980-01-01

    Multilamellar (MLV) and large unilamellar (LUV) lipid vesicles (liposomes) trap the metallochromic dye arsenazo III [2,7-bis(arsonophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid ] in their aqueous compartments. When ionophore A23187 was preincorporated into either MLV or LUV above 0.001 mol%, addition of Ca to the outside of liposomes produced spectral shifts characteristic of the Ca . AIII2 complex. The method permitted detection of two molecules of A23187 per liposome. Liposomes with A23187 were permselective: divalent cations were translocated in the order Mn greater than Ca greater than Sr greater than Mg congruent to Ba. Because prostaglandins (PGs) may act as Ca ionophores, we have incorporated into MLVs and LUVs stable prostaglandins (PGE2, PGI2, PGB1), endoperoxide analogs, and a water-soluble, polymeric derivative of PGB1:PGBx. None acted as ionophore. In contrast, when added to the outside of preformed MLV or LUV, PGBx, at concentrations above 1 micro M, provoked permselective uptake of Ca equivalent to that induced by 10 nM A23187. These studies demonstrate not only that liposomes containing arsenazo III may be employed in a sensitive asssay for agents that translocate divalent cations, but that a water-soluble derivative of a naturally occurring fatty acid, PGBx, is a potent ionophore. PMID:6769114

  14. Clinical efficacy of liposome-encapsulated Aloe vera on melasma treatment during pregnancy.

    Science.gov (United States)

    Ghafarzadeh, Masoumeh; Eatemadi, Ali

    2017-06-01

    Melasma is a challenging dermatological condition during pregnancy. The aim of this study was to determine the clinical efficacy of a topical liposome-encapsulated Aloe vera preparation, on melasma in pregnant women. In order to enhance the bioavailability of Aloe vera leaf gel extract (AGE), liposomes encapsulating Aloe vera were prepared and examined for their biochemical properties. In this double-blinded, randomized clinical trial, two groups of pregnant women with melasma who were at their second trimester of pregnancy or later were studied. The patients in the experimental group (90) received liposome-encapsulated AGE (in the form of gel), the other 90 patients were placed in the control group (AGE) for 5 weeks. The liposomes were prepared from a soybean lecithin (SLP-WHITE, 1.0 wt 15 %), with a high trapping efficiency for incorporating about 0.5 wt% AGE concentration. The stable liposomes were then prepared from 1.0 wt% of SLP-WHITE, and different concentrations of AGE were prepared by mechanochemical method using a microfluidizer and homogenizer. The liposomes obtained from 0.25 wt% of AGE were confirmed to be small unilamellar vesicles with a diameter Melasma Area Severity Index (MASI) score was used to record melasma severity, and analysis of co-variance (ANCOVA) was used for data analysis. After 5 weeks of melasma treatment in pregnant women, there was 32% improvement in the MASI score in the liposomal-AGE treatment group as compared to 10% improvement in the control group. The prevalence of melisma decreases with an increase in parity, i.e. 39 (43.35%), 34 (37.8%), 15 (16.7%) and 2 (2.2%) for the experimental groups, and 45 (50%), 35 (38.9%), 10 (11.1%) and 0 (0%) for the control group (p = 0.32). There was a significant difference between experimental and control groups in terms of mean MASI score after the trial. There was no significant difference between the groups regarding family history of melasma, occupation, frequency of sunscreen usage and

  15. Studying liposomes by tritium bombardment.

    Science.gov (United States)

    Kordyukova, L V; Ksenofontov, A L; Badun, G A; Baratova, L A; Shishkov, A V

    2001-12-01

    Bilayer liposomes from a mixture of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine (DPPC: DPPE = 8:2, molar ratio) or DPPC labeled with 14C-DPPC (DPPC: 14C-DPPC) were bombarded with thermally activated tritium atoms. The tritiated liposomes were hydrolyzed by phospholipase C, and the tritium incorporation into different parts of the bilayer along its thickness was determined. The tritium flux attenuation coefficients were calculated for the headgroup (k1 = 0.176+/-0.032 A(-1)) and acylglycerol residue (k2 = 0.046+/-0.004 A(-1)) layers indicating a preferential attenuation of the tritium flux in the headgroup region and relative transparence of the membrane hydrophobic part. The finding is potentially important to apply tritium bombardment for investigation of spatial organization of transmembrane proteins in their native lipid environment.

  16. DNA controlled assembly of liposomes

    DEFF Research Database (Denmark)

    Vogel, Stefan; Jakobsen, Ulla; Simonsen, Adam Cohen

    2009-01-01

    DNA-encoding of solid nanoparticles requires surfacechemistry, which is often tedious and not generally applicable. In the present study non-covalently attached DNA are used to assemble soft nanoparticles (liposomes) in solution. This process displays remarkably sharp thermal transitions from ass...... assembled to disassembled state for which reason this method allows easy and fast detection of polynucleotides (e.g. DNA or RNA), including single nucleotide polymorphisms as well as insertions and deletions....

  17. Lipid lateral organization on giant unilamellar vesicles containing lipopolysaccharides

    DEFF Research Database (Denmark)

    Kubiak, Jakub; Brewer, Jonathan R.; Hansen, Søren

    2011-01-01

    -Ra > LPS-Rc > LPS-Rd) were selected to generate GUVs composed of different LPS/E. coli polar lipid mixtures. Our procedure consists of two main steps: 1), generation and purification of oligolamellar liposomes containing LPSs; and 2), electroformation of GUVs using the LPS-containing oligolamellar vesicles...... the presence of elongated micrometer-sized lipid domains for GUVs containing either LPS-Rc or LPS-Rd above 10 mol %. Laurdan GP images confirm this finding and show that this particular lateral scenario corresponds to the coexistence of fluid disordered and gel (LPS-enriched)-like micron-sized domains......, in similarity to what is observed when LPS is replaced with lipid A. For LPSs containing the more bulky polar headgroup (i.e., LPS-smooth and LPS-Ra), an absence of micrometer-sized domains is observed for all LPS concentrations explored in the GUVs (up to ∼15 mol %). However, fluorescence correlation...

  18. Development and pharmacokinetic of antimony encapsulated in liposomes of phosphatidylserine using radioisotopes in experimental leishmaniasis; Desenvolvimento e farmacocinetica de antimonio encapsulado em lipossomas de fosfatidilserina utilizando radioisotopos em leishmaniose experimental

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta Etel Treiger

    2010-07-01

    Leishmaniasis are a complex of parasitic diseases caused by intra macrophage protozoa of the genus Leishmania, and is fatal if left untreated. Pentavalent antimonials, though toxic and their mechanism of action being unclear, remain the first-line drugs for treatment. Effective therapy could be achieved by delivering antileishmanial drugs to these sites of infection. Liposomes are phospholipid vesicles that promote improvement in the efficacy and action of drugs in target cell. Liposomes are taken up by the cells of mononuclear phagocytic system (MPS). The purpose of this study was to develop a preparation of meglumine antimonate encapsulated in liposomes of phosphatidylserine and to study its pharmacokinetic in healthy mice to establish its metabolism and distribution. Quantitative analysis of antimony from liposomes demonstrated that Neutron Activation Analysis was the most sensitive technique with almost 100 % of accuracy. All liposome formulations presented a mean diameter size of 150 nm. The determination of IC{sub 50} in infected macrophage showed that liposome formulations were between 10 - 63 fold more effective than the free drug, indicating higher selectivity index. By fluorescence microscopy, an increased uptake of fluorescent-liposomes was seen in infected macrophages during short times of incubation compared with non-infected macrophages. Biodistribution studies showed that meglumine antimonate irradiated encapsulated in liposomes of phosphatidylserine promoted a targeting of antimony for MPS tissues and maintained high doses in organs for a prolonged period. In conclusion, these data suggest that meglumine antimonate encapsulated in liposomes showed higher effectiveness than the non-liposomal drug against Leishmania infection. The development of liposome formulations should be a new alternative for the chemotherapy of infection diseases, especially Leishmaniasis, as they are used to sustain and target pharmaceuticals to the local of infection. (author)

  19. Nanoparticle Stabilized Liposomes for Acne Therapy

    Science.gov (United States)

    Fu, Victoria

    Acne vulgaris is a common skin disease that affects over 40 million people in the United States alone. The main cause of acne vulgaris is Propionibacterium acnes (P. acnes), resides deep in the pores and follicles of the skin in order to feed on oil produced by the sebaceous glands. The liposome is a lipid based nanoparticle with numerous advantages over free drug molecules as an acne treatment alternative. Bare liposomes loaded with lauric acid (LipoLA) were found to show strong antimicrobial activity against P. acnes while generating minimal toxicity. However, the platform is limited by the spontaneous tendency of liposomes to fuse with each other. Attaching nanoparticles to the surface of liposomes can overcome this challenge by providing steric repulsion and reduce surface tension. Thus, carboxyl-functionalized gold nanoparticles (AuC) were attached to the surface of liposomes (AuC-liposomes) loaded with doxycycline, a general tetracycline antibiotic. These particles were found to have a diameter of 120 nm and a zeta potential of 20.0 mV. Both fluorescent and antimicrobial studies demonstrated that based on electrostatic interaction, negatively charged AuC attached to the liposome's positively charged surface and stabilized liposomes in a neutral pH environment (pH = 7.4). Upon entering the skin's acidic environment (pH = 4), AuC detached from the liposome's surface and liposomes could fuse with P. acnes residing in the pores. Furthermore, toxicity studies showed that AuC-liposomes did not induce any significant toxicity, while two of the leading over-the-counter therapies, benzoyl peroxide and salicylic acid, generated substantial skin irritation.

  20. Self-assembly in aqueous solution of wheel-shaped Mo154 oxide clusters into vesicles.

    Science.gov (United States)

    Liu, Tianbo; Diemann, Ekkehard; Li, Huilin; Dress, Andreas W M; Müller, Achim

    2003-11-06

    Surfactants and membrane lipids readily assemble into complex structures such as micelles, liposomes or hollow vesicles owing to their amphiphilic character-the fact that part of their structure is attracted to polar environments while another part is attracted to non-polar environments. The self-assembly of complex structures also occurs in polyoxometallate chemistry, as exemplified by the molybdenum blue solutions known for centuries. But while the presence of nanometre-sized metal oxide aggregates in these solutions has long been recognized, unravelling the composition and formation process of these aggregates proved difficult. Recent work has indicated that discrete, wheel-shaped mixed-valence polyoxomolybdate clusters of the type [Mo154] (refs 2-4) assemble into well-defined nanometre-sized aggregates, including spherical structures. Here we report light-scattering data and transmission electron microscopy images of hollow spherical structures with an average, almost monodisperse radius of about 45 nm and composed of approximately 1,165 [Mo154] wheel-shaped clusters. The clusters appear to lie flat and homogeneously distributed on the vesicle surface. Unlike conventional lipid vesicles, the structures we observe are not stabilized by hydrophobic interactions. Instead, we believe the polyoxomolybdate-based vesicles form owing to a subtle interplay between short-range van der Waals attraction and long-range electrostatic repulsion, with important further stabilization arising from hydrogen bonding involving water molecules encapsulated between the wheel-shaped clusters and in the vesicles' interior.

  1. Methods for using redox liposome biosensors

    Science.gov (United States)

    Cheng, Quan; Stevens, Raymond C.

    2002-01-01

    The present invention provides methods and compositions for detecting the presence of biologically-important analytes by using redox liposome biosensors. In particular, the present invention provides liposome/sol-gel electrodes suitable for the detection of a wide variety of organic molecules, including but not limited to bacterial toxins.

  2. Anomalous freezing behavior of nanoscale liposomes

    DEFF Research Database (Denmark)

    Spangler, E. J.; Kumar, P. B. S.; Laradji, M.

    2012-01-01

    The effect of the finite size of one-component liposomes on their phase behavior is investigated via simulations of an implicit-solvent model of self-assembled lipid bilayers. We found that the high curvature of nanoscale liposomes has a significant effect on their freezing behavior. While...

  3. Radionuclide imaging of liposomal drug delivery

    NARCIS (Netherlands)

    van der Geest, Tessa; Laverman, Peter; Metselaar, Josbert M.; Storm, G; Boerman, Otto C.

    2016-01-01

    Introduction: Ever since their discovery, liposomes have been radiolabeled to monitor their fate in vivo. Despite extensive preclinical studies, only a limited number of radiolabeled liposomal formulations have been examined in patients. Since they can play a crucial role in patient management, it

  4. Radionuclide imaging of liposomal drug delivery

    NARCIS (Netherlands)

    Geest, T. van der; Laverman, P.; Metselaar, J.M.; Storm, G.; Boerman, O.C.

    2016-01-01

    Ever since their discovery, liposomes have been radiolabeled to monitor their fate in vivo. Despite extensive preclinical studies, only a limited number of radiolabeled liposomal formulations have been examined in patients. Since they can play a crucial role in patient management, it is of

  5. The protein corona of circulating PEGylated liposomes.

    Science.gov (United States)

    Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

    2016-02-01

    Following systemic administration, liposomes are covered by a 'corona' of proteins, and preserving the surface functionality is challenging. Coating the liposome surface with polyethylene glycol (PEG) is the most widely used anti-opsonization strategy, but it cannot fully preclude protein adsorption. To date, protein binding has been studied following in vitro incubation to predict the fate of liposomes in vivo, while dynamic incubation mimicking in vivo conditions remains largely unexplored. The main aim of this investigation was to determine whether shear stress, produced by physiologically relevant dynamic flow, could influence the liposome-protein corona. The corona of circulating PEGylated liposome was thoroughly compared with that formed by incubation in vitro. Systematic comparison in terms of size, surface charge and quantitative composition was made by dynamic light scattering, microelectrophoresis and nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS). Size of coronas formed under static vs. dynamic incubation did not appreciably differ from each other. On the other side, the corona of circulating liposomes was more negatively charged than its static counterpart. Of note, the variety of protein species in the corona formed in a dynamic flow was significantly wider. Collectively, these results demonstrated that the corona of circulating PEGylated liposomes can be considerably different from that formed in a static fluid. This seems to be a key factor to predict the biological activity of a liposomal formulation in a physiological environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Conveying a newly designed hydrophilic anti-human thymidylate synthase peptide to cisplatin resistant cancer cells: are pH-sensitive liposomes more effective than conventional ones?

    Science.gov (United States)

    Sacchetti, Francesca; D'Arca, Domenico; Genovese, Filippo; Pacifico, Salvatore; Maretti, Eleonora; Hanuskova, Miriam; Iannuccelli, Valentina; Costi, Maria Paola; Leo, Eliana

    2017-03-01

    LR-peptide, a novel hydrophilic peptide synthetized and characterized in previous work, is able to reduce the multi-drug resistance response in cisplatin (cDPP) resistant cancer cells by inhibiting human thymidylate synthase (hTS) overexpressed in several tumors, including ovarian and colon-rectal cancers, but it is unable to enter the cells spontaneously. The aim of this work was to design and characterize liposomal vesicles as drug delivery systems for the LR peptide, evaluating the possible benefits of the pH-responsive feature in improving intracellular delivery. For this purpose, conventional and pH-sensitive liposomes were formulated, compared regarding their physical-chemical properties (size, PDI, morphology, in vitro stability and drug release) and studied for in vitro cytotoxicity against a cDDP-resistant cancer cells. Results indicated that LR peptide was successfully encapsulated in both liposomal formulations but at short incubation time only LR loaded pH-sensitive liposomes showed cell inhibition activity while for long incubation time the two kinds of liposomes demonstrated the same efficacy. Data provide evidence that acidic pH-triggered liposomal delivery is able to significantly reduce the time required by the systems to deliver the drug to the cells without inducing an enhancement of the efficacy of the drug.

  7. Stability of phospholipid vesicles studied by asymmetrical flow field-flow fractionation and capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Yohannes, Gebrenegus [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland); Pystynen, Kati-Henna [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland); Riekkola, Marja-Liisa [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland); Wiedmer, Susanne K. [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland)]. E-mail: susanne.wiedmer@helsinki.fi

    2006-02-23

    The stability of zwitterionic phosphatidylcholine vesicles in the presence of 20 mol% phosphatidyl serine (PS), phosphatidic acid (PA), phosphatidyl inositol (PI), and diacylphosphatidyl glycerol (PG) phospholipid vesicles, and cholesterol or calcium chloride was investigated by asymmetrical flow field-flow fractionation (AsFlFFF). Large unilamellar vesicles (LUV, diameter 100 nm) prepared by extrusion at 25 deg. C were used. Phospholipid vesicles (liposomes) were stored at +4 and -18 deg. C over an extended period of time. Extruded egg yolk phosphatidylcholine (EPC) particle diameters at peak maximum and mean measured by AsFlFFF were 101 {+-} 3 nm and 122 {+-} 5 nm, respectively. No significant change in diameter was observed after storage at +4 deg. C for about 5 months. When the storage period was extended to about 8 months (250 days) larger destabilized aggregates were formed (172 and 215 nm at peak maximum and mean diameters, respectively). When EPC was stored at -18 deg. C, large particles with diameters of 700-800 nm were formed as a result of dehydration, aggregation, and fusion processes. In the presence of calcium chloride, EPC alone did not form large aggregates. Addition of 20 mol% of negatively charged phospholipids (PS, PA, PI, or PG) to 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) vesicles increased the electrostatic interactions between calcium ion and the vesicles and large aggregates were formed. In the presence of cholesterol, large aggregates of about 250-350 nm appeared during storage at +4 and -18 deg. C for more than 1 day. The effect of liposome storage temperature on phospholipid coatings applied in capillary electrophoresis (CE) was studied by measuring the electroosmotic flow (EOF). EPC coatings with and without cholesterol, PS, or calcium chloride, prepared from liposomes stored at +25, +4, and -18 deg. C, were studied at 25 deg. C. The performances of the coatings were further evaluated with three uncharged compounds

  8. Liposome imaging agents in personalized medicine

    DEFF Research Database (Denmark)

    Petersen, Anncatrine Luisa; Hansen, Anders Elias; Gabizon, Alberto

    2012-01-01

    that selectively localize in tumor tissue can transport both drugs and imaging agents, which allows for a theranostic approach with great potential in personalized medicine. Radiolabeling of liposomes have for many years been used in preclinical studies for evaluating liposome in vivo performance and has been...... an important tool in the development of liposomal drugs. However, advanced imaging systems now provide new possibilities for non-invasive monitoring of liposome biodistribution in humans. Thus, advances in imaging and developments in liposome radiolabeling techniques allow us to enter a new arena where we...... start to consider how to use imaging for patient selection and treatment monitoring in connection to nanocarrier based medicines. Nanocarrier imaging agents could furthermore have interesting properties for disease diagnostics and staging. Here, we review the major advances in the development...

  9. α-Synuclein Dimers Impair Vesicle Fission during Clathrin-Mediated Synaptic Vesicle Recycling

    Directory of Open Access Journals (Sweden)

    Audrey T. Medeiros

    2017-12-01

    Full Text Available α-Synuclein is a presynaptic protein that regulates synaptic vesicle (SV trafficking. In Parkinson’s disease (PD and several other neurodegenerative disorders, aberrant oligomerization and aggregation of α-synuclein lead to synaptic dysfunction and neurotoxicity. Despite evidence that α-synuclein oligomers are generated within neurons under physiological conditions, and that altering the balance of monomers and oligomers contributes to disease pathogenesis, how each molecular species of α-synuclein impacts SV trafficking is currently unknown. To address this, we have taken advantage of lamprey giant reticulospinal (RS synapses, which are accessible to acute perturbations via axonal microinjection of recombinant proteins. We previously reported that acute introduction of monomeric α-synuclein inhibited SV recycling, including effects on the clathrin pathway. Here, we report the effects of α-synuclein dimers at synapses. Similar to monomeric α-synuclein, both recombinant α-synuclein dimers that were evaluated bound to small liposomes containing anionic lipids in vitro, but with reduced efficacy. When introduced to synapses, the α-synuclein dimers also induced SV recycling defects, which included a build up of clathrin-coated pits (CCPs with constricted necks that were still attached to the plasma membrane, a phenotype indicative of a vesicle fission defect. Interestingly, both α-synuclein dimers induced longer necks on CCPs as well as complex, branching membrane tubules, which were distinct from the CCPs induced by a dynamin inhibitor, Dynasore. In contrast, monomeric α-synuclein induced a buildup of free clathrin-coated vesicles (CCVs, indicating an inhibition of clathrin-mediated endocytosis at a later stage during the clathrin uncoating process. Taken together, these data further support the conclusion that excess α-synuclein impairs SV recycling. The data additionally reveal that monomeric and dimeric α-synuclein produce

  10. Application of Various Types of Liposomes in Drug Delivery Systems

    Directory of Open Access Journals (Sweden)

    Mehran Alavi

    2017-04-01

    Full Text Available Liposomes, due to their various forms, require further exploration. These structures can deliver both hydrophilic and hydrophobic drugs for cancer, antibacterial, antifungal, immunomodulation, diagnostics, ophtalmica, vaccines, enzymes and genetic elements. Preparation of liposomes results in different properties for these systems. In addition, based on preparation methods, liposomes types can be unilamellar, multilamellar and giant unilamellar; however, there are many factors and difficulties that affect the development of liposome drug delivery structure. In the present review, we discuss some problems that impact drug delivery by liposomes. In addition, we discuss a new generation of liposomes, which is utilized for decreasing the limitation of the conventional liposomes.

  11. Bovine binder-of-sperm protein BSP1 promotes protrusion and nanotube formation from liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Lafleur, Michel, E-mail: michel.lafleur@umontreal.ca [Department of Chemistry, Center for Self-Assembled Chemical Systems, Universite de Montreal, C.P. 6128, Succ. Centre Ville, Montreal, Quebec, Canada H3C 3J7 (Canada); Courtemanche, Lesley [Department of Chemistry, Center for Self-Assembled Chemical Systems, Universite de Montreal, C.P. 6128, Succ. Centre Ville, Montreal, Quebec, Canada H3C 3J7 (Canada); Karlsson, Goeran; Edwards, Katarina [Department of Physical and Analytical Chemistry, Uppsala University, Box 579, S-751 23 Uppsala (Sweden); Schwartz, Jean-Louis [Department of Physiology, Groupe d' etude des Proteines Membranaires, Universite de Montreal, C.P. 6128, Succ. Centre Ville, Montreal, Quebec, Canada H3C 3J7 (Canada); Manjunath, Puttaswamy [Maisonneuve-Rosemont Hospital Research Center and Faculty of Medecine, Universite de Montreal, 5415 L' Assomption Blvd, Montreal, Quebec, Canada H1T 2M4 (Canada)

    2010-08-27

    Research highlights: {yields} Binder-of-sperm protein 1 (BSP1) modifies the morphology of lipidic vesicles inducing bead necklace-like and thread-like structures. {yields} In the presence of multilamellar liposomes, BSP1 leads to the formation of long nanotubes. {yields} The insertion of BSP1 in the external lipid leaflet of membranes induces local changes in bilayer curvature. -- Abstract: Binder-of-sperm (BSP) proteins interact with sperm membranes and are proposed to extract selectively phosphatidylcholine and cholesterol from these. This change in lipid composition is a key step in sperm capacitation. The present work demonstrates that the interactions between the protein BSP1 and model membranes composed with phosphatidylcholine lead to drastic changes in the morphology of the lipidic self-assemblies. Using cryo-electron microscopy and fluorescence microscopy, we show that, in the presence of the protein, the lipid vesicles elongate, and form bead necklace-like structures that evolve toward small vesicles or thread-like structures. In the presence of multilamellar vesicles, where a large reservoir of lipid is available, the presence of BSP proteins lead to the formation of long nanotubes. Long spiral-like threads, associated with lipid/protein complexes, are also observed. The local curvature of lipid membranes induced by the BSP proteins may be involved in lipid domain formation and the extraction of some lipids during the sperm maturation process.

  12. Extracellular Vesicles in Cardiovascular Theranostics

    OpenAIRE

    Bei, Yihua; Das, Saumya; Rodosthenous, Rodosthenis S.; Holvoet, Paul; Vanhaverbeke, Maarten; Monteiro,Marta Chagas; Monteiro, Valter Vinicius Silva; Radosinska, Jana; Bartekova, Monika; Jansen, Felix; Li, Qian; Rajasingh, Johnson; Xiao, Junjie

    2017-01-01

    Extracellular vesicles (EVs) are small bilayer lipid membrane vesicles that can be released by most cell types and detected in most body fluids. EVs exert key functions for intercellular communication via transferring their bioactive cargos to recipient cells or activating signaling pathways in target cells. Increasing evidence has shown the important regulatory effects of EVs in cardiovascular diseases (CVDs). EVs secreted by cardiomyocytes, endothelial cells, fibroblasts, and stem cells pla...

  13. Immunotherapeutic Potential of Extracellular Vesicles

    OpenAIRE

    Zhang, Bin; Yin, Yijun; Lai, Ruenn Chai; Lim, Sai Kiang

    2014-01-01

    Extracellular vesicle or EV is a term that encompasses all classes of secreted lipid membrane vesicles. Despite being scientific novelties, EVs are gaining importance as a mediator of important physiological and pathological intercellular activities possibly through the transfer of their cargo of protein and RNA between cells. In particular, exosomes, the currently best characterized EVs have been notable for their in vitro and in vivo immunomodulatory activities. Exosomes are nanometer-sized...

  14. RNA in extracellular vesicles.

    Science.gov (United States)

    Kim, Kyoung Mi; Abdelmohsen, Kotb; Mustapic, Maja; Kapogiannis, Dimitrios; Gorospe, Myriam

    2017-07-01

    Cells release a range of membrane-enclosed extracellular vesicles (EVs) into the environment. Among them, exosomes and microvesicles (collectively measuring 40-1000 nm in diameter) carry proteins, signaling lipids, and nucleic acids from donor cells to recipient cells, and thus have been proposed to serve as intercellular mediators of communication. EVs transport cellular materials in many physiologic processes, including differentiation, stem cell homeostasis, immune responses, and neuronal signaling. EVs are also increasingly recognized as having a direct role in pathologies such as cancer and neurodegeneration. Accordingly, EVs have been the focus of intense investigation as biomarkers of disease, prognostic indicators, and even therapeutic tools. Here, we review the classes of RNAs present in EVs, both coding RNAs (messenger RNAs) and noncoding RNAs (long noncoding RNAs, microRNAs, and circular RNAs). The rising attention to EV-resident RNAs as biomarkers stems from the fact that RNAs can be detected at extremely low quantities using a number of methods. To illustrate the interest in EV biology, we discuss EV RNAs in cancer and neurodegeneration, two major age-associated disease processes. WIREs RNA 2017, 8:e1413. doi: 10.1002/wrna.1413 For further resources related to this article, please visit the WIREs website. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  15. Extracellular Vesicles in Renal Pathophysiology.

    Science.gov (United States)

    Pomatto, Margherita A C; Gai, Chiara; Bussolati, Benedetta; Camussi, Giovanni

    2017-01-01

    Extracellular vesicles are a heterogeneous population of microparticles released by virtually all living cells which have been recently widely investigated in different biological fields. They are typically composed of two primary types (exosomes and microvesicles) and are recently commanding increasing attention as mediators of cellular signaling. Indeed, these vesicles can affect recipient cells by carrying and delivering complex cargos of biomolecules (including proteins, lipids and nucleic acids), protected from enzymatic degradation in the environment. Their importance has been demonstrated in the pathophysiology of several organs, in particular in kidney, where different cell types secrete extracellular vesicles that mediate their communication with downstream urinary tract cells. Over the past few years, evidence has been shown that vesicles participate in kidney development and normal physiology. Moreover, EVs are widely demonstrated to be implicated in cellular signaling during renal regenerative and pathological processes. Although many EV mechanisms are still poorly understood, in particular in kidney, the discovery of their role could help to shed light on renal biological processes which are so far elusive. Lastly, extracellular vesicles secreted by renal cells gather in urine, thus becoming a great resource for disease or recovery markers and a promising non-invasive diagnostic instrument for renal disease. In the present review, we discuss the most recent findings on the role of extracellular vesicles in renal physiopathology and their potential implication in diagnosis and therapy.

  16. Extracellular vesicles in renal disease.

    Science.gov (United States)

    Karpman, Diana; Ståhl, Anne-Lie; Arvidsson, Ida

    2017-09-01

    Extracellular vesicles, such as exosomes and microvesicles, are host cell-derived packages of information that allow cell-cell communication and enable cells to rid themselves of unwanted substances. The release and uptake of extracellular vesicles has important physiological functions and may also contribute to the development and propagation of inflammatory, vascular, malignant, infectious and neurodegenerative diseases. This Review describes the different types of extracellular vesicles, how they are detected and the mechanisms by which they communicate with cells and transfer information. We also describe their physiological functions in cellular interactions, such as in thrombosis, immune modulation, cell proliferation, tissue regeneration and matrix modulation, with an emphasis on renal processes. We discuss how the detection of extracellular vesicles could be utilized as biomarkers of renal disease and how they might contribute to disease processes in the kidney, such as in acute kidney injury, chronic kidney disease, renal transplantation, thrombotic microangiopathies, vasculitides, IgA nephropathy, nephrotic syndrome, urinary tract infection, cystic kidney disease and tubulopathies. Finally, we consider how the release or uptake of extracellular vesicles can be blocked, as well as the associated benefits and risks, and how extracellular vesicles might be used to treat renal diseases by delivering therapeutics to specific cells.

  17. Fatty acid vesicles acting as expanding horizon for transdermal delivery.

    Science.gov (United States)

    Kumar, Lalit; Verma, Shivani; Kumar, Sanjeev; Prasad, Deo Nandan; Jain, Amit Kumar

    2017-03-01

    The body is protected against the external environment by the skin due to its physical barrier nature. Stratum corneum composed of corneocytes surrounded by lipid region performs a major barrier function as it lies in the uppermost area of skin. Alteration in barrier function, increase in permeability, and disorganization of stratum corneum represent diseased skin. Drugs applied to the diseased skin should induce a local effect at the site of application or area close to it along with cutaneous absorption rather than percutaneous absorption. Conventional formulations like ointments, gels, and creams suffer from the drawback of limited local activity. For the enhancement of drug penetration and localization of the drug at the site of action approaches explored are liposomes, niosomes, ethosomes microparticles, and solid lipid nanoparticles. Vesicles composed of fatty acids like oleic acid and linoleic acid represent the new approach used for transdermal penetration and localization. In this review article, our major aim was to explore the applications of fatty acid vesicles for transdermal delivery of various bioactives.

  18. Stabilization of liophilized liposomal products

    Directory of Open Access Journals (Sweden)

    2001-08-01

    Full Text Available Liposomes as a drug carrier have numerous dominancy. Liophilization is the most propr form of these products for long-term maintenance, but this procedure is affected by unstabilizing agent that results in destruction of membrane, release of content and change in size and microbial contamination; hence for prevention of the adverse effects, the protective role of sugars such as: Maltose, Fructose, Glucose, Galactose, Saccharose and Lactose were studied. For this purpose, after preparation of liposomal suspention, categorized in for duplicate groups and concentrations of 25, 50, 100 percent of these sugars were added to those. On the basis of color and consistency of products, the best method of freezing is as application of absolute alcohol and then chilling in-70 oc for 16 h. In survey of protective substances concentrations 0.7, 1.4, 2.8, and 5.6 percent of the mentioned sugars were used for calculating of leakage percent (Upon on the ratio of optical density of treated samples to untreated. In this study, released maltose had highest effect. Level of fusion and aggregation had any significant difference between pre and post lyophilized samples in centrifugation with 10000 rpm. Microbial state of recent samples were studied by culturing in SCD and SCDA media that indicated microbial growth in both samples.     

  19. Influence of the Encapsulation Efficiency and Size of Liposome on the Oral Bioavailability of Griseofulvin-Loaded Liposomes

    OpenAIRE

    Sandy Gim Ming Ong; Long Chiau Ming; Kah Seng Lee; Kah Hay Yuen

    2016-01-01

    The objective of the present study was to investigate the influence of the encapsulation efficiency and size of liposome on the oral bioavailability of griseofulvin-loaded liposomes. Griseofulvin-loaded liposomes with desired characteristics were prepared from pro-liposome using various techniques. To study the effect of encapsulation efficiency, three preparations of griseofulvin, namely, griseofulvin aqueous suspension and two griseofulvin-loaded liposomes with different amounts of griseofu...

  20. Functional Micelles and Vesicles as Organic Reagents

    Science.gov (United States)

    1992-05-15

    flop. The survey was next extended to lipids of varying skeletons and backbones. We found that liposomes constructed from pseudoglyceryl lipids (16, R...Both the cis (oleoyl) and trans (elaidoly) modifications of 18 afforded liposomes in which the half-times for 6 ,indo - exo lipid flip-flop were much...unbranched,la staturated1 7 alkyl chains on a pseudoglyceryl backbone14 lead to relatively stable endo/ exo surface differentiated3 liposomes. The

  1. Enhanced transdermal delivery of diclofenac sodium via conventional liposomes, ethosomes, and transfersomes.

    Science.gov (United States)

    Ghanbarzadeh, Saeed; Arami, Sanam

    2013-01-01

    The aim of this study was to improve the transdermal permeation of Diclofenac sodium, a poorly water-soluble drug, employing conventional liposomes, ethosomes, and transfersomes. The prepared formulations had been characterized for the loaded drug amount and vesicle size. The prepared vesicular systems were incorporated into 1% Carbopol 914 gel, and a survey of in vitro drug release and drug retention into rat skin has been done on them using a modified Franz diffusion cell. The cumulative amount of drug permeated after 24 h, flux, and permeability coefficient were assessed. Stability studies were performed for three months. The size of vesicles ranged from 145 to 202 nm, and the encapsulation efficiency of the Diclofenac sodium was obtained between 42.61% and 51.72%. The transfersomes and ethosomes provided a significantly higher amount of cumulative permeation, steady state flux, permeability coefficient, and residual drug into skin compared to the conventional liposomes, conventional gel, or hydroethanolic solution. The in vitro release data of all vesicular systems were well fit into Higuchi model (RSD > 0.99). Stability tests indicated that the vesicular formulations were stable over three months. Results revealed that both ethosome and transfersome formulations can act as drug reservoir in skin and extend the pharmacologic effects of Diclofenac sodium.

  2. Enhanced Transdermal Delivery of Diclofenac Sodium via Conventional Liposomes, Ethosomes, and Transfersomes

    Directory of Open Access Journals (Sweden)

    Saeed Ghanbarzadeh

    2013-01-01

    Full Text Available The aim of this study was to improve the transdermal permeation of Diclofenac sodium, a poorly water-soluble drug, employing conventional liposomes, ethosomes, and transfersomes. The prepared formulations had been characterized for the loaded drug amount and vesicle size. The prepared vesicular systems were incorporated into 1% Carbopol 914 gel, and a survey of in vitro drug release and drug retention into rat skin has been done on them using a modified Franz diffusion cell. The cumulative amount of drug permeated after 24 h, flux, and permeability coefficient were assessed. Stability studies were performed for three months. The size of vesicles ranged from 145 to 202 nm, and the encapsulation efficiency of the Diclofenac sodium was obtained between 42.61% and 51.72%. The transfersomes and ethosomes provided a significantly higher amount of cumulative permeation, steady state flux, permeability coefficient, and residual drug into skin compared to the conventional liposomes, conventional gel, or hydroethanolic solution. The in vitro release data of all vesicular systems were well fit into Higuchi model (RSD > 0.99. Stability tests indicated that the vesicular formulations were stable over three months. Results revealed that both ethosome and transfersome formulations can act as drug reservoir in skin and extend the pharmacologic effects of Diclofenac sodium.

  3. Extracellular Vesicles in Lung Disease.

    Science.gov (United States)

    Kubo, Hiroshi

    2018-01-01

    Accumulating evidence suggests that extracellular vesicles (EVs) play a role in the pathogenesis of lung diseases. These vesicles include exosomes, ectosomes (ie, microparticles, extracellular vesicles, microvesicles, and shedding vesicles), and apoptotic bodies. Exosomes are generated by inward budding of the membrane (endocytosis), subsequent forming of multivesicular bodies, and release by exocytosis. Ectosomes are formed by outward blebbing from the plasma membrane and are then released by proteolytic cleavage from the cell surface. Apoptotic bodies are generated on apoptotic cell shrinkage and death. Extracellular vesicles are released when the cells are activated or undergo apoptosis under inflammatory conditions. The number and types of released EVs are different according to the pathophysiological status of the disease. Therefore, EVs can be novel biomarkers for various lung diseases. EVs contain several molecules, including proteins, mRNA, microRNA, and DNA; they transfer these molecules to distant recipient cells. Circulating EVs modify the targeted cells and influence the microenvironment of the lungs. For this unique capability, EVs are expected to be a new drug delivery system and a novel therapeutic target. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  4. Progress involving new techniques for liposome preparation

    Directory of Open Access Journals (Sweden)

    Zhenjun Huang

    2014-08-01

    Full Text Available The article presents a review of new techniques being used for the preparation of liposomes. A total of 28 publications were examined. In addition to the theories, characteristics and problems associated with traditional methods, the advantages and drawbacks of the latest techniques were reviewed. In the light of developments in many relevant areas, a variety of new techniques are being used for liposome preparation and each of these new technique has particular advantages over conventional preparation methods. However, there are still some problems associated with these new techniques that could hinder their applications and further improvements are needed. Generally speaking, due to the introduction of these latest techniques, liposome preparation is now an improved procedure. These applications promote not only advances in liposome research but also the methods for their production on an industrial scale.

  5. Pegylated liposomal doxorubicin in ovarian cancer.

    Science.gov (United States)

    Strother, Robert; Matei, Daniela

    2009-06-01

    The encapsulation of doxorubicin in a pegylated liposomal matrix led to a reformulated agent with a different toxicity profile and improved clinical utility. Liposomal doxorubicin is devoid of the cardiac toxicity associated with doxorubicin, but is associated with predictable muco-cutaneous toxicity. The liposomal formulation leads to improved delivery to the target tumor tissue, allowing enhanced uptake by cancer cells. These properties translate into clinical utility in recurrent ovarian cancer as demonstrated by phase II and III trials, this proven clinical efficacy leading to FDA approval in second-line therapy for ovarian cancer. New combinations with cytotoxics, in particular with carboplatin, have demonstrated an acceptable toxicity profile and clinical utility in platinum-sensitive ovarian cancer. A favorable toxicity profile renders liposomal doxorubicin an ideal partner for combination regimens with other cytotoxics, and more recently with biological agents. Such combinations are the subject of ongoing clinical trials.

  6. Cystadenoma of the seminal vesicle

    Directory of Open Access Journals (Sweden)

    Gil Antônio O.

    2003-01-01

    Full Text Available Primary tumors of the seminal vesicle are extremely rare. Among them, there is a spectrum of tumors derived from both epithelium and stroma and so classified as epithelial-stromal tumors. Herein, we report a case of a cystadenoma in a 49-year-old asymptomatic man, detected in a routine ultrasonography for liver disease follow-up. The digital rectal examination detected a large mass anterior to rectum and posterior to bladder. Computed tomography scan and magnetic resonance imaging showed a normal prostate and a 9.0 cm cystic tumor, replacing the left seminal vesicle. The gross appearance and microscopic aspect was compatible with cystadenoma of seminal vesicle. Patient's postoperative recovery was uneventful. He is currently alive, 3 years after the diagnosis, with no signs of recurrence.

  7. When to biopsy seminal vesicles.

    Science.gov (United States)

    Panach-Navarrete, J; García-Morata, F; Hernández-Medina, J A; Martínez-Jabaloyas, J M

    2015-05-01

    The involvement of seminal vesicles in prostate cancer can affect the prognosis and determine the treatment. The objective of this study was to determine whether we could predict its infiltration at the time of the prostate biopsy to know when to indicate the biopsy of the seminal vesicles. observational retrospective study of 466 patients who underwent seminal vesicle biopsy. The indication for this biopsy was a prostate-specific antigen (PSA) level greater than 10 ng/ml or an asymmetric or obliterated prostatoseminal angle. The following variables were included in the analysis: PSA level, PSA density, prostate volume, number of cores biopsied, suspicious rectal examination, and preservation of the prostatoseminal angle, studying its relationship with the involvement of the seminal vesicles. Forty-one patients (8.8%) had infiltrated seminal vesicles and 425 (91.2%) had no involvement. In the univariate analysis, the cases with infiltration had a higher mean PSA level (P 19.60 ng/dL (P < .01) and 2.95 times higher if there is a suspicious rectal examination (P = .014). Furthermore, this probability increases by 1.04 times for each unit of prostate volume lower (P < .01). The ROC curves showed maximum sensitivity and specificity at 19.6 ng/mL for PSA and 0.39 for PSA density. In this series, greater involvement of seminal vesicles was associated with a PSA level ≥20 ng/ml, a suspicious rectal examination and a lack of prostatoseminal angle preservation. Copyright © 2014 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  8. Liposomal Formulation of Amphiphilic Fullerene Antioxidants

    Science.gov (United States)

    Zhou, Zhiguo; Lenk, Robert P.; Dellinger, Anthony; Wilson, Stephen R.; Sadler, Robert; Kepley, Christopher L.

    2010-01-01

    Novel amphiphilic fullerene[70] derivatives that are rationally designed to intercalate in lipid bilayers are reported, as well as its vesicular formulation with surprisingly high loading capacity up to 65% by weight. The amphiphilic C70 bisadduct forms uniform and dimensionally stable liposomes with auxiliary natural phospholipids as demonstrated by buoyant density test, particle size distribution and 31P NMR. The antioxidant property of fullerenes is retained in the bipolarly functionalized C70 derivative, Amphiphilic Liposomal Malonylfullerene[70] (ALM) as well as in its liposomal formulations, as shown by both electron paramagnetic resonance (EPR) studies and in vitro reactive oxygen species (ROS) inhibition experiments. The liposomally formulated ALM efficiently quenched hydroxyl radicals and superoxide radicals. In addition, the fullerene liposome inhibited radical-induced lipid peroxidation and maintained the integrity of the lipid bilayer structure. This new class of liposomally formulated, amphipathic fullerene compounds represents a novel drug delivery system for fullerenes and provides a promising pathway to treat oxidative stress-related diseases. PMID:20839887

  9. Pegylated liposomal doxorubicin in ovarian cancer

    Directory of Open Access Journals (Sweden)

    Robert Strother

    2009-08-01

    Full Text Available Robert Strother1,2, Daniela Matei1–51Department of Medicine, 2Indiana University Melvin and Bren Simon Cancer Center, 3Department of Obstetrics and Gynecology, 4Department of Biochemistry and Molecular Biology, 5VA Roudebush Hospital Indiana University School of Medicine, 535 Barnhill Drive, Indianapolis, IN, 46202Abstract: The encapsulation of doxorubicin in a pegylated liposomal matrix led to a reformulated agent with a different toxicity profile and improved clinical utility. Liposomal doxorubicin is devoid of the cardiac toxicity associated with doxorubicin, but is associated with predictable muco-cutaneous toxicity. The liposomal formulation leads to improved delivery to the target tumor tissue, allowing enhanced uptake by cancer cells. These properties translate into clinical utility in recurrent ovarian cancer as demonstrated by phase II and III trials, this proven clinical efficacy leading to FDA approval in second-line therapy for ovarian cancer. New combinations with cytotoxics, in particular with carboplatin, have demonstrated an acceptable toxicity profile and clinical utility in platinum-sensitive ovarian cancer. A favorable toxicity profile renders liposomal doxorubicin an ideal partner for combination regimens with other cytotoxics, and more recently with biological agents. Such combinations are the subject of ongoing clinical trials.Keywords: ovarian cancer, doxorubicin, liposomes, pegylated liposomal doxorubicin

  10. Engineering liposomal nanoparticles for targeted gene therapy.

    Science.gov (United States)

    Zylberberg, C; Gaskill, K; Pasley, S; Matosevic, S

    2017-08-01

    Recent mechanistic studies have attempted to deepen our understanding of the process by which liposome-mediated delivery of genetic material occurs. Understanding the interactions between lipid nanoparticles and cells is still largely elusive. Liposome-mediated delivery of genetic material faces systemic obstacles alongside entry into the cell, endosomal escape, lysosomal degradation and nuclear uptake. Rational design approaches for targeted delivery have been developed to reduce off-target effects and enhance transfection. These strategies, which have included the modification of lipid nanoparticles with target-specific ligands to enhance intracellular uptake, have shown significant promise at the proof-of-concept stage. Control of physical and chemical specifications of liposome composition, which includes lipid-to-DNA charge, size, presence of ester bonds, chain length and nature of ligand complexation, is integral to the performance of targeted liposomes as genetic delivery agents. Clinical advances are expected to rely on such systems in the therapeutic application of liposome nanoparticle-based gene therapy. Here, we discuss the latest breakthroughs in the development of targeted liposome-based agents for the delivery of genetic material, paying particular attention to new ligand and cationic lipid design as well as recent in vivo advances.

  11. A computational study of liposome logic: towards cellular computing from the bottom up.

    Science.gov (United States)

    Smaldon, James; Romero-Campero, Francisco J; Fernández Trillo, Francisco; Gheorghe, Marian; Alexander, Cameron; Krasnogor, Natalio

    2010-09-01

    In this paper we propose a new bottom-up approach to cellular computing, in which computational chemical processes are encapsulated within liposomes. This "liposome logic" approach (also called vesicle computing) makes use of supra-molecular chemistry constructs, e.g. protocells, chells, etc. as minimal cellular platforms to which logical functionality can be added. Modeling and simulations feature prominently in "top-down" synthetic biology, particularly in the specification, design and implementation of logic circuits through bacterial genome reengineering. The second contribution in this paper is the demonstration of a novel set of tools for the specification, modelling and analysis of "bottom-up" liposome logic. In particular, simulation and modelling techniques are used to analyse some example liposome logic designs, ranging from relatively simple NOT gates and NAND gates to SR-Latches, D Flip-Flops all the way to 3 bit ripple counters. The approach we propose consists of specifying, by means of P systems, gene regulatory network-like systems operating inside proto-membranes. This P systems specification can be automatically translated and executed through a multiscaled pipeline composed of dissipative particle dynamics (DPD) simulator and Gillespie's stochastic simulation algorithm (SSA). Finally, model selection and analysis can be performed through a model checking phase. This is the first paper we are aware of that brings to bear formal specifications, DPD, SSA and model checking to the problem of modeling target computational functionality in protocells. Potential chemical routes for the laboratory implementation of these simulations are also discussed thus for the first time suggesting a potentially realistic physiochemical implementation for membrane computing from the bottom-up.

  12. Stability of diether C(25,25) liposomes from the hyperthermophilic archaeon Aeropyrum pernix K1.

    Science.gov (United States)

    Gmajner, Dejan; Ota, Ajda; Sentjurc, Marjeta; Ulrih, Nataša Poklar

    2011-03-01

    Temperature and pH effects were studied for stability, structural organization, fluidity and permeability of vesicles from a polar lipid methanol fraction isolated from the Aeropyrum pernix. We determined the permeability of C(25,25) liposomes using fluorescence intensity of released calcein. At pH 7.0 and 9.0, and from 85°C to 98°C, only 10% of entrapped calcein was released. After 10 h at 90°C, calcein release reached 27%, independent of pH. Fluorescence anisotropy measurements of hydrophobic probe 1,6-diphenyl-1,3,5-hexatriene revealed gradual changes up to 60°C. At higher temperatures, the anisotropy did not change significantly. Fluorescence alone did not provide detailed and direct structural information about these C(25,25) liposomes, so we used electron paramagnetic resonance spectroscopy (EPR) and differential scanning calorimetry (DSC). From EPR spectra, mean membrane fluidity determined according to maximal hyperfine splitting and empirical correlation times showed continuous increases with temperature. Computer simulation of EPR spectra showed heterogeneous membranes of these C(25,25) liposomes: at low temperatures, they showed three types of membrane regions characterized by different motional modes. Above 65°C, the membrane becomes homogeneous with only one fluid-like region. DSC thermograms of C(25,25) liposomes reveal a very broad and endothermic transition in the temperature range from 0°C to 40°C. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  13. SMALL VESICLES, BIG VEHICLES: EXOSOMES.

    Directory of Open Access Journals (Sweden)

    Saiz-Lopez P

    2016-09-01

    Full Text Available Exosomes are small membranous vesicles released by different cell types. Since their discovery, they have evolved from being considered simple vehicles for the liberation of cellular wastes, to become one of the most promising fields in the area of biomedical research, and more specifically in oncology, since the different malignant tumors release exosomes to all biological fluids, being involved in various functions of the neoplastic process. At present, it is possible to study these vesicles by minimally invasive techniques in patients, which approach us to obtain a more detailed diagnosis and prognosis, as well as to the discovery of new antitumoral therapies

  14. Protection of DPPC phospholipid liposomal membrane against radiation oxidative damage by antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Marathe, D.L.; Pandey, B.N.; Mishra, K.P [Bhabha Atomic Research Centre, Mumbai (India)

    2000-05-01

    Investigations in our laboratory on egg lecithin liposomes have recently showed a marked protection against damage by gamma radiation when cholesterol was present in the composition of vesicles suggesting a role of bilayer molecular architecture in the mechanism of free radical mediated lipid peroxidation. Present study was designed to determine the changes in bilayer permeability in DPPC unilamelar vesicles after exposure to gamma radiation by monitoring the leakage of pre-loaded carboxyfluorescein (CF), a marker loaded in aqueous interior of vesicle and fluidity alterations in the bilayer using fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), a membrane bilayer probe. It was found that radiation doses of an order of magnitude higher were required to produce detectable changes in vesicles of DPPC than in the vesicles of egg lecithin suggesting a modulating role of chemical nature of composition in the membrane radiation sensitivity. It was significant to find that the leakage of CF from and incorporation of DPH into vesicle bilayer showed similar response pattern to radiation doses (0.1-6 kGy) which was also found to be dose rate dependent. Presence of antioxidants; alpha-tocopherol (0.15 mole %) in the bilayer membrane or ascorbic acid (0.1 mM) in the aqueous region significantly protected DPPC vesicles from radiation damage as determined from DPH uptake kinetics suggesting involvement of reactive free radicals of lipids as well as water radicals in the mechanism of membrane peroxidative damage. The magnitude of protection was found to increase with the increasing concentration of both these antioxidants but comparisons showed that {alpha}-tocopherol was far more effective in protecting the vesicles than ascorbic acid. These results contribute to our understanding of the mechanism of radiation oxidative damage and its modification by radical scavenging and/or organizational modulation which emphasize the importance of structure and composition of

  15. Vesicles and vesicle fusion: coarse-grained simulations

    DEFF Research Database (Denmark)

    Shillcock, Julian C.

    2010-01-01

    Biological cells are highly dynamic, and continually move material around their own volume and between their interior and exterior. Much of this transport encapsulates the material inside phospholipid vesicles that shuttle to and fro, fusing with, and budding from, other membranes. A feature of v...

  16. Control of Liposomal Penetration into Three-Dimensional Multicellular Tumor Spheroids by Modulating Liposomal Membrane Rigidity.

    Science.gov (United States)

    Takechi-Haraya, Yuki; Goda, Yukihiro; Sakai-Kato, Kumiko

    2017-06-05

    Effective penetration of drug-carrying nanoparticles into solid tumors is a major challenge in cancer therapy. Exploration of the physicochemical properties of nanoparticles that affect penetration efficiency is required to achieve maximum therapeutic effects. Here, we used confocal laser scanning microscopy to evaluate the efficiencies of penetration of fluorescently labeled liposomes into three-dimensional spheroids composed of HeLa cells. The prepared liposomes were composed of phosphatidylcholines and varying contents of cholesterol and/or a polyethylene glycol-modified phospholipid. We demonstrated that the efficiency of penetration into spheroids increased with the bending modulus (i.e., membrane rigidity) of the liposome, as determined by atomic force microscopy (correlation coefficient, 0.84). To clarify the mechanism by which membrane rigidity contributes to the penetration behavior of liposomes, we also analyzed the cellular uptake using monolayer cells. We showed that penetration efficiency was explained partially by cellular uptake efficiency, but that other factors such as liposome diffusion efficiency in the intercellular space of tumor spheroids contributed. Our results quantitatively demonstrate that the bending modulus of the liposomal membrane is a major determinant of liposomal penetration into three-dimensional spheroids. The present study will contribute to the understanding and control of tumor penetration of liposomal formulations.

  17. Ultrasound effects on brain-targeting mannosylated liposomes: in vitro and blood–brain barrier transport investigations

    Directory of Open Access Journals (Sweden)

    Zidan AS

    2015-07-01

    Full Text Available Ahmed S Zidan,1,2 Hibah Aldawsari1 1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt Abstract: Delivering drugs to intracerebral regions can be accomplished by improving the capacity of transport through blood–brain barrier. Using sertraline as model drug for brain targeting, the current study aimed at modifying its liposomal vesicles with mannopyranoside. Box-Behnken design was employed to statistically optimize the ultrasound parameters, namely ultrasound amplitude, time, and temperature, for maximum mannosylation capacity, sertraline entrapment, and surface charge while minimizing vesicular size. Moreover, in vitro blood–brain barrier transport model was established to assess the transendothelial capacity of the optimized mannosylated vesicles. Results showed a dependence of vesicular size, mannosylation capacity, and sertraline entrapment on cavitation and bubble implosion events that were related to ultrasound power amplitude, temperature. However, short ultrasound duration was required to achieve >90% mannosylation with nanosized vesicles (<200 nm of narrow size distribution. Optimized ultrasound parameters of 65°C, 27%, and 59 seconds for ultrasound temperature, amplitude, and time were elucidated to produce 81.1%, 46.6 nm, and 77.6% sertraline entrapment, vesicular size, and mannosylation capacity, respectively. Moreover, the transendothelial ability was significantly increased by 2.5-fold by mannosylation through binding with glucose transporters. Hence, mannosylated liposomes processed by ultrasound could be a promising approach for manufacturing and scale-up of brain-targeting liposomes. Keywords: CNS delivery, sizing, lipid based formulations, quality by design, sertraline hydrochloride

  18. Rapidly profiling blood-brain barrier penetration with liposome EKC.

    Science.gov (United States)

    Wang, Yongjun; Sun, Jin; Liu, Hongzhuo; He, Zhonggui

    2007-07-01

    This report intended to study the potential of liposome EKC (LEKC) as a convenient and high-throughput screening tool to assess drug penetration across the blood-brain barrier (BBB). The retention factors (k) of 24 structurally diverse compounds were determined with LEKC and vesicle EKC (VEKC), respectively. Principal component analysis of the steady-state concentrations ratio of compounds in the brain and in the blood expressed as log BB, log k(LEKC), log k(VEKC), and other lipophilic descriptors including octanol/water partition coefficient (Clog P), octanol/water distribution coefficients (log D(7.4)), and polar surface area (PSA), showed the maximum similarity of partitioning processes in LEKC to drug penetration across the BBB. Furthermore, the log BB were correlated with the above five lipophilic descriptors, and the results showed that log k(LEKC) gave the better correlation coefficient (r(2) = 0.811, p <0.0001) than those of log D(7.4), Clog P, PSA, and log k(VEKC) (r(2) = 0.730, 0.672, 0.627, and 0.620, p <0.0001). This is the first report of the use of LEKC as a promising rapid tool to profile drug penetration across the BBB.

  19. Structure and Function of Trypsin-Loaded Fibrinolytic Liposomes

    Directory of Open Access Journals (Sweden)

    Anna Tanka-Salamon

    2017-01-01

    Full Text Available Protease encapsulation and its targeted release in thrombi may contribute to the reduction of haemorrhagic complications of thrombolysis. We aimed to prepare sterically stabilized trypsin-loaded liposomes (SSLT and characterize their structure and fibrinolytic efficiency. Hydrogenated soybean phosphatidylcholine-based SSLT were prepared and their structure was studied by transmission electron microscopy combined with freeze fracture (FF-TEM, Fourier transform infrared spectroscopy (FT-IR, and small-angle X-ray scattering (SAXS. Fibrinolytic activity was examined at 45, 37, or 24°C on fibrin or plasma clots with turbidimetric and permeation-driven lysis assays. Trypsin was shown to be attached to the inner surface of vesicles (SAXS and FF-TEM close to the lipid hydrophilic/hydrophobic interface (FT-IR. The thermosensitivity of SSLT was evidenced by enhanced fibrinolysis at 45°C: time to reduce the maximal turbidity to 20% decreased by 8.6% compared to 37°C and fibrin degradation product concentration in the permeation lysis assay was 2-fold to 5-fold higher than that at 24°C. SSLT exerted its fibrinolytic action on fibrin clots under both static and dynamic conditions, whereas plasma clot dissolution was observed only in the permeation-driven assay. The improved fibrinolytic efficiency of SSLT under dynamic conditions suggests that they may serve as a novel therapeutic candidate for dissolution of intravascular thrombi, which are typically exposed to permeation forces.

  20. Peptide-Mediated Liposome Fusion: The Effect of Anchor Positioning.

    Science.gov (United States)

    Crone, Niek S A; Minnee, Dirk; Kros, Alexander; Boyle, Aimee L

    2018-01-10

    A minimal model system for membrane fusion, comprising two complementary peptides dubbed "E" and "K" joined to a cholesterol anchor via a polyethyleneglycol spacer, has previously been developed in our group. This system promotes the fusion of large unilamellar vesicles and facilitates liposome-cell fusion both in vitro and in vivo. Whilst several aspects of the system have previously been investigated to provide an insight as to how fusion is facilitated, anchor positioning has not yet been considered. In this study, the effects of placing the anchor at either the N-terminus or in the center of the peptide are investigated using a combination of circular dichroism spectroscopy, dynamic light scattering, and fluorescence assays. It was discovered that anchoring the "K" peptide in the center of the sequence had no effect on its structure, its ability to interact with membranes, or its ability to promote fusion, whereas anchoring the 'E' peptide in the middle of the sequence dramatically decreases fusion efficiency. We postulate that anchoring the 'E' peptide in the middle of the sequence disrupts its ability to form homodimers with peptides on the same membrane, leading to aggregation and content leakage.

  1. Peptide-Mediated Liposome Fusion: The Effect of Anchor Positioning

    Directory of Open Access Journals (Sweden)

    Niek S. A. Crone

    2018-01-01

    Full Text Available A minimal model system for membrane fusion, comprising two complementary peptides dubbed “E” and “K” joined to a cholesterol anchor via a polyethyleneglycol spacer, has previously been developed in our group. This system promotes the fusion of large unilamellar vesicles and facilitates liposome-cell fusion both in vitro and in vivo. Whilst several aspects of the system have previously been investigated to provide an insight as to how fusion is facilitated, anchor positioning has not yet been considered. In this study, the effects of placing the anchor at either the N-terminus or in the center of the peptide are investigated using a combination of circular dichroism spectroscopy, dynamic light scattering, and fluorescence assays. It was discovered that anchoring the “K” peptide in the center of the sequence had no effect on its structure, its ability to interact with membranes, or its ability to promote fusion, whereas anchoring the ‘E’ peptide in the middle of the sequence dramatically decreases fusion efficiency. We postulate that anchoring the ‘E’ peptide in the middle of the sequence disrupts its ability to form homodimers with peptides on the same membrane, leading to aggregation and content leakage.

  2. Development and optimization of a new processing approach for manufacturing topical liposomes-in-hydrogel drug formulations by dual asymmetric centrifugation.

    Science.gov (United States)

    Ingebrigtsen, Sveinung G; Škalko-Basnet, Nataša; Holsæter, Ann Mari

    2016-09-01

    The objective of the present study was to utilize dual asymmetric centrifugation (DAC) as a novel processing approach for the production of liposomes-in-hydrogel formulations. Lipid films of phosphatidylcholine, with and without chloramphenicol (CAM), were hydrated and homogenized by DAC to produce liposomes in the form of vesicular phospholipid gels with a diameter in the size range of 200-300 nm suitable for drug delivery to the skin. Different homogenization processing parameters were investigated along with the effect of adding propylene glycol (PG) to the formulations prior to homogenization. The produced liposomes were incorporated into a hydrogel made of 2.5% (v/v) soluble β-1,3/1,6-glucan (SBG) and mixed by DAC to achieve a homogenous liposomes-in-hydrogel-formulation suitable for topical application. CAM-containing liposomes with a vesicle diameter of 282 ± 30 nm and polydispersity index (PI) of 0.13 ± 0.02 were successfully produced by DAC after 50 min centrifugation at 3500 rpm, and homogenously (< 4% content variation) incorporated into the SBG hydrogel. Addition of PG decreased the necessary centrifugation time to 2 min and 55 s, producing liposomes of 230 ± 51 nm and PI of 0.25 ± 0.04. All formulations had an entrapment efficiency of approximately 50%. We managed to develop a relatively fast and reproducible new method for the production of liposomes-in-hydrogel formulations by DAC.

  3. A gamma scintigraphy study to investigate uterine targeting efficiency of raloxifene-loaded liposomes administered intravaginally in New Zealand white female rabbits.

    Science.gov (United States)

    Patel, Arpita; Tyagi, Amit; Sharma, Rakesh Kumar; Thakkar, Hetal

    2016-11-01

    Raloxifene hydrochloride (RLH), a selective estrogen receptor modulator, shows antiproliferative and apoptotic effects on Leiomyoma. Its extensive first pass metabolism leads to oral bioavailability of 2%. The aim of this investigation was to formulate RLH-loaded liposomes and study its uterine-targeting efficiency after intravaginal administration. Liposomes were prepared by thin film hydration method using 1:1 molar ratio of DSPC:Cholesterol and characterized for vesicle size, zeta potential, %entrapment efficiency, loading, drug release and transmission electron microscopy. Radiolabeling of RLH was performed with reduced technetium-99m ((99m)Tc). Binding affinity of (99m)Tc-labeled complexes was assessed by diethylene triamine penta acetic acid (DTPA) challenge test. Biodistribution study was done in New Zealand white female rabbits by administering the formulation intravaginally. Spherical and discrete liposomes of size 119 nm were seen in TEM results. Liposomes had high entrapment efficiency of 90.96% with drug loading of 27.25%w/w. Liposomes were able to sustain the drug release for 6 days. (99m)Tc-labeled complexes showed high labeling efficiency and stability both in saline and serum. DTPA challenge test confirmed low transchelation of (99m)Tc-labeled complexes. Biodistribution study by gamma scintigraphy revealed the preferential uptake of the formulation by uterus when administered vaginally. Compared to plain drug, liposomes were concentrated and retained within the uterus for a longer period of time. Uterine targeting of RLH-loaded liposomes indicates its potential to overcome the limitations of marketed formulation. Drug targeting to site of action anticipates dose reduction needed to elicit the therapeutic effect.

  4. Plasmonic Vesicles of Amphiphilic Nanocrystals: Optically Active Multifunctional Platform for Cancer Diagnosis and Therapy.

    Science.gov (United States)

    Song, Jibin; Huang, Peng; Duan, Hongwei; Chen, Xiaoyuan

    2015-09-15

    Vesicular structures with compartmentalized, water-filled cavities, such as liposomes of natural and synthetic amphiphiles, have tremendous potential applications in nanomedicine. When block copolymers self-assemble, the result is polymersomes with tailored structural properties and built-in releasing mechanisms, controlled by stimuli-responsive polymer building blocks. More recently, chemists are becoming interested in multifunctional hybrid vesicles containing inorganic nanocrystals with unique optical, electronic, and magnetic properties. In this Account, we review our recent progress in assembling amphiphilic plasmonic nanostructures to create a new class of multifunctional hybrid vesicles and applying them towards cancer diagnosis and therapy. Localized surface plasmon resonance (LSPR) gives plasmonic nanomaterials a unique set of optical properties that are potentially useful for both biosensing and nanomedicine. For instance, the strong light scattering at their LSPR wavelength opens up the applications of plasmonic nanostructures in single particle plasmonic imaging. Their superior photothermal conversion properties, on the other hand, make them excellent transducers for photothermal ablation and contrast agents for photoacoustic imaging. Of particular note for ultrasensitive detection is that the confined electromagnetic field resulting from excitation of LSPR can give rise to highly efficient surface enhanced Raman scattering (SERS) for molecules in close proximity. We have explored several ways to combine well-defined plasmonic nanocrystals with amphiphilic polymer brushes of diverse chemical functionalities. In multiple systems, we have shown that the polymer grafts impart amphiphilicity-driven self-assembly to the hybrid nanoparticles. This has allowed us to synthesize well-defined vesicles in which we have embedded plasmonic nanocrystals in the shell of collapsed hydrophobic polymers. The hydrophilic brushes extend into external and interior aqueous

  5. Ca2+ Dependence of Synaptic Vesicle Endocytosis.

    Science.gov (United States)

    Leitz, Jeremy; Kavalali, Ege T

    2016-10-01

    Ca(2+)-dependent synaptic vesicle recycling is essential for structural homeostasis of synapses and maintenance of neurotransmission. Although, the executive role of intrasynaptic Ca(2+) transients in synaptic vesicle exocytosis is well established, identifying the exact role of Ca(2+) in endocytosis has been difficult. In some studies, Ca(2+) has been suggested as an essential trigger required to initiate synaptic vesicle retrieval, whereas others manipulating synaptic Ca(2+) concentrations reported a modulatory role for Ca(2+) leading to inhibition or acceleration of endocytosis. Molecular studies of synaptic vesicle endocytosis, on the other hand, have consistently focused on the roles of Ca(2+)-calmodulin dependent phosphatase calcineurin and synaptic vesicle protein synaptotagmin as potential Ca(2+) sensors for endocytosis. Most studies probing the role of Ca(2+) in endocytosis have relied on measurements of synaptic vesicle retrieval after strong stimulation. Strong stimulation paradigms elicit fusion and retrieval of multiple synaptic vesicles and therefore can be affected by several factors besides the kinetics and duration of Ca(2+) signals that include the number of exocytosed vesicles and accumulation of released neurotransmitters thus altering fusion and retrieval processes indirectly via retrograde signaling. Studies monitoring single synaptic vesicle endocytosis may help resolve this conundrum as in these settings the impact of Ca(2+) on synaptic fusion probability can be uncoupled from its putative role on synaptic vesicle retrieval. Future experiments using these single vesicle approaches will help dissect the specific role(s) of Ca(2+) and its sensors in synaptic vesicle endocytosis. © The Author(s) 2015.

  6. Extracellular vesicles in physiological and pathological conditions

    NARCIS (Netherlands)

    Yuana, Yuana; Sturk, Auguste; Nieuwland, Rienk

    2013-01-01

    Body fluids contain surprising numbers of cell-derived vesicles which are now thought to contribute to both physiology and pathology. Tools to improve the detection of vesicles are being developed and clinical applications using vesicles for diagnosis, prognosis, and therapy are under investigation.

  7. Membrane Trafficking and Vesicle Fusion

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Membrane Trafficking and Vesicle Fusion: Post-Palade Era Researchers Win the Nobel Prize. Riddhi Atul Jani Subba Rao Gangi Setty. General Article Volume 19 Issue 5 May 2014 pp 421-445 ...

  8. Recovery of symptomatic extravasation of liposomal doxorubicin after dexrazoxane treatment.

    NARCIS (Netherlands)

    Vos, F.Y.F.L. de; Lesterhuis, W.J.; Bruggemann, R.J.M.; Graaf, W.T.A. van der

    2012-01-01

    A patient with metastatic ovarian cancer was treated with liposomal doxorubicin and carboplatin. She had an extravasation during liposomal doxorubicin infusion. Initially, she was treated conservatively with cold compresses and topical treatment. However, because of worsening of symptoms, she

  9. Macrophages and liposomes in inflammatory disease : Friends or foes?

    NARCIS (Netherlands)

    Crielaard, B J; Lammers, T; Morgan, M E; Chaabane, L; Carboni, S; Greco, B; Zaratin, P; Kraneveld, A D; Storm, G

    2011-01-01

    Liposome-encapsulated corticosteroids have shown to exert strong beneficial effects in inflammatory diseases, such as arthritis and cancer. To extend the clinical applicability of these potent nanomedicines, the therapeutic effect of dexamethasone phosphate loaded long-circulating liposomes

  10. ANTISTAPHYLOCOCCAL ACTIVITY OF LIPOSOMAL FORMS OF LINCOMYCIN

    Directory of Open Access Journals (Sweden)

    Derkach SA

    2015-04-01

    Full Text Available Nowadays the vital problem of modern medicine is a tendency to emerging of both nosocomial and community-acquired strains before antibiotic resistance forming. The complexity of antibiotic therapy of diseases caused by methicillin resistant staphylococci having high poly resistance almost to every classes of antibacterial agents is of prime importance. One of the ways to improve antibacterial preparations still remains the development of their liposomal forms. This work studies antistaphylococcal activity (according to MIC of the liposomal form of lincomycin developed in the Institute of Dermatology and Venereology of Ukraine by Ivanova N. N., the Candidate of Сhemical Sciences.The purpose of this research work was to study liposomal inhibiting concentration of the liposomalny form of lincomycin and a commercial preparation lincomycin (produced by CJSC “Pharmaceutical firm "Darnitsa". Determination of the minimum inhibiting concentration was carried out by a tablet micromethod by consecutive cultivations of the samples under study.It is shown that MIC of liposomal lincomycin is eight times as low as usual lincomycin (0,23mkg/ml to 1,87 mkg/ml. Antibacterial activity of the liposomal form of lincomycin is studied concerning the patients selected from the different biotopes with pyo inflammatory diseases of staphylococcus strains (15 strains – methicillin sensitive, 12 strains - methicillin resistant.It is shown authentically the higher sensitivity of S. aureus strains to the liposomal form of lincomycin in comparison with usual lincomycin . Also 50.0% of MRSA strains were sensitive to the liposomalny form of lincomycin that shows the perspective for the development of the liposomal forms of antibiotics to cure staphylococcal infections.

  11. Boron-Containing Compounds for Liposome-Mediated Tumor Localization and Application to Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, M. Frederick [Univ. of California, Los Angeles, CA (United States)

    2005-04-07

    Medical application of boron neutron capture therapy (BNCT) has been significantly hindered by the slow development of boron drug-targeting methodologies for the selective delivery of high boron concentration sto malignant cells. We have successfully sought to fill this need by creating liposomes suitable as in vivo boron delivery vehicles for BNCT. Delivery of therapeutic quantities of boron to tumors in murine models has been achieved with small unilamellar boron-rich liposomes. Subsequently, attempts have been made to improve delivery efficiency of liposomes encapsulating boron-containing water-soluble species into their hollow core by incorporating lipophilic boron compounds as addenda to the liposome bilayer, incorporating boron compounds as structural components of the bilayer (which however, poses the risk of sacrificing some stability), and combinations thereof. Regardless of the method, approximately 90% of the total liposome mass remains therapeutically inactive and comprised of the vehicle's construction materials, while less than 5% is boron for neutron targeting. Following this laboratory's intensive study, the observed tumor specificity of certain liposomes has been attributed to their diminutive size of these liposomes (30-150 nm), which enables these small vesicles to pass through the porous, immature vasculature of rapidly growing tumor tissue. We surmised that any amphiphilic nanoparticle of suitable size could possess some tumor selectivity. Consequently, the discovery of a very boron-rich nanoparticle delivery agent with biodistribution performance similar to unilamellar liposomes became one of our goals. Closomers, a new class of polyhedral borane derivatives, attracted us as an alternative BNCT drug-delivery system. We specifically envisioned dodeca (nido-carboranyl)-substituted closomers as possibly having a great potential role in BNCT drug delivery. They could function as extraordinarily boron-rich BNCT drugs since they are

  12. Experiments on and Numerical Modeling of the Capture and Concentration of Transcription-Translation Machinery inside Vesicles.

    Science.gov (United States)

    Mavelli, Fabio; Stano, Pasquale

    2015-01-01

    Synthetic or semi-synthetic minimal cells are those cell-like artificial compartments that are based on the encapsulation of molecules inside lipid vesicles (liposomes). Synthetic cells are currently used as primitive cell models and are very promising tools for future biotechnology. Despite the recent experimental advancements and sophistication reached in this field, the complete elucidation of many fundamental physical aspects still poses experimental and theoretical challenges. The interplay between solute capture and vesicle formation is one of the most intriguing ones. In a series of studies, we have reported that when vesicles spontaneously form in a dilute solution of proteins, ribosomes, or ribo-peptidic complexes, then, contrary to statistical predictions, it is possible to find a small fraction of liposomes (<1%) that contain a very large number of solutes, so that their local (intravesicular) concentrations largely exceed the expected value. More recently, we have demonstrated that this effect (spontaneous crowding) operates also on multimolecular mixtures, and can drive the synthesis of proteins inside vesicles, whereas the same reaction does not proceed at a measurable rate in the external bulk phase. Here we firstly introduce and discuss these already published observations. Then, we present a computational investigation of the encapsulation of transcription-translation (TX-TL) machinery inside vesicles, based on a minimal protein synthesis model and on different solute partition functions. Results show that experimental data are compatible with an entrapment model that follows a power law rather than a Gaussian distribution. The results are discussed from the viewpoint of origin of life, highlighting open questions and possible future research directions.

  13. Evaluation of iron transport from ferrous glycinate liposomes using ...

    African Journals Online (AJOL)

    Background: Iron fortification of foods is currently a strategy employed to fight iron deficiency in countries. Liposomes were assumed to be a potential carrier of iron supplements. Objective: The objective of this study was to investigate the iron transport from ferrous glycinate liposomes, and to estimate the effects of liposomal ...

  14. Cerebrovascular Involvement in Liposome - Induced Cardiopulmonary Distress in Pigs

    Science.gov (United States)

    2005-01-01

    distance was 12-35 mm. The electrodes were covered with dental acrylic cement (Cranioplastic Powder, Plastics One, Roanoke, VA). An electrical impedance...by liposomes and liposome-encapsulated hemoglobin in pigs: a model for pseudo- allergic cardiopulmonary reactions to liposomes. Role of complement and

  15. Characterization of Diclofenac Liposomes Formulated with Palm Oil ...

    African Journals Online (AJOL)

    Purpose: To characterize diclofenac sodium (DS) liposomes prepared using palm oil fractions. Methods: Reverse-phase evaporation method was used to prepare liposomes containing 10, 20, 30 , 40 or 50% palm oil fractions. The effect of palm oil content on liposome formation, surface morphology, shape, size and zeta ...

  16. Targeting of liposomes containing methotrexate towards Tetrahymena pyriformis cells.

    Science.gov (United States)

    Kotsifaki, H; Kapoulas, V; Deliconstantinos, G

    1985-01-01

    The uptake of liposomes containing methotrexate by Tetrahymena pyriformis cells was investigated with the aim of producing liposome-cell association enabling methotrexate to be introduced into the cytoplasm of intact cells. Incubation of liposomes containing methotrexate with tetrahymena pyriformis cells resulted in a time and concentration-dependent uptake of entrapped methotrexate by the cells. The uptake by Tetrahymena pyriformis cells (at 1 hr) of liposomes prepared by phospholipids and gangliosides extracted from Tetrahymena pyriformis cells was approximately three fold higher than that of liposomes prepared by commercial phospholipids. Approximately 90% of liposome uptake could be inhibited by cytochalasin B and also by NaN3 and 2-deoxyglucose. This was consistent with the uptake being the result of endocytosis. The remaining uptake was probably the result of adhesion of liposomes to the cell membrane. The rate of efflux vs time of methotrexate entrapped in liposomes was much slower than that of free methotrexate which reinforces the concept that endocytosis is the main mode of liposomes uptake by the cells. Liposomes containing methotrexate at concentrations as low as 4.5 microM effectively inhibited the activity of dihydrofolate reductase which was used as a function parameter in this study. Similar inhibition of the enzyme activity by free methotrexate was achieved only at concentrations as high as 880 microM. The influence of liposomes lipid composition on the targeting of liposomes to Tetrahymena pyriformis cells was discussed.

  17. A novel liposomal formulation of flavopiridol.

    Science.gov (United States)

    Yang, Xiaojuan; Zhao, Xiaobin; Phelps, Mitch A; Piao, Longzhu; Rozewski, Darlene M; Liu, Qing; Lee, L James; Marcucci, Guido; Grever, Michael R; Byrd, John C; Dalton, James T; Lee, Robert J

    2009-01-05

    Flavopiridol has shown promising activities in hematologic and solid tumor models, as well as in clinical trials in chronic lymphocytic leukemia patients. Flavopiridol has relatively low solubility and high plasma protein-binding. To address these issues and to provide an alternative strategy to achieve clinical efficacy, we encapsulated flavopiridol into a liposomal carrier and characterized its physicochemical and pharmacokinetic properties. The liposomes, comprising hydrogenated soy phosphatidylcholine (HSPC), cholesterol and poly (ethylene glycol) 2000-distearoyl phosphatidylethanolamine (PEG-DSPE), were prepared by polycarbonate membrane extrusion and then loaded with flavopiridol by a pH-gradient driven remote loading procedure. The liposomes had a mean diameter of 120.7 nm and a flavopiridol entrapment efficiency of 70.4%. Pharmacokinetic study in mice after i.v. bolus injection showed that the liposomal flavopiridol had an increased elimination phase half-life (T((1/2)beta), 339.7 min vs. 57.0 min), decreased clearance (CL, 0.012 L/min vs. 0.036 L/min), and increased area under the plasma concentration-time curve (AUC, 10.8 min micromol/L vs. 3.4 min micromol/L) compared to the free drug. This indicates a significant and potentially beneficial change in flavopiridol pharmacokinetics for the liposomal formulation. Further preclinical studies are warranted to define the toxicity and therapeutic efficacy of this novel formulation.

  18. Liposomal adjuvant development for leishmaniasis vaccines.

    Science.gov (United States)

    Askarizadeh, Anis; Jaafari, Mahmoud Reza; Khamesipour, Ali; Badiee, Ali

    2017-08-01

    Leishmaniasis is a parasitic disease that ranges in severity from skin lesions to fatality. Since long-lasting protection is induced upon recovery from cutaneous leishmaniasis, development of an effective vaccine is promising. However, there is no vaccine for use in humans yet. It seems limited efficacy in leishmaniasis vaccines is due to lack of an appropriate adjuvant or delivery system. Hence, the use of particulate adjuvants such as liposomes for effective delivery to the antigen presenting cells (APCs) is a valuable strategy to enhance leishmaniasis vaccine efficacy. The extraordinary versatility of liposomes because of their unique amphiphilic and biphasic nature allows for using antigens or immunostimulators within the core, on the surface or within the bilayer, and modulates both the magnitude and the T-helper bias of the immune response. In this review article, we attempt to summarize the role of liposomal adjuvants in the development of Leishmania vaccines and describe the main physicochemical properties of liposomes like phospholipid composition, surface charge, and particle size during formulation design. We also suggest potentially useful formulation strategies in order for future experiments to have a chance to succeed as liposomal vaccines against leishmaniasis.

  19. Treatment of Digital Ischemia with Liposomal Bupivacaine

    Directory of Open Access Journals (Sweden)

    José Raul Soberón

    2014-01-01

    Full Text Available Objective. This report describes a case in which the off-label use of liposomal bupivacaine (Exparel in a peripheral nerve block resulted in marked improvement of a patient’s vasoocclusive symptoms. The vasodilating and analgesic properties of liposomal bupivacaine in patients with ischemic symptoms are unknown, but our clinical experience suggests a role in the management of patients suffering from vasoocclusive disease. Case Report. A 45-year-old African American female was admitted to the hospital with severe digital ischemic pain. She was not a candidate for any vascular surgical or procedural interventions. Two continuous supraclavicular nerve blocks were placed with modest clinical improvement. These effects were also short-lived, with the benefits resolving after the discontinuation of the peripheral nerve blocks. She continued to report severe pain and was on multiple anticoagulant medications, so a decision was made to perform an axillary nerve block using liposomal bupivacaine (Exparel given the compressibility of the site as well as the superficial nature of the target structures. Conclusions. This case report describes the successful off-label usage of liposomal bupivacaine (Exparel in a patient with digital ischemia. Liposomal bupivacaine (Exparel is currently FDA approved only for wound infiltration use at this time.

  20. Ferrocene-Modified Phospholipid: An Innovative Precursor for Redox-Triggered Drug Delivery Vesicles Selective to Cancer Cells.

    Science.gov (United States)

    Noyhouzer, Tomer; L'Homme, Chloé; Beaulieu, Isabelle; Mazurkiewicz, Stephanie; Kuss, Sabine; Kraatz, Heinz-Bernhard; Canesi, Sylvain; Mauzeroll, Janine

    2016-05-03

    Controlled payload release is one of the key elements in the creation of a reliable drug delivery system. We report the discovery of a drug delivery vessel able to transport chemotherapeutic agents to target cancer cells and selectively trigger their release using the electrochemical activity of a ferrocene-modified phospholipid. Supported by in vitro assays, the competitive advantages of this discovery are (i) the simple one step scalability of the synthetic process, (ii) the stable encapsulation of toxic drugs (doxorubicin) during transport, and (iii) the selective redox triggering of the liposomes to harness their cytotoxic payload at the cancer site. Specifically, the redox-modified giant unilamellar vesicle and liposomes were characterized using advanced methods such as scanning electrochemical microscopy (SECM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and fluorescent imaging.

  1. Liposomal membrane disruption by means of miniaturized dielectric-barrier discharge in air: liposome characterization

    Science.gov (United States)

    Svarnas, P.; Asimakoulas, L.; Katsafadou, M.; Pachis, K.; Kostazos, N.; Antimisiaris, S. G.

    2017-08-01

    The increasing interest of the plasma community in the application of atmospheric-pressure cold plasmas to bio-specimen treatment has led to the creation of the emerging field of plasma biomedicine. Accordingly, plasma setups based on dielectric-barrier discharges have already been widely tested for the inactivation of various cells. Most of these systems refer to the plasma jet concept where noble gases penetrate atmospheric air and are subjected to the influence of high electric fields, thus forming guided streamers. Following the original works of our group where liposomal membranes were proposed as models for studying the interaction between plasma jets and cells, we present herein a study on liposomal membrane disruption by means of miniaturized dielectric-barrier discharge running in atmospheric air. Liposomal membranes of various lipid compositions, lamellarities, and sizes are treated at different times. It is shown that the dielectric-barrier discharge of low mean power leads to efficient liposomal membrane disruption. The latter is achieved in a controllable manner and depends on liposome properties. Additionally, it is clearly demonstrated that liposomal membrane disruption takes place even after plasma extinction, i.e. during post-treatment, resembling thus an ‘apoptosis’ effect, which is well known today mainly for cell membranes. Thus, the adoption of the present concept would be beneficial for tailoring studies on plasma-treated cell-mimics. Finally, the liposome treatment is discussed with respect to possible physicochemical mechanisms and potential discharge modification due to the various compositions of the liquid electrode.

  2. Magnetic nanoparticles for "smart liposomes".

    Science.gov (United States)

    Nakayama, Yoshitaka; Mustapić, Mislav; Ebrahimian, Haleh; Wagner, Pawel; Kim, Jung Ho; Hossain, Md Shahriar Al; Horvat, Joseph; Martinac, Boris

    2015-12-01

    Liposomal drug delivery systems (LDDSs) are promising tools used for the treatment of diseases where highly toxic pharmacological agents are administered. Currently, destabilising LDDSs by a specific stimulus at a target site remains a major challenge. The bacterial mechanosensitive channel of large conductance (MscL) presents an excellent candidate biomolecule that could be employed as a remotely controlled pore-forming nanovalve for triggered drug release from LDDSs. In this study, we developed superparamagnetic nanoparticles for activation of the MscL nanovalves by magnetic field. Synthesised CoFe2O4 nanoparticles with the radius less than 10 nm were labelled by SH groups for attachment to MscL. Activation of MscL by magnetic field with the nanoparticles attached was examined by the patch clamp technique showing that the number of activated channels under ramp pressure increased upon application of the magnetic field. In addition, we have not observed any cytotoxicity of the nanoparticles in human cultured cells. Our study suggests the possibility of using magnetic nanoparticles as a specific trigger for activation of MscL nanovalves for drug release in LDDSs.

  3. The readily releasable pool of synaptic vesicles.

    Science.gov (United States)

    Kaeser, Pascal S; Regehr, Wade G

    2017-04-01

    Each presynaptic bouton is densely packed with many vesicles, only a small fraction of which are available for immediate release. These vesicles constitute the readily releasable pool (RRP). The RRP size, and the probability of release of each vesicle within the RRP, together determine synaptic strength. Here, we discuss complications and recent advances in determining the size of the physiologically relevant RRP. We consider molecular mechanisms to generate and regulate the RRP, and discuss the relationship between vesicle docking and the RRP. We conclude that many RRP vesicles are docked, that some docked vesicles may not be part of the RRP, and that undocked vesicles can contribute to the RRP by rapid recruitment to unoccupied, molecularly activated ready-to-release sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Membrane fusion of pH-sensitive liposomes – a quantitative study using giant unilamellar vesicles

    DEFF Research Database (Denmark)

    Trier, Sofie; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2011-01-01

    This article presents a methodology for developing small-signal behavioral electromagnetic (EM) models of p-i-n photodiodes (PDs) for high-speed applications. The EM model includes RC bandwidth limitation effect and transit-time effect. The model is capable of accurately modeling arbitrary complex...

  5. Liposomal siRNA for ovarian cancer.

    Science.gov (United States)

    Mangala, Lingegowda S; Han, Hee Dong; Lopez-Berestein, Gabriel; Sood, Anil K

    2009-01-01

    Discovery of RNA interference (RNAi) has been one of the most important findings in the last ten years. In recent years, small interfering RNA (siRNA)-mediated gene silencing is beginning to show substantial promise as a new treatment modality in preclinical studies because of its robust gene selective silencing. However, until recently, delivery of siRNA in vivo was a major impediment to its use as a therapeutic modality. We have used a neutral liposome, 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC), for highly efficient in vivo siRNA delivery. Using siRNA tagged with Alexa-555, incorporated in DOPC liposomes, we have demonstrated efficient intra-tumoral delivery following either intraperitoneal or intravenous injection. Furthermore, EphA2-targeted siRNA in DOPC liposomes showed significant target modulation and anti-tumor efficacy.

  6. Phospholipid Vesicles in Materials Science

    Energy Technology Data Exchange (ETDEWEB)

    Granick, Steve [Univ. of Illinois, Champaign, IL (United States)

    2016-05-11

    The objective of this research was to develop the science basis needed to deploy phospholipid vesicles as functional materials in energy contexts. Specifically, we sought to: (1) Develop an integrated molecular-level understanding of what determines their dynamical shape, spatial organization, and responsiveness to complex, time-varying environments; and (2) Develop understanding of their active transportation in crowded environments, which our preliminary measurements in cells suggest may hold design principles for targeting improved energy efficiency in new materials systems. The methods to do this largely involved fluorescence imaging and other spectroscopy involving single particles, vesicles, particles, DNA, and endosomes. An unexpected importance outcome was a new method to image light-emitting diodes during actual operation using super-resolution spectroscopy.

  7. Dynamics of endocytic vesicle creation.

    Science.gov (United States)

    Perrais, David; Merrifield, Christien J

    2005-11-01

    Clathrin-mediated endocytosis is the main path for receptor internalization in metazoans and is essential for controlling cell integrity and signaling. It is driven by a large array of protein and lipid interactions that have been deciphered mainly by biochemical and genetic means. To place these interactions into context, and ultimately build a fully operative model of endocytosis at the molecular level, it is necessary to know the kinetic details of the role of each protein in this process. In this review, we describe the recent efforts made, by using live cell imaging, to define clear steps in the formation of endocytic vesicles and to observe the recruitment of key proteins during membrane invagination, the scission of a newly formed vesicle, and its movement away from the plasma membrane.

  8. Extracellular vesicles and blood diseases.

    Science.gov (United States)

    Nomura, Shosaku

    2017-04-01

    Extracellular vesicles (EVs) are small membrane vesicles released from many different cell types by the exocytic budding of the plasma membrane in response to cellular activation or apoptosis. EVs disseminate various bioactive effectors originating from the parent cells and transfer functional RNA and protein between cells, enabling them to alter vascular function and induce biological responses involved in vascular homeostasis. Although most EVs in human blood originate from platelets, EVs are also released from leukocytes, erythrocytes, endothelial cells, smooth muscle cells, and cancer cells. EVs were initially thought to be small particles with procoagulant activity; however, they can also evoke cellular responses in the immediate microenvironments and transport microRNAs (miRNA) into target cells. In this review, we summarize the recent literature relevant to EVs, including a growing list of clinical disorders that are associated with elevated EV levels. These studies suggest that EVs play roles in various blood diseases.

  9. Recent Trends of Polymer Mediated Liposomal Gene Delivery System

    Directory of Open Access Journals (Sweden)

    Shyamal Kumar Kundu

    2014-01-01

    Full Text Available Advancement in the gene delivery system have resulted in clinical successes in gene therapy for patients with several genetic diseases, such as immunodeficiency diseases, X-linked adrenoleukodystrophy (X-ALD blindness, thalassemia, and many more. Among various delivery systems, liposomal mediated gene delivery route is offering great promises for gene therapy. This review is an attempt to depict a portrait about the polymer based liposomal gene delivery systems and their future applications. Herein, we have discussed in detail the characteristics of liposome, importance of polymer for liposome formulation, gene delivery, and future direction of liposome based gene delivery as a whole.

  10. Immunotherapeutic potential of extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Bin eZhang

    2014-10-01

    Full Text Available Extracellular vesicles or EVs is a term that encompasses all classes of secreted lipid membrane vesicles. Despite being scientific novelties, EVs are gaining importance as a mediator of important physiological and pathological intercellular activities possibly through the transfer of their cargo of protein and RNA between cells. In particular, exosomes the currently best characterized EVs have been notable for their in vitro and in vivo immunomodulatory activities. Exosomes are nanometer-sized endosome-derived vesicles secreted by many cell types and their immunomodulatory potential is independent of their cell source. Besides immune cells such as dendritic cells, macrophages and T cells, cancer and stem cells also secrete immunologically active exosomes that could influence both physiological and pathological processes. The immunological activities of exosomes affect both innate and adaptive immunity and include antigen presentation, T cell activation, T cell polarisation to Tregs, immune suppression and anti-inflammation. As such, exosomes carry much immunotherapeutic potential as a therapeutic agent and a therapeutic target.

  11. Therapeutic gas delivery via microbubbles and liposomes.

    Science.gov (United States)

    Fix, Samantha M; Borden, Mark A; Dayton, Paul A

    2015-07-10

    Gaseous molecules including nitric oxide, hydrogen sulfide, carbon monoxide and oxygen mediate numerous cell signaling pathways and have important physiological roles. Several noble gasses have been shown to elicit biological responses. These bioactive gasses hold great therapeutic potential, however, their controlled delivery remains a significant challenge. Recently, researchers have begun using microbubbles and liposomes to encapsulate such gasses for parenteral delivery. The resultant particles are acoustically active, and ultrasound can be used to stimulate and/or image gas release in a targeted region. This review provides a summary of recent advances in therapeutic gas delivery using microbubbles and liposomes. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Liposomes as a gene delivery system

    Directory of Open Access Journals (Sweden)

    C. Ropert

    1999-02-01

    Full Text Available Gene therapy is an active field that has progressed rapidly into clinical trials in a relatively short time. The key to success for any gene therapy strategy is to design a vector able to serve as a safe and efficient gene delivery vehicle. This has encouraged the development of nonviral DNA-mediated gene transfer techniques such as liposomes. Many liposome-based DNA delivery systems have been described, including molecular components for targeting given cell surface receptors or for escaping from the lysosomal compartment. Another recent technology using cationic lipids has been evaluated and has generated substantial interest in this approach to gene transfer.

  13. Liposomal Drug Delivery of Anticancer Agents

    DEFF Research Database (Denmark)

    Pedersen, Palle Jacob

    In the first part of the thesis the work towards a new generation of liposomal drug delivery systems for anticancer agents is described. The drug delivery system takes advantage of the elevated level of secretory phospholipase A2 (sPLA2) IIA in many tumors and the enhanced permeability...... and retention (EPR) effect. The liposomes consists of sPLA2 IIA sensitive phospholipids having anticancer drugs covalently attached to the sn-2 position of the glycerol backbone in the phospholipids, hence drug leakage is avoided from the carrier system. Various known anticancer agents, like chlorambucil, all...

  14. Ligand-Mediated Coating of Liposomes with Human Serum Albumin.

    Science.gov (United States)

    Sato, Hikari; Nakhaei, Elnaz; Kawano, Takahito; Murata, Masaharu; Kishimura, Akihiro; Mori, Takeshi; Katayama, Yoshiki

    2018-02-13

    Coating liposome surfaces with human serum albumin (HSA) can improve the colloidal stability and prevent opsonization. HSA coating via specific binding with alkyl ligands is promising because although the ligand-mediated coating is relatively stable it can spontaneously exchange with fresh HSA. However, to achieve surface coating with HSA, multiple hydrophobic ligands must be exposed to an aqueous medium prior to binding with HSA. This presents a challenge, as hydrophobic ligands tend to be buried in the liposomal membrane. Here we present the first HSA modification of liposome surfaces via alkyl ligands. We found that a relatively short alkyl ligand, or a long alkyl ligand with a terminal carboxylate, could be exposed on the liposome surface without causing aggregation of the liposomes and these ligands could subsequently bind HSA. The resulting HSA-coated liposomes were as inert as conventional PEGylated liposomes in terms of macrophage recognition.

  15. Double-Tailed Cystine Derivatives as Novel Substitutes of Phospholipids with Special Reference to Liposomes.

    Science.gov (United States)

    Bhattarai, Ravi; Sutradhar, Tanushree; Roy, Biplab; Guha, Pritam; Chettri, Priyam; Mandal, Amit Kumar; Bykov, Alexey G; Akentiev, Alexander V; Noskov, Boris A; Panda, Amiya Kumar

    2016-10-12

    Cystine-based gemini surfactants with dodecyl, tetradecyl, hexadecyl, and octadecyl hydrocarbon chains were synthesized, and their interactions with unsaturated (soy phosphatidylcholine, SPC)/saturated (hydrogenated SPC, HSPC) soy phosphatidylcholines in the forms of a monolayer and a model liposome were estimated for different combinations of the components in the mixed systems. Studies of Langmuir monolayers at the air-aqueous buffer interface revealed condensation of the monomolecular films with the addition of surfactants. The effect of surfactants decreased according to the following order: octadecyl > hexadecyl > tetradecyl > dodecyl homologs. The nonideal mixing between the components was estimated using the deviation of the experimental molecular area from the ideal area per molecule. The excess molecular area increased with the increase in the surfactant chain length and phospholipid saturation. The 50 mol % mixture of cystine derivatives and phospholipids formed thermodynamically stable monolayers. The surfactants increased the rigidity of SPC monolayers and decreased that of HSPC monolayers, as observed by the studies of surface dialational rheology. The film structure at the air-water interface could differentiate the SPC- and HSPC-comprising systems through the formation of organized regions, especially at a higher surface pressure. The constriction of surfactant/phospholipid hybrid vesicles was observed with an increase in the length of surfactant hydrocarbon chains. The negative zeta potential of vesicles took the highest values and did not change with time for 20 and 50 mol % surfactant. The spherical shape of the vesicles was confirmed by transmission electron microscopy. Differential scanning calorimetry revealed an increase in fluidity of HSPC bilayers and rigidity of SPS bilayers under the influence of surfactants. These effects were confirmed by fluorescence spectroscopy. All of the vesicle formulations were found to be nontoxic from the 3

  16. Radiolabeled liposome imaging determines an indication for liposomal anticancer agent in ovarian cancer mouse xenograft models.

    Science.gov (United States)

    Ito, Ken; Hamamichi, Shusei; Asano, Makoto; Hori, Yusaku; Matsui, Junji; Iwata, Masao; Funahashi, Yasuhiro; Umeda, Izumi O; Fujii, Hirofumi

    2016-01-01

    Liposomal anticancer agents can effectively deliver drugs to tumor lesions, but their therapeutic effects are enhanced in only limited number of patients. Appropriate biomarkers to identify responder patients to these liposomal agents will improve their treatment efficacies. We carried out pharmacological and histopathological analyses of mouse xenograft models bearing human ovarian cancers (Caov-3, SK-OV-3, KURAMOCHI, and TOV-112D) to correlate the therapeutic effects of doxorubicin-encapsulated liposome (Doxil(®) ) and histological characteristics linked to the enhanced permeability and retention effect. We next generated (111) In-encapsulated liposomes to examine their capacities to determine indications for Doxil(®) treatment by single-photon emission computed tomography (SPECT)/CT imaging. Antitumor activities of Doxil(®) were drastically enhanced in Caov-3, moderately in SK-OV-3, and minimally in KURAMOCHI and TOV-112D when compared to doxorubicin. Microvessel density and vascular perfusion were high in Caov-3 and SK-OV-3, indicating a close relation with the enhanced antitumor effects. Next, (111) In-encapsulated liposomes were given i.v. to the animals. Their tumor accumulation and area under the curve values over 72 h were high in Caov-3, relatively high in SK-OV-3, and low in two other tumors. Importantly, as both Doxil(®) effects and liposomal accumulation varied in the SK-OV-3 group, we individually obtained SPECT/CT images of SK-OV-3-bearing mouse (n = 11) before Doxil(®) treatment. Clear correlation between liposomal tumor accumulation and effects of Doxil(®) was confirmed (R(2) = 0.73). Taken together, our experiments definitely verified that enhanced therapeutic effects through liposomal formulations of anticancer agents depend on tumor accumulation of liposomes. Tumor accumulation of the radiolabeled liposomes evaluated by SPECT/CT imaging is applicable to appropriately determine indications for liposomal antitumor agents. © 2015 The Authors

  17. Enhanced Therapeutic Efficacy of iRGD-Conjugated Crosslinked Multilayer Liposomes for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Yarong Liu

    2013-01-01

    Full Text Available Targeting nanoparticles by conjugating various specific ligands has shown potential therapeutic efficacy in nanomedicine. However, poor penetration of antitumor drugs into solid tumors remains a major obstacle. Here, we describe a targeting strategy for antitumor drug delivery by conjugating a crosslinked multilamellar liposomal vesicle (cMLV formulation with a tumor-penetrating peptide, iRGD. The results showed that iRGD peptides could facilitate the binding and cellular uptake of drug-loaded cMLVs and consequently enhance the antitumor efficacy in breast tumor cells, including multidrug-resistant cells. Moreover, colocalization data revealed that iRGD-conjugated cMLVs (iRGD-cMLVs entered cells via the clathrin-mediated pathway, followed by endosome-lysosome transport for efficient drug delivery. Finally, in vivo study indicated that iRGD-cMLVs could deliver anticancer drugs efficiently to mediate significant tumor suppression.

  18. Development of a novel fusogenic viral liposome system (HVJ-liposomes) and its applications to the treatment of acquired diseases.

    Science.gov (United States)

    Kaneda, Y

    1999-01-01

    Toward human gene therapy and gene analysis in vivo, a novel hybrid vector based on liposome has been developed for more efficient gene delivery and gene expression. The liposome was decorated with HVJ (Sendal virus) envelope fusion proteins to introduce DNA directly into the cytoplasm, and contained DNA and DNA-binding nuclear protein to enhance expression of the gene. Recently, several types of HVJ-liposomes were developed by altering the lipid components of the liposomes. HVJ-cationic liposomes increased gene delivery 100-800 times more efficiently in vitro than the conventional HVJ-anionic liposomes. HVJ-cationic liposomes were also more useful for gene expression in restricted portions of organs and for gene therapy of disseminated cancers. It was further discovered that the use of anionic liposomes with a virus-mimicking lipid composition (HVJ-AVE liposomes) increased transfection efficiency by several fold in vivo, especially in liver and muscle. By coupling the Epstein-Barr (EB) virus replicon apparatus to HVJ-liposomes, transgene expression was sustained in vitro and in vivo. Most animal organs were found to be suitable targets for the fusigenic-viral liposome system, and numerous gene therapy strategies using this system were successful in animals.

  19. Encapsulation of (-)-epigallocatechin gallate into liposomes and into alginate or chitosan microparticles reinforced with liposomes.

    Science.gov (United States)

    Istenič, Katja; Cerc Korošec, Romana; Poklar Ulrih, Nataša

    2016-10-01

    (-)-Epigallocatechin gallate (EGCG) was encapsulated into liposomes that were further incorporated into alginate and chitosan microparticles. The stability of free and encapsulated EGCG in all three systems was evaluated at different pH values and in fruit nectar. Furthermore, the interactions between EGCG and the compounds of the microparticles were studied using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). All three encapsulation systems showed high encapsulation efficiency (>97%) and sustained release; in 14 days, no more than 15% of EGCG was released. The encapsulation systems successfully protected EGCG against degradation at alkaline pH. For non-encapsulated EGCG, >70% was degraded after 14 days, while there was no significant degradation of encapsulated EGCG in these three systems. In fruit nectar, >30% of non-encapsulated EGCG was degraded in 14 days, while only 6% of EGCG encapsulated into liposomes or chitosan microparticles reinforced with liposomes was degraded at that time. The DSC and FTIR analyses showed that the main interactions occurred between the liposomes and the EGCG. This study demonstrates that liposomes as well as alginate and chitosan microparticles reinforced with liposomes have the potential to enhance EGCG stability in food products during storage. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  20. Human Melanoma-Derived Extracellular Vesicles Regulate Dendritic Cell Maturation.

    Science.gov (United States)

    Maus, Rachel L G; Jakub, James W; Nevala, Wendy K; Christensen, Trace A; Noble-Orcutt, Klara; Sachs, Zohar; Hieken, Tina J; Markovic, Svetomir N

    2017-01-01

    Evolution of melanoma from a primary tumor to widespread metastasis is crucially dependent on lymphatic spread. The mechanisms regulating the initial step in metastatic dissemination via regional lymph nodes remain largely unknown; however, evidence supporting the establishment of a pre-metastatic niche is evolving. We have previously described a dysfunctional immune profile including reduced expression of dendritic cell (DC) maturation markers in the first node draining from the primary tumor, the sentinel lymph node (SLN). Importantly, this phenotype is present prior to evidence of nodal metastasis. Herein, we evaluate melanoma-derived extracellular vesicles (EVs) as potential mediators of the premetastatic niche through cargo-specific polarization of DCs. DCs matured in vitro in the presence of melanoma EVs demonstrated significantly impaired expression of CD83 and CD86 as well as decreased expression of Th1 polarizing chemokines Flt3L and IL15 and migration chemokines MIP-1α and MIP-1β compared to liposome-treated DCs. Profiling of melanoma EV cargo identified shared proteomic and RNA signatures including S100A8 and S100A9 protein cargo, which in vitro compromised DC maturation similar to melanoma EVs. Early evidence demonstrates that similar EVs can be isolated from human afferent lymphatic fluid ex vivo. Taken together, here, we propose melanoma EV cargo as a mechanism by which DC maturation is compromised warranting further study to consider this as a potential mechanism enabled by the primary tumor to establish the premetastatic niche in tumor-draining SLNs of patients.

  1. Synaptic vesicle proteins and active zone plasticity

    Directory of Open Access Journals (Sweden)

    Robert J Kittel

    2016-04-01

    Full Text Available Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone. The complex molecular architecture of active zones mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of active zones vary significantly, even for a given connection. Thus, there appear to be distinct active zone states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the active zone.The protein-rich cytomatrix at the active zone (CAZ provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1 and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and active zone states, which has heretofore received little attention.

  2. Single-vesicle imaging reveals different transport mechanisms between glutamatergic and GABAergic vesicles

    NARCIS (Netherlands)

    Farsi, Z.; Preobraschenski, J.; Bogaart, G. van den; Riedel, D.; Jahn, R.; Woehler, A.

    2016-01-01

    Synaptic transmission is mediated by the release of neurotransmitters, which involves exo-endocytotic cycling of synaptic vesicles. To maintain synaptic function, synaptic vesicles are refilled with thousands of neurotransmitter molecules within seconds after endocytosis, using the energy provided

  3. HVJ liposomes and HVJ envelope vectors.

    Science.gov (United States)

    Kaneda, Yasufumi

    2011-10-01

    This protocol describes techniques for construction of fusion-mediated vectors based on inactivated HVJ (hemagglutinating virus of Japan; Sendai virus). HVJ liposomes are constructed by fusing liposomes containing DNA with inactivated HVJ. The HVJ envelope vector, a more simplified vector, incorporates DNA into inactivated HVJ particles without liposomes. Both vectors have many advantages. They can be used to introduce proteins, peptides, oligonucleotides (including antisense oligonucleotides, decoy oligonucleotides, and ribozymes), and short interfering RNA (siRNA), as well as plasmid DNA, into cultured cells in vitro and into organs in vivo. Fusion-mediated delivery avoids the degradation of therapeutic molecules before reaching the cytoplasm. Finally, repeated injection of the vector in vivo is not inhibited and even enhances the effects of the delivered molecules. These vectors have been used in many gene therapy experiments in animal models to address problems such as liver cirrhosis, hearing impairment, ischemic brain damage, peripheral arterial diseases, and cancers. This protocol describes methods for the preparation of HVJ liposomes and of HVJ envelope vectors and their use in delivery of plasmid DNA into various cells and tissues.

  4. Properties of liposomal membranes containing lysolecithin.

    Science.gov (United States)

    Kitagawa, T; Inoue, K; Nojima, S

    1976-06-01

    Liposomes have been prepared with lysolecithin (1-acyl-sn-3-glycerylphosphorylcholine), egg lecithin (3-sn-phosphatidylcholine), dicetyl phosphate, and cholesterol. The ability to function as a barrier to the diffusion of glucose marker and the sensitivities of the liposomes to hypotonic treatment and other reagents which modified the permeability were examined. Generally, lysolecithin incorporation decreased the effectiveness of the membranes as a barrier to glucose and made the membranes more "osmotically fragile." Cholesterol incorporation counteracted the effect of incorporated lysolecithin. The more cholesterol incorporated into liposomes, the more lysolecthin could be incorporated into the membrane without loss of function as a barrier. With more than 50 mole% of colesterol, lysolecithin alone could form membranes which were practically impermeable to glucose. The hemolytic activity of lysolecithin was affected by mixing with various lecithins or cholesterol. Liposomes containing lysolecithin, which have the ability to trap glucose marker, showed poor hemolytic activity, while lipid micelles with lysolecithin (which could trap little glucose) showed almost the same hemolytic activity as lysolecithin itself. There seems to be a close correlation between hemolytic activity and barrier function of lipid micelles.

  5. Extracellular Vesicles: Evolving Contributors in Autoimmunity

    OpenAIRE

    Katsiougiannis, Stergios

    2015-01-01

    Extracellular vesicles, including microvesicles, exosomes and apoptotic bodies are recognized as carriers of pathogen-associated molecules with direct involvement in immune signaling and inflammation. Those observations have enforced the way these membranous vesicles are being considered as promising immunotherapeutic targets. In this review, we discuss the emerging roles of extracellular vesicles in autoimmunity and highlights their potential use as disease biomarkers as well as targets for ...

  6. Exosomes: secreted vesicles and intercellular communications

    OpenAIRE

    Théry, Clotilde

    2011-01-01

    Exosomes are small membrane vesicles of endocytic origin secreted by most cell types, and are thought to play important roles in intercellular communications. Although exosomes were originally described in 1983, interest in these vesicles has really increased dramatically in the last 3 years, after the finding that they contain mRNA and microRNA. This discovery sparked renewed interest for the general field of membrane vesicles involved in intercellular communications, and research on these s...

  7. The effect of solution electrolytes on the uptake of photosensitizers by liposomal membranes: a salting-out effect.

    Science.gov (United States)

    Minnes, Refael; Ytzhak, Shany; Weitman, Hana; Ehrenberg, Benjamin

    2008-09-01

    In this study we investigated, spectroscopically, the effect of electrolytes on the partitioning of hematoporphyrin IX (HP) and hypericin (Hy) into non-charged lipid vesicles. Our aim was to assess the salting-out effect of electrolytes on membrane-partitioning. We titrated aqueous solutions of HP and Hy with lecithin liposomes, at different concentrations of several monovalent and divalent electrolytes in the suspension. The partitioning constant of HP to lecithin liposomes increased from 3.3 (mL/mg) in water containing only 5mM buffer to 8.7 (mL/mg) at 0.36M KCl. KF had a similar effect. NaCl caused a 3-fold increase in the partitioning of Hy to liposomes. MgSO(4) and MgCl(2) also increased the partitioning of HP, by a factor of more than 4 and this occurred already at 0.03M concentration. We analyze the comparative effects of the electrolytes in relation to the Hofmeister series. The salting-out effect could be utilized to enhance the uptake of HP and Hy, and possibly other photosensitizers as well, by artificial and natural membranes.

  8. Turbiscan lab expert analysis of the stability of ethosomes and ultradeformable liposomes containing a bilayer fluidizing agent.

    Science.gov (United States)

    Celia, Christian; Trapasso, Elena; Cosco, Donato; Paolino, Donatella; Fresta, Massimo

    2009-08-01

    The stability of vesicular drug carriers containing linoleic acid, as a model of bilayer fluidizing agent, was evaluated using a Turbiscan optical analyzer, an innovative analytical instrument able to determine the long-time stability of colloidal systems. Ethosomes and ultradeformable liposomes were prepared using Phospholipon 100G as the lecithin component, while ethanol and sodium cholate were used for the specific preparation of ethosomes and ultradeformable liposomes, respectively. The advantages of the Turbiscan optical analyzer are: (i) its ability to measure reversible (creaming and sedimentation) and irreversible (coalescence and segregation) destabilization phenomena directly in the sample without any dilution and (ii) to detect these phenomena much earlier and easier than other apparatuses. Turbiscan data showed that both colloidal vesicles demonstrate a good stability during the 3h of the experiment. No modification of Turbiscan backscattering profiles of colloidal suspensions occurred when different amounts of linoleic acid were used to prepare ethosomes and ultradeformable liposomes. No coalescence, sedimentation, flocculation or clarification occurred. The results were very encouraging and confirmed the fact that the Turbiscan optical analyzer can be used to study the stability of colloidal formulations even in the presence of deformable agents.

  9. A NANOSCALE POLYNUCLEOTIDE-NEUTRAL LIPOSOME SELF-ASSEMBLIES FORMULATED FOR THERAPEUTIC GENE DELIVERY

    Directory of Open Access Journals (Sweden)

    Erhan Süleymanoglu,

    2004-01-01

    Full Text Available Human gene therapy research is currently discouraging due to the lack of suitable delivery vehicles for nucleic acid transfer to affected cell types. There is an urgent need for optimized gene delivery tools capable of protecting the polynucleotide from degradation through its route from site of administration to gene expression. Besides difficulties arising during the preparation of the currently employed cationic lipids, their cytotoxicity has been an unavoidable hurdle. Some energetics issues related to preparation and use of self-assemblies formed between neutral lipid and polynucleotides with various conformation and size are presented. The divalent metal cation-governed adsorption, aggregation and adhesion between single- and double-stranded polynucleotides with multilamellar and unilamellar phosphatidylcholine vesicles was followed turbidimetrically. Thermotropic phase transitions of zwitterionic liposomes and their complexes with polynucleotides and calf thymus DNA with Ca2+ and Mg2+ is presented and compared to the previous data for various electrostatic lipid - nucleic acid complexes. Differential scanning microcalorimetric measurements of synthetic phosphatidylcholine vesicles and polynucleotides and their ternary complexes with inorganic cations were used to build the thermodynamic model of their structural transitions. The increased thermal stability of the phospholipid bilayers is achieved by affecting their melting transition temperature by nucleic acid induced electrostatic charge screening. Thermodynamic measurements give evidence for the stabilization of polynucleotide helices upon their association with liposomes in presence of divalent metal cations. It is thus possible to suggest this self-assembly as an improved formulation with further potential in gene therapy trials. Although the pharmacodynamical features of the zwitterionic lipid-metal ion-DNA nanocondensates remain to be tested in further transfection experiments, at

  10. Influence of the Encapsulation Efficiency and Size of Liposome on the Oral Bioavailability of Griseofulvin-Loaded Liposomes.

    Science.gov (United States)

    Ong, Sandy Gim Ming; Ming, Long Chiau; Lee, Kah Seng; Yuen, Kah Hay

    2016-08-26

    The objective of the present study was to investigate the influence of the encapsulation efficiency and size of liposome on the oral bioavailability of griseofulvin-loaded liposomes. Griseofulvin-loaded liposomes with desired characteristics were prepared from pro-liposome using various techniques. To study the effect of encapsulation efficiency, three preparations of griseofulvin, namely, griseofulvin aqueous suspension and two griseofulvin-loaded liposomes with different amounts of griseofulvin encapsulated [i.e., F1 (32%) and F2(98%)], were administered to rats. On the other hand, to study the effect of liposome size, the rats were given three different griseofulvin-loaded liposomes of various sizes, generated via different mechanical dispersion techniques [i.e., FTS (142 nm), MS (357 nm) and NS (813 nm)], but with essentially similar encapsulation efficiencies (about 93%). Results indicated that the extent of bioavailability of griseofulvin was improved 1.7-2.0 times when given in the form of liposomes (F1) compared to griseofulvin suspension. Besides that, there was an approximately two-fold enhancement of the extent of bioavailability following administration of griseofulvin-loaded liposomes with higher encapsulation efficiency (F2), compared to those of F1. Also, the results showed that the extent of bioavailability of liposomal formulations with smaller sizes were higher by approximately three times compared to liposomal formulation of a larger size. Nevertheless, a further size reduction of griseofulvin-loaded liposome (≤400 nm) did not promote the uptake or bioavailability of griseofulvin. In conclusion, high drug encapsulation efficiency and small liposome size could enhance the oral bioavailability of griseofulvin-loaded liposomes and therefore these two parameters deserve careful consideration during formulation.

  11. Influence of the Encapsulation Efficiency and Size of Liposome on the Oral Bioavailability of Griseofulvin-Loaded Liposomes

    Directory of Open Access Journals (Sweden)

    Sandy Gim Ming Ong

    2016-08-01

    Full Text Available The objective of the present study was to investigate the influence of the encapsulation efficiency and size of liposome on the oral bioavailability of griseofulvin-loaded liposomes. Griseofulvin-loaded liposomes with desired characteristics were prepared from pro-liposome using various techniques. To study the effect of encapsulation efficiency, three preparations of griseofulvin, namely, griseofulvin aqueous suspension and two griseofulvin-loaded liposomes with different amounts of griseofulvin encapsulated [i.e., F1 (32% and F2(98%], were administered to rats. On the other hand, to study the effect of liposome size, the rats were given three different griseofulvin-loaded liposomes of various sizes, generated via different mechanical dispersion techniques [i.e., FTS (142 nm, MS (357 nm and NS (813 nm], but with essentially similar encapsulation efficiencies (about 93%. Results indicated that the extent of bioavailability of griseofulvin was improved 1.7–2.0 times when given in the form of liposomes (F1 compared to griseofulvin suspension. Besides that, there was an approximately two-fold enhancement of the extent of bioavailability following administration of griseofulvin-loaded liposomes with higher encapsulation efficiency (F2, compared to those of F1. Also, the results showed that the extent of bioavailability of liposomal formulations with smaller sizes were higher by approximately three times compared to liposomal formulation of a larger size. Nevertheless, a further size reduction of griseofulvin-loaded liposome (≤400 nm did not promote the uptake or bioavailability of griseofulvin. In conclusion, high drug encapsulation efficiency and small liposome size could enhance the oral bioavailability of griseofulvin-loaded liposomes and therefore these two parameters deserve careful consideration during formulation.

  12. Influence of the Encapsulation Efficiency and Size of Liposome on the Oral Bioavailability of Griseofulvin-Loaded Liposomes

    Science.gov (United States)

    Ong, Sandy Gim Ming; Ming, Long Chiau; Lee, Kah Seng; Yuen, Kah Hay

    2016-01-01

    The objective of the present study was to investigate the influence of the encapsulation efficiency and size of liposome on the oral bioavailability of griseofulvin-loaded liposomes. Griseofulvin-loaded liposomes with desired characteristics were prepared from pro-liposome using various techniques. To study the effect of encapsulation efficiency, three preparations of griseofulvin, namely, griseofulvin aqueous suspension and two griseofulvin-loaded liposomes with different amounts of griseofulvin encapsulated [i.e., F1 (32%) and F2(98%)], were administered to rats. On the other hand, to study the effect of liposome size, the rats were given three different griseofulvin-loaded liposomes of various sizes, generated via different mechanical dispersion techniques [i.e., FTS (142 nm), MS (357 nm) and NS (813 nm)], but with essentially similar encapsulation efficiencies (about 93%). Results indicated that the extent of bioavailability of griseofulvin was improved 1.7–2.0 times when given in the form of liposomes (F1) compared to griseofulvin suspension. Besides that, there was an approximately two-fold enhancement of the extent of bioavailability following administration of griseofulvin-loaded liposomes with higher encapsulation efficiency (F2), compared to those of F1. Also, the results showed that the extent of bioavailability of liposomal formulations with smaller sizes were higher by approximately three times compared to liposomal formulation of a larger size. Nevertheless, a further size reduction of griseofulvin-loaded liposome (≤400 nm) did not promote the uptake or bioavailability of griseofulvin. In conclusion, high drug encapsulation efficiency and small liposome size could enhance the oral bioavailability of griseofulvin-loaded liposomes and therefore these two parameters deserve careful consideration during formulation. PMID:27571096

  13. Characterization of Annexin V Fusion with the Superfolder GFP in Liposomes Binding and Apoptosis Detection

    Directory of Open Access Journals (Sweden)

    Abdul Qader Abbady

    2017-05-01

    Full Text Available Programed cell death is a critical and unavoidable part of life. One of the most widely used markers for dying cells, by apoptosis or pyroptosis, is the redistribution of phosphatidylserine (PS from the inner to the outer plasma membrane leaflet. Annexin V protein is a sensitive and specific probe to mark this event because of its high affinity to the exposed PS. Beyond that, annexin V can bind to any PS-containing phospholipid bilayer of almost all tiny forms of membranous vesicles like blood platelets, exosomes, or even nanostructured liposomes. In this work, recombinant human annexin V was produced as a fusion with a highly fluorescent superfolder derivative of the green fluorescent protein (sfGFP in Escherichia coli. The fusion protein(sfGFP-ANXV, 64 kDa, annexin V (ANXV, 40 kDa, and sfGFP (27 kDa were separately produced after cloning their encoding genes in pRSET plasmid, and all proteins were expressed in a soluble form, then purified in high yields because of their N-terminal 6× His tag (~150 mg of pure protein per 1 L culture. Superiority of this fluorescent fusion protein over fluorescein-conjugated annexin V was demonstrated in binding to phospholipids (and their liposomes, prepared from natural sources (soya bean and egg yolk that have different content of PS, by using different methods including ELISA, dot-blotting, surface plasmon resonance, and flow cytometry. We also applied fluorescent annexin V in the detection of apoptotic cells by flow cytometry and fluorescent microscopy. Interestingly, sfGFP-ANXV fusion was more sensitive to early apoptotic stressed HeLa cells than fluorescein-conjugated-ANXV. This highly expressed and functional sfGFP-ANXV fusion protein provides a promising ready-to-use molecular tool for quantifying liposomes (or similarly exosomes and detecting apoptosis in cells.

  14. Characterization of Annexin V Fusion with the Superfolder GFP in Liposomes Binding and Apoptosis Detection.

    Science.gov (United States)

    Abbady, Abdul Qader; Twair, Aya; Ali, Bouthaina; Murad, Hossam

    2017-01-01

    Programed cell death is a critical and unavoidable part of life. One of the most widely used markers for dying cells, by apoptosis or pyroptosis, is the redistribution of phosphatidylserine (PS) from the inner to the outer plasma membrane leaflet. Annexin V protein is a sensitive and specific probe to mark this event because of its high affinity to the exposed PS. Beyond that, annexin V can bind to any PS-containing phospholipid bilayer of almost all tiny forms of membranous vesicles like blood platelets, exosomes, or even nanostructured liposomes. In this work, recombinant human annexin V was produced as a fusion with a highly fluorescent superfolder derivative of the green fluorescent protein (sfGFP) in Escherichia coli. The fusion protein(sfGFP-ANXV, 64 kDa), annexin V (ANXV, 40 kDa), and sfGFP (27 kDa) were separately produced after cloning their encoding genes in pRSET plasmid, and all proteins were expressed in a soluble form, then purified in high yields because of their N-terminal 6× His tag (~150 mg of pure protein per 1 L culture). Superiority of this fluorescent fusion protein over fluorescein-conjugated annexin V was demonstrated in binding to phospholipids (and their liposomes), prepared from natural sources (soya bean and egg yolk) that have different content of PS, by using different methods including ELISA, dot-blotting, surface plasmon resonance, and flow cytometry. We also applied fluorescent annexin V in the detection of apoptotic cells by flow cytometry and fluorescent microscopy. Interestingly, sfGFP-ANXV fusion was more sensitive to early apoptotic stressed HeLa cells than fluorescein-conjugated-ANXV. This highly expressed and functional sfGFP-ANXV fusion protein provides a promising ready-to-use molecular tool for quantifying liposomes (or similarly exosomes) and detecting apoptosis in cells.

  15. Trafficking of astrocytic vesicles in hippocampal slices

    Energy Technology Data Exchange (ETDEWEB)

    Potokar, Maja; Kreft, Marko [Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana (Slovenia); Celica Biomedical Center, Technology Park 24, 1000 Ljubljana (Slovenia); Lee, So-Young; Takano, Hajime; Haydon, Philip G. [Department of Neuroscience, Room 215, Stemmler Hall, University of Pennsylvania, School of Medicine, Philadelphia, PA 19104 (United States); Zorec, Robert, E-mail: Robert.Zorec@mf.uni-lj.si [Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana (Slovenia); Celica Biomedical Center, Technology Park 24, 1000 Ljubljana (Slovenia)

    2009-12-25

    The increasingly appreciated role of astrocytes in neurophysiology dictates a thorough understanding of the mechanisms underlying the communication between astrocytes and neurons. In particular, the uptake and release of signaling substances into/from astrocytes is considered as crucial. The release of different gliotransmitters involves regulated exocytosis, consisting of the fusion between the vesicle and the plasma membranes. After fusion with the plasma membrane vesicles may be retrieved into the cytoplasm and may continue to recycle. To study the mobility implicated in the retrieval of secretory vesicles, these structures have been previously efficiently and specifically labeled in cultured astrocytes, by exposing live cells to primary and secondary antibodies. Since the vesicle labeling and the vesicle mobility properties may be an artifact of cell culture conditions, we here asked whether the retrieving exocytotic vesicles can be labeled in brain tissue slices and whether their mobility differs to that observed in cell cultures. We labeled astrocytic vesicles and recorded their mobility with two-photon microscopy in hippocampal slices from transgenic mice with fluorescently tagged astrocytes (GFP mice) and in wild-type mice with astrocytes labeled by Fluo4 fluorescence indicator. Glutamatergic vesicles and peptidergic granules were labeled by the anti-vesicular glutamate transporter 1 (vGlut1) and anti-atrial natriuretic peptide (ANP) antibodies, respectively. We report that the vesicle mobility parameters (velocity, maximal displacement and track length) recorded in astrocytes from tissue slices are similar to those reported previously in cultured astrocytes.

  16. Reversibly formed bilayer vesicles: Energetics and polydispersity

    DEFF Research Database (Denmark)

    Bergstöm, M.

    1997-01-01

    orders of magnitude larger than where the local free energy minima of the equilibrium vesicle actually occur. Moreover, according to our analysis, the relative width of a vesicle size distribution, sigma(R)/R-max, is generally at full equilibrium equal to 0.283, independently of the energetic vesicle....... and a statistical-mechanical factor that accounts for the fluctuations in composition, chain packing density and shape. We demonstrate that the free energy required to form a spherical vesicle is made up of two main contributions: the (size-independent) work of bending the constituent monolayers and the work...

  17. Extracellular vesicles in cardiovascular homeostasis and disease.

    Science.gov (United States)

    Hutcheson, Joshua D; Aikawa, Elena

    2018-02-19

    Extracellular vesicles have emerged as one of the most important means through which cells interact with each other and the extracellular environment, but extracellular vesicle research remains challenging due to their small size, limited amount of material required for traditional molecular biology assays and inconsistency in the methods of their isolation. The advent of new technologies and standards in the field, however, have led to increased mechanistic insight into extracellular vesicle function. Herein, the latest studies on the role of extracellular vesicles in cardiovascular physiology and disease are discussed. Extracellular vesicles help control cardiovascular homeostasis and remodelling by mediating communication between cells and directing alterations in the extracellular matrix to respond to changes in the environment. The message carried from the parent cell to extracellular space can be intended for both local (within the same tissue) and distal (downstream of blood flow) targets. Pathological cargo loaded within extracellular vesicles could further result in various diseases. On the contrary, new studies indicate that injection of extracellular vesicles obtained from cultured cells into diseased tissues can promote restoration of normal tissue function. Extracellular vesicles are an integral part of cell and tissue function, and harnessing the properties inherent to extracellular vesicles may provide a therapeutic strategy to promote tissue regeneration.

  18. Extracellular vesicles in cartilage homeostasis and osteoarthritis.

    Science.gov (United States)

    Miyaki, Shigeru; Lotz, Martin K

    2018-01-01

    Extracellular vesicles carry bioactive molecules that can be transferred between cells and tissues. The purpose of this review is to describe how extracellular vesicles regulate functions of cells in cartilage and other joint tissues. The potential application of extracellular vesicles in the treatment of osteoarthritis and as biomarkers will also be discussed. Extracellular vesicles are found in synovial fluid, in articular cartilage and in the supernatants of synoviocytes and chondrocytes. Extracellular vesicles in cartilage have been proposed to be involved in cross talk between cells in joint tissues and to affect extracellular matrix turnover and inflammation. Extracellular vesicles from arthritic joints can promote abnormal gene expression and changes in cartilage extracellular matrix, including abnormal mineralization. Promising results were obtained in the therapeutic application of mesenchymal stem cell-derived extracellular vesicles for cartilage repair and experimental osteoarthritis. Extracellular vesicles have emerged as vehicles for the exchange of bioactive signaling molecules within cartilage and between joint tissues to promote joint homeostasis and arthritis pathogenesis. As the molecular content of extracellular vesicles can be customized, they offer utility in therapeutic applications.

  19. Tretinoin-loaded liposomal formulations: from lab to comparative clinical study in acne patients.

    Science.gov (United States)

    Rahman, Salwa Abdel; Abdelmalak, Nevine Shawky; Badawi, Alia; Elbayoumy, Tahany; Sabry, Nermeen; El Ramly, Amany

    2016-05-01

    Topical tretinoin is the most commonly used retinoid for acne. However, its irritative potential on the applied area and the barrier properties of the stratum corneum limit its use. The objective of the present study was to formulate tretinoin liposomal gel to obtain a formula with lower skin irritation potential and greater clinical effect. A statistical 2(4) factorial design was adopted. Sixteen formulae prepared and were properly evaluated. A candidate formula (F13G) prepared with 0.025% tretinoin, phospholipid- cholesterol-dicetylphosphate (9:1:0.01) and incorporated in 1% carbopol gel was selected for skin irritation test. Clinical study was conducted on acne patients and compared to marketed product. All liposomes formulations were spherical in shape. The addition of cholesterol in the film hydration method significantly decreased the vesicle size, and increased the percentage of incorporation efficiency at (p acne patients revealed that F13G showed significantly higher efficacy when compared to marketed product (p < 0.05).

  20. Analysis of the Diffusion Process by pH Indicator in Microfluidic Chips for Liposome Production

    Directory of Open Access Journals (Sweden)

    Elisabetta Bottaro

    2017-07-01

    Full Text Available In recent years, the development of nano- and micro-particles has attracted considerable interest from researchers and enterprises, because of the potential utility of such particles as drug delivery vehicles. Amongst the different techniques employed for the production of nanoparticles, microfluidic-based methods have proven to be the most effective for controlling particle size and dispersity, and for achieving high encapsulation efficiency of bioactive compounds. In this study, we specifically focus on the production of liposomes, spherical vesicles formed by a lipid bilayer encapsulating an aqueous core. The formation of liposomes in microfluidic devices is often governed by diffusive mass transfer of chemical species at the liquid interface between a solvent (i.e., alcohol and a non-solvent (i.e., water. In this work, we developed a new approach for the analysis of mixing processes within microfluidic devices. The method relies on the use of a pH indicator, and we demonstrate its utility by characterizing the transfer of ethanol and water within two different microfluidic architectures. Our approach represents an effective route to experimentally characterize diffusion and advection processes governing the formation of vesicular/micellar systems in microfluidics, and can also be employed to validate the results of numerical modelling.

  1. Hyaluronan-decorated liposomes as drug delivery systems for cutaneous administration.

    Science.gov (United States)

    Franzé, Silvia; Marengo, Alessandro; Stella, Barbara; Minghetti, Paola; Arpicco, Silvia; Cilurzo, Francesco

    2018-01-15

    The work aimed to evaluate the feasibility to design hyaluronic acid (HA) decorated flexible liposomes to enhance the skin penetration of nifedipine. Egg phosphatidylcholine (e-PC) based transfersomes (Tween 80) and transethosomes (ethanol) were prepared. HA was reacted with 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (HA-DPPE) and two molar ratios (0.5 and 3%) of conjugate with respect to e-PC were tested. The presence of HA significantly increased the packing order of the bilayer (as verified by differential scanning calorimetry), reducing both the encapsulation efficiency and the flexibility of the decorated liposomes in a dose-dependent manner. In fact, at the highest HA content the constant of deformability (K, N/mm) increased and the carriers remained on the skin surface after topical application. The stiffening effect of HA was counterbalanced by the addition of ethanol as fluidizing agent that allowed to maintain the highest HA concentration, meanwhile reducing the K value of the vesicles. HA-transethosomes allowed a suitable nifedipine permeation (J ∼ 30 ng/cm2/h) and significantly improved the drug penetration, favouring the formation of a drug depot in the epidermis. These data suggest the potentialities of HA-transethosomes as drug delivery systems intended for the treatment of cutaneous pathologies and underline the importance of studying the effect of surface functionalization on carrier deformability to rationalize the design of such systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Spin-Echo Small Angle Neutron Scattering analysis of liposomes and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Heijkamp, Leon F van; Sevcenco, Ana-Maria; Abou, Diane; Luik, Remko van; Krijger, Gerard C; Schepper, Ignatz M de; Wolterbeek, Bert; Bouwman, Wim G [Faculty of Applied Sciences, Department of Radiation, Radionuclides and Reactors, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Hagedoorn, Peter-Leon [Faculty of Applied Sciences, Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft (Netherlands); Koning, Gerben A, E-mail: l.f.vanheijkamp@tudelft.n, E-mail: w.g.bouwman@tudelft.n [Laboratory Experimental Surgical Oncology, Section Surgical Oncology, Department of Surgery, Erasmus Medical Center, POBox 1738, 3000 DR Rotterdam (Netherlands)

    2010-10-01

    Two types of liposomes, commonly used in drug delivery studies, and E. coli bacteria, all prepared in H{sub 2}O, were resuspended in D{sub 2}O and measured with Small Angle Spin-Echo Neutron Scattering (SESANS). Modeling was performed using correlation functions for solid spheres and hollow spheres. The signal strength and curve shape were more indicative of hollow particles, indicating that the H{sub 2}O-D{sub 2}O exchange occurred too fast to be observed with the available time resolution. Fitting the particle diameter and membrane thickness of the hollow sphere model to the data, gave results which were in good agreement with Dynamic Light Scattering (DLS) data and literature, showing as a proof-of-principle that SESANS is able to investigate such systems. SESANS may become a good alternative to conventional tritium studies or a tool with which to study intracellular vesicle transport phenomena, with possible in vivo applications. Calculations show that a substantial change in numbers of a mixed system of small and large biological particles should be observable. A possible application is the destruction by external means of great numbers of liposomes in the presence of tumor cells for triggered drug release in cancer treatment. Since SESANS is both non-invasive and non-destructive and can handle relatively thick samples, it could be a useful addition to more conventional techniques.

  3. Formulation optimization of itraconazole loaded PEGylated liposomes for parenteral administration by using design of experiments.

    Science.gov (United States)

    Curić, Anamarija; Reul, Regina; Möschwitzer, Jan; Fricker, Gert

    2013-05-01

    The aim of this study was to systematically characterize and optimize the encapsulation process of itraconazole (ITZ) into the PEGylated liposomes. ITZ was used as a model compound for poorly soluble drugs. PEGylated liposomes were prepared using the film hydration method combined with sonication in order to produce small unilamellar vesicles (SUV). The concentration of encapsulated ITZ was measured by a reversed phase-high-performance liquid chromatography (RP-HPLC) method. Systematic characterization of encapsulation process was performed using the design of experiments (DoE) approach. The systematic screening of process parameters and well designed settings of parameter levels in optimization phase improved the ITZ encapsulation process. Optimization demonstrated that only minimal range of design space could be used to achieve the highest encapsulation efficiency (EE (%)), more precisely the EE of 90% was gained using 25mg/ml of lipid and drug loading of 0.3% (w/w). However, the desirable drug loading could be predicted and adjusted by using mathematical modeling behind the DoE approach. The entire encapsulation process was shown to be repeatable with high significance (pDoE plays an important role in optimization experiments leading to robust results supporting high quality. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Theoretical Assessment of Fluorinated Phospholipids in the Design of Liposomal Drug-Delivery Systems.

    Science.gov (United States)

    Madsen, Jesper J; Fristrup, Peter; Peters, Günther H

    2016-09-15

    Fluorinated phospholipid analogues are investigated as potential substrates for phospholipase A2 (PLA2) using classical molecular dynamics simulations and quantum mechanics/density functional theory calculations. The fluorinated phospholipid analogues are α-fluoro (HF-ProAEL) and α,α-difluoro (F2-ProAEL) conjugates of (R)-1-O-hexadecyl-2-palmitoyl-sn-glycero-3-phoshocholineglycerol (ProAEL). Our results provide a theoretical assessment of the potential usefulness of these fluorinated lipids in the rational design of liposomal drug-delivery systems. The α-fluorine-substituted phospholipid analogues are found to be substrates for secretory PLA2, with sufficient accessibility of water to the active site to allow for enzymatic hydrolysis. Because of the inherently less stable nature of HF-ProAEL and F2-ProAEL when compared to that of ProAEL, the hydrolytic reaction is predicted to occur at a progressively faster rate; the more electronegative substituent at the α-position effectively lowers the energy barrier for hydrolysis. We conclude that the partially fluorinated phospholipid analogues facilitate rational design of liposomal vesicles of phospholipid mixtures with desirable physicochemical properties and that are still subjects for important and pharmaceutically proven drug-delivery mechanisms.

  5. In vitro evolution of α-hemolysin using a liposome display.

    Science.gov (United States)

    Fujii, Satoshi; Matsuura, Tomoaki; Sunami, Takeshi; Kazuta, Yasuaki; Yomo, Tetsuya

    2013-10-15

    In vitro methods have enabled the rapid and efficient evolution of proteins and successful generation of novel and highly functional proteins. However, the available methods consider only globular proteins (e.g., antibodies, enzymes) and not membrane proteins despite the biological and pharmaceutical importance of the latter. In this study, we report the development of a method called liposome display that can evolve the properties of membrane proteins entirely in vitro. This method, which involves in vitro protein synthesis inside liposomes, which are cell-sized phospholipid vesicles, was applied to the pore-forming activity of α-hemolysin, a membrane protein derived from Staphylococcus aureus. The obtained α-hemolysin mutant possessed only two point mutations but exhibited a 30-fold increase in its pore-forming activity compared with the WT. Given the ability to synthesize various membrane proteins and modify protein synthesis and functional screening conditions, this method will allow for the rapid and efficient evolution of a wide range of membrane proteins.

  6. Eleostearic phospholipids as probes to evaluate antioxidants efficiency against liposomes oxidation.

    Science.gov (United States)

    Durand, Erwann; Delavault, André; Bourlieu, Claire; Lecomte, Jérôme; Baréa, Bruno; Figueroa Espinoza, Maria Cruz; Decker, Eric A; Salaun, Françoise Michel; Kergourlay, Gilles; Villeneuve, Pierre

    2017-12-01

    Regardless of the applications: therapeutic vehicle or membrane model to mimic complex biological systems; it is of a great importance to develop simplified, reproducible and rapid model assays allowing for a relevant assessment of the liposomal membrane oxidation and therefore antioxidant activity of selected molecules. Here, we describe a new and high-throughput assay that we called "Vesicle Conjugated Autoxidizable Triene (VesiCAT)". It is based on specific UV absorbance spectral properties of a new phospholipid probe, synthesized with natural conjugated eleostearic acid extracted from Tung oil. The VesiCAT assay has been developed with two different radical generators (2,2'-azobis(2-amidinopropane) dihydrochloride; AAPH and 2,2'-azobis(2,4-dimethylvaleronitrile); AMVN), producing a constant flux of oxidant species, either in membrane or in aqueous phase. This method appears very efficient in assessing the effect of various pure antioxidant molecules in their ability to preserve liposomes from oxidative degradation. In addition, the AAPH- and AMVN-induced oxidations offer the possibility of extracting different but complementary information with respect to the antioxidants efficacy. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Allometric scaling of pegylated liposomal anticancer drugs.

    Science.gov (United States)

    Caron, Whitney P; Clewell, Harvey; Dedrick, Robert; Ramanathan, Ramesh K; Davis, Whitney L; Yu, Ning; Tonda, Margaret; Schellens, Jan H; Beijnen, Jos H; Zamboni, William C

    2011-10-01

    Pegylated liposomal formulations contain lipid conjugated to polyethylene glycol. The disposition of encapsulated drug is dictated by the composition of the liposome, thus altering the pharmacokinetic (PK) profile of the drug. Allometric scaling is based on a power-log relationship between body weight (W) and drug clearance (CL) among mammals and has been used to compare the disposition of nonliposomal drugs across species. The objectives of this study were to use allometric scaling to: (1) compare the disposition of pegylated liposomal drugs across speciesand determine the best scaling model and (2) predict PK parameters of pegylated liposomal drugs in humans. The PK of pegylated liposomal CKD-602 (S-CKD602), doxorubicin (Doxil®), and cisplatin (SPI-077) were compared. PK studies ofS-CKD602, Doxil®, and SPI-077 were performed at the maximum tolerated dose (MTD) in male and female mice, rats, dogs and patients with refractory solid tumors. The allometric equation used to evaluate the relationship between W and CL in each species was CL = a(W)(m) (a = empirical coefficient; m = allometric exponent). Substitution of physiological variables other than body weight, such as factors representative of the mononuclear phagocyte system (MPS) were evaluated. Dedrick Plots and Maximum Life-Span Potential (MLP) were used to determine scaling feasibility. Standard allometry demonstrated a relationship between clearance of S-CKD602, Doxil®, and SPI-077 and body, spleen, liver, and kidney weights, total monocyte count, and spleen and liver blood flow. However, using scaling to predict CL of these agents in humans often resulted in differences >30%. Despite a strong correlation between body weight and MPS-associated variables with CL among preclinical species, the use of the equations did not predict CL. Thus, new methods of allometric scaling and measures of MPS function need to be developed.

  8. OPTIMIZATION OF MIXING TEMPERATURE AND SONICATION DURATION IN LIPOSOME PREPARATION

    Directory of Open Access Journals (Sweden)

    Dina Christin Ayuning Putri

    2017-11-01

    Full Text Available Liposomes are a delivery system used in pharmaceutical products and cosmetics. Liposomes have many advantages such as increase stability and efficacy, can be targeted to reduce toxicity and increase accumulation at the target site and are biocompatible.  Preparation of liposomes can be done by conventional or new methods which are still being developed. Conventional methods often require a long time and organic solvents which may be toxic. Heating (Mozafari method is one of the new methods developed in the manufacture of liposomes without organic solvents. Mixing temperature can affect the physical properties of liposomes. The particle size has become one of the important physical properties because it affects the absorption of the drug. Sonication is an easy method of choice in reducing the size of liposomes. Optimization of mixing temperature and duration of sonication in liposomes’ preparation using new heating methods and sonication were performed by factorial design with 2 factors and 3-levels to obtain optimal liposome size. Data were analyzed with two-way ANOVA. The results showed that both mixing temperature and sonication duration significantly affect liposome size, but the interaction was not statistically significant. Data analysis also showed that mixing temperature, sonication, and their interaction do not affect the polydispersity index of liposome. Results showed the optimum mixing temperature and sonication duration that can produce liposomes with size below 100 nm is at 60°C for 30 minutes.

  9. Evaluation of the schistosomicidal efficacy of liposome - Entrapped Oxamniquine

    Directory of Open Access Journals (Sweden)

    Frédéric Frézard

    1997-03-01

    Full Text Available Oxamniquine (OXA was sucessfully encapsulated in small unilamellar vesicles using a pH gradient method. This procedure led to a high drug encapsulation efficiency (> 85% at a drug to lipid molar ratio of 1/10. Moreover, these liposomes were found to retain encapsulated OXA efficciently under dialysis conditions at 37º C. Liposome-entrapped OXA (LOXA, OXA, and empty liposomes were tested against Schistosoma mansoni in a murine model. LOXA produced a significant reduction of the worm burden compared to the other preparations, when inoculated by subcutaneous route (s.c. with 10 mg OXA/kg animal one day before the infection, and 3, 7, and 14 days after. However, LOXA was not effective when given 7 days before, or 35 days after infections. OXA, in the free form, was effective in relation to the untreated group, only when administered 3 days after the infection. Maximum effect of LOXA, with 97% reduction of the parasite number, was observed when the preparation was given s.c.one day before the infection. On the other hand, LOXA inoculated intraperitoneally one day before the infection didn’t show any reduction of the parasite count. It can be concluded that LOXA is more effective than OXA for the treatment of experimental schistosomiasis, particularly when administered subcutaneously at a time close to the infectionAvaliação da eficácia esquistossomicida da oxamniquina encapsulada em liposomas. Oxamniquina (OXA foi encapsulada em vesículas unilamelares pequenas de distearoilfosfatidilcolina usando-se técnica de encapsulação ativa em gradiante de pH. Este procedimento produziu uma alta eficiência de encapsulação (> 85% com uma razão molar de 1/10, além de reter, eficientemente, a droga encapsulada sob condições de diálise à 37º C. OXA encapsulada (LOXA, OXA livre (OXA, (10 mg/kg respectivamente ou liposomas vazios foram testados durante o curso da infecção experimental pelo Schistosoma mansoni. Verificou-se uma redu

  10. Preparation of drug-in-cyclodextrin-in-liposomes at a large scale using a membrane contactor: Application to trans-anethole.

    Science.gov (United States)

    Gharib, Riham; Greige-Gerges, Hélène; Jraij, Alia; Auezova, Lizette; Charcosset, Catherine

    2016-12-10

    The present study aimed to prepare liposomes loaded with cyclodextrin/drug inclusion complexes at a pilot scale based on the ethanol injection technique. Anethole (ANE), a major component of anise and fennel essential oils, was used as a model of a volatile and highly hydrophobic drug. Membrane contactor (600mL) and a pilot plant (3L) were used for liposome production. The liposome preparations obtained were characterized for size, polydispersity index, zeta potential, morphology, stability and ANE release rate. All experimental set-ups were shown to be appropriate for the preparation of small, multilamellar vesicles with narrow size distribution and good stability at 4°C. The drug release study showed that only a small amount of ANE was released from liposome formulations after 21days of storage at 4°C. The loading rate of ANE was higher when ethanol was evaporated directly on the pilot plant compared to a rotary evaporation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Comparative in vitro studies on liposomal formulations of amphotericin B and its derivative, N-methyl-N-D-fructosyl amphotericin B methyl ester (MFAME).

    Science.gov (United States)

    Cybulska, Barbara; Kupczyk, Karolina; Szlinder-Richert, Joanna; Borowski, Edward

    2002-01-01

    N-Methyl-N-D-fructosyl amphotericin B methyl ester (MFAME) is a semisynthetic derivative of the antifungal antibiotic amphotericin B (AMB). In contrast to the parent antibiotic, the derivative is characterised by low toxicity to mammalian cells and good solubility in water of its salts. Comparative studies on biological properties of free MFAME, AMB and their liposomal formulations were performed. To obtain liposomal forms, the antibiotics were incorporated into small unilamellar vesicles composed of dimyristoyl phosphatidylcholine (DMPC) and DMPC:cholesterol or ergosterol, 8:2 molar ratio. The effectivity of the liposomal and free forms of AMB and MFAME were compared by determination of fungistatic and fungicidal activity against Candida albicans ATCC 10261, potassium release from erythrocytes, and haemolysis. The results obtained indicate that in contrast to AMB, incorporation of MFAME into liposomes did not further improve its selective toxicity. Studies on the antagonistic effect of ergosterol and cholesterol on the antifungal activity of the antibiotics indicated that sterol interference was definitely less pronounced in the case of MFAME than in the case of AMB.

  12. Pegylation of DDA:TDB liposomal adjuvants reduces the vaccine depot effect and alters the Th1/Th2 immune responses.

    Science.gov (United States)

    Kaur, Randip; Bramwell, Vincent W; Kirby, Daniel J; Perrie, Yvonne

    2012-02-28

    The adjuvant efficacy of cationic liposomes composed of dimethyldioctadecylammonium bromide and trehalose dibehenate (DDA:TDB) is well established. Whilst the mechanism behind its immunostimulatory action is not fully understood, the ability of the formulation to promote a 'depot effect' is a consideration. The depot effect has been suggested to be primarily due to their cationic nature which results in electrostatic adsorption of the antigen and aggregation of the vesicles at the site of injection. The aim of the study was to further test this hypothesis by investigating whether sterically stabilising DDA:TDB with polyethylene glycol (PEG) reduces aggregation, and subsequently influences the formation of a depot at the site of injection. Results reported demonstrate that high (25%) levels of PEG was able to significantly inhibit the formation of a liposome depot and also severely limit the retention of antigen at the site, resulting in a faster drainage of the liposomes from the site of injection. This change in biodistribution profile was reflected in the immunisation response, where lower levels of IgG2b antibody and IFN-γ and higher level of IL-5 cytokine were found. Furthermore entrapping antigen within DDA:TDB liposomes did not improve antigen retention at the injection site compared surface adsorbed antigen. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Prednisolone-containing liposomes accumulate in human atherosclerotic macrophages upon intravenous administration

    NARCIS (Netherlands)

    van der Valk, Fleur M.; van Wijk, Diederik F.; Lobatto, Mark E.; Verberne, Hein J.; Storm, G|info:eu-repo/dai/nl/073356328; Willems, Martine C M; Legemate, Dink A.; Nederveen, Aart J.; Calcagno, Claudia; Mani, Venkatesh; Ramachandran, Sarayu; Paridaans, Maarten P M; Otten, Maarten J.; Dallinga-Thie, Geesje M.; Fayad, Zahi A.; Nieuwdorp, Max; Schulte, Dominik M.; Metselaar, Josbert M.|info:eu-repo/dai/nl/244207690; Mulder, Willem J M; Stroes, Erik S.

    2015-01-01

    Drug delivery to atherosclerotic plaques via liposomal nanoparticles may improve therapeutic agents' risk-benefit ratios. Our paper details the first clinical studies of a liposomal nanoparticle encapsulating prednisolone (LN-PLP) in atherosclerosis. First, PLP's liposomal encapsulation improved its

  14. The Effect of a Fluorophore Photo-Physics on the Lipid Vesicle Diffusion Coefficient Studied by Fluorescence Correlation Spectroscopy.

    Science.gov (United States)

    Drabik, Dominik; Przybyło, Magda; Sikorski, Aleksander; Langner, Marek

    2016-03-01

    Fluorescence Correlation Spectroscopy (FCS) is a technique, which allows determination of the diffusion coefficient and concentration of fluorescent objects suspended in the solution. The measured parameter is the fluctuation of the fluorescence signal emitted by diffusing molecules. When 100 nm DOPC vesicles labeled with various fluorescent dyes (Fluorescein-PE, NBD-PE, Atto488 DOPE or βBodipy FL) were measured, different values of diffusion coefficients have been obtained. These diffusion coefficients were different from the expected values measured using the dynamic light scattering method (DLS). The FCS was initially developed for solutions containing small fluorescent molecules therefore the observed inconsistency may result from the nature of vesicle suspension itself. The duration of the fluorescence signal may depend on the following factors: the exposure time of the labeled object to the excitation beam, the photo-physical properties (e.g., stability) of a fluorophore, the theoretical model used for the calculations of the diffusion coefficient and optical properties of the vesicle suspension. The diffusion coefficients determined for differently labeled liposomes show that its dependence on vesicle size and quantity of fluorescent probed used for labeling was significant demonstrating that the fluorescence properties of the fluorophore itself (bleaching and/or blinking) were critical factors for a correct outcome of FCS experiment. The new, based on combined FCS and DLS measurements, method for the determination of the focal volume prove itself to be useful for the evaluation of a fluorescence dye with respect to its applicability for FCS experiment.

  15. Extracellular Vesicles in Cardiovascular Theranostics.

    Science.gov (United States)

    Bei, Yihua; Das, Saumya; Rodosthenous, Rodosthenis S; Holvoet, Paul; Vanhaverbeke, Maarten; Monteiro, Marta Chagas; Monteiro, Valter Vinicius Silva; Radosinska, Jana; Bartekova, Monika; Jansen, Felix; Li, Qian; Rajasingh, Johnson; Xiao, Junjie

    2017-01-01

    Extracellular vesicles (EVs) are small bilayer lipid membrane vesicles that can be released by most cell types and detected in most body fluids. EVs exert key functions for intercellular communication via transferring their bioactive cargos to recipient cells or activating signaling pathways in target cells. Increasing evidence has shown the important regulatory effects of EVs in cardiovascular diseases (CVDs). EVs secreted by cardiomyocytes, endothelial cells, fibroblasts, and stem cells play essential roles in pathophysiological processes such as cardiac hypertrophy, cardiomyocyte survival and apoptosis, cardiac fibrosis, and angiogenesis in relation to CVDs. In this review, we will first outline the current knowledge about the physical characteristics, biological contents, and isolation methods of EVs. We will then focus on the functional roles of cardiovascular EVs and their pathophysiological effects in CVDs, as well as summarize the potential of EVs as therapeutic agents and biomarkers for CVDs. Finally, we will discuss the specific application of EVs as a novel drug delivery system and the utility of EVs in the field of regenerative medicine.

  16. Advances and Challenges of Liposome Assisted Drug Delivery

    Directory of Open Access Journals (Sweden)

    Lisa eSercombe

    2015-12-01

    Full Text Available The application of liposomes to assist drug delivery has already had a major impact on many biomedical areas. They have been shown to be beneficial for stabilizing therapeutic compounds, overcoming obstacles to cellular and tissue uptake, and improving biodistribution of compounds to target sites in vivo. This enables effective delivery of encapsulated compounds to target sites while minimizing systemic toxicity. Liposomes present as an attractive delivery system due to their flexible physicochemical and biophysical properties, which allow easy manipulation to address different delivery considerations. Despite considerable research in the last 50 years and the plethora of positive results in preclinical studies, the clinical translation of liposome assisted drug delivery platforms has progressed incrementally. In this review, we will discuss the advances in liposome assisted drug delivery, biological challenges that still remain, and current clinical and experimental use of liposomes for biomedical applications. The translational obstacles of liposomal technology will also be presented.

  17. Preparation and characterization of liposomes entrapping allergenic proteins

    Directory of Open Access Journals (Sweden)

    E. C. M. Cabral

    2004-06-01

    Full Text Available This work presents results of the preparation and characterization of small unilamellar liposomes for entrapping allergenic proteins extracted from the biomass of Dreschlera (Helminthosporium monoceras cultivated by solid fermentation. Protein was entrapped by the dehydration-rehydration method, using lyophilization of preformed liposomes in order to prevent their degradation The reconstitution of lyophilized liposomes by hydration, their capacity for entrapping allergenic proteins and their stability in plasma were analyzed. Liposomes were reconstituted in size by including trehalose sugar in the formulation. The protection of the liposomal membrane by trehalose was characterized by differential scanning calorimetry and X-ray diffraction. The reconstituted membrane had an osmotic behavior similar to that of nondehydrated ones. Allergenic proteins ranging in molecular weight from 14 to 170 kDa were entrapped in the lipid matrix with an efficiency of approximately 80%. These results are promising for producing liposomes by entrapping allergenic proteins from mold extracts, which can be useful for allergy therapy.

  18. Illuminating the physiology of extracellular vesicles

    OpenAIRE

    Choi, Hongyoon; Lee, Dong Soo

    2016-01-01

    Extracellular vesicles play a crucial role in intercellular communication by transmitting biological materials from donor cells to recipient cells. They have pathophysiologic roles in cancer metastasis, neurodegenerative diseases, and inflammation. Extracellular vesicles also show promise as emerging therapeutics, with understanding of their physiology including targeting, distribution, and clearance therefore becoming an important issue. Here, we review recent advances in methods for trackin...

  19. Extracellular vesicles in coronary artery disease.

    Science.gov (United States)

    Boulanger, Chantal M; Loyer, Xavier; Rautou, Pierre-Emmanuel; Amabile, Nicolas

    2017-05-01

    Membrane vesicles released in the extracellular space are composed of a lipid bilayer enclosing soluble cytosolic material and nuclear components. Extracellular vesicles include apoptotic bodies, exosomes, and microvesicles (also known previously as microparticles). Originating from different subcellular compartments, the role of extracellular vesicles as regulators of transfer of biological information, acting locally and remotely, is now acknowledged. Circulating vesicles released from platelets, erythrocytes, leukocytes, and endothelial cells contain potential valuable biological information for biomarker discovery in primary and secondary prevention of coronary artery disease. Extracellular vesicles also accumulate in human atherosclerotic plaques, where they affect major biological pathways, including inflammation, proliferation, thrombosis, calcification, and vasoactive responses. Extracellular vesicles also recapitulate the beneficial effect of stem cells to treat cardiac consequences of acute myocardial infarction, and now emerge as an attractive alternative to cell therapy, opening new avenues to vectorize biological information to target tissues. Although interest in microvesicles in the cardiovascular field emerged about 2 decades ago, that for extracellular vesicles, in particular exosomes, started to unfold a decade ago, opening new research and therapeutic avenues. This Review summarizes current knowledge on the role of extracellular vesicles in coronary artery disease, and their emerging potential as biomarkers and therapeutic agents.

  20. Detection of extracellular vesicles: size does matter

    NARCIS (Netherlands)

    van der Pol, E.

    2015-01-01

    Cells release small sacks filled with fluid, which are called "extracellular vesicles". The diameter of extracellular vesicles (EV) typically ranges from 30 nm to 1 µm. Because cells release EV into their environment, our body fluids contain numerous EV. Cells release EV to remove waste and to

  1. Synaptic vesicle distribution by conveyor belt.

    Science.gov (United States)

    Moughamian, Armen J; Holzbaur, Erika L F

    2012-03-02

    The equal distribution of synaptic vesicles among synapses along the axon is critical for robust neurotransmission. Wong et al. show that the continuous circulation of synaptic vesicles throughout the axon driven by molecular motors ultimately yields this even distribution. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Urinary extracellular vesicles: biomarkers and beyond

    NARCIS (Netherlands)

    M. Salih (Mahdi)

    2017-01-01

    markdownabstractExtracellular vesicles have been isolated in various body fluids including urine. The cargo of urinary extracellular vesicles (uEVs) is composed of proteins and nucleic acids reflecting the physiological and possibly the pathophysiological state of cells lining the nephron. Because

  3. Fusion Competent Synaptic Vesicles Persist upon Active Zone Disruption and Loss of Vesicle Docking.

    Science.gov (United States)

    Wang, Shan Shan H; Held, Richard G; Wong, Man Yan; Liu, Changliang; Karakhanyan, Aziz; Kaeser, Pascal S

    2016-08-17

    In a nerve terminal, synaptic vesicle docking and release are restricted to an active zone. The active zone is a protein scaffold that is attached to the presynaptic plasma membrane and opposed to postsynaptic receptors. Here, we generated conditional knockout mice removing the active zone proteins RIM and ELKS, which additionally led to loss of Munc13, Bassoon, Piccolo, and RIM-BP, indicating disassembly of the active zone. We observed a near-complete lack of synaptic vesicle docking and a strong reduction in vesicular release probability and the speed of exocytosis, but total vesicle numbers, SNARE protein levels, and postsynaptic densities remained unaffected. Despite loss of the priming proteins Munc13 and RIM and of docked vesicles, a pool of releasable vesicles remained. Thus, the active zone is necessary for synaptic vesicle docking and to enhance release probability, but releasable vesicles can be localized distant from the presynaptic plasma membrane. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Alternative methods for characterization of extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Fatemeh eMomen-Heravi

    2012-09-01

    Full Text Available Extracellular vesicles are nano-sized vesicles released by all cells in vitro as well as in vivo. Their role has been implicated mainly in cell-cell communication, but also in disease biomarkers and more recently in gene delivery. They represent a snapshot of the cell status at the moment of release and carry bioreactive macromolecules such as nucleic acids, proteins and lipids. A major limitation in this emerging new field is the availability/awareness of techniques to isolate and properly characterize Extracellular vesicles. The lack of gold standards makes comparing different studies very difficult and may potentially hinder some Extracellular vesicles -specific evidence. Characterization of Extracellular vesicles has also recently seen many advances with the use of Nanoparticle Tracking Analysis (NTA, flow cytometry, cryo-EM instruments and proteomic technologies. In this review, we discuss the latest developments in translational technologies involving characterization methods including the facts in their support and the challenges they face.

  5. Extracellular vesicles: new players in cardiovascular diseases.

    Science.gov (United States)

    Gaceb, Abderahim; Martinez, Maria Carmen; Andriantsitohaina, Ramaroson

    2014-05-01

    Extracellular vesicles, particles released by all cell types, represent a new way to convey information between cells such as proteins, second messengers, and genetic information to modify the phenotype and function of the target cells. Recent data suggest that extracellular vesicles play a crucial role in both physiology and pathology, including coagulation, angiogenesis, cell survival, modulation of the immune response, and inflammation. Thus extracellular vesicles participate in the processes of cardiovascular diseases from atherosclerosis, myocardial infarction to heart failure. Consequently, extracellular vesicles can potentially be exploited for therapy, prognosis, and biomarkers for health and disease. This review focuses on the role of extracellular vesicles in the development of cardiovascular diseases, as well as the deleterious and beneficial effects that they may provide in vascular cells and myocardium. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. [Transvesical Removal of Seminal Vesicle Cystadenoma].

    Science.gov (United States)

    Takayasu, Kenta; Harada, Jiro; Kawa, Gen; Ota, Syuichi; Sakurai, Takanori

    2015-07-01

    Primary tumors of the seminal vesicles are extremely rare. There have been 25 reports of this tumor from overseas and most cases are cystadenoma. We report a case of seminal vesicle cystadenoma in a 70-year-old man who presented with lower abdominal pain and urinary frequency. A digital rectal examination detected a projecting and hard mass in the right side of the prostate. Magnetic resonance imaging (MRI) showed a 15 cm multiple cystic mass continuous with the right seminal vesicle. A transrectal needle biopsy revealed benign tissue. The tumor was resected using an open transvesical approach that enabled full exposure of the seminal vesicle without damaging the nerves and blood supply of the bladder. Pathology was consistent with a benign seminal vesicle cystadenoma. We describe the natural history, pathology,and surgical approach in this case.

  7. Pushing synaptic vesicles over the RIM.

    Science.gov (United States)

    Kaeser, Pascal S

    2011-05-01

    In a presynaptic nerve terminal, neurotransmitter release is largely restricted to specialized sites called active zones. Active zones consist of a complex protein network, and they organize fusion of synaptic vesicles with the presynaptic plasma membrane in response to action potentials. Rab3-interacting molecules (RIMs) are central components of active zones. In a recent series of experiments, we have systematically dissected the molecular mechanisms by which RIMs operate in synaptic vesicle release. We found that RIMs execute two critical functions of active zones by virtue of independent protein domains. They tether presyanptic Ca(2+) channels to the active zone, and they activate priming of synaptic vesicles by monomerizing homodimeric, constitutively inactive Munc13. These data indicate that RIMs orchestrate synaptic vesicle release into a coherent process. In conjunction with previous studies, they suggest that RIMs form a molecular platform on which plasticity of synaptic vesicle release can operate.

  8. Apoptotic Bodies: Selective Detection in Extracellular Vesicles.

    Science.gov (United States)

    Hauser, Paul; Wang, Sha; Didenko, Vladimir V

    2017-01-01

    Normal and dying cells release various types of membrane-bound vesicles including microvesicles, exosomes, and apoptotic bodies. These vesicles play important roles in intercellular communication and signal transduction. However, their diverse forms and subtypes fluctuate in size and other properties. In result current purification approaches do not fully discriminate between different categories of extracellular vesicles. Here, we present a fluorescence technique that specifically identifies apoptotic bodies in preparations of microvesicles, exosomes, and other extracellular vesicles.The approach exclusively labels the vesicles that contain DNA with 5'PO 4 blunt-ended DNA breaks, such as those produced by the apoptotic CAD nuclease during apoptotic DNA degradation. The technique can be useful in studies of apoptosis involving microvesicles and exosomes.

  9. Monosaccharide transport in protein-depleted vesicles from erythrocyte membranes

    National Research Council Canada - National Science Library

    M A Zoccoli; G E Lienhard

    1977-01-01

    .... Based on comparisons between erythrocytes and vesicles with regard to specificity, temparture dependence, and effects of inhibitors, we conclude that sorbose uptake into the vesicles occurs by way...

  10. Lipossomas e suas aplicações terapêuticas: estado da arte Liposomes and their therapeutic: state of art applications

    Directory of Open Access Journals (Sweden)

    Cinthia Meireles Batista

    2007-06-01

    Full Text Available Lipossomas são vesículas constituídas de uma ou mais bicamadas fosfolipídicas orientadas concentricamente em torno de um compartimento aquoso e servem como carreadores de fármacos, biomoléculas ou agentes de diagnóstico. A estabilidade dos lipossomas pode ser afetada por fatores químicos, físicos e biológicos. Após administração intravenosa, lipossomas convencionais são rapidamente capturados pelo sistema fagocitário mononuclear. Para evitar essa captura, lipossomas furtivos foram desenvolvidos, os quais apresentam a superfície modificada com componentes hidrofílicos. Para permitir a liberação seletiva do fármaco nos sítios alvos, ligantes de reconhecimento específico são conjugados na superfície de lipossomas. Em geral, os métodos de preparação de lipossomas incluem hidratação de um filme lipídico seguida de sonicação ou extrusão para redução do tamanho das vesículas. Os lipossomas são caracterizados quanto ao tamanho e composição química das vesículas e conteúdo do material encapsulado. Nesta revisão, constata-se que os lipossomas oferecem maior eficácia e segurança com relação aos tratamentos convencionais. Apesar de algumas formulações lipossomais serem comercializadas desde os anos 1980 para tratamento de infecções fúngicas sistêmicas e do câncer, problemas de ordem tecnológica e biológica fazem com que os lipossomas sejam ainda extensivamente estudados para desenvolvimento de formulações estáveis no organismo visando à terapia de várias doenças, principalmente do câncer.Liposomes are vesicles that consist of one or more concentric phospholipidic bilayers organized around an aqueous inner compartment. They are carriers of drugs, biomolecules and diagnostic agents. The stability of liposomes can be influenced by chemical or physical factors. Once injected in the circulatory system, conventional liposomes suffer uptake by the mononuclear phagocytic system. To avoid such a capture

  11. Comparative study of liposomes, transfersomes and ethosomes as carriers for improving topical delivery of celecoxib.

    Science.gov (United States)

    Bragagni, Marco; Mennini, Natascia; Maestrelli, Francesca; Cirri, Marzia; Mura, Paola

    2012-01-01

    Topical administration of celecoxib proved to be an effective mean of preventing skin cancer development and improving anticancer drugs effectiveness in skin tumors treatment. The aim of this study was the development of an effective topical formulation of celecoxib, able to promote drug skin delivery, providing its in depth penetration through the skin layers. Three kinds of vesicular formulations have been investigated as drug carriers: liposomes containing a surfactant, or transfersomes and ethosomes, containing suitable edge activators. Firstly, the effect of membrane composition variations on the system performance has been evaluated for each vesicle type. Selected formulations were characterized for particle size, polydispersity index and encapsulation efficiency. The best formulations were subjected to ex vivo permeation studies through excised human skin. All vesicular formulations markedly (p ethosomes, respectively. In particular, ethosomes containing Tween 20 as edge activator not only showed the best vesicle dimensions and homogeneity, and the highest encapsulation efficacy (54.4%), but also enabled the highest increase in drug penetration through the skin, probably due to the simultaneous presence in their composition of ethanol and Tween 20, both acting as permeation enhancers. Therefore, among the various vesicular formulations examined in the study, Tween 20-ethosomes can be considered the most promising one as carrier for topical celecoxib applications aimed to prevent skin cancer development and increase the anticancer drugs effectiveness against skin tumors.

  12. Liposome as nanocarrier: Site targeted delivery in lung cancer

    Directory of Open Access Journals (Sweden)

    Najeeb Ullah

    2017-08-01

    Full Text Available Lung cancer is fatal and spreading rapidly worldwide. Different clinical strategies are applied to stop this cancer. As the lung is a delicate organ, special clinical applications must be used and nanodrugs delivery systems are the most important applications of all. This review discusses the lung problems such as lung cancer, lung inflammation and bronchi constrictions followed by repetitive intake of some drugs. The objective of this review is to study how nanodrug delivery systems were synthesized and used in lung disorder treatment especially in lung cancer. The authors studied some articles from 1989 to 2015. Liposome encapsulation was done in various ways for the delivery of different drugs such as metaproterenol into liposomes caused bronchodilation, immunoliposomes bearing antibodies for doxorubicin reduced 50% inhibitory effects, radioliposomes with high penetrating ability to peripheral airways, aerosol delivery systems with deep pulmonary deposition, polymeric drug delivery having potential to improve beneficial index of drug, solid lipid liposomes, liposomal gentamicin with altered different clinical susceptibilities of resistance, transferrin conjugated liposomes to deliver cytostatic drugs to site of lungs, anti-inflammatory drugs with mannosylated liposomes, liposomal suspensions with single stranded RNAs and peptide encapsulation of liposomes. This review indicates that many animals perished with intravenous administration of drugs but survived in liposomal targeting groups.

  13. Liposomal delivery of radionuclides for cancer diagnostics and radiotherapy

    DEFF Research Database (Denmark)

    Petersen, Anncatrine Luisa

    of 64Cu in PET imaging. Article I and Patent I present our work focused on developing a remote (active) loading technique using a new lipophilic chelator (2-hydroxyquinoline) to load 64Cu into preformed (pre-manufactured) liposomes. We optimized the remote loading technique through several liposomal...... of PEGylated 64Cu-liposomes with and without TATE, and their ability to image NE tumors in tumor-bearing mice using PET. Further, we compare the liposome tumor accumulation and imaging capability with that of the radiolabeled somatostatin analog 64Cu-DOTA-TATE. During the past 30 years, ionophores...

  14. How liposomal Cisplatin overcomes chemoresistance in ovarian tumour cells.

    Science.gov (United States)

    Stölting, Daniel Philipp; Borrmann, Michaela; Koch, Martin; Wiese, Michael; Royer, Hans-Dieter; Bendas, Gerd

    2014-01-01

    The frequent development of cellular resistance to cisplatin in cancer patients is a serious limitation for clinical drug therapy. However, cisplatin resistance is incompletely understood. We have shown that cisplatin-resistant A2780 ovarian cancer cells (A2780cis) can efficiently be eliminated by liposomal cisplatin, which displayed similar cytotoxicity towards both A2780 and A2780cis cells. This may, at least in part, be related to a higher intracellular accumulation of the drug within the resistant cells after liposomal entry. However, the superior cytotoxicity of the liposomal drug was not reflected by DNA platination. This suggests a more complex mode of action of liposomal cisplatin, most likely affecting different signaling pathways. To gain insight into the resistance gene signature, a whole-genome gene expression analysis was performed for A2780cis cells, untreated or treated with half-minimal inhibitory concentration (IC50) of free and liposomal cisplatin. Strong differences in the functional networks affected by free and liposomal cisplatin became evident. p53 was identified as a key factor directing differences in the apoptotic processes. While free cisplatin induced the intrinsic pathway of apoptosis, liposomal cisplatin induced expression of genes of DNA damage pathways and of the extrinsic pathway of apoptosis. These predictions from gene expression data were confirmed at the protein and function level. This sheds new light on liposomal drug carrier approaches in cancer and suggests liposomal cisplatin as a promising strategy for the treatment of cisplatin-resistant ovarian carcinoma.

  15. Transformation of actin-encapsulating liposomes induced by cytochalasin D.

    OpenAIRE

    Miyata, H.; Kinosita, K

    1994-01-01

    Liposomes encapsulating actin filaments were prepared by swelling at 0 degrees C lipid film consisting of a mixture of dimyristoyl phosphatidylcholine and cardiolipin (equal amounts by weight) in 100 microM rabbit skeletal muscle actin and 0.5 mM CaCl2 followed by polymerization of actin at 30 degrees C. Liposomes initially assumed either disk or dumbbell shape, but when cytochalasin D was added to the medium surrounding the liposomes, they were found to become spindle shaped. Liposomes conta...

  16. Liposome-encapsulated photosensitizers against bacteria.

    Science.gov (United States)

    Chen, Chin- Tin; Chen, Chueh- Pin; Yang, Jen- Chang; Tsai, Tsuimin

    2013-08-01

    Photodynamic therapy (PDT), utilizing photosensitizers and light, has received considerable interests for its potential to treat microbial infections. The advantages of antimicrobial PDT include a broad spectrum of action, efficient killing against wild-type as well as drug-resistant pathogens. Therefore, antimicrobial PDT could be valuable to rapidly reduce the microbial burden during the management of local infections, especially for the antibiotic resistance. A variety of photosensitizers have been examined its efficacy against pathogens. To increase the efficacy of photosensitizers, various drug delivery systems have been developed. Among these carrier systems, liposomes showed their PDT efficacy and safety in delivering photosensitizers. This review is focused on the application of liposomes mediated photodynamic inactivation of bacteria along with the discussion of few of recent patents.

  17. Pegylated liposomal doxorubicin in ovarian cancer

    OpenAIRE

    Matei, Daniela

    2009-01-01

    Robert Strother1,2, Daniela Matei1–51Department of Medicine, 2Indiana University Melvin and Bren Simon Cancer Center, 3Department of Obstetrics and Gynecology, 4Department of Biochemistry and Molecular Biology, 5VA Roudebush Hospital Indiana University School of Medicine, 535 Barnhill Drive, Indianapolis, IN, 46202Abstract: The encapsulation of doxorubicin in a pegylated liposomal matrix led to a reformulated agent with a different toxicity profile and improved clinical utility. Lip...

  18. Liposomal cancer therapy: exploiting tumor characteristics

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Andresen, Thomas Lars

    2010-01-01

    the reader will gain: The review focuses on strategies that exploit characteristic features of solid tumors, such as abnormal vasculature, overexpression of receptors and enzymes, as well as acidic and thiolytic characteristics of the tumor microenvironment. Take home message: It is concluded that the design...... of new liposomal drug delivery systems that better exploit tumor characteristic features is likely to result in more efficacious cancer treatments....

  19. Low CO2 permeability of cholesterol-containing liposomes detected by stopped-flow fluorescence spectroscopy.

    Science.gov (United States)

    Tsiavaliaris, Georgios; Itel, Fabian; Hedfalk, Kristina; Al-Samir, Samer; Meier, Wolfgang; Gros, Gerolf; Endeward, Volker

    2015-05-01

    Here we ask the following: 1) what is the CO2 permeability (Pco2) of unilamellar liposomes composed of l-α-phosphatidylcholine (PC)/l-α-phosphatidylserine (PS) = 4:1 and containing cholesterol (Chol) at levels often occurring in biologic membranes (50 mol%), and 2) does incorporation of the CO2 channel aquaporin (AQP)1 cause a significant increase in membrane Pco2? Presently, a drastic discrepancy exists between the answers to these two questions obtained from mass-spectrometric (18)O-exchange measurements (Chol reduces Pco2 100-fold, AQP1 increases Pco2 10-fold) vs. from stopped-flow approaches observing CO2 uptake (no effects of either Chol or AQP1). A novel theory of CO2 uptake by vesicles predicts that in a stopped-flow apparatus this fast process can only be resolved temporally and interpreted quantitatively, if 1) a very low CO2 partial pressure (pCO2) is used (e.g., 18 mmHg), and 2) intravesicular carbonic anhydrase (CA) activity is precisely known. With these prerequisites fulfilled, we find by stopped-flow that 1) Chol-containing vesicles possess a Pco2 = 0.01cm/s, and Chol-free vesicles exhibit ∼1 cm/s, and 2) the Pco2 of 0.01 cm/s is increased ≥ 10-fold by AQP1. Both results agree with previous mass-spectrometric results and thus resolve the apparent discrepancy between the two techniques. We confirm that biologic membranes have an intrinsically low Pco2 that can be raised when functionally necessary by incorporating protein-gas channels such as AQP1. © FASEB.

  20. In vitro and in vivo aspects of N-acyl-phosphatidylethanolamine-containing liposomes

    DEFF Research Database (Denmark)

    Vermehren, C.; Clausen-Beck, B.; Frøkjær, S.

    2003-01-01

    cells may be expected, resulting in a favorable delivery of drug to the target cell. In this study, NAPE has been tested as a potential liposomal component of phosphatidylcholine-liposomes. The liposomes were characterized by size, long-term stability and phase transition temperature (T). In vivo...... behavior of NAPE-liposomes was determined by the blood-circulation half-life in mice. A characterization of the liposomes revealed that high content of NAPE resulted in liposomes of increased size compared to pure phosphatidylcholine-liposomes. However, the liposomes showed only a slight increase in size...... during storage for 5 weeks. Determination of T for NAPE-liposomes showed increasing values of T by increasing percentage of NAPE in the liposomal bilayer, due to the higher T of NAPE compared to phosphatidylcholine. Blood-clearance studies showed an initial increase in blood-circulation of liposomes...

  1. Partitioning of organophosphorus pesticides into phosphatidylcholine small unilamellar vesicles studied by second-derivative spectrophotometry

    Science.gov (United States)

    Takegami, Shigehiko; Kitamura, Keisuke; Ohsugi, Mayuko; Ito, Aya; Kitade, Tatsuya

    2015-06-01

    In order to quantitatively examine the lipophilicity of the widely used organophosphorus pesticides (OPs) chlorfenvinphos (CFVP), chlorpyrifos-methyl (CPFM), diazinon (DZN), fenitrothion (FNT), fenthion (FT), isofenphos (IFP), profenofos (PFF) and pyraclofos (PCF), their partition coefficient (Kp) values between phosphatidylcholine (PC) small unilamellar vesicles (SUVs) and water (liposome-water system) were determined by second-derivative spectrophotometry. The second-derivative spectra of these OPs in the presence of PC SUV showed a bathochromic shift according to the increase in PC concentration and distinct derivative isosbestic points, demonstrating the complete elimination of the residual background signal effects that were observed in the absorption spectra. The Kp values were calculated from the second-derivative intensity change induced by addition of PC SUV and obtained with a good precision of R.S.D. below 10%. The Kp values were in the order of CPFM > FT > PFF > PCF > IFP > CFVP > FNT ⩾ DZN and did not show a linear correlation relationship with the reported partition coefficients obtained using an n-octanol-water system (R2 = 0.530). Also, the results quantitatively clarified the effect of chemical-group substitution in OPs on their lipophilicity. Since the partition coefficient for the liposome-water system is more effective for modeling the quantitative structure-activity relationship than that for the n-octanol-water system, the obtained results are toxicologically important for estimating the accumulation of these OPs in human cell membranes.

  2. Partitioning of organophosphorus pesticides into phosphatidylcholine small unilamellar vesicles studied by second-derivative spectrophotometry.

    Science.gov (United States)

    Takegami, Shigehiko; Kitamura, Keisuke; Ohsugi, Mayuko; Ito, Aya; Kitade, Tatsuya

    2015-06-15

    In order to quantitatively examine the lipophilicity of the widely used organophosphorus pesticides (OPs) chlorfenvinphos (CFVP), chlorpyrifos-methyl (CPFM), diazinon (DZN), fenitrothion (FNT), fenthion (FT), isofenphos (IFP), profenofos (PFF) and pyraclofos (PCF), their partition coefficient (Kp) values between phosphatidylcholine (PC) small unilamellar vesicles (SUVs) and water (liposome-water system) were determined by second-derivative spectrophotometry. The second-derivative spectra of these OPs in the presence of PC SUV showed a bathochromic shift according to the increase in PC concentration and distinct derivative isosbestic points, demonstrating the complete elimination of the residual background signal effects that were observed in the absorption spectra. The Kp values were calculated from the second-derivative intensity change induced by addition of PC SUV and obtained with a good precision of R.S.D. below 10%. The Kp values were in the order of CPFM>FT>PFF>PCF>IFP>CFVP>FNT⩾DZN and did not show a linear correlation relationship with the reported partition coefficients obtained using an n-octanol-water system (R(2)=0.530). Also, the results quantitatively clarified the effect of chemical-group substitution in OPs on their lipophilicity. Since the partition coefficient for the liposome-water system is more effective for modeling the quantitative structure-activity relationship than that for the n-octanol-water system, the obtained results are toxicologically important for estimating the accumulation of these OPs in human cell membranes. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Extracellular vesicles as emerging intercellular communicasomes.

    Science.gov (United States)

    Yoon, Yae Jin; Kim, Oh Youn; Gho, Yong Song

    2014-10-01

    All living cells release extracellular vesicles having pleiotropic functions in intercellular communication. Mammalian extracellular vesicles, also known as exosomes and microvesicles, are spherical bilayered proteolipids composed of various bioactive molecules, including RNAs, DNAs, proteins, and lipids. Extracellular vesicles directly and indirectly control a diverse range of biological processes by transferring membrane proteins, signaling molecules, mRNAs, and miRNAs, and activating receptors of recipient cells. The active interaction of extracellular vesicles with other cells regulates various physiological and pathological conditions, including cancer, infectious diseases, and neurodegenerative disorders. Recent developments in high-throughput proteomics, transcriptomics, and lipidomics tools have provided ample data on the common and specific components of various types of extracellular vesicles. These studies may contribute to the understanding of the molecular mechanism involved in vesicular cargo sorting and the biogenesis of extracellular vesicles, and, further, to the identification of disease-specific biomarkers. This review focuses on the components, functions, and therapeutic and diagnostic potential of extracellular vesicles under various pathophysiological conditions.

  4. Structure of Amphiphilic Terpolymer Raspberry Vesicles

    Directory of Open Access Journals (Sweden)

    Yingying Guo

    2017-07-01

    Full Text Available Terpolymer raspberry vesicles contain domains of different chemical affinities. They are potential candidates as multi-compartment cargo carriers. Their efficacy depends on their stability and load capacity. Using a model star terpolymer system in an aqueous solution, a dissipative particle dynamic (DPD simulation is employed to investigate how equilibrium aggregate structures are affected by polymer concentration and pairwise interaction energy in a solution. It is shown that a critical mass of polymer is necessary for vesicle formation. The free energy of the equilibrium aggregates are calculated and the results show that the transition from micelles to vesicles is governed by the interactions between the longest solvophobic block and the solvent. In addition, the ability of vesicles to encapsulate solvent is assessed. It is found that reducing the interaction energy favours solvent encapsulation, although solvent molecules can permeate through the vesicle’s shell when repulsive interactions among monomers are low. Thus, one can optimize the loading capacity and the release rate of the vesicles by turning pairwise interaction energies of the polymer and the solvent. The ability to predict and control these aspects of the vesicles is an essential step towards designing vesicles for specific purposes.

  5. Liposomal nanoparticles as a drug delivery vehicle against osteosarcoma

    Science.gov (United States)

    Dhule, Santosh Subhashrao

    The delivery of curcumin, a broad-spectrum anticancer drug, has been explored in the form of liposomal nanoparticles to treat osteosarcoma (OS). Curcumin is water insoluble and an effective delivery route is through encapsulation in cyclodextrins followed by a second encapsulation in liposomes. Liposomal curcumin's potential was evaluated against cancer models of mesenchymal (OS) and epithelial origin (breast cancer). The resulting 2-Hydroxypropyl-gamma-cyclodextrin/curcumin - liposome complex shows promising anticancer potential both in vitro and in vivo against KHOS OS cell line and MCF-7 breast cancer cell line. An interesting aspect is that liposomal curcumin initiates the caspase cascade that leads to apoptotic cell death in vitro in comparison with DMSO-curcumin induced autophagic cell death. In addition, the efficiency of the liposomal curcumin formulation was confirmed in vivo using a xenograft OS model. Curcumin-loaded gamma-cyclodextrin liposomes indicate significant potential as delivery vehicles for the treatment of cancers of different tissue origin. The second part of this study examines the anti-tumor potential of curcumin and C6 ceramide (C6) against osteosarcoma cell lines when both are encapsulated in the bilayer of liposomal nanoparticles. Curcumin in combination with C6 showed 1.5 times enhanced cytotoxic effect in the case of MG-63 and KHOS OS cell lines, in comparison with systems with curcumin alone. Interestingly, C6-curcumin liposomes were found to be less toxic on untransformed human cells in comparison to OS cell lines. In addition, cell cycle assays on a KHOS cell line after treatment revealed that curcumin only liposomes induced G 2/M arrest by upregulation of cyclin B1, while C6 only liposomes induced G1 arrest by downregulation of cyclin D1. C6-curcumin liposomes induced G2/M arrest and showed a combined effect in the expression levels of cyclin D1 and cyclin B1. Using pegylated liposomes to increase the plasma half-life and tagging

  6. Illuminating the physiology of extracellular vesicles.

    Science.gov (United States)

    Choi, Hongyoon; Lee, Dong Soo

    2016-04-16

    Extracellular vesicles play a crucial role in intercellular communication by transmitting biological materials from donor cells to recipient cells. They have pathophysiologic roles in cancer metastasis, neurodegenerative diseases, and inflammation. Extracellular vesicles also show promise as emerging therapeutics, with understanding of their physiology including targeting, distribution, and clearance therefore becoming an important issue. Here, we review recent advances in methods for tracking and imaging extracellular vesicles in vivo and critically discuss their systemic distribution, targeting, and kinetics based on up-to-date evidence in the literature.

  7. Liposomal systems as viable drug delivery technology for skin cancer sites with an outlook on lipid-based delivery vehicles and diagnostic imaging inputs for skin conditions'.

    Science.gov (United States)

    Akhtar, Naseem; Khan, Riaz A

    2016-10-01

    Skin cancer is among one of the most common human malignancies wide-spread world-over with mortality statistics rising continuously at an alarming rate. The increasing frequency of these malignancies has marked the need for adopting effective treatment plan coupled with better and site-specific delivery options for the desired therapeutic agent's availability at the affected site. The concurrent delivery approaches to cancerous tissues are under constant challenge and, as a result, are evolving and gaining advancements in terms of delivery modes, therapeutic agents and site-specificity of the therapeutics delivery. The lipid-based liposomal drug delivery is an attractive and emerging option, and which is meticulously shaping up beyond a threshold level to a promising, and viable route for the effective delivery of therapeutic agents and other required injuctions to the skin cancer. An update on liposomal delivery of chemotherapeutic agents, natural-origin compounds, photosensitizer, and DNA repair enzymes as well as other desirable and typical delivery modes employed in drug delivery and in the treatment of skin cancers is discussed in details. Moreover, liposomal delivery of nucleic acid-based therapeutics, i.e., small interfering RNA (siRNA), mRNA therapy, and RGD-linked liposomes are among the other promising novel technology under constant development. The current clinical applicability, viable clinical plans, future prospects including transport feasibility of delivery vesicles and imaging techniques in conjunction with the therapeutic agents is also discussed. The ongoing innovations in liposomal drug delivery technology for skin cancers hold promise for further development of the methodology for better, more effective and site-specific delivery as part of the better treatment plan by ensuring faster drug transport, better and full payload delivery with enough and required concentration of the dose. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Protease-sensitive, polymer-caged liposomes: a method for making highly targeted liposomes using triggered release.

    Science.gov (United States)

    Basel, Matthew T; Shrestha, Tej B; Troyer, Deryl L; Bossmann, Stefan H

    2011-03-22

    Liposomes have become useful and well-known drug delivery vehicles because of their ability to entrap drugs without chemically modifying them and to deliver them somewhat selectively to tumorous tissue via the enhanced permeation and retention (EPR) effect. Although useful, liposome preparations are still less than ideal because of imperfect specificity, slow release kinetics in the tumor, and leakiness prior to reaching the tumor site. Cancer-associated proteases (CAPs), which are differentially expressed in tumors, have also gained traction recently as a method for tumor targeting and drug delivery. By combining the EPR effect with CAPs sensitivity, a much more specific liposome can be produced. The method described here creates an improved liposome system that can target more specifically, with faster release kinetics and lower general leaking, by deliberately producing a very unstable liposome (loaded with hyperosmotic vehicle) that is subsequently stabilized by a cross-linked polymer shell containing consensus sequences for cancer-associated proteases (protease-triggered, caged liposomes). A cholesterol-anchored, graft copolymer, composed of a short peptide sequence for urokinase plasminogen activator (uPA) and poly(acrylic acid), was synthesized and incorporated into liposomes prepared at high osmolarities. Upon cross-linking of the polymers, the protease-triggered, caged liposomes showed significant resistance to osmotic swelling and leaking of contents. Protease-triggered, caged liposomes also showed significant and substantial differential release of contents in the presence of uPA, while bare liposomes showed no differential effect in the presence of uPA. Thus a protease-sensitive liposome system with fast release kinetics was developed that could be used for more specific targeting to tumors.

  9. Classification, Functions, and Clinical Relevance of Extracellular Vesicles

    NARCIS (Netherlands)

    van der Pol, Edwin; Böing, Anita N.; Harrison, Paul; Sturk, Augueste; Nieuwland, Rienk

    2012-01-01

    Both eukaryotic and prokaryotic cells release small, phospholipid-enclosed vesicles into their environment. Why do cells release vesicles? Initial studies showed that eukaryotic vesicles are used to remove obsolete cellular molecules. Although this release of vesicles is beneficial to the cell, the

  10. Slow fusion of liposomes composed of membrane-spanning lipids

    NARCIS (Netherlands)

    Elferink, MGL; vanBreemen, J; Konings, WN; Driessen, AJM; Wilschut, J; Elferink, Marieke G.L.

    1997-01-01

    The fusion characteristics of large unilamellar liposomes composed of bipolar tetraether lipids extracted from the thermophilic archaeon Sulfolobus acidocaldarius, was investigated. These lipids span the entire membrane and form single monolayer liposomes in aqueous media [Elferink, M.G.L., de Wit,

  11. Calcipotriol delivery into the skin with PEGylated liposomes

    DEFF Research Database (Denmark)

    Knudsen, Nina Østergaard; Rønholt, Stine; Salte, Ragnhild Djønne

    2012-01-01

    for the development of dosage forms containing liposomes is to maintain the colloidal stability in the formulation. The purpose of this study was to investigate the effect of stabilising liposomes with the lipopolymer poly(ethylene glycol)-distearoylphosphoethanolamine (PEG-DSPE) on the physicochemical properties...

  12. Evaluation of iron transport from ferrous glycinate liposomes using ...

    African Journals Online (AJOL)

    2017-09-03

    Sep 3, 2017 ... Abstract. Background: Iron fortification of foods is currently a strategy employed to fight iron deficiency in countries. Liposomes were assumed to be a potential carrier of iron supplements. Objective: The objective of this study was to investigate the iron transport from ferrous glycinate liposomes, and to ...

  13. Optimization and characterization of liposome formulation by mixture design.

    Science.gov (United States)

    Maherani, Behnoush; Arab-tehrany, Elmira; Kheirolomoom, Azadeh; Reshetov, Vadzim; Stebe, Marie José; Linder, Michel

    2012-02-07

    This study presents the application of the mixture design technique to develop an optimal liposome formulation by using the different lipids in type and percentage (DOPC, POPC and DPPC) in liposome composition. Ten lipid mixtures were generated by the simplex-centroid design technique and liposomes were prepared by the extrusion method. Liposomes were characterized with respect to size, phase transition temperature, ζ-potential, lamellarity, fluidity and efficiency in loading calcein. The results were then applied to estimate the coefficients of mixture design model and to find the optimal lipid composition with improved entrapment efficiency, size, transition temperature, fluidity and ζ-potential of liposomes. The response optimization of experiments was the liposome formulation with DOPC: 46%, POPC: 12% and DPPC: 42%. The optimal liposome formulation had an average diameter of 127.5 nm, a phase-transition temperature of 11.43 °C, a ζ-potential of -7.24 mV, fluidity (1/P)(TMA-DPH)((¬)) value of 2.87 and an encapsulation efficiency of 20.24%. The experimental results of characterization of optimal liposome formulation were in good agreement with those predicted by the mixture design technique.

  14. Polyelectrolyte stabilized multilayered liposomes for oral delivery of paclitaxel

    DEFF Research Database (Denmark)

    Jain, Sanyog; Kumar, Dinesh; Swarnakar, Nitin K

    2012-01-01

    Paclitaxel (PTX) loaded layersome formulations were prepared using layer-by-layer assembly of the polyelectrolytes over liposomes. Stearyl amine was utilized to provide positive charge to the liposomes, which were subsequently coated with anionic polymer polyacrylic acid (PAA) followed by coating...

  15. Cationic liposomes as carriers for gene delivery: Physico-chemical ...

    African Journals Online (AJOL)

    The inter-correlations among the parameters that influence the transfection efficiency of liposome-DNA complexes (lipoplexes) as carriers in gene therapy, optimum procedures for transfection and mechanism of cell transfection were investigated. The morphology, size and ζ-potential of liposomes and lipoplexes were ...

  16. Recent advances in liposomal nanohybrid cerasomes as promising drug nanocarriers.

    Science.gov (United States)

    Yue, Xiuli; Dai, Zhifei

    2014-05-01

    Liposomes have been extensively investigated as possible carriers for diagnostic or therapeutic agents due to their unique properties. However, liposomes still have not attained their full potential as drug and gene delivery vehicles because of their insufficient morphological stability. Recently, a super-stable and freestanding hybrid liposomal cerasome (partially ceramic- or silica-coated liposome) has drawn much attention as a novel drug delivery system because its atomic layer of polyorganosiloxane surface imparts higher morphological stability than conventional liposomes and its liposomal bilayer structure reduces the overall rigidity and density greatly compared to silica nanoparticles. Cerasomes are more biocompatible than silica nanoparticles due to the incorporation of the liposomal architecture into cerasomes. Cerasomes combine the advantages of both liposomes and silica nanoparticles but overcome their disadvantages so cerasomes are ideal drug delivery systems. The present review will first highlights some of the key advances of the past decade in the technology of cerasome production and then review current biomedical applications of cerasomes, with a view to stimulating further research in this area of study. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Formulation of a New Generation of Liposomes from Bacterial and ...

    African Journals Online (AJOL)

    Purpose: To evaluate the application of bacterial liposomes and archaeosomes as a novel drug delivery system for in vitro cytoplasmic delivery of molecules into cancer cells. Methods: Bacterial membrane lipids were extracted using chloroform and methanol. Bacterial liposomes and archaeosomes of E. coli, Acidianus ...

  18. Enzyme-Responsive Liposomes for the Delivery of Anticancer Drugs.

    Science.gov (United States)

    Fouladi, Farnaz; Steffen, Kristine J; Mallik, Sanku

    2017-04-19

    Liposomes are nanocarriers that deliver the payloads at the target site, leading to therapeutic drug concentrations at the diseased site and reduced toxic effects in healthy tissues. Several approaches have been used to enhance the ability of the nanocarrier to target the specific tissues, including ligand-targeted liposomes and stimuli-responsive liposomes. Ligand-targeted liposomes exhibit higher uptake by the target tissue due to the targeting ligand attached to the surface, while the stimuli-responsive liposomes do not release their cargo unless they expose to an endogenous or exogenous stimulant at the target site. In this review, we mainly focus on the liposomes that are responsive to pathologically increased levels of enzymes at the target site. Enzyme-responsive liposomes release their cargo upon contact with the enzyme through several destabilization mechanisms: (1) structural perturbation in the lipid bilayer, (2) removal of a shielding polymer from the surface and increased cellular uptake, (3) cleavage of a lipopeptide or lipopolymer incorporated in the bilayer, and (4) activation of a prodrug in the liposomes.

  19. Vesicle-MaNiA: extracellular vesicles in liquid biopsy and cancer

    OpenAIRE

    Torrano, Veronica; Royo, Felix; Peinado, Héctor; Loizaga-Iriarte, Ana; Unda, Miguel; Falcón-Perez, Juan M.; Carracedo, Arkaitz

    2016-01-01

    Normal and tumor cells shed vesicles to the environment. Within the large family of extracellular vesicles, exosomes and microvesicles have attracted much attention in the recent years. Their interest ranges from mediators of cancer progression, inflammation, immune regulation and metastatic niche regulation, to non-invasive biomarkers of disease. In this respect, the procedures to purify and analyze extracellular vesicles have quickly evolved and represent a source of variability for data in...

  20. Presence of electrostatically adsorbed polysaccharides improves spray drying of liposomes.

    Science.gov (United States)

    Karadag, Ayse; Özçelik, Beraat; Sramek, Martin; Gibis, Monika; Kohlus, Reinhard; Weiss, Jochen

    2013-02-01

    Spray drying of liposomes with conventional wall materials such as maltodextrins often yields nonfunctional powders, that is, liposomes break down during drying and rehydration. Electrostatically coating the surface of liposomes with a charged polymer prior to spray drying may help solve this problem. Anionic lecithin liposomes (approximately 400 nm) were coated with lower (approximately 500 kDa, LMW-C) or higher (approximately 900 kDa, HMW-C) molecular weight cationic chitosan using the layer-by-layer depositing method. Low (DE20, LMW-MD) or high molecular weight (DE2, HMW-MD) maltodextrin was added as wall material to facilitate spray drying. If surfaces of liposomes (1%) were completely covered with chitosan (0.4%), no bridging or depletion flocculation would occur, and mean particle diameters would be approximately 500 nm. If maltodextrins (20%) were added to uncoated liposomes, extensive liposomal breakdown would occur making the system unsuitable for spray drying. No such aggregation or breakdown was observed when maltodextrin was added to chitosan-coated liposomes. Size changed little or even decreased slightly depending on the molecular weight of maltodextrin added. Scanning electron microscopy images of powders containing chitosan-coated liposomes revealed that their morphologies depended on the type of maltodextrin added. Powders prepared with LMW-MD contained mostly spherical particles while HMW-MD powders contained particles with concavities and dents. Upon redispersion, coated liposomes yielded back dispersions with particle size distributions similar to the original ones, except for LMW-C coated samples that had been spray dried with HMW-MD which yielded aggregates (approximately 30 μm). Results show that coating of liposomes with an absorbing polymer allows them to be spray dried with conventional maltodextrin wall materials. Liposomes have attracted considerable attention in the food and agricultural, biomedical industries for the delivery of

  1. Stability of Spherical Vesicles in Electric Fields

    Science.gov (United States)

    2010-01-01

    The stability of spherical vesicles in alternating (ac) electric fields is studied theoretically for asymmetric conductivity conditions across their membranes. The vesicle deformation is obtained from a balance between the curvature elastic energies and the work done by the Maxwell stresses. The present theory describes and clarifies the mechanisms for the four types of morphological transitions observed experimentally on vesicles exposed to ac fields in the frequency range from 500 to 2 × 107 Hz. The displacement currents across the membranes redirect the electric fields toward the membrane normal to accumulate electric charges by the Maxwell−Wagner mechanism. These accumulated electric charges provide the underlying molecular mechanism for the morphological transitions of vesicles as observed on the micrometer scale. PMID:20575588

  2. Kinetic regulation of coated vesicle secretion

    CERN Document Server

    Foret, Lionel

    2008-01-01

    The secretion of vesicles for intracellular transport often rely on the aggregation of specialized membrane-bound proteins into a coat able to curve cell membranes. The nucleation and growth of a protein coat is a kinetic process that competes with the energy-consuming turnover of coat components between the membrane and the cytosol. We propose a generic kinetic description of coat assembly and the formation of coated vesicles, and discuss its implication to the dynamics of COP vesicles that traffic within the Golgi and with the Endoplasmic Reticulum. We show that stationary coats of fixed area emerge from the competition between coat growth and the recycling of coat components, in a fashion resembling the treadmilling of cytoskeletal filaments. We further show that the turnover of coat components allows for a highly sensitive switching mechanism between a quiescent and a vesicle producing membrane, upon a slowing down of the exchange kinetics. We claim that the existence of this switching behaviour, also tri...

  3. The Treatment of Breast Cancer Using Liposome Technology

    Directory of Open Access Journals (Sweden)

    Sarah Brown

    2012-01-01

    Full Text Available Liposome-based chemotherapeutics used in the treatment of breast cancer can in principle enhance the therapeutic index of otherwise unencapsulated anticancer drugs. This is partially attributed to the fact that encapsulation of cytotoxic agents within liposomes allows for increased concentrations of the drug to be delivered to the tumor site. In addition, the presence of the phospholipid bilayer prevents the encapsulated active form of the drug from being broken down in the body prior to reaching tumor tissue and also serves to minimize exposure of the drug to healthy sensitive tissue. While clinically approved liposome-based chemotherapeutics such as Doxil have proven to be quite effective in the treatment of breast cancer, significant challenges remain involving poor drug transfer between the liposome and cancerous cells. In this review, we discuss the recent advancements made in the development of liposome-based chemotherapeutics with respect to improved drug transfer for use in breast cancer therapy.

  4. Recent Developments of Liposomes as Nanocarriers for Theranostic Applications.

    Science.gov (United States)

    Xing, Hang; Hwang, Kevin; Lu, Yi

    2016-01-01

    Liposomes are nanocarriers comprised of lipid bilayers encapsulating an aqueous core. The ability of liposomes to encapsulate a wide variety of diagnostic and therapeutic agents has led to significant interest in utilizing liposomes as nanocarriers for theranostic applications. In this review, we highlight recent progress in developing liposomes as nanocarriers for a) diagnostic applications to detect proteins, DNA, and small molecule targets using fluorescence, magnetic resonance, ultrasound, and nuclear imaging; b) therapeutic applications based on small molecule-based therapy, gene therapy and immunotherapy; and c) theranostic applications for simultaneous detection and treatment of heavy metal toxicity and cancers. In addition, we summarize recent studies towards understanding of interactions between liposomes and biological components. Finally, perspectives on future directions in advancing the field for clinical translations are also discussed.

  5. ["PEG dilemma" for liposomes and its solving approaches].

    Science.gov (United States)

    Zhang, Di; Xu, Huan; Hu, Mei-na; Deng, Yi-hui

    2015-03-01

    Polyethylene glycol (PEG) is extensively used to increasing the in vivo and in vitro stability of liposomes. However, PEGylated liposomes also produce some negative effects with further research, such as low cellular uptake, poor "endosomal escape" of pH sensitive liposome (PSL) and accelerated blood clearance (ABC) phenomenon, and this situation is referred as the "PEG dilemma". "PEG dilemma" posed severe challenges for the targeted delivery of PEGylated liposomes-loaded anticancer drugs, effective intracellular release of PEGylated PSL-encapsulated gene and protein drugs, and repeated administration of PEGylated liposomes. Therefore, it is urgent to solve the "PEG dilemma". This review focused on the definition, classification of "PEG dilemma", and discussed several possible approaches to overcome "PEG dilemma".

  6. Interactions of a Photochromic Spiropyran with Liposome Model Membranes

    KAUST Repository

    Jonsson, Fabian

    2013-02-19

    The interactions between anionic or zwitterionic liposomes and a water-soluble, DNA-binding photochromic spiropyran are studied using UV/vis absorption and linear dichroism (LD) spectroscopy. The spectral characteristics as well as the kinetics of the thermal isomerization process in the absence and presence of the two different liposome types provide information about the environment and whether or not the spiropyran resides in the liposome membrane. By measuring LD on liposomes deformed and aligned by shear flow, further insight is obtained about interaction and binding geometry of the spiropyran at the lipid membranes. We show that the membrane interactions differ between the two types of liposomes used as well as the isomeric forms of the spiropyran photoswitch. © 2013 American Chemical Society.

  7. Enhanced antitumor effect of novel dual-targeted paclitaxel liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Meng Shuyan; Su Bo; Li Wei; Ding Yongmei; Tang Liang; Zhou Wei; Song Yin; Li Heyan; Zhou Caicun, E-mail: caicunzhou@yahoo.com.cn [Cancer Institute of Tongji University School of Medicine, Shanghai Pulmonary Hospital, 507 Zhengmin Road, Shanghai (China)

    2010-10-15

    A novel dual-targeted peptide containing an alpha V integrins specific ligand and a neuropilin-1 specific motif was developed which showed an increased specific targeting affinity to tumors. Active dual-targeted liposomes were then produced with this peptide and exhibited greater binding activity than single-targeted liposomes in vitro. Paclitaxel entrapped in this formulation greatly increased the uptake of paclitaxel in the targeting cells and significantly suppressed the growth of HUVEC and A549 cells compared with general paclitaxel injections (Taxol) and single-targeted paclitaxel liposomes. The treatment of tumor xenograft models with dual-targeted paclitaxel liposomes also resulted in better tumor growth inhibition than any other treatment groups. Therefore, the dual-targeted paclitaxel liposomes prepared in the present study might be a more promising drug for cancer treatment. Furthermore, the dual-targeting approach may produce synergistic effects that can be applied in the development of new targeted drug delivery systems.

  8. Mutations in Synaptojanin Disrupt Synaptic Vesicle Recycling

    OpenAIRE

    Harris, Todd W.; Hartwieg, Erika; Horvitz, H. Robert; Jorgensen, Erik M.

    2000-01-01

    Synaptojanin is a polyphosphoinositide phosphatase that is found at synapses and binds to proteins implicated in endocytosis. For these reasons, it has been proposed that synaptojanin is involved in the recycling of synaptic vesicles. Here, we demonstrate that the unc-26 gene encodes the Caenorhabditis elegans ortholog of synaptojanin. unc-26 mutants exhibit defects in vesicle trafficking in several tissues, but most defects are found at synaptic termini. Specifically, we observed defects in ...

  9. Concentration-Independent Spontaneously Forming Biomimetric Vesicles

    Science.gov (United States)

    Nieh, M.-P.; Harroun, T. A.; Raghunathan, V. A.; Glinka, C. J.; Katsaras, J.

    2003-10-01

    In this Letter we present small-angle neutron scattering data from a biomimetic system composed of the phospholipids dimyristoyl and dihexanoyl phosphorylcholine (DMPC and DHPC, respectively). Doping DMPC-DHPC multilamellar vesicles with either the negatively charged lipid dimyristoyl phosphorylglycerol (DMPG, net charge -1) or the divalent cation, calcium (Ca2+), leads to the spontaneous formation of energetically stabilized monodisperse unilamellar vesicles whose radii are concentration independent and in contrast with previous experimental observations.

  10. Labeling Extracellular Vesicles for Nanoscale Flow Cytometry

    OpenAIRE

    Aizea Morales-Kastresana; Bill Telford; Musich, Thomas A.; Katherine McKinnon; Cassandra Clayborne; Zach Braig; Ari Rosner; Thorsten Demberg; Watson, Dionysios C.; Karpova, Tatiana S.; Freeman, Gordon J.; DeKruyff, Rosemarie H.; Pavlakis, George N.; Masaki Terabe; Marjorie Robert-Guroff

    2017-01-01

    Extracellular vesicles (EVs), including exosomes and microvesicles, are 30?800?nm vesicles that are released by most cell types, as biological packages for intercellular communication. Their importance in cancer and inflammation makes EVs and their cargo promising biomarkers of disease and cell-free therapeutic agents. Emerging high-resolution cytometric methods have created a pressing need for efficient fluorescent labeling procedures to visualize and detect EVs. Suitable labels must be brig...

  11. Formulation and in vitro characterization of protein-loaded liposomes

    Science.gov (United States)

    Kuzimski, Lauren

    Background/Objective: Protein-based drugs are increasingly used to treat a variety of conditions including cancer and cardio-vascular disease. Due to the immune system's innate ability to degrade the foreign particles quickly, protein-based treatments are generally short-lived. To address this limitation, the objective of the study was to: 1) develop protein-loaded liposomes; 2) characterize size, stability, encapsulation efficiency and rate of protein release; and 3) determine intracellular uptake and distribution; and 4) protein structural changes. Method: Liposomes were loaded with a fluorescent-albumin using freeze-thaw (F/T) methodology. Albumin encapsulation and release were quantified by fluorescence spectroscopic techniques. Flow cytometry was used to determine liposome uptake by macrophages. Epifluorescence microscopy was used to determine cellular distribution of liposomes. Stability was determined using dynamic light scattering by measuring liposome size over one month period. Protein structure was determined using circular dichroism (CD). Result: Encapsulation of albumin in liposome was ˜90% and was dependent on F/T rates, with fifteen cycles yielding the highest encapsulation efficacy (p < 0.05). Albumin-loaded liposomes demonstrated consistent size (<300nm). Release of encapsulated albumin in physiological buffer at 25°C was ˜60% in 72 h. Fluorescence imaging suggested an endosomal route of cellular entry for the FITC-albumin liposome with maximum uptake rates in immune cells (30% at 2hour incubation). CD suggested protein structure is minimally impacted by freeze-thaw methodology. Conclusion: Using F/T as a loading method, we were able to successfully achieve a protein-loaded liposome that was under 300nm, had encapsulation of ˜90%. Synthesized liposomes demonstrated a burst release of encapsulate protein (60%) at 72 hours. Cellular trafficking confirmed endosomal uptake, and minimal protein damage was noticed in CD.

  12. Liposomal dry powders as aerosols for pulmonary delivery of proteins.

    Science.gov (United States)

    Lu, Dongmei; Hickey, Anthony J

    2005-12-21

    The purpose of this research was to develop liposomal dry powder aerosols for protein delivery. The delivery of stable protein formulations is essential for protein subunit vaccine delivery, which requires local delivery to macrophages in the lungs. Beta-glucuronidase (GUS) was used as a model protein to evaluate dry powder liposomes as inhaled delivery vehicles. Dimyristoyl phosphatylcholine:cholesterol (7:3) was selected as the liposome composition. The lyophilization of liposomes, micronization of the powders, aerosolization using a dry powder inhaler (DPI), and in vitro aerodynamic fine particle fraction upon collection in a twin-stage liquid impinger were evaluated. After lyophilization and jet-milling, the total amount of GUS and its activity, representing encapsulation efficiency and stability, were evaluated. The GUS amount and activity were measured and compared with freshly-prepared liposomes in the presence of mannitol, 43% of initial GUS amount, 29% of GUS activity after lyophilization and 36% of GUS amount, 22% of activity after micronization were obtained. Emitted doses from dry powder inhaler were 53%, 58%, 66%, and 73% for liposome powder:mannitol carrier ratios of 1:0, 1:4, 1:9, and 1:19. Fifteen percent of the liposome particles were less than 6.4 mum in aerodynamic diameter. The results demonstrate that milled liposome powders containing protein molecules can be aerosolized effectively at a fixed flow rate. Influences of different cryoprotectants on lyophilization of protein liposome formulations are reported. The feasibility of using liposomal dry powder aerosols for protein delivery has been demonstrated but further optimization is required in the context of specific therapeutic proteins.

  13. Cellular Phenotype and Extracellular Vesicles: Basic and Clinical Considerations

    OpenAIRE

    Quesenberry, Peter J.; Goldberg, Laura R.; Aliotta, Jason M.; Mark S Dooner; Pereira, Mandy G.; Wen, Sicheng; Camussi, Giovanni

    2014-01-01

    Early work on platelet and erythrocyte vesicles interpreted the phenomena as a discard of material from cells. Subsequently, vesicles were studied as possible vaccines and, most recently, there has been a focus on the effects of vesicles on cell fate. Recent studies have indicated that extracellular vesicles, previously referred to as microvesicles or exosomes, have the capacity to change the phenotype of neighboring cells. Extensive work has shown that vesicles derived from either the lung o...

  14. Hierarchical unilamellar vesicles of controlled compositional heterogeneity.

    Directory of Open Access Journals (Sweden)

    Maik Hadorn

    Full Text Available Eukaryotic life contains hierarchical vesicular architectures (i.e. organelles that are crucial for material production and trafficking, information storage and access, as well as energy production. In order to perform specific tasks, these compartments differ among each other in their membrane composition and their internal cargo and also differ from the cell membrane and the cytosol. Man-made structures that reproduce this nested architecture not only offer a deeper understanding of the functionalities and evolution of organelle-bearing eukaryotic life but also allow the engineering of novel biomimetic technologies. Here, we show the newly developed vesicle-in-water-in-oil emulsion transfer preparation technique to result in giant unilamellar vesicles internally compartmentalized by unilamellar vesicles of different membrane composition and internal cargo, i.e. hierarchical unilamellar vesicles of controlled compositional heterogeneity. The compartmentalized giant unilamellar vesicles were subsequently isolated by a separation step exploiting the heterogeneity of the membrane composition and the encapsulated cargo. Due to the controlled, efficient, and technically straightforward character of the new preparation technique, this study allows the hierarchical fabrication of compartmentalized giant unilamellar vesicles of controlled compositional heterogeneity and will ease the development of eukaryotic cell mimics that resemble their natural templates as well as the fabrication of novel multi-agent drug delivery systems for combination therapies and complex artificial microreactors.

  15. Elastic energy of polyhedral bilayer vesicles.

    Science.gov (United States)

    Haselwandter, Christoph A; Phillips, Rob

    2011-06-01

    In recent experiments [M. Dubois, B. Demé, T. Gulik-Krzywicki, J.-C. Dedieu, C. Vautrin, S. Désert, E. Perez, and T. Zemb, Nature (London) 411, 672 (2001)] the spontaneous formation of hollow bilayer vesicles with polyhedral symmetry has been observed. On the basis of the experimental phenomenology it was suggested [M. Dubois, V. Lizunov, A. Meister, T. Gulik-Krzywicki, J. M. Verbavatz, E. Perez, J. Zimmerberg, and T. Zemb, Proc. Natl. Acad. Sci. USA 101, 15082 (2004)] that the mechanism for the formation of bilayer polyhedra is minimization of elastic bending energy. Motivated by these experiments, we study the elastic bending energy of polyhedral bilayer vesicles. In agreement with experiments, and provided that excess amphiphiles exhibiting spontaneous curvature are present in sufficient quantity, we find that polyhedral bilayer vesicles can indeed be energetically favorable compared to spherical bilayer vesicles. Consistent with experimental observations we also find that the bending energy associated with the vertices of bilayer polyhedra can be locally reduced through the formation of pores. However, the stabilization of polyhedral bilayer vesicles over spherical bilayer vesicles relies crucially on molecular segregation of excess amphiphiles along the ridges rather than the vertices of bilayer polyhedra. Furthermore, our analysis implies that, contrary to what has been suggested on the basis of experiments, the icosahedron does not minimize elastic bending energy among arbitrary polyhedral shapes and sizes. Instead, we find that, for large polyhedron sizes, the snub dodecahedron and the snub cube both have lower total bending energies than the icosahedron.

  16. Endothelial Extracellular Vesicles-Promises and Challenges.

    Science.gov (United States)

    Hromada, Carina; Mühleder, Severin; Grillari, Johannes; Redl, Heinz; Holnthoner, Wolfgang

    2017-01-01

    Extracellular vesicles, including exosomes, microparticles, and apoptotic bodies, are phospholipid bilayer-enclosed vesicles that have once been considered as cell debris lacking biological functions. However, they have recently gained immense interest in the scientific community due to their role in intercellular communication, immunity, tissue regeneration as well as in the onset, and progression of various pathologic conditions. Extracellular vesicles of endothelial origin have been found to play a versatile role in the human body, since they are on the one hand known to contribute to cardiovascular diseases, but on the other hand have also been reported to promote endothelial cell survival. Hence, endothelial extracellular vesicles hold promising therapeutic potential to be used as a new tool to detect as well as treat a great number of diseases. This calls for clinically approved, standardized, and efficient isolation and characterization protocols to harvest and purify endothelial extracellular vesicles. However, such methods and techniques to fulfill stringent requirements for clinical trials have yet to be developed or are not harmonized internationally. In this review, recent advances and challenges in the field of endothelial extracellular vesicle research are discussed and current problems and limitations regarding isolation and characterization are pointed out.

  17. Skin penetration and retention of L-ascorbic acid 2-phosphate using multilamellar vesicles.

    Science.gov (United States)

    Yoo, Juno; Shanmugam, Srinivasan; Song, Chung-Kil; Kim, Dae-Duk; Choi, Han-Gon; Yong, Chul-Soon; Woo, Jong-Soo; Yoo, Bong Kyu

    2008-12-01

    Transdermal formulation of L-ascorbic acid 2-phosphate magnesium salt (A2P) was prepared using multilamellar vesicles (MLV). A2P was either physically mixed with or entrapped into three different MLVs of neutral, cationic, and anionic liposome vesicles. For the preparation of neutral MLVs, phosphatidylcholine (PC) and cholesterol (CH) were used. For cationic and anionic MLVs, dioleoyl-trimethylammonium-propane and dimyristoyl glycerophosphate were added as surface charge inducers, respectively, in addition to PC and CH. Particle size of the three A2P-loaded MLVs was submicron, and polydispersity index revealed homogenous distribution of the prepared MLVs except neutral ones. Skin penetration study with hairless mouse skin showed that both physical mixtures of A2P with empty MLVs and A2P-loaded MLVs increased penetration of the drug compared to aqueous A2P solution. During the penetration, however, significant amount of the drug was metabolized into L-ascorbic acid, which has no beneficial effect on stimulation of hair growth. Out of the physical mixtures and A2P-loaded MLVs tested, physical mixture of A2P with empty cationic MLV resulted in the greatest skin penetration and retention in hairless mouse skin.

  18. Ethosomes as Vesicles for Effective Transdermal Delivery: From Bench to Clinical Implementation.

    Science.gov (United States)

    Akhtar, Nida; Varma, Anurag; Pathak, Kamla

    2016-01-01

    Drug delivery across the deeper layers of skin to make it systemically available is a considerable challenge in the development of a carrier. Numerous efforts have been put forward to find ways to overcome the formidable barrier of stratum corneum. Various lipid based vesicles viz liposomes, transfersomes, and invasomes have gained prominent deliberations across the globe. More recently, ethosomes have been investigated for their potential for transdermal delivery of several drugs. In the present review an attempt has been made to illustrate preclinical and clinical studies depicting enhanced safety and efficacy of drugs delivered via ethosomes. Further, patents on transdermal delivery have been highlighted specifying the effectiveness of ethosomes in the transport of therapeutic actives. Through the search engine "Scopus" literature on therapeutic categories such as antimicrobials, anti-inflammatory, and drugs acting on CNS has been collected. Preclinical and clinical studies that have been carried out by various researchers affirm the potentiality of ethosomes for delivering wide variety of drugs belonging to different therapeutic categories. In vitro and in vivo permeability analyses delineated the enhancement of permeability. Consequently, enhanced transdermal flux was reported and in vivo confocal laser scanning microscopy depicted the quantity as well as depth of penetrability via ethosomes. From various research reports, it can be concluded that ethosomes are the competent and efficient vesicles to provide better drug transport via transdermal route.

  19. Delivery of aerosolized drugs encapsulated in liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yung-Sung; Lyons, C.R. [Univ. of New Mexico, Albuquerque, NM (United States); Schmid, M.H.

    1995-12-01

    Mycobacterium tuberculosis (Mtb) is an infectious disease that resides in the human lung. Due to the difficulty in completely killing off the disease in infected individuals, Mtb has developed drug-resistant forms and is on the rise in the human population. Therefore, ITRI and the University of New Mexico are collaborating to explore the treatment of Mtb by an aerosolized drug delivered directly to the lungs. In conclusion, it is feasible to obtain an appropriate size and concentration of the liposomes before and after aerosolization.

  20. Advanced strategies in liposomal cancer therapy

    DEFF Research Database (Denmark)

    Andresen, Thomas Lars; Jensen, Simon Skøde; Jørgensen, Kent

    2005-01-01

    Tumor specific drug delivery has become increasingly interesting in cancer therapy, as the use of chemotherapeutics is often limited due to severe side effects. Conventional drug delivery systems have shown low efficiency and a continuous search for more advanced drug delivery principles......, none of them have yet led to marketed drugs and are still far from achieving this goal. The most advanced and prospective technologies are probably the prodrug strategies where nontoxic drugs are carried and activated specifically in the malignant tissue by overexpressed enzymes. In the second part...... by secretory phospholipase A2. We furthermore give examples of the biological performance of the enzymatically degradable liposomes as advanced drug delivery systems....

  1. A Liposome-Based Approach to the Integrated Multi-Component Antigen Microarrays

    OpenAIRE

    Denong Wang

    2015-01-01

    This report describes an experimental procedure for constructing integrated lipid, carbohydrate, and protein microarrays. In essence, it prints liposomes on nitrocellulose-coated micro-glass slides, a biochip substrate for spotting protein and carbohydrate microarrays, and the substances that can form liposomes (homo-liposomes) or can be incorporated into liposomes (hetero-liposomes) are suitable for microarray construction using existing microarray spotting devices. Importantly, this technol...

  2. Extracellular Vesicles in Metabolic Syndrome.

    Science.gov (United States)

    Martínez, M Carmen; Andriantsitohaina, Ramaroson

    2017-05-12

    Metabolic syndrome defines a cluster of interrelated risk factors for cardiovascular disease and diabetes mellitus. These factors include metabolic abnormalities, such as hyperglycemia, elevated triglyceride levels, low high-density lipoprotein cholesterol levels, high blood pressure, and obesity, mainly central adiposity. In this context, extracellular vesicles (EVs) may represent novel effectors that might help to elucidate disease-specific pathways in metabolic disease. Indeed, EVs (a terminology that encompasses microparticles, exosomes, and apoptotic bodies) are emerging as a novel mean of cell-to-cell communication in physiology and pathology because they represent a new way to convey fundamental information between cells. These microstructures contain proteins, lipids, and genetic information able to modify the phenotype and function of the target cells. EVs carry specific markers of the cell of origin that make possible monitoring their fluctuations in the circulation as potential biomarkers inasmuch their circulating levels are increased in metabolic syndrome patients. Because of the mixed components of EVs, the content or the number of EVs derived from distinct cells of origin, the mode of cell stimulation, and the ensuing mechanisms for their production, it is difficult to attribute specific functions as drivers or biomarkers of diseases. This review reports recent data of EVs from different origins, including endothelial, smooth muscle cells, macrophages, hepatocytes, adipocytes, skeletal muscle, and finally, those from microbiota as bioeffectors of message, leading to metabolic syndrome. Depicting the complexity of the mechanisms involved in their functions reinforce the hypothesis that EVs are valid biomarkers, and they represent targets that can be harnessed for innovative therapeutic approaches. © 2017 American Heart Association, Inc.

  3. Effect of Lipid Composition on In Vitro Release and Skin Deposition of Curcumin Encapsulated Liposomes

    Directory of Open Access Journals (Sweden)

    Geethi Pamunuwa

    2016-01-01

    Full Text Available Liposomal encapsulation improves numerous physiochemical and biological properties of curcumin. The aim of this work was to impart slow release and skin delivery of curcumin via liposomal encapsulation. Liposomes were made using egg yolk phosphatidylcholine as the staple lipid while incorporating polysorbate 80 and stearylamine to prepare hybrid liposomes and positively charged liposomes, respectively. Negatively charged liposomes exhibited the highest encapsulation efficiencies (87.8±4.3% and loading capacities (3.4±0.2%. The sizes of all formulations were about 250 nm, while stearylamine increased the polydispersity index. Positively charged liposomes showed lower degradation temperatures than negatively charged liposomes by 10–15°C, attributable to the presence of stearylamine. The melting temperatures of positively charged liposomes (40–50°C were much higher than those of negatively charged liposomes (14-15°C, which may have affected release and skin deposition behavior of liposomes. The positively charged liposomes exhibited the slowest release of curcumin in phosphate buffered saline (pH 6.8 and the release profiles of all liposomal formulations conformed to the Gompertz model. The negatively charged liposomes facilitated the highest skin deposition of curcumin as revealed by studies conducted using excised pig ear skin. Concisely, positively and negatively charged liposomes were optimal for slow release and skin deposition of curcumin, respectively.

  4. Multimodality imaging demonstrates trafficking of liposomes preferentially to ischemic myocardium.

    Science.gov (United States)

    Lipinski, Michael J; Albelda, M Teresa; Frias, Juan C; Anderson, Stasia A; Luger, Dror; Westman, Peter C; Escarcega, Ricardo O; Hellinga, David G; Waksman, Ron; Arai, Andrew E; Epstein, Stephen E

    2016-03-01

    Nanoparticles may serve as a promising means to deliver novel therapeutics to the myocardium following myocardial infarction. We sought to determine whether lipid-based liposomal nanoparticles can be shown through different imaging modalities to specifically target injured myocardium following intravenous injection in an ischemia-reperfusion murine myocardial infarction model. Mice underwent ischemia-reperfusion surgery and then either received tail-vein injection with gadolinium- and fluorescent-labeled liposomes or no injection (control). The hearts were harvested 24h later and underwent T1 and T2-weighted ex vivo imaging using a 7 Tesla Bruker magnet. The hearts were then sectioned for immunohistochemistry and optical fluorescent imaging. The mean size of the liposomes was 100nm. T1-weighted signal intensity was significantly increased in the ischemic vs. the non-ischemic myocardium for mice that received liposomes compared with control. Optical imaging demonstrated significant fluorescence within the infarct area for the liposome group compared with control (163±31% vs. 13±14%, p=0.001) and fluorescent microscopy confirmed the presence of liposomes within the ischemic myocardium. Liposomes traffic to the heart and preferentially home to regions of myocardial injury, enabling improved diagnosis of myocardial injury and could serve as a vehicle for drug delivery. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Formulation and Evaluation of Rifampicin Liposomes for Buccal Drug Delivery.

    Science.gov (United States)

    Lankalapalli, Srinivas; Tenneti, V S Vinai Kumar

    2016-01-01

    Drug delivery through liposomes offers several advantages, but still challenging to the researchers for the use of liposomes as carriers in drug delivery due to their poor physical stability, unpredictable drug encapsulation and systemic availability of the loaded drug. The present investigation was planned with an objective to prepare Rifampicin loaded liposomes by using response surface methodology of statistical 32 factorial design and further to formulate them into pastilles for deliver through buccal route thereby to enhance systemic absorption. Rifampicin liposomes were prepared by using different ratios of soya lecithin and cholesterol by solvent Injection method. These liposomes were characterized by using optical microscopy, Scanning Electron Microscopy (SEM) and evaluated for particle size, entrapment efficiency (EE), in vitro and ex vivo drug release. Main effects and interaction terms of the formulation variables were evaluated quantitatively using a mathematical statistical model approach showing that both independent variables have significant (P value membrane (P value: 0.0047) and percentage drug release through porcine buccal membrane (P value: 0.0019). The statistical factorial design of liposomal formulations fulfilled all the requirements of the target set and exhibited suitable values for the selected test parameters. Pastilles were prepared for liposomes using glycerol gelatin base and were found to be soft, smooth with uniform drug content and drug release.

  6. Development of liposomal salbutamol sulfate dry powder inhaler formulation.

    Science.gov (United States)

    Huang, Wen-Hua; Yang, Zhi-Jun; Wu, Heng; Wong, Yuen-Fan; Zhao, Zhong-Zhen; Liu, Liang

    2010-01-01

    The purpose of our study was to develop a formulation of liposomal salbutamol sulfate (SBS) dry powder inhaler (DPI) for the treatment of asthma. Liposomes of high encapsulation efficiency (more than 80%) were prepared by a vesicular phospholipid gel (VPG) technique. SBS VPG liposomes were subjected to lyophilization using different kinds of cryoprotectants in various mass ratios. Coarse lactose (63-106 microm) in different mass ratios was used as a carrier. Magnesium stearate (0.5%) was added as a lubricator. The dry liposomal powders were then crushed by ball milling and sieved through a 400-mesh sieve to control the mean particle size at about 10 microm. The effects of different kinds of cryoprotectants and the amount of lactose carrier on the fine particle fraction (FPF) of SBS were investigated. The results showed that the developed formulation of liposomal dry powder inhaler was obtained using lactose as a cryoprotectant with a mass ratio of lyophilized powder to carrier lactose at 1 : 5; 0.5% magnesium stearate was used as a lubricator. The value of FPF for SBS was 41.51+/-2.22% for this formulation. Sustained release of SBS from the VPG liposomes was found in the in vitro release study. The study results offer the promising possibility of localized pulmonary liposomal SBS delivery in the anhydrous state.

  7. Multimodality imaging demonstrates trafficking of liposomes preferentially to ischemic myocardium

    Energy Technology Data Exchange (ETDEWEB)

    Lipinski, Michael J., E-mail: mjlipinski12@gmail.com [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States); Albelda, M. Teresa [GIBI2" 3" 0, Grupo de Investigación Biomédica en Imagen, IIS La Fe, Valencia (Spain); Frias, Juan C. [Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, Valencia (Spain); Anderson, Stasia A. [Advanced Cardiovascular Imaging Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Luger, Dror; Westman, Peter C.; Escarcega, Ricardo O.; Hellinga, David G.; Waksman, Ron [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States); Arai, Andrew E. [Advanced Cardiovascular Imaging Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Epstein, Stephen E. [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States)

    2016-03-15

    Introduction: Nanoparticles may serve as a promising means to deliver novel therapeutics to the myocardium following myocardial infarction. We sought to determine whether lipid-based liposomal nanoparticles can be shown through different imaging modalities to specifically target injured myocardium following intravenous injection in an ischemia–reperfusion murine myocardial infarction model. Methods: Mice underwent ischemia–reperfusion surgery and then either received tail-vein injection with gadolinium- and fluorescent-labeled liposomes or no injection (control). The hearts were harvested 24 h later and underwent T1 and T2-weighted ex vivo imaging using a 7 Tesla Bruker magnet. The hearts were then sectioned for immunohistochemistry and optical fluorescent imaging. Results: The mean size of the liposomes was 100 nm. T1-weighted signal intensity was significantly increased in the ischemic vs. the non-ischemic myocardium for mice that received liposomes compared with control. Optical imaging demonstrated significant fluorescence within the infarct area for the liposome group compared with control (163 ± 31% vs. 13 ± 14%, p = 0.001) and fluorescent microscopy confirmed the presence of liposomes within the ischemic myocardium. Conclusions: Liposomes traffic to the heart and preferentially home to regions of myocardial injury, enabling improved diagnosis of myocardial injury and could serve as a vehicle for drug delivery.

  8. Evaluation the influence of Polyethylene glycol in circulation and biodistribution of pH-sensitive liposomes, radiolabeled with Technetium 99m in experimental models; Avaliacao da influencia do polietilenoglicol na circulacao e biodistribuicao de lipossomas pH-sensiveis, radiomarcados com Tecnecio 99m em modelos experimentais

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Shirleide Santos

    2016-07-01

    Liposomes are lipid vesicles widely studied throughout the world as nanocarriers for different substances. The hydrophilic polymer polyethylene glycol (PEG) might be added onto the surface of liposomes to prolong the circulation time by reducing the opsonization of the vesicles, leading to a reduced uptake by the mononuclear phagocyte system (MPS). Several studies claim that the molecular weight of the PEG, as well as combination of different types of PEG with different molecular weights may alter the pharmacokinetics of the liposome. Therefore, the purpose of this study was to evaluate the influence of molecular weight and PEG combinations with different chain sizes in the pharmacokinetics and biodistribution of pH-sensitive liposomes containing {sup 99m}Tc-HYNIC-βAla-Bombesin complex (7-14 ) in tumor models (4T1 and Ehrlich). Eight liposomal formulations were prepared, the results showed that the liposomes exhibited adequate chemical and physical-chemical properties, such as mean diameter less than 300nm, monodisperse populations, neutral zeta potential, and encapsulation content of 26.4 to 38.7%. The images obtained by transmission electron cryomicroscopy (cryo-TEM) allowed visualization of unilamellar vesicles with an average diameter of 90 nm. There was no difference in blood half-life (T1/2), thereby for the composition of liposomes used in this study, PEG did not increase blood circulation time. Biodistribution studies and scintigraphic images showed high uptake by organs of the SMF, liver and spleen. The PEG2000 formulation showed higher concentration in blood. Liposomes with DSPE, PEG2000 or PEG1000 / 5000 showed higher uptake in the tumor compared to the contralateral muscle, but there was no statistical difference between the formulations when tumor-to-muscle ratio, obtained in the biodistribution studies or scintigraphic images, was analyzed. The results suggest that for this specific formulation, the addition of PEG was not efficient for increasing

  9. A two phase field model for tracking vesicle-vesicle adhesion.

    Science.gov (United States)

    Gu, Rui; Wang, Xiaoqiang; Gunzburger, Max

    2016-11-01

    A multi-phase-field model for simulating the adhesion between two vesicles is constructed. Two phase field functions are introduced to simulate each of the two vesicles. An energy model is defined which accounts for the elastic bending energy of each vesicle and the contact potential energy between the two vesicles; the vesicle volume and surface area constraints are imposed using a penalty method. Numerical results are provided to verify the efficacy of our model and to provide visual illustrations of the different types of contact. The method can be adjusted to solve endocytosis problems by modifying the bending rigidity coefficients of the two elastic bending energies. The method can also be extended to simulate multi-cell adhesions, one example of which is erythrocyte rouleaux. A comparison with laboratory observations demonstrates the effectiveness of the multi-phase field approach.

  10. Insights into the self-reproduction of oleate vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Stano, P [' Enrico Fermi' Centre, Compendio Viminale, 00184 Rome (Italy); Wehrli, E [Electron Microscopy Centre (EMEZ), Applied Physics Institute, ETH Hoenggerberg, 8093 Zurich (Switzerland); Luisi, P L [Biology Department, University of RomaTre, Viale Marconi 446, 00146 Rome (Italy)

    2006-08-23

    In view of the importance of vesicles as models for early cells, several groups have started work looking for conditions under which vesicles can undergo growth and division. Evidence for growth and division has been obtained with the help of ferritin-labelled vesicles; furthermore, it has been shown that in such processes the vesicle size distribution is largely conserved. In both cases, the data suggest that the process under study is mainly characterized by vesicle growth and eventually division into daughter vesicles. However, direct evidence for vesicle division has not been obtained. In this paper, mostly based on freeze-fracture electron microscopy, we describe conditions under which for the first time division intermediates can be trapped in the form of twin vesicles. This finding, together with supporting dynamic light scattering and fluorescence investigations, permits us to establish some additional points in the mechanism of vesicle self-reproduction.

  11. Mucosal Vaccine Development Based on Liposome Technology.

    Science.gov (United States)

    Bernasconi, Valentina; Norling, Karin; Bally, Marta; Höök, Fredrik; Lycke, Nils Y

    2016-01-01

    Immune protection against infectious diseases is most effective if located at the portal of entry of the pathogen. Hence, there is an increasing demand for vaccine formulations that can induce strong protective immunity following oral, respiratory, or genital tract administration. At present, only few mucosal vaccines are found on the market, but recent technological advancements and a better understanding of the principles that govern priming of mucosal immune responses have contributed to a more optimistic view on the future of mucosal vaccines. Compared to live attenuated vaccines, subcomponent vaccines, most often protein-based, are considered safer, more stable, and less complicated to manufacture, but they require the addition of nontoxic and clinically safe adjuvants to be effective. In addition, another limiting factor is the large antigen dose that usually is required for mucosal vaccines. Therefore, the combination of mucosal adjuvants with the recent progress in nanoparticle technology provides an attractive solution to these problems. In particular, the liposome technology is ideal for combining protein antigen and adjuvant into an effective mucosal vaccine. Here, we describe and discuss recent progress in nanoparticle formulations using various types of liposomes that convey strong promise for the successful development of the next generation of mucosal vaccines.

  12. RGD-TPGS decorated theranostic liposomes for brain targeted delivery.

    Science.gov (United States)

    Sonali; Singh, Rahul Pratap; Sharma, Gunjan; Kumari, Lakshmi; Koch, Biplob; Singh, Sanjay; Bharti, Shreekant; Rajinikanth, Paruvathanahalli Siddalingam; Pandey, Bajarangprasad L; Muthu, Madaswamy S

    2016-11-01

    The aim of this work was to formulate RGD-TPGS decorated theranostic liposomes, which contain both docetaxel (DTX) and quantum dots (QDs) for brain cancer imaging and therapy. RGD conjugated TPGS (RGD-TPGS) was synthesized and conjugation was confirmed by Fourier transform infrared (FTIR) spectroscopy and electrospray ionisation (ESI) mass spectroscopy (ESI-MS). The theranostic liposomes were prepared by the solvent injection method and characterized for their particle size, polydispersity, zeta-potential, surface morphology, drug encapsulation efficiency, and in-vitro release study. Biocompatibility and safety of theranostic liposomes were studied by reactive oxygen species (ROS) generation study and histopathology of brain. In-vivo study was performed for determination of brain theranostic effects in comparison with marketed formulation (Docel™) and free QDs. The particle sizes of the non-targeted and targeted theranostic liposomes were found in between 100 and 200nm. About 70% of drug encapsulation efficiency was achieved with liposomes. The drug release from RGD-TPGS decorated liposomes was sustained for more than 72h with 80% of drug release. The in-vivo results demonstrated that RGD-TPGS decorated theranostic liposomes were 6.47- and 6.98-fold more effective than Docel™ after 2h and 4h treatments, respectively. Further, RGD-TPGS decorated theranostic liposomes has reduced ROS generation effectively, and did not show any signs of brain damage or edema in brain histopathology. The results of this study have indicated that RGD-TPGS decorated theranostic liposomes are promising carrier for brain theranostics. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Properties of hybrid complexes composed of photosynthetic reaction centers from the purple bacterium Rhodobacter sphaeroides and quantum dots in lecithin liposomes.

    Science.gov (United States)

    Zagidullin, V E; Lukashev, E P; Knox, P P; Seifullina, N Kh; Sokolova, O S; Pechnikova, E V; Lokstein, H; Paschenko, V Z

    2014-11-01

    Quantum dots (QDs) can absorb ultraviolet and long-wavelength light energy much more efficiently than natural light-harvesting proteins and transfer the excitation energy to photosynthetic reaction centers (RCs). Inclusion into liposomes of RC membrane pigment-protein complexes combined with QDs as antennae opens new opportunities for using such hybrid systems as a basis for artificial energy-transforming devices that potentially can operate with greater efficiency and stability than devices based only on biological components. RCs from Rhodobacter sphaeroides and QDs with fluorescence maximum at 530 nm (CdSe/ZnS with hydrophilic covering) were embedded in lecithin liposomes by extrusion of a solution of multilayer lipid vesicles through a polycarbonate membrane or by dialysis of lipids and proteins dispersed with excess detergent. The dimensions of the resulting hybrid systems were evaluated using dynamic light scattering and by transmission cryoelectron microscopy. The efficiency of RC and QD interaction within the liposomes was estimated using fluorescence excitation spectra of the photoactive bacteriochlorophyll of the RCs and by measuring the fluorescence decay kinetics of the QDs. The functional activity of the RCs in hybrid complexes was fully maintained, and their stability was even increased.

  14. Carbopol-lectin conjugate coated liposomes for oral peptide delivery.

    Science.gov (United States)

    Werle, Martin; Makhlof, Abdallah; Takeuchi, Hirofumi

    2010-03-01

    Within the current study, a delivery system based on a novel polymer-lectin conjugate (carbopol-lectin) was evaluated for the oral delivery of therapeutic peptides and proteins. It was demonstrated that covalent attachment of lectin to carbopol does neither decrease nor abolish the specific binding properties of lectin. Bioadhesion studies revealed that liposomes coated with carbopol lectin are more bioadhesive than liposomes coated with unmodified carbopol. Finally, the in vivo data suggest that carbopol-lectin conjugate coated liposomes are effective oral peptide delivery systems which are capable of increasing the pharmacological effect of orally administered calcitonin.

  15. Mechanics of post-fusion exocytotic vesicle.

    Science.gov (United States)

    Stephens, Thomas; Wu, Zhanghan; Liu, Jian

    2017-05-23

    Exocytosis is an important cellular process controlled by metabolic signaling. It involves vesicle fusion to the plasma membrane, followed by the opening of a fusion pore, and the subsequent release of the vesicular lumen content into the extracellular space. While most modeling efforts focus on the events leading to membrane fusion, how the vesicular membrane remodels after fusing to plasma membrane remains unclear. This latter event dictates the nature and the efficiency of exocytotic vesicular secretions, and is thus critical for exocytotic function. We provide a generic membrane mechanical model to systematically study the fate of post-fusion vesicles. We show that while membrane stiffness favors full-collapse vesicle fusion into the plasma membrane, the intravesicular pressure swells the vesicle and causes the fusion pore to shrink. Dimensions of the vesicle and its associated fusion pore further modulate this mechanical antagonism. We systematically define the mechanical conditions that account for the full spectrum of the observed vesicular secretion modes. Our model therefore can serve as a unified theoretical framework that sheds light on the elaborate control mechanism of exocytosis.

  16. Astrocytic Vesicle Mobility in Health and Disease

    Directory of Open Access Journals (Sweden)

    Robert Zorec

    2013-05-01

    Full Text Available Astrocytes are no longer considered subservient to neurons, and are, instead, now understood to play an active role in brain signaling. The intercellular communication of astrocytes with neurons and other non-neuronal cells involves the exchange of molecules by exocytotic and endocytotic processes through the trafficking of intracellular vesicles. Recent studies of single vesicle mobility in astrocytes have prompted new views of how astrocytes contribute to information processing in nervous tissue. Here, we review the trafficking of several types of membrane-bound vesicles that are specifically involved in the processes of (i intercellular communication by gliotransmitters (glutamate, adenosine 5'-triphosphate, atrial natriuretic peptide, (ii plasma membrane exchange of transporters and receptors (EAAT2, MHC-II, and (iii the involvement of vesicle mobility carrying aquaporins (AQP4 in water homeostasis. The properties of vesicle traffic in astrocytes are discussed in respect to networking with neighboring cells in physiologic and pathologic conditions, such as amyotrophic lateral sclerosis, multiple sclerosis, and states in which astrocytes contribute to neuroinflammatory conditions.

  17. Mechanics of post-fusion exocytotic vesicle

    Science.gov (United States)

    Stephens, Thomas; Wu, Zhanghan; Liu, Jian

    2017-06-01

    Exocytosis is an important cellular process controlled by metabolic signaling. It involves vesicle fusion to the plasma membrane, followed by the opening of a fusion pore, and the subsequent release of the vesicular lumen content into the extracellular space. While most modeling efforts focus on the events leading to membrane fusion, how the vesicular membrane remodels after fusing to plasma membrane remains unclear. This latter event dictates the nature and the efficiency of exocytotic vesicular secretions, and is thus critical for exocytotic function. We provide a generic membrane mechanical model to systematically study the fate of post-fusion vesicles. We show that while membrane stiffness favors full-collapse vesicle fusion into the plasma membrane, the intravesicular pressure swells the vesicle and causes the fusion pore to shrink. Dimensions of the vesicle and its associated fusion pore further modulate this mechanical antagonism. We systematically define the mechanical conditions that account for the full spectrum of the observed vesicular secretion modes. Our model therefore can serve as a unified theoretical framework that sheds light on the elaborate control mechanism of exocytosis.

  18. EXTRACELLULAR VESICLES: CLASSIFICATION, FUNCTIONS AND CLINICAL RELEVANCE

    Directory of Open Access Journals (Sweden)

    A. V. Oberemko

    2014-12-01

    Full Text Available This review presents a generalized definition of vesicles as bilayer extracellular organelles of all celular forms of life: not only eu-, but also prokaryotic. The structure and composition of extracellular vesicles, history of research, nomenclature, their impact on life processes in health and disease are discussed. Moreover, vesicles may be useful as clinical instruments for biomarkers, and they are promising as biotechnological drug. However, many questions in this area are still unresolved and need to be addressed in the future. The most interesting from the point of view of practical health care represents a direction to study the effect of exosomes and microvesicles in the development and progression of a particular disease, the possibility of adjusting the pathological process by means of extracellular vesicles of a particular type, acting as an active ingredient. Relevant is the further elucidation of the role and importance of exosomes to the surrounding cells, tissues and organs at the molecular level, the prospects for the use of non-cellular vesicles as biomarkers of disease.

  19. Purple-bacterial photosynthetic reaction centers and quantum-dot hybrid-assemblies in lecithin liposomes and thin films.

    Science.gov (United States)

    Lukashev, Eugeny P; Knox, Petr P; Gorokhov, Vladimir V; Grishanova, Nadezda P; Seifullina, Nuranija Kh; Krikunova, Maria; Lokstein, Heiko; Paschenko, Vladimir Z

    2016-11-01

    Quantum dots (QDs) absorb ultraviolet and long-wavelength visible light energy much more efficiently than natural bacterial light-harvesting proteins and can transfer the excitation energy to photosynthetic reaction centers (RCs). Inclusion of RCs combined with QDs as antennae into liposomes opens new opportunities for using such hybrid systems as a basis for artificial energy-transforming devices that potentially can operate with greater efficiency and stability than devices based only on biological components or inorganic components alone. RCs from Rhodobacter sphaeroides and QDs (CdSe/ZnS with hydrophilic covering) were embedded in lecithin liposomes by extrusion of a solution of multilayer lipid vesicles through a polycarbonate membrane or by dialysis of lipids and proteins dispersed with excess detergent. The efficiency of RC and QD interaction within the liposomes was estimated using fluorescence excitation spectra of the photoactive bacteriochlorophyll of the RCs and by measuring the fluorescence decay kinetics of the QDs. The functional activity of the RCs in hybrid complexes was fully maintained, and their stability was even increased. The efficiency of energy transfer between QDs and RCs and conditions of long-term stability of function of such hybrid complexes in film preparations were investigated as well. It was found that dry films containing RCs and QDs, maintained at atmospheric humidity, are capable of maintaining their functional activity for at least some months as judged by measurements of their spectral characteristics, efficiency of energy transfer from QDs to RCs and RC electron transport activity. Addition of trehalose to the films increases the stability further, especially for films maintained at low humidity. These stable hybrid film structures are promising for further studies towards developing new phototransformation devices for biotechnological applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Meta-analysis of inter-patient pharmacokinetic variability of liposomal and non-liposomal anticancer agents

    Science.gov (United States)

    Schell, Ryan F.; Sidone, Brian J.; Caron, Whitney P.; Walsh, Mark D.; Zamboni, Beth A.; Ramanathan, Ramesh K.; Zamboni, William C.

    2013-01-01

    Purpose A meta-analysis was conducted to evaluate the inter-patient pharmacokinetic (PK) variability of liposomal and small molecule (SM) anticancer agents. Methods Inter-patient PK variability of 9 liposomal and SM formulations of the same drug were evaluated. PK variability was measured as coefficient of variance (CV%) of area under the plasma concentration versus time curve (AUC) and the fold-difference between AUCmax and AUCmin (AUC range). Results CV% of AUC and AUC ranges were 2.7-fold (P<0.001) and 16.7-fold (P=0.13) greater, respectively, for liposomal compared with SM drugs. There was an inverse linear relationship between the clearance (CL) of liposomal agents and PK variability with a lower CL associated with greater PK variability (R2 = 0.39). PK variability of liposomal agents was greater when evaluated from 0–336 h compared with 0–24 h. Conclusion PK variability of liposomes is significantly greater than SM. The factors associated with the PK variability of liposomal agents needs to be evaluated. PMID:23891988

  1. Functionally polymerized surfactant vesicles: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Tundo, P.; Kippenberger, D.J.; Klahn, P.L.; Prieto, N.E.; Fendler, J.H.

    1982-01-27

    Bis(2-(10-undecenoyloxycarbony bromide, bis(2-(10-undecenoyloxycarbony (2-hydroxyethyl)methylammonium bromide, bis(2-(10-undecenoyloxycarbony acid, bis(2-(10-undecenoyloxycarbony allylbis(2-dodecanoyloxycarbon bromide, and dimethyl-n-hexadecyl (10-(p-vin decyl)ammonium bromide have been synthesized. The predominantly single compartment bilayer vesicles formed from these surfactants could be polymerized either by exposure to ultraviolet irradiation or by the use of azoisobutyronitrile as an initiator. The presence of vesicles (unpolymerized and polymeric) has been demonstrated by electron micrography, H/sup 1/ NMR, gel filtration, phase transition, turbidity changes, substrate entrapment, and permeability. Polymerized vesicles are considerably more stable and less permeable and have reduced rates of turbidity changes compared to their unpolymerized counterparts. 19 references.

  2. Directed vesicle transport by diffusio-osmosis

    Science.gov (United States)

    Michler, D.; Shahidzadeh, N.; Sprik, R.; Bonn, D.

    2015-04-01

    We present a study on surfactant vesicles that spontaneously move towards an oil droplet that is deposited on a glass substrate. Tracer particles in the surfactant solution show that the motion is not self-propelled: the vesicles are entrained by a macroscopic hydrodynamic flow. Measurements of the flow velocity suggest that the flow is of diffusio-osmotic nature. The surfactant is observed to move into the oil phase which creates a gradient in ion concentration in the vicinity of the droplet. As the diffusion coefficients of the surfactant's co- and counter-ions differ, a charge separation takes place and an electric field arises. This electric field then generates a hydrodynamic flow along the charged glass substrate in which the vesicles are entrained.

  3. Functionalization of Block Copolymer Vesicle Surfaces

    Directory of Open Access Journals (Sweden)

    Wolfgang Meier

    2011-01-01

    Full Text Available In dilute aqueous solutions certain amphiphilic block copolymers self-assemble into vesicles that enclose a small pool of water with a membrane. Such polymersomes have promising applications ranging from targeted drug-delivery devices, to biosensors, and nanoreactors. Interactions between block copolymer membranes and their surroundings are important factors that determine their potential biomedical applications. Such interactions are influenced predominantly by the membrane surface. We review methods to functionalize block copolymer vesicle surfaces by chemical means with ligands such as antibodies, adhesion moieties, enzymes, carbohydrates and fluorophores. Furthermore, surface-functionalization can be achieved by self-assembly of polymers that carry ligands at their chain ends or in their hydrophilic blocks. While this review focuses on the strategies to functionalize vesicle surfaces, the applications realized by, and envisioned for, such functional polymersomes are also highlighted.

  4. Potential effect of cationic liposomes on interactions with oral bacterial cells and biofilms.

    Science.gov (United States)

    Sugano, Marika; Morisaki, Hirobumi; Negishi, Yoichi; Endo-Takahashi, Yoko; Kuwata, Hirotaka; Miyazaki, Takashi; Yamamoto, Matsuo

    2016-01-01

    Although oral infectious diseases have been attributed to bacteria, drug treatments remain ineffective because bacteria and their products exist as biofilms. Cationic liposomes have been suggested to electrostatically interact with the negative charge on the bacterial surface, thereby improving the effects of conventional drug therapies. However, the electrostatic interaction between oral bacteria and cationic liposomes has not yet been examined in detail. The aim of the present study was to examine the behavior of cationic liposomes and Streptococcus mutans in planktonic cells and biofilms. Liposomes with or without cationic lipid were prepared using a reverse-phase evaporation method. The zeta potentials of conventional liposomes (without cationic lipid) and cationic liposomes were -13 and 8 mV, respectively, and both had a mean particle size of approximately 180 nm. We first assessed the interaction between liposomes and planktonic bacterial cells with a flow cytometer. We then used a surface plasmon resonance method to examine the binding of liposomes to biofilms. We confirmed the binding behavior of liposomes with biofilms using confocal laser scanning microscopy. The interactions between cationic liposomes and S. mutans cells and biofilms were stronger than those of conventional liposomes. Microscopic observations revealed that many cationic liposomes interacted with the bacterial mass and penetrated the deep layers of biofilms. In this study, we demonstrated that cationic liposomes had higher affinity not only to oral bacterial cells, but also biofilms than conventional liposomes. This electrostatic interaction may be useful as a potential drug delivery system to biofilms.

  5. Flow Cytometric Analysis to Evaluate Morphological Changes in Giant Liposomes as Observed in Electrofusion Experiments.

    Science.gov (United States)

    Sunami, Takeshi; Shimada, Kunihiro; Tsuji, Gakushi; Fujii, Satoshi

    2017-12-07

    Liposome fusion is a way of supplying additional components for in-liposome biochemical reactions. Electrofusion is a method that does not require the addition of fusogens, which often alter the liposome dispersion, and is therefore useful for repetitive liposome fusion. However, the details of electrofusion have not been elucidated because of the limitations surrounding observing liposomes using a microscope. Therefore, we introduced fluorescent markers and high-throughput flow cytometry to analyze the morphological changes that occur in liposome electrofusion. i) The content mixing was evaluated by a calcein-Co2+-EDTA system, in which green fluorescence from dequenched free calcein is detected when the quenched calcein-Co2+ complex and EDTA are mixed together. ii) Liposome destruction was evaluated from the decrease in the total membrane volume of giant liposomes. iii) Liposome fission was evaluated from the increase in the number of giant liposomes. By applying the flow cytometric analysis, we investigated the effect of three parameters (DC pulses, AC field, and lipid composition) on liposome electrofusion. The larger numbers or higher voltages of DC pulses induced liposome fusion and destruction with higher probability. The longer application time of the AC field induced liposome fusion, fission, and destruction with higher probability. Higher content of negatively charged POPG (≥19%) strongly inhibited liposome electrofusion.

  6. Electrohydrodynamics of a compound vesicle under an AC electric field.

    Science.gov (United States)

    Sinha, Kumari Priti; Thaokar, Rochish M

    2017-07-12

    Compound vesicles are relevant as simplified models for biological cells as well as in technological applications such as drug delivery. Characterization of these compound vesicles, especially the inner vesicle, remains a challenge. Similarly their response to electric field assumes importance in light of biomedical applications such as electroporation. Fields lower than that required for electroporation cause electrodeformation in vesicles and can be used to characterize their mechanical and electrical properties. A theoretical analysis of the electrohydrodynamics of a compound vesicle with outer vesicle of radius R o and an inner vesicle of radius [Formula: see text], is presented. A phase diagram for the compound vesicle is presented and elucidated using detailed plots of electric fields, free charges and electric stresses. The electrohydrodynamics of the outer vesicle in a compound vesicle shows a prolate-sphere and prolate-oblate-sphere shape transitions when the conductivity of the annular fluid is greater than the outer fluid, and vice-versa respectively, akin to single vesicle electrohydrodynamics reported in the literature. The inner vesicle in contrast shows sphere-prolate-sphere and sphere-prolate-oblate-sphere transitions when the inner fluid conductivity is greater and smaller than the annular fluid, respectively. Equations and methodology are provided to determine the bending modulus and capacitance of the outer as well as the inner membrane, thereby providing an easy way to characterize compound vesicles and possibly biological cells.

  7. Electrohydrodynamics of a compound vesicle under an AC electric field

    Science.gov (United States)

    Priti Sinha, Kumari; Thaokar, Rochish M.

    2017-07-01

    Compound vesicles are relevant as simplified models for biological cells as well as in technological applications such as drug delivery. Characterization of these compound vesicles, especially the inner vesicle, remains a challenge. Similarly their response to electric field assumes importance in light of biomedical applications such as electroporation. Fields lower than that required for electroporation cause electrodeformation in vesicles and can be used to characterize their mechanical and electrical properties. A theoretical analysis of the electrohydrodynamics of a compound vesicle with outer vesicle of radius R o and an inner vesicle of radius λ {{R}o} , is presented. A phase diagram for the compound vesicle is presented and elucidated using detailed plots of electric fields, free charges and electric stresses. The electrohydrodynamics of the outer vesicle in a compound vesicle shows a prolate-sphere and prolate-oblate-sphere shape transitions when the conductivity of the annular fluid is greater than the outer fluid, and vice-versa respectively, akin to single vesicle electrohydrodynamics reported in the literature. The inner vesicle in contrast shows sphere-prolate-sphere and sphere-prolate-oblate-sphere transitions when the inner fluid conductivity is greater and smaller than the annular fluid, respectively. Equations and methodology are provided to determine the bending modulus and capacitance of the outer as well as the inner membrane, thereby providing an easy way to characterize compound vesicles and possibly biological cells.

  8. Formation of drug nanocrystals under nanoconfinement afforded by liposomes

    DEFF Research Database (Denmark)

    Cipolla, D.; Wu, H.; Salentinig, Stefan

    2016-01-01

    Nanocrystals of drug substances have important therapeutic applications, but their preparation is often difficult due to size control in bottom up approaches, or energetic milling and surface activation in top down processing. In this study, confinement within liposome nanocompartments...

  9. Liposomal prednisolone promotes macrophage lipotoxicity in experimental atherosclerosis

    NARCIS (Netherlands)

    van der Valk, Fleur M; Schulte, Dominik M; Meiler, Svenja; Tang, Jun; Zheng, Kang He; Van den Bossche, Jan; Seijkens, Tom; Laudes, Matthias; de Winther, Menno; Lutgens, Esther; Alaarg, Amr|info:eu-repo/dai/nl/370549465; Metselaar, Josbert M|info:eu-repo/dai/nl/244207690; Dallinga-Thie, Geesje M; Mulder, Willem J M; Stroes, Erik S G; Hamers, Anouk A J

    2016-01-01

    Atherosclerosis is a lipid-driven inflammatory disease, for which nanomedicinal interventions are under evaluation. Previously, we showed that liposomal nanoparticles loaded with prednisolone (LN-PLP) accumulated in plaque macrophages, however, induced proatherogenic effects in patients. Here, we

  10. Liposome surface charge influence on skin penetration behaviour.

    Science.gov (United States)

    Gillet, A; Compère, P; Lecomte, F; Hubert, P; Ducat, E; Evrard, B; Piel, G

    2011-06-15

    Vesicular systems have shown their ability to increase dermal and transdermal drug delivery. Their mechanism of drug transport into and through the skin has been investigated but remains a much debated question. Several researchers have outlined that drug penetration can be influenced by modifying the surface charge of liposomes. In the present work we study the influence of particle surface charge on skin penetration. The final purpose is the development of a carrier system which is able to enhance the skin delivery of two model drugs, betamethasone and betamethasone dipropionate. Liposomes were characterised by their size, morphology, zeta potential, encapsulation efficiency and stability. Ex vivo diffusion studies using Franz diffusion cells were performed. Confocal microscopy was performed to visualise the penetration of fluorescently labelled liposomes into the skin. This study showed the potential of negatively charged liposomes to enhance the skin penetration of betamethasone and betamethasone dipropionate. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. [Development of ultrasonic cancer therapy using ultrasound sensitive liposome].

    Science.gov (United States)

    Suzuki, Ryo; Oda, Yusuke; Utoguchi, Naoki; Maruyama, Kazuo

    2010-12-01

    Ultrasound (US) has been utilized as a useful tool for diagnosis and therapy. US mediated drug and gene delivery is paid to attention as a non-invasive system. The combination of US and microbubbles generated microjet stream by inducing disruption of bubbles and resulted in enhancing permeability of cell membrane. This phenomenon has been utilized as driving force for drug and gene delivery. Recently, we developed ultrasound sensitive liposome [Bubble liposome (BL)] containing perfluoropropane gas. US combined with BL could effectively transfer gene in vivo compared to conventional cationic liposomes. Using this method, we succeeded to obtain a therapeutic effect in cancer gene therapy with Interleukin-12 corded plasmid DNA. Therefore, it is expected that US combined with BL might be a useful non-viral vector system. From this result, the fusion of liposomal and ultrasound technologies would be important for establishment of advanced cancer therapy.

  12. Lipid-anchored Synaptobrevin Provides Little or No Support for Exocytosis or Liposome Fusion.

    Science.gov (United States)

    Chang, Che-Wei; Chiang, Chung-Wei; Gaffaney, Jon D; Chapman, Edwin R; Jackson, Meyer B

    2016-02-05

    SNARE proteins catalyze many forms of biological membrane fusion, including Ca(2+)-triggered exocytosis. Although fusion mediated by SNAREs generally involves proteins anchored to each fusing membrane by a transmembrane domain (TMD), the role of TMDs remains unclear, and previous studies diverge on whether SNAREs can drive fusion without a TMD. This issue is important because it relates to the question of the structure and composition of the initial fusion pore, as well as the question of whether SNAREs mediate fusion solely by creating close proximity between two membranes versus a more active role in transmitting force to the membrane to deform and reorganize lipid bilayer structure. To test the role of membrane attachment, we generated four variants of the synaptic v-SNARE synaptobrevin-2 (syb2) anchored to the membrane by lipid instead of protein. These constructs were tested for functional efficacy in three different systems as follows: Ca(2+)-triggered dense core vesicle exocytosis, spontaneous synaptic vesicle exocytosis, and Ca(2+)-synaptotagmin-enhanced SNARE-mediated liposome fusion. Lipid-anchoring motifs harboring one or two lipid acylation sites completely failed to support fusion in any of these assays. Only the lipid-anchoring motif from cysteine string protein-α, which harbors many lipid acylation sites, provided support for fusion but at levels well below that achieved with wild type syb2. Thus, lipid-anchored syb2 provides little or no support for exocytosis, and anchoring syb2 to a membrane by a TMD greatly improves its function. The low activity seen with syb2-cysteine string protein-α may reflect a slower alternative mode of SNARE-mediated membrane fusion. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Vesicle-MaNiA: extracellular vesicles in liquid biopsy and cancer.

    Science.gov (United States)

    Torrano, Veronica; Royo, Felix; Peinado, Héctor; Loizaga-Iriarte, Ana; Unda, Miguel; Falcón-Perez, Juan M; Carracedo, Arkaitz

    2016-08-01

    Normal and tumor cells shed vesicles to the environment. Within the large family of extracellular vesicles, exosomes and microvesicles have attracted much attention in the recent years. Their interest ranges from mediators of cancer progression, inflammation, immune regulation and metastatic niche regulation, to non-invasive biomarkers of disease. In this respect, the procedures to purify and analyze extracellular vesicles have quickly evolved and represent a source of variability for data integration in the field. In this review, we provide an updated view of the potential of exosomes and microvesicles as biomarkers and the available technologies for their isolation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Comparison of conventional chemotherapy, stealth liposomes and temperature-sensitive liposomes in a mathematical model.

    Science.gov (United States)

    Gasselhuber, Astrid; Dreher, Matthew R; Rattay, Frank; Wood, Bradford J; Haemmerich, Dieter

    2012-01-01

    Various liposomal drug carriers have been developed to overcome short plasma half-life and toxicity related side effects of chemotherapeutic agents. We developed a mathematical model to compare different liposome formulations of doxorubicin (DOX): conventional chemotherapy (Free-DOX), Stealth liposomes (Stealth-DOX), temperature sensitive liposomes (TSL) with intra-vascular triggered release (TSL-i), and TSL with extra-vascular triggered release (TSL-e). All formulations were administered as bolus at a dose of 9 mg/kg. For TSL, we assumed locally triggered release due to hyperthermia for 30 min. Drug concentrations were determined in systemic plasma, aggregate body tissue, cardiac tissue, tumor plasma, tumor interstitial space, and tumor cells. All compartments were assumed perfectly mixed, and represented by ordinary differential equations. Contribution of liposomal extravasation was negligible in the case of TSL-i, but was the major delivery mechanism for Stealth-DOX and for TSL-e. The dominant delivery mechanism for TSL-i was release within the tumor plasma compartment with subsequent tissue- and cell uptake of released DOX. Maximum intracellular tumor drug concentrations for Free-DOX, Stealth-DOX, TSL-i, and TSL-e were 3.4, 0.4, 100.6, and 15.9 µg/g, respectively. TSL-i and TSL-e allowed for high local tumor drug concentrations with reduced systemic exposure compared to Free-DOX. While Stealth-DOX resulted in high tumor tissue concentrations compared to Free-DOX, only a small fraction was bioavailable, resulting in little cellular uptake. Consistent with clinical data, Stealth-DOX resulted in similar tumor intracellular concentrations as Free-DOX, but with reduced systemic exposure. Optimal release time constants for maximum cellular uptake for Stealth-DOX, TSL-e, and TSL-i were 45 min, 11 min, and constants were shorter for MDR cells, with ∼4 min for Stealth-DOX and for TSL-e. Tissue concentrations correlated well quantitatively with a prior in-vivo study

  15. Liposomal temozolomide drug delivery using convection enhanced delivery.

    Science.gov (United States)

    Nordling-David, Mirjam M; Yaffe, Roni; Guez, David; Meirow, Hadar; Last, David; Grad, Etty; Salomon, Sharona; Sharabi, Shirley; Levi-Kalisman, Yael; Golomb, Gershon; Mardor, Yael

    2017-09-10

    Even though some progress in diagnosis and treatment has been made over the years, there is still no definitive treatment available for Glioblastoma multiforme (GBM). Convection-enhanced delivery (CED), a continuous infusion-mediated pressure gradient via intracranial catheters, studied in clinical trials, enables in situ drug concentrations several orders of magnitude greater than those achieved by systemic administration. We hypothesized that the currently limited efficacy of CED could be enhanced by a liposomal formulation, thus achieving enhanced drug localization to the tumor site with minimal toxicity. We hereby describe a novel approach for treating GBM by CED of liposomes containing the known chemotherapeutic agent, temozolomide (TMZ). A new technique for encapsulating TMZ in hydrophilic (PEGylated) liposomes, characterized by nano-size (121nm), low polydispersity index (<0.13) and with near-neutral charge (-ʒ,0.2mV), has been developed. Co-infusion of PEGylated Gd-DTPA liposomes and TMZ-liposomes by CED in GBM bearing rats, resulted in enhanced tumor detection with longer residence time than free Gd-DTPA. Treatment of GBM-bearing rats with either TMZ solution or TMZ-liposomes resulted in greater tumor inhibition and significantly higher survival. However, the longer survival and smaller tumor volumes exhibited by TMZ liposomal treatment in comparison to TMZ in solution were insignificant (p<0.053); and only significantly lower edema volumes were observed. Thus, there are no clear-cut advantages to use a liposomal delivery system of TMZ via CED over a drug solution. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. 2-Mercaptopropionyiglycine Affords Enhanced Radioprotection After a Liposome Encapsulation

    OpenAIRE

    R.N., SHARAN; A., ALAM; SANGHAMITRA, CHAKRABORTY; JYOTI R., SAIKIA; P.N., SRIVASTAVA; lmmunology Laboratory, Department of Biochemistry, School of Life Sciences North-Eastern Hill University; Radiation &Molecular Biology Unit, Department of Biochemistry, School of Life Sciences North-Eastern Hill University; Nuclear Science Center, JNU Campus

    1995-01-01

    Use of radioprotective drugs in radiotherapy is desirable to protect normal tissues. 2-mercaptopropionyiglycine (MPG) has shown promising results in experimental radioprotection. In this report, a liposome drug delivery system for MPG has been used in Swiss albino mice exposed to 1 to 8 Gy whole body Gamma-irradiation to test whether or not this modality enhances the MPG afforded radio-protection. A statistically significant, dose dependent enhancement of protection by liposome encapsulated M...

  17. USE OF LIPOSOMES AND NANOPARTICLES FOR BRAIN DRUG TARGETING

    OpenAIRE

    Goutam Pal; Partha Palit

    2012-01-01

    The Blood Brain Barrier (BBB) poses a obstacle for a drugs, including antineoplastic agent, antibiotics, neuropeptides, CNS active agents, to be delivered to the brain for therapeutic reasons. The use of formulation dependent strategy such as the use of heterogenous pharmaceutical systems for its effective targeting to the brain is being explored recently. Liposomes and Nanoparticles are good possibilities to achieve the goal. Chemically modified liposomes and nanoparticles are tried in recen...

  18. Engineering of an Inhalable DDA/TDB Liposomal Adjuvant

    DEFF Research Database (Denmark)

    Ingvarsson, Pall Thor; Yang, Mingshi; Mulvad, Helle

    2013-01-01

    The purpose of this study was to identify and optimize spray drying parameters of importance for the design of an inhalable powder formulation of a cationic liposomal adjuvant composed of dimethyldioctadecylammonium (DDA) bromide and trehalose-6,6'-dibehenate (TDB).......The purpose of this study was to identify and optimize spray drying parameters of importance for the design of an inhalable powder formulation of a cationic liposomal adjuvant composed of dimethyldioctadecylammonium (DDA) bromide and trehalose-6,6'-dibehenate (TDB)....

  19. Liposomes and pulmonary alveolar macrophages: functional and morphologic interactions.

    Science.gov (United States)

    Gonzalez-Rothi, R J; Straub, L; Cacace, J L; Schreier, H

    1991-01-01

    In vitro toxicity of liposomes and their functional and morphologic interactions with rat pulmonary alveolar macrophage (AMs) were investigated using viability (trypan blue exclusion), phagocytic and killing activity (uptake and digestion of live S. cerevisiae), surface adherence, respiratory burst (nitro-blue tetrazolium reduction), and morphometry (computerized image analysis) as indicators. Liposome stability in physiologic solutions and uptake of liposome-encapsulated carboxyfluorescein (CF) by AMs was assessed by fluorescence spectroscopy and microscopy. Liposomes made from saturated phospholipids and cholesterol were stable, whereas liposomes consisting of unsaturated phospholipids without cholesterol lost 30% to 40% of their content over 24 h. However, CF uptake was highest with unsaturated phospholipid preparations, whereas uptake of the three other formulations was comparable. Although liposome exposure did not affect macrophage viability, a reduction in the number of phagocytizing macrophages to 73% of control was noted after 24-h incubation with the highest lipid concentration tested (10 mumol/ml). Phagocytic killing was similar under all circumstances observed. The fraction of intracellularly killed yeast ranged from 32% to 42% for both control and experimental samples. An increase in cell surface area from 166.1 +/- 39.9 microns 2 on day O (n = 709) to 196.3 +/- 57.6 microns 2 on day 1 (n = 516) and 211.2 +/- 48.0 microns 2 on day 4 (n = 834) was observed after liposome treatment. The corresponding average cell areas of control samples did not change during the observation period. There was no net cell loss of adherence from monolayers as determined by protein assay. The respiratory burst, indicating generation of intracellular superoxide, was also similar--84% to 92% of experimental and control cells under all conditions showed a strong nitro-blue tetrazolium reduction. In summary, in vitro exposure of AMs to large concentrations of liposomes

  20. Interaction of isopropylthioxanthone with phospholipid liposomes.

    Science.gov (United States)

    Momo, Federico; Fabris, Sabrina; Stevanato, Roberto

    2007-04-01

    Isopropylthioxanthone (ITX) is a highly lipophilic molecule which can be released in foods and beverages from the packages, where it is present as photoinitiator of inks in printing processes. Recently it was found in babies milk, and its toxicity cannot be excluded. The structure of the molecule suggests a possible strong interaction with the lipid moiety of biological membranes, and this is the first study of its effects on phospholipid organization, using differential scanning calorimetry (DSC) and spin labelling techniques. The data obtained with multilamellar liposomes of saturated phospholipids of different length, with and without cholesterol, point out that the molecule changes the lipid structure; in particular, in the gel state, behaving like a disordering agent it increases the mobility of the bilayer, while, in the fluid state, tends to rigidify the membrane, in a cholesterol like way. This behavior supports the hypothesis that ITX experiences a relocation process when the lipid matrix passes from the gel to the fluid state.

  1. Interaction of fluoxetine with phosphatidylcholine liposomes.

    Science.gov (United States)

    Momo, Federico; Fabris, Sabrina; Stevanato, Roberto

    2005-10-22

    Fluoxetine (Prozac) is one of the latest of a new generation of antidepressants, approved by FDA in 2002. The interactions of fluoxetine with multilamellar liposomes of pure phosphatidylcholine (PC) or containing cholesterol 10% molar were studied as a function of the lipid chain lengths, using differential scanning calorimetry and spin labelling EPR techniques. The DSC profiles of the gel-to-fluid state transition of liposomes of DMPC (C14:0) are broadened and shifted towards lower temperatures at increasing dopant concentrations and, with less than 10% fluoxetine, any detectable transition is destroyed. The broadened profiles and the lowered transition temperatures demonstrate that both the size and the packing of the cooperative units undergoing the transition are modified by fluoxetine, leading to a looser and more flexible bilayer. No phase separation was observed. The effects of fluoxetine on the thermotropic phase behaviour of DPPC (C16:0) and, even more, of DSPC (C18:0) are different from that of DMPC. In fact, in the former cases, two peaks appeared at increasing dopant concentrations, suggesting the occurrence of a phase separation phenomenon, which is a sign of a binding of fluoxetine in the phosphate region. In cholesterol containing membranes, fluoxetine, even at low concentrations, leads to a general corruption of the membrane, both in terms of packing and cooperativity, and the formation of any new phase is no longer observable. EPR spectra reflect the disordered motion of acyl chains in the bilayer. It was found that fluoxetine lowers the order of the lipid chains mainly in correspondence of the fifth carbon position of SASL, indicating a possible accumulation near the interfacial region.

  2. The effect of incorporation of cloxacillin in liposomes on treatment of experimental staphylococcal mastitis in mice.

    Science.gov (United States)

    Anderson, J C; Kirby, C J

    1986-09-01

    The effect of incorporation of cloxacillin in liposomes on the treatment of staphylococcal mastitis was assessed bacteriologically 18 h after treatment of experimental infections in mice caused by two strains of Staphylococcus aureus. Intramammary treatments were cloxacillin incorporated in liposomes, cloxacillin in combination with liposomes, empty liposomes, cloxacillin in saline and saline alone. In none of the experiments did entrapment of cloxacillin within liposomes enhance its antibacterial effects. Electron microscopic studies demonstrated the presence of liposomes in neutrophils which also contained staphylococci. The results support the hypothesis that intracellular staphylococci are metabolically dormant and therefore not susceptible to the action of inhibitors of cell wall synthesis such as cloxacillin.

  3. Effectiveness of liposomal paclitaxel against MCF-7 breast cancer cells.

    Science.gov (United States)

    Heney, Melanie; Alipour, Misagh; Vergidis, Dimitrios; Omri, Abdelwahab; Mugabe, Clement; Th'ng, John; Suntres, Zacharias

    2010-12-01

    Paclitaxel is an effective chemotherapeutic agent that is widely used for the treatment of several cancers, including breast, ovarian, and non-small-cell lung cancer. Due to its high lipophilicity, paclitaxel is difficult to administer and requires solubilization with Cremophor EL (polyethoxylated castor oil) and ethanol, which often lead to adverse side effects, including life-threatening anaphylaxis. Incorporation of paclitaxel in dimyristoylphosphatidylcholine:dimyristoylphosphatidylglycerol (DPPC:DMPG) liposomes can facilitate its delivery to cancer cells and eliminate the adverse reactions associated with the Cremophor EL vehicle. Accordingly, the effectiveness of liposomal paclitaxel on MCF-7 breast cancer cells was examined. The results from this study showed that (i) the lipid components of the liposomal formulation were nontoxic, (ii) the cytotoxic effects of liposomal paclitaxel were improved when compared with those seen with conventional paclitaxel, and (iii) the intracellular paclitaxel levels were higher in MCF-7 cells treated with the liposomal paclitaxel formulation. The results of these studies showed that delivery of paclitaxel as a liposomal formulation could be a promising strategy for enhancing its chemotherapeutic effects.

  4. Effects of PEGylation on Liposome Degradation by a Model Phospholipase

    Science.gov (United States)

    Zhang, Pin; Villanueva, Veronica; Donovan, Alexander; Lin, Binhua; Bu, Wei; Liu, Ying; Department Of Chemical Engineering, University Of Illinois At Chicago Team; Center For Advanced Radiation Sources, University Of Chicago Collaboration

    Polyethylene glycol (PEG) has been conjugated to phospholipids to form liposomes with longer blood circulation time, since PEG brushes prevent non-specific protein adsorption and help particles escape phagocytosis. Although PEG provides steric repulsions, it also affects lipid packing and liposome stability. We report here liposomes hydrolysis catalyzed by secreted phospholipase A2 (sPLA2), with an emphasis on revealing the contradictory effects of PEG. The kinetics of liposome hydrolysis were studied by dynamic light scattering. We measured the hydrolysis lag times of liposomes by monitoring the changes in size after mixing with different concentrations of sPLA2. The results followed two exponential functions, defining regimes of degradation kinetics. The effects of PEGylation on the packing of the phospholipid monolayers were studied using X-ray reflectivity and grazing incidence diffraction. The packing of phospholipid monolayers was just slightly disturbed with the inclusion of 5-10% PEGylation (PEG Mw 2000-5000). However, sPLA2 induced hydrolysis of liposomes with higher degrees of PEGylation appeared to be attenuated. In sum, the effects of PEGylation on the protection of lipid assemblies overcomes their disturbance on the lipid packing in the range of our experiments. Author 1-3, 6.

  5. Pegylated liposomal doxorubicin/carboplatin combination in ovarian cancer, progressing on single-agent pegylated liposomal doxorubicin

    OpenAIRE

    Grenader, Tal; Rosengarten, Ora; Isacson, Rut; Plotkin, Yevgeni; Gabizon, Alberto

    2012-01-01

    AIM: To assess the efficacy and safety of the combination of pegylated liposomal doxorubicin (PLD) and carboplatin in patients with recurrent epithelial ovarian carcinoma (ROC), following disease progression on single agent PLD.

  6. The role of extracellular vesicles in malaria biology and pathogenesis.

    Science.gov (United States)

    Sampaio, Natalia Guimaraes; Cheng, Lesley; Eriksson, Emily M

    2017-06-09

    In the past decade, research on the functions of extracellular vesicles in malaria has expanded dramatically. Investigations into the various vesicle types, from both host and parasite origin, has revealed important roles for extracellular vesicles in disease pathogenesis and susceptibility, as well as cell-cell communication and immune responses. Here, work relating to extracellular vesicles in malaria is reviewed, and the areas that remain unknown and require further investigations are highlighted.

  7. Adsorption of DOPC vesicles on hydrophobic substrates in the ...

    Indian Academy of Sciences (India)

    Administrator

    In the present study, the interaction between an intact DOPC vesicle and the hydropho- bic surface is mainly through van der Waals interac- tion. In presence of increasing concentrations of electrolytes, counter ions are present in the vicinity of the DOPC vesicle. As the vesicle approaches the solid substrate, the counter ions ...

  8. Single-vesicle imaging reveals different transport mechanisms between glutamatergic and GABAergic vesicles.

    Science.gov (United States)

    Farsi, Zohreh; Preobraschenski, Julia; van den Bogaart, Geert; Riedel, Dietmar; Jahn, Reinhard; Woehler, Andrew

    2016-02-26

    Synaptic transmission is mediated by the release of neurotransmitters, which involves exo-endocytotic cycling of synaptic vesicles. To maintain synaptic function, synaptic vesicles are refilled with thousands of neurotransmitter molecules within seconds after endocytosis, using the energy provided by an electrochemical proton gradient. However, it is unclear how transmitter molecules carrying different net charges can be efficiently sequestered while maintaining charge neutrality and osmotic balance. We used single-vesicle imaging to monitor pH and electrical gradients and directly showed different uptake mechanisms for glutamate and γ-aminobutyric acid (GABA) operating in parallel. In contrast to glutamate, GABA was exchanged for protons, with no other ions participating in the transport cycle. Thus, only a few components are needed to guarantee reliable vesicle filling with different neurotransmitters. Copyright © 2016, American Association for the Advancement of Science.

  9. Role of Outer Membrane Vesicles of Bacteria

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 8. Role of Outer Membrance Vesicles of Bacteria. M V Jagannadham M K Chattopadhyay. General Article Volume 20 Issue 8 ... Keywords. Outer membrane ves ic les (OMVs); secretion; communication; virulence; antibiotic resistance; vaccines.

  10. Vesicle Pools: Lessons from Adrenal Chromaffin Cells

    Directory of Open Access Journals (Sweden)

    David R Stevens

    2011-02-01

    Full Text Available The adrenal chromaffin cell serves as a model system to study fast Ca2+-dependent exocytosis. Membrane capacitance measurements in combination with Ca2+ uncaging offers a temporal resolution in the millisecond range and reveals that catecholamine release occurs in three distinct phases. Release of a readily releasable (RRP and a slowly releasable (SRP pool are followed by sustained release, due to maturation and release of vesicles which were not release-ready at the start of the stimulus. Trains of depolarizations, a more physiological stimulus, induce release from a small immediately releasable pool of vesicles residing adjacent to calcium channels, as well as from the RRP. The SRP is poorly activated by depolarization. A sequential model, in which non-releasable docked vesicles are primed to a slowly releasable state, and then further mature to the readily releasable state, has been proposed. The docked state, dependent on membrane proximity, requires SNAP-25, synaptotagmin and syntaxin. The ablation or modification of SNAP-25 and syntaxin, components of the SNARE complex, as well as of synaptotagmin, the calcium sensor, and modulators such complexins and Snapin alter the properties and/or magnitudes of different phases of release, and in particular can ablate the RRP. These results indicate that the composition of the SNARE complex and its interaction with modulatory molecules drives priming and provides a molecular basis for different pools of releasable vesicles.

  11. Towards traceable size determination of extracellular vesicles

    NARCIS (Netherlands)

    Varga, Zoltán; Yuana, Yuana; Grootemaat, Anita E.; van der Pol, Edwin; Gollwitzer, Christian; Krumrey, Michael; Nieuwland, Rienk

    2014-01-01

    Extracellular vesicles (EVs) have clinical importance due to their roles in a wide range of biological processes. The detection and characterization of EVs are challenging because of their small size, low refractive index, and heterogeneity. In this manuscript, the size distribution of an

  12. Functional transferred DNA within extracellular vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jin [Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Jiangsu Province (China); Wu, Gengze [Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Jose, Pedro A. [Division of Nephrology, Department of Medicine and Physiology, University of Maryland, School of Medicine, Baltimore, MD 21201 (United States); Zeng, Chunyu, E-mail: Chunyuzeng01@163.com [Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China)

    2016-11-15

    Extracellular vesicles (EVs) are small membrane vesicles including exosomes and shedding vesicles that mediated a cell-to-cell communication. EVs are released from almost all cell types under both physiological and pathological conditions and incorporate nuclear and cytoplasmic molecules for intercellular delivery. Besides protein, mRNA, and microRNA of these molecules, as recent studies show, specific DNA are prominently packaged into EVs. It appears likely that some of exosomes or shedding vesicles, bearing nuclear molecules are released upon bubble-like blebs. Specific interaction of EVs with susceptible recipients performs the uptake of EVs into the target cells, discharging their cargo including nuclear and cytoplasmic macromolecules into the cytosol. These findings expand the nucleic acid content of EVs to include increased levels of specific DNA. Thus, EVs contain a repertoire of genetic information available for horizontal gene transfer and potential use as blood biomarkers for cancer and atherosclerosis. In this review, the focus is on the characteristics, biological functions, and roles in diseases of DNA within EVs. - Highlights: • This review is focused on the DNA within EVs including its characteristics, biological functions, and roles in diseases. • It is clear that DNA within EVs might have important physiological and pathological roles in various diseases. • Knowledge in this area may provides us alternative methods for disease diagnosis or therapy in the future.

  13. Theory of Disk-to-Vesicle Transformation

    Science.gov (United States)

    Li, Jianfeng; Shi, An-Chang

    2009-03-01

    Self-assembled membranes from amphiphilic molecules, such as lipids and block copolymers, can assume a variety of morphologies dictated by energy minimization of system. The membrane energy is characterized by a bending modulus (κ), a Gaussian modulus (κG), and the line tension (γ) of the edge. Two basic morphologies of membranes are flat disks that minimize the bending energy at the cost of the edge energy, and enclosed vesicles that minimize the edge energy at the cost of bending energy. In our work, the transition from disk to vesicle is studied theoretically using the string method, which is designed to find the minimum energy path (MEP) or the most probable transition path between two local minima of an energy landscape. Previous studies of disk-to-vesicle transition usually approximate the transitional states by a series of spherical cups, and found that the spherical cups do not correspond to stable or meta-stable states of the system. Our calculation demonstrates that the intermediate shapes along the MEP are very different from spherical cups. Furthermore, some of these transitional states can be meta-stable. The disk-to-vesicle transition pathways are governed by two scaled parameters, κG/κ and γR0/4κ, where R0 is the radius of the disk. In particular, a meta-stable intermediate state is predicted, which may correspond to the open morphologies observed in experiments and simulations.

  14. Characterization of Extracellular Vesicles using Raman Spectroscopy

    NARCIS (Netherlands)

    Lee, Wooje; Nanou, Afroditi; Terstappen, Leonardus Wendelinus Mathias Marie; Rho, Hoon Suk; le Gac, Severine; Offerhaus, Herman L.

    2017-01-01

    In this research, we aim to characterize extracellular vesicles(EVs) with Confocal Raman spectroscopy to reveal relevant spectral lines that signify differences between EVs derived from different cell lines. In the first stage we performed confocal Raman measurements on various EV samples. For these

  15. Antibody-Hapten Recognition at the Surface of Functionalized Liposomes Studied by SPR: Steric Hindrance of Pegylated Phospholipids in Stealth Liposomes Prepared for Targeted Radionuclide Delivery

    Directory of Open Access Journals (Sweden)

    Eliot. P. Botosoa

    2011-01-01

    Full Text Available Targeted PEGylated liposomes could increase the amount of drugs or radionuclides delivered to tumor cells. They show favorable stability and pharmacokinetics, but steric hindrance of the PEG chains can block the binding of the targeting moiety. Here, specific interactions between an antihapten antibody (clone 734, specific for the DTPA-indium complex and DTPA-indium-tagged liposomes were characterized by surface plasmon resonance (SPR. Non-PEGylated liposomes fused on CM5 chips whereas PEGylated liposomes did not. By contrast, both PEGylated and non-PEGylated liposomes attached to L1 chips without fusion. SPR binding kinetics showed that, in the absence of PEG, the antibody binds the hapten at the surface of lipid bilayers with the affinity of the soluble hapten. The incorporation of PEGylated lipids hinders antibody binding to extents depending on PEGylated lipid fraction and PEG molecular weight. SPR on immobilized liposomes thus appears as a useful technique to optimize formulations of liposomes for targeted therapy.

  16. Aggregation of liposomes in presence of La3+ : A study of the fractal dimension

    Science.gov (United States)

    Sabín, Juan; Prieto, Gerardo; Ruso, Juan M.; Messina, Paula; Sarmiento, Félix

    2007-07-01

    A study of the fractal dimension of the aggregation of three different types of large unilamellar vesicles, formed by egg yolk phosphatidylcholine (EYPC), dimyristoyl-phosphocholine (DMPC), and dipalmitoyl-phosphocholine (DPPC), in the presence of La3+ , is presented. Aggregate liposome fractal dimensions were calculated by two methods, aggregation kinetics, using the approaches diffusion-limited cluster aggregation (DLCA) and reaction-limited cluster aggregation (RLCA) and angle-scattering light dispersion. Electrophoretic measurements show a similar variation of the zeta potential ( ζ potential) for EYPC and DPPC, with a small increase of initial positive values. However, the ζ potential of DMPC changes from a initial negative value to near zero with increasing La3+ concentration. The evolution of the aggregate sizes was followed by light scattering. DPPC and DMPC show a RLCA regimen growth at low La3+ concentrations and a DLCA regimen at higher concentrations. In the case of EYPC, the final size of aggregation strongly depends on La3+ concentration. The calculated fractal dimension is in the range 1.8 to 2.1.

  17. Nonallergenic urushiol derivatives inhibit the oxidation of unilamellar vesicles and of rat plasma induced by various radical generators.

    Science.gov (United States)

    Kim, Jin Young; Cho, Jeong-Yong; Ma, Young Kyu; Lee, Yu Geon; Moon, Jae-Hak

    2014-06-01

    Urushiols consist of an o-dihydroxybenzene (catechol) structure and an alkyl chain of 15 or 17 carbons in the 3-position of a benzene ring and are allergens found in the family Anacardiaceae. We synthesized various veratrole (1,2-dimethoxybenzene)-type and catechol-type urushiol derivatives that contained alkyl chains of various carbon atom lengths, including -H, -C1H3, -C5H11, -C10H21, -C15H31, and -C20H41, and investigated their contact hypersensitivities and antioxidative activities. 3-Decylcatechol and 3-pentadecylcatechol displayed contact hypersensitivity, but the other compounds did not induce an allergic reaction, when the ears of rats were sensitized by treatment with the compounds every day for 20 days. Catechol-type urushiol derivatives (CTUDs) exerted very high radical-scavenging activity on the 1,1-diphenyl-2-picrylhydrazyl radical and inhibited lipid peroxidation in a methyl linoleate solution induced by 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). However, veratrole-type urushiol derivatives did not scavenge or inhibit lipid peroxidation. CTUDs also acted as effective inhibitors of lipid peroxidation of the egg yolk phosphatidylcholine large unilamellar vesicle (PC LUV) liposome system induced by various radical generators such as AMVN, 2,2'-azobis(2-amidino-propane) dihydrochloride, and copper ions, although their efficiencies differed slightly. In addition, CTUDs suppressed formation of cholesteryl ester hydroperoxides in rat blood plasma induced with copper ions. CTUDs containing more than five carbon atoms in the alkyl chain showed excellent lipophilicity in a n-octanol/water partition experiment. These compounds also exhibited high affinities to the liposome membrane using the ultrafiltration method of the PC LUV liposome system. Therefore, CTUDs seem to act as efficient antioxidative compounds against membranous lipid peroxidation owing to their localization in the phospholipid bilayer. These results suggest that nonallergenic CTUDs act as

  18. Genetically Controlled Fusion, Exocytosis and Fission of Artificial Vesicles

    DEFF Research Database (Denmark)

    Bönzli, Eva; Hadorn, Maik; De Lucrezia, Davide

    if a special class of viral proteins, termed fusogenic peptides, were added to the external medium. In the present work, we intend to develop genetically controlled fusion, fission and exocytosis of vesicles by the synthesis of peptides within vesicles. First, we enclosed synthesized peptides in vesicles...... to induce in a next step fusion of adjacent vesicles, fission and exocytosis of nested vesicles. Second, we will replace the peptides by an enclosed cell-free expression system to internally synthesize fusion peptides. To control the gene expression, different mechanisms are available, e.g. addition...... fusion, fission and exocytosis....

  19. Loading of Vesicles into Soft Amphiphilic Nanotubes using Osmosis.

    Science.gov (United States)

    Erne, Petra M; van Bezouwen, Laura S; Štacko, Peter; van Dijken, Derk Jan; Chen, Jiawen; Stuart, Marc C A; Boekema, Egbert J; Feringa, Ben L

    2015-12-07

    The facile assembly of higher-order nanoarchitectures from simple building blocks is demonstrated by the loading of vesicles into soft amphiphilic nanotubes using osmosis. The nanotubes are constructed from rigid interdigitated bilayers which are capped with vesicles comprising phospholipid-based flexible bilayers. When a hyperosmotic gradient is applied to these vesicle-capped nanotubes, the closed system loses water and the more flexible vesicle bilayer is pulled inwards. This leads to inclusion of vesicles inside the nanotubes without affecting the tube structure, showing controlled reorganization of the self-assembled multicomponent system upon a simple osmotic stimulus. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Coated vesicles as protein release mechanism in myeloma cells.

    Science.gov (United States)

    Trombetta, L D; Lazarus, S S

    An electron microscopic study was undertaken of the protein release mechanism within myeloma cells showing a very high degree of protein production. Smooth surfaced vesicles (50 millimicrons) were seen to originate from the outer margin of the perinuclear cistern. Similar vesicles were also associated with distended Golgi sacs. Possible function of these vesicles could not be determined. Coated vesicles (60 millimicrons) originated as evaginations from endoplasmic reticulum in the transitional region. They were present throughout the cytoplasm and were seen to fuse with the cell membrane discharging an electron dense material. These vesicles are, therefore, thought to transport protein from the rough endoplasmic reticulum and discharge it at the cell surface.

  1. Kupffer cell targeting by intraportal injection of the HVJ cationic liposome.

    Science.gov (United States)

    Yoshida, Masanori; Yamamoto, N; Uehara, T; Terao, R; Nitta, T; Harada, N; Hatano, E; Iimuro, Y; Yamaoka, Y

    2002-01-01

    The aim of this study was to target Kupffer cells (KCs) selectively and efficiently by the intraportal injection of fusigenic cationic liposomes with hemagglutinating virus of Japan components (HVJ cationic liposomes). Phosphorothioate FITC-oligodeoxynucleotides (FITC-ODNs) encapsulated in either HVJ cationic liposomes, HVJ anionic liposomes or conventional cationic liposomes without HVJ were transferred to the rat. FITC-ODNs in HVJ cationic liposomes administered via portal vein were selectively transfected to KCs for up to 24 h with no apparent cytotoxicity at higher transfection efficiency than FITC-ODNs in conventional cationic liposomes without HVJ administered via portal vein or tail vein. On the other hand, FITC-ODNs in HVJ anionic liposomes were observed mainly in hepatocytes, not KCs. This new method will be useful for the modulation of KCs activity in both basic research and clinical applications. Copyright 2002 S. Karger AG, Basel

  2. Oxidative stability of Liposomes composed of docosahexaenoic acid-containing phospholipids

    DEFF Research Database (Denmark)

    Vikbjerg, Anders Falk; Andresen, Thomas Lars; Jørgensen, Kent

    2007-01-01

    Oxidative stability of liposomes made of (Docosahexaenoic acid) DHA-containing phosphatidylcholine (PC) was examined during preparation and storage. After preparation of the liposomes, the concentration of primary (conjugated dienes) and secondary oxidation products (Thiobarbituric acid-reactive...

  3. Etoposide Incorporated into Camel Milk Phospholipids Liposomes Shows Increased Activity against Fibrosarcoma in a Mouse Model

    Directory of Open Access Journals (Sweden)

    Hamzah M. Maswadeh

    2015-01-01

    Full Text Available Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS. Anticancer drug etoposide (ETP was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes. The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

  4. Etoposide incorporated into camel milk phospholipids liposomes shows increased activity against fibrosarcoma in a mouse model.

    Science.gov (United States)

    Maswadeh, Hamzah M; Aljarbou, Ahmad N; Alorainy, Mohammed S; Alsharidah, Mansour S; Khan, Masood A

    2015-01-01

    Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS). Anticancer drug etoposide (ETP) was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP) and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes) and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes). The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

  5. Exploring the fate of liposomes in the intestine by dynamic in vitro lipolysis

    DEFF Research Database (Denmark)

    Parmentier, Johannes; Thomas, Nicky; Müllertz, Anette

    2012-01-01

    Liposomes are generally well tolerated drug delivery systems with a potential use for the oral route. However, little is known about the fate of liposomes during exposure to the conditions in the gastro-intestinal tract (GIT). To gain a better understanding of liposome stability in the intestine......, a dynamic in vitro lipolysis model, which so far has only been used for the in vitro characterisation of other lipid-based drug delivery systems, was applied to different liposomal formulations. Liposome size and phospholipid (PL) digestion were determined as two markers for liposome stability. In addition...... by titration and HPLC. Size of liposomes was determined by dynamic light scattering during incubation in lipolysis medium (LM) and during lipolysis. SPC-based (soy phosphatidylcholine) liposomes were stable in LM, whereas for EPC-3-based (hydrated egg phosphatidylcholine) formulations the formation...

  6. Etoposide Incorporated into Camel Milk Phospholipids Liposomes Shows Increased Activity against Fibrosarcoma in a Mouse Model

    Science.gov (United States)

    Maswadeh, Hamzah M.; Aljarbou, Ahmad N.; Alorainy, Mohammed S.; Alsharidah, Mansour S.; Khan, Masood A.

    2015-01-01

    Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS). Anticancer drug etoposide (ETP) was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP) and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes) and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes). The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs. PMID:25821817

  7. Liposomal encapsulation of dexamethasone modulates cytotoxicity, inflammatory cytokine response, and migratory properties of primary human macrophages

    NARCIS (Netherlands)

    Bartneck, M.; Peters, F.M.; Warzecha, K.T.; Bienert, M.; van Bloois, L.; Trautwein, C.; Lammers, Twan Gerardus Gertudis Maria; Tacke, F.

    2014-01-01

    The encapsulation of drugs into liposomes aims to enhance their efficacy and reduce their toxicity. Corticosteroid-loaded liposomes are currently being evaluated in patients suffering from rheumatoid arthritis, atherosclerosis, colitis, and cancer. Here, using several different fluorophore-labeled

  8. Histopathologic Study Following Administration of Liposome-Encapsulated Hemoglobin in the Normovolemic Rat

    National Research Council Canada - National Science Library

    Rudolph, Alan

    1995-01-01

    ... bovine hemoglobin in the normovolemic rat. We have also examined the administration of the liposome vehicle, tetrameric bovine hemoglobin, and liposome encapsulated bovine hemoglobin that had been lyophilized with 300 mM trehalose...

  9. Tissue distribution of radiolabeled phosphatidylserine-containing liposome in mice

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta E.T.; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia], e-mail: samanta@usp.br, e-mail: nnascime@ipen.br; Andrade Junior, Heitor F. de [Instituto de Medicina Tropical de Sao Paulo (IMTSP), Sao Paulo, SP (Brazil)], e-mail: hfandrad@usp.br; Osso Junior, Joao A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia], e-mail: jaosso@ipen.br

    2009-07-01

    Liposomes are used as drug delivery systems to modify pharmacokinetic of drugs and also to improve their action in target cells. Liposomes containing phosphatidylserine are efficiently eliminated from the blood by cells of the mononuclear phagocytic system (MPS), predominantly Kupffer cells in the liver. In this way, this is a valuable approach to treat infectious diseases involving MPS, especially leishmaniasis. Leishmaniasis is a severe parasitic disease, caused by intramacrophage protozoa Leishmania sp., and is fatal if left untreated. Leishmania resides mainly in the liver and the spleen. Antileishmanial agents containing-liposomes showed more effective therapies with reduction of toxicity and adverse side effects. The purpose of this study was to investigate the tissue distribution of radioactive meglumine antimoniate encapsulated in phosphatidylserine-containing liposome. Meglumine antimoniate was neutron irradiated inside the IEA-R1 nuclear reactor to produce antimony radiotracers, {sup 122}Sb and {sup 124}Sb, and encapsulated in liposome. Healthy mice received a single intraperitoneal dose of the radiolabeled drug. Analysis of the mean radioactive tissue concentration-time data curves showed that liver and spleen had the highest levels of radioactivity. In addition these levels of drug remained for more than 48 hours. The dominant route of elimination was via biliary excretion with slow rate. Small fraction of the drug was found in the kidneys with very fast elimination. In conclusion, the phosphatidylserine-containing liposome showed to be a very useful tool to target antileishmanial agents to MPS and to sustain the drug levels for longer times. Besides, radiolabeled liposome is the easiest approach to perform biodistribution evaluation. (author)

  10. Spectroscopic studies and photodynamic actions of hypocrellin B in liposomes.

    Science.gov (United States)

    Yu, C; Chen, S; Zhang, M; Shen, T

    2001-05-01

    Hypocrellin B (HB), a lipid-soluble natural pigment of perylenequinone derivative, is considered as potential photosensitizer for photodynamic therapy. Liposomes loaded with HB can constitute a simple model system, appropriate for better understanding the photodynamic action of HB in vivo. The steady-state absorption and emission spectra, quantum yield and lifetime of fluorescence of HB incorporated into egg L-a-phosphatidyl-choline (EPC) liposome were examined. The photochemical properties (Type I and/or Type II) of HB have also been studied in aqueous dispersions of small unilamellar liposomes of EPC using electron paramagnetic resonance and spectrophotometric methods, respectively. The quantum yield of 1O2 generated by HB is ca 0.76 in chloroform solution and it did not change upon the incorporation of HB into liposomes of EPC. The superoxide anion radical was generated by the electron transfer from the anion radical of HB (HB.-) to oxygen. The disproportionation of O2.- can generate H2O2 and ultimately the highly reactive .OH via the Fenton reaction. It could be that the disproportionation proceeded too fast, so we could not detect O2.- directly in aqueous dispersions of liposome EPC. Moreover, the self-sensitized photooxygenation of HB embedded in liposomes was studied, and almost fully (87%) inhibiting this reaction of HB by p-benzoquinone (as the quencher of O2.-) in aqueous dispersion of liposome EPC indicated that the radical mechanism (Type I) might be mainly involved in this oxygenation. All these findings suggested that the photodynamic action of HB proceeded via both Type-I and -II mechanisms, but Type-I mechanism might play a more important role in the aqueous dispersion.

  11. Interaction of insulin with SDS/CTAB catanionic Vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Tah, Bidisha; Pal, Prabir; Talapatra, G.B., E-mail: spgbt@iacs.res.in

    2014-01-15

    In the present study, a novel method was used for entrapping the protein, insulin into the catanionic SDS/CTAB vesicle membrane. The anionic SDS and cationic CTAB formed catanionic vesicles at particular concentration (35:65 by volume). In this study, vesicle membrane can be considered as model membrane. The vesicle formation and entrapment efficiency depend on the pH of the aqueous solution. The insulin molecules have attached with the vesicular membrane at pH 7.0. However, at acidic pH, the vesicles were ruptured and the insulin did not entrap into the vesicle membrane, whereas at alkaline pH insulin became fibriller. The scanning electron microscope (SEM), Dynamic light scattering (DLS), and Zeta potential studies established the self-assembled structure formation of insulin and catanionic vesicles. To know the protein confirmations, Circular dichroism (CD) was also employed. The temperature dependent steady state and time resolved emission spectroscopy show that at room temperature (25 °C), apart from the 305 nm tyrosine fluorescence, a new emission peak at 450 nm was observed only in case of insulin-vesicle system, and was assigned as the tyrosine phosphorescence. This phosphorescence peak is the signature of the entrapment of insulin into the vesicle membrane. Highlights: • SDS-CTAB based catanionic vesicle has been fabricated. • Insulin has been successfully immobilized on these vesicles. • Immobilized insulin shows room temperature phosphorescence.

  12. Interaction of Colistin and Colistin Methanesulfonate with Liposomes: Colloidal Aspects and Implications for Formulation

    OpenAIRE

    WALLACE, STEPHANIE J.; Li, Jian; Nation, Roger L.; Richard J Prankerd; Boyd, Ben J.

    2012-01-01

    Interaction of colistin and colistin methanesulfonate (CMS) with liposomes has been studied with the view to understanding the limitations to the use of liposomes as a more effective delivery system for pulmonary inhalation of this important class of antibiotic. Thus, in this study, liposomes containing colistin or CMS were prepared and characterized with respect to colloidal behavior and drug encapsulation and release. Association of anionic CMS with liposomes induced negative charge on the ...

  13. Soft vesicles in the synthesis of hard materials.

    Science.gov (United States)

    Dong, Renhao; Liu, Weimin; Hao, Jingcheng

    2012-04-17

    Vesicles of surfactants in aqueous solution have received considerable attention because of their use as simple model systems for biological membranes and their applications in various fields including colloids, pharmaceuticals, and materials. Because of their architecture, vesicles could prove useful as "soft" templates for the synthesis of "hard materials". The vesicle phase, however, has been challenging and difficult to work with in the construction of hard materials. In the solution-phase synthesis of various inorganic or macromolecular materials, templating methods provide a powerful strategy to control the size, morphology, and composition of the resulting micro- and nanostructures. In comparison with hard templates, soft templates are generally constructed using amphiphilic molecules, especially surfactants and amphiphilic polymers. These types of compounds offer advantages including the wide variety of available templates, simple fabrication processes under mild conditions, and easy removal of the templates with less damage to the final structures. Researchers have used many ordered molecular aggregates such as vesicles, micelles, liquid crystals, emulsion droplets, and lipid nanotubes as templates or structure-directing agents to control the synthesis or assembly hard micro- and nanomaterials composed from inorganic compounds or polymers. In addition to their range of sizes and morphologies, vesicles present unique structures that can simultaneously supply different microenvironments for the growth and assembly of hard materials: the inner chamber of vesicles, the outer surface of the vesicles, and the space between bilayers. Two main approaches for applying vesicles in the field of hard materials have been explored: (i) in situ synthesis of micro- or nanomaterials within a specific microenvironment by vesicle templating and (ii) the assembly or incorporation of guest materials during the formation of vesicles. This Account provides an in-depth look at

  14. Cationic liposomal drug delivery system for specific targeting of human cd14+ monocytes in whole blood

    DEFF Research Database (Denmark)

    2013-01-01

    This invention concerns a liposome comprising lipids and at least one active ingredient, wherein at least one of the lipids is a cationic lipid; said liposome exhibiting a net positive charge at physiological conditions at which said liposome preferentially adheres to monocytes in freshly drawn b......, an infectious disease, an inflammatory disease, an autoimmune disease or allergy....

  15. Curcumin liposomes prepared with milk fat globule membrane phospholipids and soybean lecithin.

    Science.gov (United States)

    Jin, Hong-Hao; Lu, Qun; Jiang, Jian-Guo

    2016-03-01

    Using thin film ultrasonic dispersion method, the curcumin liposomes were prepared with milk fat globule membrane (MFGM) phospholipids and soybean lecithins, respectively, to compare the characteristics and stability of the 2 curcumin liposomes. The processing parameters of curcumin liposomes were investigated to evaluate their effects on the encapsulation efficiency. Curcumin liposomes were characterized in terms of size distribution, ζ-potential, and in vitro release behavior, and then their storage stability under various conditions was evaluated. The curcumin liposomes prepared with MFGM phospholipids had an encapsulation efficiency of about 74%, an average particle size of 212.3 nm, and a ζ-potential of -48.60 mV. The MFGM liposomes showed higher encapsulation efficiency, smaller particle size, higher absolute value of ζ-potential, and slower in vitro release than soybean liposomes. The retention rate of liposomal curcumin was significantly higher than that of free curcumin. The stability of the 2 liposomes under different pH was almost the same, but MFGM liposomes displayed a slightly higher stability than soybean liposomes under the conditions of Fe(3+), light, temperature, oxygen, and relative humidity. In conclusion, MFGM phospholipids have potential advantages in the manufacture of curcumin liposomes used in food systems. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Liposomes : Vehicles for the targeted and controlled delivery of peptides and proteins

    NARCIS (Netherlands)

    Crommelin, DJA; Daemen, T; Scherphof, GL; Vingerhoeds, MH; Heeremans, JLM; Kluft, C; Storm, G

    1997-01-01

    Several approaches are presented that have been developed for the liposomal delivery of peptides and proteins. For a rational design of targeted liposomes, the anatomical and physiological constraints with respect to the distribution of liposomes in the body have to be taken into account. Target

  17. A stimuli responsive liposome loaded hydrogel provides flexible on-demand release of therapeutic agents

    NARCIS (Netherlands)

    O'Neill, Hugh S.; Herron, Caroline C.; Hastings, Conn L.; Deckers, Roel; Lopez Noriega, Adolfo; Kelly, Helena M.; Hennink, Wim E.; McDonnell, Ciarán O.; O'Brien, Fergal J.; Ruiz-Hernández, Eduardo; Duffy, Garry P.

    2017-01-01

    Lysolipid-based thermosensitive liposomes (LTSL) embedded in a chitosan-based thermoresponsive hydrogel matrix (denoted Lipogel) represents a novel approach for the spatiotemporal release of therapeutic agents. The entrapment of drug-loaded liposomes in an injectable hydrogel permits local liposome

  18. Fluorescent cell-traceable dexamethasone-loaded liposomes for the treatment of inflammatory liver diseases

    NARCIS (Netherlands)

    Bartneck, Matthias; Scheyda, Katharina M; Warzecha, Klaudia T; Rizzo, Larissa Y; Hittatiya, Kanishka; Luedde, Tom; Storm, G|info:eu-repo/dai/nl/073356328; Trautwein, Christian; Lammers, Twan|info:eu-repo/dai/nl/304824577; Tacke, Frank

    Liposomes are routinely used carrier materials for delivering drug molecules to pathological sites. Besides in tumors and inflammatory sites, liposomes also strongly accumulate in liver and spleen. The potential of using liposomes to treat acute and chronic liver disorders, however, has not yet been

  19. Fluorescent cell-traceable dexamethasone-loaded liposomes for the treatment of inflammatory liver diseases

    NARCIS (Netherlands)

    Bartneck, M.; Scheyda, K.M.; Warzecha, K.T.; Rizzo, L.Y.; Hittatiya, K.; Luedde, T.; Storm, Gerrit; Trautwein, C.; Lammers, Twan Gerardus Gertudis Maria; Tacke, F.

    2015-01-01

    Liposomes are routinely used carrier materials for delivering drug molecules to pathological sites. Besides in tumors and inflammatory sites, liposomes also strongly accumulate in liver and spleen. The potential of using liposomes to treat acute and chronic liver disorders, however, has not yet been

  20. Cyclodextrin as membrane protectant in spray-drying and freeze-drying of PEGylated liposomes

    NARCIS (Netherlands)

    van den Hoven, J.M.; Metselaar, Josbert Maarten; Storm, Gerrit; Beijnen, J.H.; Nuijen, B.

    2012-01-01

    Abstract In this study it was investigated whether hydroxypropyl-β-cyclodextrin (HPβCD) is able to stabilize the liposomal membranes during drying of long circulating polyethylene glycol (PEG) coated liposomes, as compared to the disaccharides trehalose and sucrose. PEGylated liposomes loaded with

  1. Liposome-based immunity-inducing systems for cancer immunotherapy.

    Science.gov (United States)

    Yuba, Eiji

    2017-11-08

    Cancer immunotherapy has gained much attention for next-generation cancer treatment. To conduct cancer immunotherapy, efficient antigen delivery systems must be able to deliver an antigen selectively to antigen-presenting cells, release it at suitable sites for induction of cross-presentation, and simultaneously induce activation of immunocompetent cells. Liposomes are a candidate for use as such multifunctional antigen delivery carriers because of their capability for easy functionalization. This review describes the rational design of liposome-based antigen delivery systems. Surface modification of liposomes by pH-responsive or fusogenic materials can achieve cytoplasmic delivery of antigen, leading to cross-presentation of exogenous antigen via a "cytosolic pathway." In contrast, targeting surface receptors on antigen presenting cells or the selective release of antigen in early endosome induced "vacuolar pathway"-mediated cross-presentation. Introduction of adjuvant molecules such as Toll like receptor agonists, synthetic cationic lipids or bioactive polysaccharides to liposomes improved their immunity-inducing ability. Combination with cancelling systems of immunosuppression in tumor microenvironment enhanced antitumor immunity of antigen delivery systems. Further understanding of immunity-inducing mechanism and molecular basis of tumor immunosuppressive environments and purposeful design of liposome-based antigen delivery systems can provide effective immunity-inducing systems for cancer immunotherapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. A new class of pegylated plasmonic liposomes: synthesis and characterization.

    Science.gov (United States)

    Stiufiuc, Rares; Iacovita, Cristian; Stiufiuc, Gabriela; Florea, Adrian; Achim, Marcela; Lucaciu, Constantin M

    2015-01-01

    The multifunctional nanoobjects that can be controlled, manipulated and triggered using external stimuli represent very promising candidates for nanoscale therapeutic and diagnostic applications. In this study we report the successful synthesis and characterization of a new class of very stable multifunctional nanoobjects, containing cationic liposomes decorated with PEGylated gold nanoparticles (PEGAuNPs). The multifunctional hybrid nanoobjects (mHyNp) were prepared by taking advantage of the electrostatic interactions between small unilamelar cationic liposomes and negatively charged gold nanoparticles. The mHyNps have been investigated by UV-VIS absorption spectroscopy, Dynamic Light Scattering (DLS), Zeta Potential Measurements and Transmission Electron Microscopy (TEM). The TEM images clearly revealed the attachment of individual gold nanoparticles onto the spherical outer surface of the cationic liposomes which was also confirmed by DLS and UV-VIS data. Furthermore, the plasmonic properties of the hybrid complexes have been evaluated by using the Surface Enhanced Raman Spectroscopy (SERS) technique. It is shown that PEG mediated interaction between the liposomes and the gold nanoparticles enabled the recording of the SER spectra of the liposomes in aqueous environment, thus demonstrating the plasmonic properties of the hybrids. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. A "Dock and Lock" Approach to Preparation of Targeted Liposomes.

    Science.gov (United States)

    Backer, Marina V; Backer, Joseph M

    2017-01-01

    We developed a strategy for covalent coupling of targeting proteins to liposomes decorated with a standard adapter protein. This strategy is based on "dock and lock" interactions between two mutated fragments of human RNase I, a 1-15 aa fragment with the R4C amino acid substitution (Cys-tag), and a 21-127-aa fragment with the V118C substitution, (Ad-C). Upon binding to each other, Cys-tag and Ad-C spontaneously form a disulfide bond between the complementary 4C and 118C residues. Therefore, any targeting protein expressed with Cys-tag can be easily coupled to liposomes decorated with Ad-C. Here we describe the preparation of Ad-liposomes followed by coupling them to two Cys-tagged targeted proteins, human vascular endothelial growth factor expressed with N-terminal Cys-tag and a 254-aa long N-terminal fragment of anthrax lethal factor carrying C-terminal Cys-tag. Both proteins retain functional activity after coupling to Ad-C-decorated drug-loaded liposomes. We expect that our "dock and lock" strategy will open new opportunities for development of targeted therapeutic liposomes for research and clinical use.

  4. Application of Liposomes in Treatment of Rheumatoid Arthritis: Quo Vadis

    Directory of Open Access Journals (Sweden)

    Bhupinder Kapoor

    2014-01-01

    Full Text Available The most common treatments for rheumatoid arthritis include nonsteroidal anti-inflammatory drugs (NSAIDs, corticosteroids, disease modifying antirheumatic drugs (DMARDs, and some biological agents. However, none of the treatments available is able to achieve the ultimate goal of treatment, that is, drug-free remission. This limitation has shifted the focus of treatment to delivery strategies with an ability to deliver the drugs into the synovial cavity in the proper dosage while mitigating side effects to other tissues. A number of approaches like microemulsions, microspheres, liposomes, microballoons, cocrystals, nanoemulsions, dendrimers, microsponges, and so forth, have been used for intrasynovial delivery of these drugs. Amongst these, liposomes have proven to be very effective for retaining the drug in the synovial cavity by virtue of their size and chemical composition. The fast clearance of intra-synovially administered drugs can be overcome by use of liposomes leading to increased uptake of drugs by the target synovial cells, which in turn reduces the exposure of nontarget sites and eliminates most of the undesirable effects associated with therapy. This review focuses on the use of liposomes in treatment of rheumatoid arthritis and summarizes data relating to the liposome formulations of various drugs. It also discusses emerging trends of this promising technology.

  5. Detection of Liposome Membrane Viscosity Perturbations with Ratiometric Molecular Rotors

    Science.gov (United States)

    Nipper, Matthew E.; Dakanali, Marianna; Theodorakis, Emmanuel

    2011-01-01

    Molecular rotors are a form of fluorescent intramolecular charge-transfer complexes that can undergo intramolecular twisting motion upon photoexcitation. Twisted-state formation leads to non-radiative relaxation that competes with fluorescence emission. In bulk solutions, these molecules exhibit a viscosity-dependent quantum yield. On the molecular scale, the fluorescence emission is a function of the local free volume, which in turn is related to the local microviscosity. Membrane viscosity, and the inverse; fluidity, are characteristic terms used to describe the ease of movement withing the membrane. Often, changes in membrane viscosity govern intracellular processes and are indicative of a disease state. Molecular rotors have been used to investigate viscosity changes in liposomes and cells, but accuracy is affected by local concentration gradients and sample optical properties. We have developed self-calibrating ratiometric molecular rotors to overcome this challenge and integrated the new molecules into a DLPC liposome model exposed to the membrane-fluidizing agent propanol. We show that the ratiometric emission intensity linearly decreases with the pentanol exposure and that the ratiometric intensity is widely independent of the total liposome concentration. Conversely, dye concentration inside liposomes influences the sensitivity of the system. We suggest that the new self-calibrating dyes can be used for real-time viscosity sensing in liposome systems with the advantages of lifetime measurements, but with low-cost steady-state instrumentation. PMID:21354253

  6. Diurnal Variations of Circulating Extracellular Vesicles Measured by Nano Flow Cytometry.

    Directory of Open Access Journals (Sweden)

    Kirsty M Danielson

    Full Text Available The identification of extracellular vesicles (EVs as intercellular conveyors of biological information has recently emerged as a novel paradigm in signaling, leading to the exploitation of EVs and their contents as biomarkers of various diseases. However, whether there are diurnal variations in the size, number, and tissue of origin of blood EVs is currently not known, and could have significant implications when using EVs as biomarkers for disease progression. Currently available technologies for the measurement of EV size and number are either time consuming, require specialized equipment, or lack sufficient accuracy across a range of EV sizes. Flow cytometry represents an attractive alternative to these methods; however, traditional flow cytometers are only capable of measuring particles down to 500 nm, which is significantly larger than the average and median sizes of plasma EVs. Utilizing a Beckman Coulter MoFlo XDP flow cytometer with NanoView module, we employed nanoscale flow cytometry (termed nanoFCM to examine the relative number and scatter distribution of plasma EVs at three different time points during the day in 6 healthy adults. Analysis of liposomes and plasma EVs proved that nanoFCM is capable of detecting biologically-relevant vesicles down to 100 nm in size. With this high resolution configuration, we observed variations in the relative size (FSC/SSC distributions and concentration (proportions of EVs in healthy adult plasma across the course of a day, suggesting that there are diurnal variations in the number and size distribution of circulating EV populations. The use of nanoFCM provides a valuable tool for the study of EVs in both health and disease; however, additional refinement of nanoscale flow cytometric methods is needed for use of these instruments for quantitative particle counting and sizing. Furthermore, larger scale studies are necessary to more clearly define the diurnal variations in circulating EVs, and thus

  7. Signaling by Extracellular Vesicles Advances Cancer Hallmarks.

    Science.gov (United States)

    Kanada, Masamitsu; Bachmann, Michael H; Contag, Christopher H

    2016-02-01

    Mammalian cells secrete various extracellular vesicles (EVs; exosomes, microvesicles, and apoptotic bodies) that differ in biogenesis, composition, and function. Each vesicle type can originate from normal or cancerous cells, transfer molecular cargo to both neighboring and distant cells, and modulate cellular behaviors involved in eubiology and pathology, such as tumor development. Here, we review evidence for the role of EVs in the establishment and maintenance of cancer hallmarks, including sustaining proliferative signaling, evading growth suppression, resisting cell death, reprogramming energy metabolism, acquiring genomic instability, and remodeling the tumor microenvironment. We also discuss how EVs are implicated in the induction of angiogenesis, control of cellular invasion, initiation of premetastatic niches, maintenance of inflammation, and evasion of immune surveillance. The deeper understanding of the biology of EVs and their contribution to the development and progression of tumors is leading to new opportunities in the diagnosis and treatment of cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Seminal vesicle cystadenoma: a rare clinical perspective.

    Science.gov (United States)

    Lorber, Gideon; Pizov, Galina; Gofrit, Ofer N; Pode, Dov

    2011-08-01

    A 52-yr-old man presented with severe obstructive urinary symptoms. Ten years earlier, a digital rectal examination disclosed a small mass above the prostate, and a computed tomography (CT) scan showed a 3.5-cm cystic tumor of the right seminal vesicle. He had been followed conservatively elsewhere. Reevaluation of the mass with a CT scan and magnetic resonance imaging showed that the mass had grown to a maximal diameter of 14 cm. A transabdominal needle biopsy revealed benign fibromuscular tissue. The tumor was then resected by an open transvesical approach. Pathology was consistent with a benign seminal vesicle cystadenoma. The natural history, pathology, and surgical approach are described. Copyright © 2009 European Association of Urology. Published by Elsevier B.V. All rights reserved.

  9. Docking of secretory vesicles is syntaxin dependent.

    Directory of Open Access Journals (Sweden)

    Heidi de Wit

    Full Text Available Secretory vesicles dock at the plasma membrane before they undergo fusion. Molecular docking mechanisms are poorly defined but believed to be independent of SNARE proteins. Here, we challenged this hypothesis by acute deletion of the target SNARE, syntaxin, in vertebrate neurons and neuroendocrine cells. Deletion resulted in fusion arrest in both systems. No docking defects were observed in synapses, in line with previous observations. However, a drastic reduction in morphologically docked secretory vesicles was observed in chromaffin cells. Syntaxin-deficient chromaffin cells showed a small reduction in total and plasma membrane staining for the docking factor Munc18-1, which appears insufficient to explain the drastic reduction in docking. The sub-membrane cortical actin network was unaffected by syntaxin deletion. These observations expose a docking role for syntaxin in the neuroendocrine system. Additional layers of regulation may have evolved to make syntaxin redundant for docking in highly specialized systems like synaptic active zones.

  10. Morphology transition of raft-model membrane induced by osmotic pressure: Formation of double-layered vesicle similar to an endo- and/or exocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Onai, Teruaki; Hirai, Mitsuhiro, E-mail: mhirai@fs.aramaki.gunma-u.ac.j [Department of Physics, Gunma University, Maebashi 371-8510 (Japan)

    2010-10-01

    The effect of osmotic pressure on the structure of large uni-lamellar vesicle (LUV) of the lipid mixtures of monosialoganglioside (G{sub M1})-cholesterol-dioleoyl-phosphatidylcholine (DOPC) was studies by using wide-angle X-ray scattering (WAXS) method. The molar ratios of the mixtures were 0.1/0.1/1, 0/0.1/1, and 0/0/1. The ternary lipid mixture is a model of lipid rafts. The value of osmotic pressure was varied from 0 to 4.16x10{sup 5} N/m{sup 2} by adding the polyvinylpyrrolidone (PVP) in the range from 0 to 25 % w/v. In the case of the mixtures without G{sub M1}, the rise of the osmotic pressure just enhances the multi-lamellar stacking with deceasing the inter-lamellar spacing. On the other hand, the mixture containing G{sub M1} shows the structural transition from a uni-lamellar vesicle to a double-layered vesicle (a liposome including a smaller one inside) by the rise of osmotic pressure. In this morphology transition the total surface area of the double-layered vesicle is mostly as same as that of the LUV at the initial state. The polar head region of G{sub M1} is bulky and highly hydrophilic due to the oligosaccharide chain containing a sialic acid residue. Then, the present results suggest that the existence of G{sub M1} in the outer-leaflet of the LUV is essentially important for such a double-layered vesicle formation. Alternatively, a phenomenon similar to an endo- and/or exocytosis in cells can be caused simply by a variation of osmotic pressure.

  11. Vitrification of Germinal Vesicle Stage Oocytes

    OpenAIRE

    ABE, Yasuyuki; AONO, Nobuya; Hara, Kenshiro; Matsumoto, Hiromichi; BAKHTIYARI, Mehrdad; Sasada, Hiroshi; Sato, Eimei

    2004-01-01

    In order to cryopreserve germinal vesicle (GV) stage oocytes, we first need to develop a novel container for keeping large quantities of GV oocytes, because of collecting them as cumulus oocytes complexes (COCs) that have bigger size and larger volume than oocytes themselves, and second modify a protocol for optimizing vitrification of them. In this mini-review, we describe our recent progress for attaining these objectives. When 65 bovine COCs having GV oocytes could be placed on a sheet of ...

  12. Inflammatory Stroke Extracellular Vesicles Induce Macrophage Activation.

    Science.gov (United States)

    Couch, Yvonne; Akbar, Naveed; Davis, Simon; Fischer, Roman; Dickens, Alex M; Neuhaus, Ain A; Burgess, Annette I; Rothwell, Peter M; Buchan, Alastair M

    2017-08-01

    Extracellular vesicles (EVs) are protein-lipid complexes released from cells, as well as actively exocytosed, as part of normal physiology, but also during pathological processes such as those occurring during a stroke. Our aim was to determine the inflammatory potential of stroke EVs. EVs were quantified and analyzed in the sera of patients after an acute stroke (inflammation in immune cells. © 2017 American Heart Association, Inc.

  13. A readily retrievable pool of synaptic vesicles

    OpenAIRE

    Hua, Y; Sinha, R.; Thiel, C.; Schmidt, R.; Hueve, J.; Martens, H.; Hell, S.; Egner, A.; Klingauf, J.

    2011-01-01

    Abstract Although clathrin-mediated endocytosis (CME) is thought to be the predominant mechanism of synaptic vesicle (SV) recycling, it seems to be too slow for fast recycling. Therefore, it was suggested that a pre-sorted and pre-assembled pool of SV proteins on the presynaptic membrane might support a first wave of fast CME. In this study we monitored the temporal dynamics of such a 'readily retrievable pool' of SV proteins in rat hippocampal neurons using a novel probe. Applying...

  14. Endothelial microparticles: Sophisticated vesicles modulating vascular function

    Science.gov (United States)

    Curtis, Anne M; Edelberg, Jay; Jonas, Rebecca; Rogers, Wade T; Moore, Jonni S; Syed, Wajihuddin; Mohler, Emile R

    2015-01-01

    Endothelial microparticles (EMPs) belong to a family of extracellular vesicles that are dynamic, mobile, biological effectors capable of mediating vascular physiology and function. The release of EMPs can impart autocrine and paracrine effects on target cells through surface interaction, cellular fusion, and, possibly, the delivery of intra-vesicular cargo. A greater understanding of the formation, composition, and function of EMPs will broaden our understanding of endothelial communication and may expose new pathways amenable for therapeutic manipulation. PMID:23892447

  15. ATP: The crucial component of secretory vesicles.

    Science.gov (United States)

    Estévez-Herrera, Judith; Domínguez, Natalia; Pardo, Marta R; González-Santana, Ayoze; Westhead, Edward W; Borges, Ricardo; Machado, José David

    2016-07-12

    The colligative properties of ATP and catecholamines demonstrated in vitro are thought to be responsible for the extraordinary accumulation of solutes inside chromaffin cell secretory vesicles, although this has yet to be demonstrated in living cells. Because functional cells cannot be deprived of ATP, we have knocked down the expression of the vesicular nucleotide carrier, the VNUT, to show that a reduction in vesicular ATP is accompanied by a drastic fall in the quantal release of catecholamines. This phenomenon is particularly evident in newly synthesized vesicles, which we show are the first to be released. Surprisingly, we find that inhibiting VNUT expression also reduces the frequency of exocytosis, whereas the overexpression of VNUT drastically increases the quantal size of exocytotic events. To our knowledge, our data provide the first demonstration that ATP, in addition to serving as an energy source and purinergic transmitter, is an essential element in the concentration of catecholamines in secretory vesicles. In this way, cells can use ATP to accumulate neurotransmitters and other secreted substances at high concentrations, supporting quantal transmission.

  16. Detection of platelet vesicles by flow cytometry.

    Science.gov (United States)

    Nolan, John P; Jones, Jennifer C

    2017-05-01

    The composition and function of platelet-derived extracellular vesicles (EVs) in health and in disease are a major topic of investigation in biomedical research. However, efforts to delineate specific molecular repertoires and roles for different types of EVs in the circulation are limited not only by the lack of flow cytometers capable of analyzing submicron- and nano-materials across the full size spectrum of plasma EVs, but also by the lack of standardized methods and reference materials that would permit inter-laboratory reproducibility for these analyses. In this review, we summarize the flow cytometry of EVs, with a focus on platelet vesicles in plasma. In addition to delineating the basic principles that govern what precautions must be considered when using flow cytometry for the analysis of platelet vesicles, we provide an overview for how to standardize, control, annotate, and report EV flow cytometry data reproducibly, while looking forward to a next generation of high sensitivity instruments for the analysis of EVs and other submicron biomaterials in the circulation.

  17. Routes and mechanisms of extracellular vesicle uptake

    Directory of Open Access Journals (Sweden)

    Laura Ann Mulcahy

    2014-08-01

    Full Text Available Extracellular vesicles (EVs are small vesicles released by donor cells that can be taken up by recipient cells. Despite their discovery decades ago, it has only recently become apparent that EVs play an important role in cell-to-cell communication. EVs can carry a range of nucleic acids and proteins which can have a significant impact on the phenotype of the recipient. For this phenotypic effect to occur, EVs need to fuse with target cell membranes, either directly with the plasma membrane or with the endosomal membrane after endocytic uptake. EVs are of therapeutic interest because they are deregulated in diseases such as cancer and they could be harnessed to deliver drugs to target cells. It is therefore important to understand the molecular mechanisms by which EVs are taken up into cells. This comprehensive review summarizes current knowledge of EV uptake mechanisms. Cells appear to take up EVs by a variety of endocytic pathways, including clathrin-dependent endocytosis, and clathrin-independent pathways such as caveolin-mediated uptake, macropinocytosis, phagocytosis, and lipid raft–mediated internalization. Indeed, it seems likely that a heterogeneous population of EVs may gain entry into a cell via more than one route. The uptake mechanism used by a given EV may depend on proteins and glycoproteins found on the surface of both the vesicle and the target cell. Further research is needed to understand the precise rules that underpin EV entry into cells.

  18. Topographic analysis by atomic force microscopy of proteoliposomes matrix vesicle mimetics harboring TNAP and AnxA5

    DEFF Research Database (Denmark)

    Bolean, Maytê; Borin, Ivana A; Simão, Ana M S

    2017-01-01

    Atomic force microscopy (AFM) is one of the most commonly used scanning probe microscopy techniques for nanoscale imaging and characterization of lipid-based particles. However, obtaining images of such particles using AFM is still a challenge. The present study extends the capabilities of AFM to...... to proteoliposomes harboring AnxA5 alone. The present study achieved the topographic analysis of lipid vesicles by direct visualization of structural changes, resulting from protein incorporation, without the need for fluorescent probes....... to the characterization of proteoliposomes, a special class of liposomes composed of lipids and proteins, mimicking matrix vesicles (MVs) involved in the biomineralization process. To this end, proteoliposomes were synthesized, composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl...... fluidity. Surface protrusions were measurable in TNAP-proteoliposomes but barely detectable in AnxA5-proteoliposomes. More complex surface structures were observed for proteoliposomes harboring both TNAP and AnxA5 concomitantly, resulting in a lower affinity for type II collagen fibers compared...

  19. Development of lysosome-mimicking vesicles to study the effect of abnormal accumulation of sphingosine on membrane properties.

    Science.gov (United States)

    Carreira, Ana C; de Almeida, Rodrigo F M; Silva, Liana C

    2017-06-21

    Synthetic systems are widely used to unveil the molecular mechanisms of complex cellular events. Artificial membranes are key examples of models employed to address lipid-lipid and lipid-protein interactions. In this work, we developed a new synthetic system that more closely resembles the lysosome - the lysosome-mimicking vesicles (LMVs) - displaying stable acid-to-neutral pH gradient across the membrane. To evaluate the advantages of this synthetic system, we assessed the distinct effects of sphingosine (Sph) accumulation in membrane structure and biophysical properties of standard liposomes (no pH gradient) and in LMVs with lipid composition tuned to mimic physiological- or NPC1-like lysosomes. Ternary 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/Sphingomyelin (SM)/Cholesterol (Chol) mixtures with, respectively, low and high Chol/SM levels were prepared. The effect of Sph on membrane permeability and biophysical properties was evaluated by fluorescence spectroscopy, electrophoretic and dynamic light scattering. The results showed that overall Sph has the ability to cause a shift in vesicle surface charge, increase membrane order and promote a rapid increase in membrane permeability. These effects are enhanced in NPC1- LMVs. The results suggest that lysosomal accumulation of these lipids, as observed under pathological conditions, might significantly affect lysosomal membrane structure and integrity, and therefore contribute to the impairment of cell function.

  20. Extracellular Vesicles in Renal Diseases: More than Novel Biomarkers?

    Science.gov (United States)

    Erdbrügger, Uta; Le, Thu H

    2016-01-01

    Extracellular vesicles from the urine and circulation have gained significant interest as potential diagnostic biomarkers in renal diseases. Urinary extracellular vesicles contain proteins from all sections of the nephron, whereas most studied circulating extracellular vesicles are derived from platelets, immune cells, and the endothelium. In addition to their diagnostic role as markers of kidney and vascular damage, extracellular vesicles may have functional significance in renal health and disease by facilitating communication between cells and protecting against kidney injury and bacterial infection in the urinary tract. However, the current understanding of extracellular vesicles has derived mostly from studies with very small numbers of patients or in vitro data. Moreover, accurate assessment of these vesicles remains a challenge, in part because of a lack of consensus in the methodologies to measure extracellular vesicles and the inability of most techniques to capture the entire size range of these vesicles. However, newer techniques and standardized protocols to improve the detection of extracellular vesicles are in development. A clearer understanding of the composition and biology of extracellular vesicles will provide insights into their pathophysiologic, diagnostic, and therapeutic roles. Copyright © 2016 by the American Society of Nephrology.

  1. Extracellular vesicles in cardiovascular disease: are they Jedi or Sith?

    Science.gov (United States)

    Osteikoetxea, Xabier; Németh, Andrea; Sódar, Barbara W; Vukman, Krisztina V; Buzás, Edit Irén

    2016-06-01

    In the recent past, extracellular vesicles have become recognized as important players in cell biology and biomedicine. Extracellular vesicles, including exosomes, microvesicles and apoptotic bodies, are phospholipid bilayer-enclosed structures found to be secreted by most if not all cells. Extracellular vesicle secretion represents a universal and highly conserved active cellular function. Importantly, increasing evidence supports that extracellular vesicles may serve as biomarkers and therapeutic targets or tools in human diseases. Cardiovascular disease undoubtedly represents one of the most intensely studied and rapidly growing areas of the extracellular vesicle field. However, in different studies related to cardiovascular disease, extracellular vesicles have been shown to exert diverse and sometimes discordant biological effects. Therefore, it might seem a puzzle whether these vesicles are in fact beneficial or detrimental to cardiovascular health. In this review we provide a general introduction to extracellular vesicles and an overview of their biological roles in cardiovascular diseases. Furthermore, we aim to untangle the various reasons for the observed discrepancy in biological effects of extracellular vesicles in cardiovascular diseases. To this end, we provide several examples that demonstrate that the observed functional diversity is in fact due to inherent differences among various types of extracellular vesicles. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  2. Lipophilic drug transfer between liposomal and biological membranes

    DEFF Research Database (Denmark)

    Fahr, Alfred; van Hoogevest, Peter; Kuntsche, Judith

    2006-01-01

    This review presents the current knowledge on the interaction of lipophilic, poorly water soluble drugs with liposomal and biological membranes. The center of attention will be on drugs having the potential to dissolve in a lipid membrane without perturbing them too much. The degree of interaction...... is described as solubility of a drug in phospholipid membranes and the kinetics of transfer of a lipophilic drug between membranes. Finally, the consequences of these two factors on the design of lipid-based carriers for oral, as well as parenteral use, for lipophilic drugs and lead selection of oral...... lipophilic drugs is described. Since liposomes serve as model-membranes for natural membranes, the assessment of lipid solubility and transfer kinetics of lipophilic drug using liposome formulations may additionally have predictive value for bioavailability and biodistribution and the pharmacokinetics...

  3. Recent Trends in Multifunctional Liposomal Nanocarriers for Enhanced Tumor Targeting

    Directory of Open Access Journals (Sweden)

    Federico Perche

    2013-01-01

    Full Text Available Liposomes are delivery systems that have been used to formulate a vast variety of therapeutic and imaging agents for the past several decades. They have significant advantages over their free forms in terms of pharmacokinetics, sensitivity for cancer diagnosis and therapeutic efficacy. The multifactorial nature of cancer and the complex physiology of the tumor microenvironment require the development of multifunctional nanocarriers. Multifunctional liposomal nanocarriers should combine long blood circulation to improve pharmacokinetics of the loaded agent and selective distribution to the tumor lesion relative to healthy tissues, remote-controlled or tumor stimuli-sensitive extravasation from blood at the tumor’s vicinity, internalization motifs to move from tumor bounds and/or tumor intercellular space to the cytoplasm of cancer cells for effective tumor cell killing. This review will focus on current strategies used for cancer detection and therapy using liposomes with special attention to combination therapies.

  4. PEG minocycline-liposomes ameliorate CNS autoimmune disease.

    Directory of Open Access Journals (Sweden)

    Wei Hu

    Full Text Available Minocycline is an oral tetracycline derivative with good bioavailability in the central nervous system (CNS. Minocycline, a potent inhibitor of matrix metalloproteinase (MMP-9, attenuates disease activity in experimental autoimmune encephalomyelitis (EAE, an animal model of multiple sclerosis (MS. Potential adverse effects associated with long-term daily minocycline therapy in human patients are concerning. Here, we investigated whether less frequent treatment with long-circulating polyethylene glycol (PEG minocycline liposomes are effective in treating EAE.Performing in vitro time kinetic studies of PEG minocycline-liposomes in human peripheral blood mononuclear cells (PBMCs, we determined that PEG minocycline-liposome preparations stabilized with CaCl(2 are effective in diminishing MMP-9 activity. Intravenous injections of PEG minocycline-liposomes every five days were as effective in ameliorating clinical EAE as daily intraperitoneal injections of minocycline. Treatment of animals with PEG minocycline-liposomes significantly reduced the number of CNS-infiltrating leukocytes, and the overall expression of MMP-9 in the CNS. There was also a significant suppression of MMP-9 expression and proteolytic activity in splenocytes of treated animals, but not in CNS-infiltrating leukocytes. Thus, leukocytes gaining access to the brain and spinal cord require the same absolute amount of MMP-9 in all treatment groups, but minocycline decreases the absolute cell number.Our data indicate that less frequent injections of PEG minocycline-liposomes are an effective alternative pharmacotherapy to daily minocycline injections for the treatment of CNS autoimmune diseases. Also, inhibition of MMP-9 remains a promising treatment target in EAE and patients with MS.

  5. PEG minocycline-liposomes ameliorate CNS autoimmune disease.

    Science.gov (United States)

    Hu, Wei; Metselaar, Josbert; Ben, Li-Hong; Cravens, Petra D; Singh, Mahendra P; Frohman, Elliot M; Eagar, Todd N; Racke, Michael K; Kieseier, Bernd C; Stüve, Olaf

    2009-01-01

    Minocycline is an oral tetracycline derivative with good bioavailability in the central nervous system (CNS). Minocycline, a potent inhibitor of matrix metalloproteinase (MMP)-9, attenuates disease activity in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Potential adverse effects associated with long-term daily minocycline therapy in human patients are concerning. Here, we investigated whether less frequent treatment with long-circulating polyethylene glycol (PEG) minocycline liposomes are effective in treating EAE. Performing in vitro time kinetic studies of PEG minocycline-liposomes in human peripheral blood mononuclear cells (PBMCs), we determined that PEG minocycline-liposome preparations stabilized with CaCl(2) are effective in diminishing MMP-9 activity. Intravenous injections of PEG minocycline-liposomes every five days were as effective in ameliorating clinical EAE as daily intraperitoneal injections of minocycline. Treatment of animals with PEG minocycline-liposomes significantly reduced the number of CNS-infiltrating leukocytes, and the overall expression of MMP-9 in the CNS. There was also a significant suppression of MMP-9 expression and proteolytic activity in splenocytes of treated animals, but not in CNS-infiltrating leukocytes. Thus, leukocytes gaining access to the brain and spinal cord require the same absolute amount of MMP-9 in all treatment groups, but minocycline decreases the absolute cell number. Our data indicate that less frequent injections of PEG minocycline-liposomes are an effective alternative pharmacotherapy to daily minocycline injections for the treatment of CNS autoimmune diseases. Also, inhibition of MMP-9 remains a promising treatment target in EAE and patients with MS.

  6. Efficient liposome fusion mediated by lipid-nucleic acid conjugates

    DEFF Research Database (Denmark)

    Ries, O; Löffler, P M G; Rabe, A

    2017-01-01

    The fusion of biomembranes with release of encapsulated content in a controlled way is crucial for cell signaling, endo- and exocytosis and intracellular trafficking. Programmable fusion of liposomes and an efficient mixing of their contents have the potential to enable the study of chemical...... and enzymatic processes in a confined environment and under crowded conditions outside biological systems. We report on DNA-controlled fusion of lipid bilayer membranes using lipid-nucleic acid conjugates (LiNAs) to mediate lipid and content mixing of liposomes. Screening of different membrane anchor and linker...

  7. Drug delivery by phospholipase A(2) degradable liposomes

    DEFF Research Database (Denmark)

    Davidsen, Jesper; Vermehren, C.; Frøkjær, S.

    2001-01-01

    The effect of poly(ethylene glycol)-phospholipid (PE-PEG) lipopolymers on phospholipase A(2) (PLA(2)) hydrolysis of liposomes composed of stearoyl-oleoylphosphatidylcholine (SOPC) was investigated. The PLA(2) lag-time, which is inversely related to the enzymatic activity, was determined by fluore......The effect of poly(ethylene glycol)-phospholipid (PE-PEG) lipopolymers on phospholipase A(2) (PLA(2)) hydrolysis of liposomes composed of stearoyl-oleoylphosphatidylcholine (SOPC) was investigated. The PLA(2) lag-time, which is inversely related to the enzymatic activity, was determined...

  8. Glycosphingolipids in signaling and development: from liposomes to model organisms.

    Science.gov (United States)

    Pontier, Stephanie M; Schweisguth, François

    2012-01-01

    Since the launch of the raft hypothesis in 1997, data generated in liposomes and cultured cells have highlighted the role of glycosphingolipids (GSLs) in the dynamic organization of biological membranes and the activity of signaling complexes. In parallel studies, genetic analysis of the GSL synthetic pathway has begun to reveal some of the specific roles of GSLs in vivo. Here, we review the role of GSLs in signaling in the context of a refined raft hypothesis. Recent genetic studies in worms, flies, and mice give us the opportunity to integrate these in vivo data with earlier in vitro liposome studies. Copyright © 2011 Wiley Periodicals, Inc.

  9. Factorial design studies of antiretroviral drug-loaded stealth liposomal injectable: PEGylation, lyophilization and pharmacokinetic studies

    Science.gov (United States)

    Sudhakar, Beeravelli; Krishna, Mylangam Chaitanya; Murthy, Kolapalli Venkata Ramana

    2016-01-01

    The aim of the present study was to formulate and evaluate the ritonavir-loaded stealth liposomes by using 32 factorial design and intended to delivered by parenteral delivery. Liposomes were prepared by ethanol injection method using 32 factorial designs and characterized for various physicochemical parameters such as drug content, size, zeta potential, entrapment efficiency and in vitro drug release. The optimization process was carried out using desirability and overlay plots. The selected formulation was subjected to PEGylation using 10 % PEG-10000 solution. Stealth liposomes were characterized for the above-mentioned parameters along with surface morphology, Fourier transform infrared spectrophotometer, differential scanning calorimeter, stability and in vivo pharmacokinetic studies in rats. Stealth liposomes showed better result compared to conventional liposomes due to effect of PEG-10000. The in vivo studies revealed that stealth liposomes showed better residence time compared to conventional liposomes and pure drug solution. The conventional liposomes and pure drug showed dose-dependent pharmacokinetics, whereas stealth liposomes showed long circulation half-life compared to conventional liposomes and pure ritonavir solution. The results of statistical analysis showed significance difference as the p value is (<0.05) by one-way ANOVA. The result of the present study revealed that stealth liposomes are promising tool in antiretroviral therapy.

  10. Bleomycin-Loaded pH-Sensitive Polymer–Lipid-Incorporated Liposomes for Cancer Chemotherapy

    Directory of Open Access Journals (Sweden)

    Eiji Yuba

    2018-01-01

    Full Text Available Cancer chemotherapeutic systems with high antitumor effects and less adverse effects are eagerly desired. Here, a pH-sensitive delivery system for bleomycin (BLM was developed using egg yolk phosphatidylcholine liposomes modified with poly(ethylene glycol-lipid (PEG-PE for long circulation in the bloodstream and 2-carboxycyclohexane-1-carboxylated polyglycidol-having distearoyl phosphatidylethanolamine (CHexPG-PE for pH sensitization. The PEG-PE/CHexPG-PE-introduced liposomes showed content release responding to pH decrease and were taken up by tumor cells at a rate 2.5 times higher than that of liposomes without CHexPG-PE. BLM-loaded PEG-PE/CHexPG-PE-introduced liposomes exhibited comparable cytotoxicity with that of the free drug. Intravenous administration of these liposomes suppressed tumor growth more effectively in tumor-bearing mice than did the free drug and liposomes without CHexPG-PE. However, at a high dosage of BLM, these liposomes showed severe toxicity to the spleen, liver, and lungs, indicating the trapping of liposomes by mononuclear phagocyte systems, probably because of recognition of the carboxylates on the liposomes. An increase in PEG molecular weight on the liposome surface significantly decreased toxicity to the liver and spleen, although toxicity to the lungs remained. Further improvements such as the optimization of PEG density and lipid composition and the introduction of targeting ligands to the liposomes are required to increase therapeutic effects and to reduce adverse effects.

  11. Fluorescent cell-traceable dexamethasone-loaded liposomes for the treatment of inflammatory liver diseases.

    Science.gov (United States)

    Bartneck, Matthias; Scheyda, Katharina M; Warzecha, Klaudia T; Rizzo, Larissa Y; Hittatiya, Kanishka; Luedde, Tom; Storm, Gert; Trautwein, Christian; Lammers, Twan; Tacke, Frank

    2015-01-01

    Liposomes are routinely used carrier materials for delivering drug molecules to pathological sites. Besides in tumors and inflammatory sites, liposomes also strongly accumulate in liver and spleen. The potential of using liposomes to treat acute and chronic liver disorders, however, has not yet been evaluated. We here explored the therapeutic potential of dexamethasone (Dex)-loaded liposomes for inflammatory liver diseases, using experimental models of acute and chronic liver injury in mice. Fluorescently labeled liposomes predominantly accumulated in hepatic phagocytes, but also in T cells. Importantly, Dex-loaded liposomes reduced T cells in blood and liver, more effectively than free Dex, and endorsed the anti-inflammatory polarization of hepatic macrophages. In experimental chronic liver damage, Dex-loaded liposomes significantly reduced liver injury and liver fibrosis. In immune-mediated acute hepatitis Dex-loaded liposomes, but not free Dex, significantly reduced disease severity. T cells, not macrophages, were significantly depleted by Dex liposomes in liver disease models in vivo, as further supported by mechanistic cell death in vitro studies. Our data indicate that Dex liposomes may be an interesting treatment option for liver diseases, in particular for immune-mediated hepatitis. The depletion of T cells might represent the major mechanism of action of Dex liposomes, rather than their macrophage-polarizing activities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Acute Pancreatitis by liposomal amphotericin B.

    Directory of Open Access Journals (Sweden)

    Rafael Hernández

    2016-11-01

    Full Text Available BACKGROUND: The most frequently observed adverse reactions of a liposomal formulation of amphotericin B (LAB on the first dose of fever and rigors are, hypokalemia and renal toxicity. Acute pancreatitis is not listed in the Summary of Product Characteristics of LAB, although some non-severe cases of pancreatitis toxicity after LAB are described in the literature. CASE SUMMARY: We present the case of an 88-year-old male with not known allergies and diagnosed with arterial hypertension and Grade III chronic kidney disease. One month before was admitted because of pneumonia, acute kidney injury, atrial fibrillation and pancytopenia; he was discharged on January 13, 2016, and two weeks later, he returned to the Urgency Department with severe deterioration of the general condition, fever, and a skin rash , these symptoms were attributed to a delayed allergic reaction to levofloxacin. During his first admission, he was treated with acetylsalicylic acid 100 mg, digoxin, metamizole, pantoprazole, valsartan/amlodipine. The Lab results showed pancytopenia. It was performed a bone marrow aspiration, suggesting a case of leishmaniasis. It was initiated intravenous treatment with LAB at 3 mg / kg / day. The first day of treatment, the patient showed a severe bronchospasm, exacerbation of the previous rash possibly caused by quinolones treatment, was treated with corticosteroids, antihistamines, aerosol therapy and oxygen therapy until full recovery. During the following days, LAB was administrated at a slow infusion rate and premedication with appropriate tolerance. On the fifth day of the treatment, the patient started with a diffuse abdominal pain, anorexia, and vomiting. The amylase lab result was 431 IU/L. An abdominal scanner showed edematous pancreatitis. After 48 hours the amylase and lipase lab values were normal. And the abdominal Scanner was repeated with no changes. The evolution of patient was aggravating until reaching multiple organs failure a

  13. Neuronal Depolarization Drives Increased Dopamine Synaptic Vesicle Loading via VGLUT.

    Science.gov (United States)

    Aguilar, Jenny I; Dunn, Matthew; Mingote, Susana; Karam, Caline S; Farino, Zachary J; Sonders, Mark S; Choi, Se Joon; Grygoruk, Anna; Zhang, Yuchao; Cela, Carolina; Choi, Ben Jiwon; Flores, Jorge; Freyberg, Robin J; McCabe, Brian D; Mosharov, Eugene V; Krantz, David E; Javitch, Jonathan A; Sulzer, David; Sames, Dalibor; Rayport, Stephen; Freyberg, Zachary

    2017-08-30

    The ability of presynaptic dopamine terminals to tune neurotransmitter release to meet the demands of neuronal activity is critical to neurotransmission. Although vesicle content has been assumed to be static, in vitro data increasingly suggest that cell activity modulates vesicle content. Here, we use a coordinated genetic, pharmacological, and imaging approach in Drosophila to study the presynaptic machinery responsible for these vesicular processes in vivo. We show that cell depolarization increases synaptic vesicle dopamine content prior to release via vesicular hyperacidification. This depolarization-induced hyperacidification is mediated by the vesicular glutamate transporter (VGLUT). Remarkably, both depolarization-induced dopamine vesicle hyperacidification and its dependence on VGLUT2 are seen in ventral midbrain dopamine neurons in the mouse. Together, these data suggest that in response to depolarization, dopamine vesicles utilize a cascade of vesicular transporters to dynamically increase the vesicular pH gradient, thereby increasing dopamine vesicle content. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Human mammospheres secrete hormone-regulated active extracellular vesicles.

    Directory of Open Access Journals (Sweden)

    Esperanza Gonzalez

    Full Text Available Breast cancer is a leading cause of cancer-associated death worldwide. One of the most important prognostic factors for survival is the early detection of the disease. Recent studies indicate that extracellular vesicles may provide diagnostic information for cancer management. We demonstrate the secretion of extracellular vesicles by primary breast epithelial cells enriched for stem/progenitor cells cultured as mammospheres, in non-adherent conditions. Using a proteomic approach we identified proteins contained in these vesicles whose expression is affected by hormonal changes in the cellular environment. In addition, we showed that these vesicles are capable of promoting changes in expression levels of genes involved in epithelial-mesenchymal transition and stem cell markers. Our findings suggest that secreted extracellular vesicles could represent potential diagnostic and/or prognostic markers for breast cancer and support a role for extracellular vesicles in cancer progression.

  15. Gram-negative and Gram-positive bacterial extracellular vesicles.

    Science.gov (United States)

    Kim, Ji Hyun; Lee, Jaewook; Park, Jaesung; Gho, Yong Song

    2015-04-01

    Like mammalian cells, Gram-negative and Gram-positive bacteria release nano-sized membrane vesicles into the extracellular environment either in a constitutive manner or in a regulated manner. These bacterial extracellular vesicles are spherical bilayered proteolipids enriched with bioactive proteins, lipids, nucleic acids, and virulence factors. Recent progress in this field supports the critical pathophysiological functions of these vesicles in both bacteria-bacteria and bacteria-host interactions. This review provides an overview of the current understanding on Gram-negative and Gram-positive bacterial extracellular vesicles, especially regarding the biogenesis, components, and functions in poly-species communities. We hope that this review will stimulate additional research in this emerging field of bacterial extracellular vesicles and contribute to the development of extracellular vesicle-based diagnostic tools and effective vaccines against pathogenic Gram-negative and Gram-positive bacteria. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Proteomic analysis of extracellular vesicles derived from Mycobacterium tuberculosis.

    Science.gov (United States)

    Lee, Jaewook; Kim, Si-Hyun; Choi, Dong-Sic; Lee, Jong Seok; Kim, Dae-Kyum; Go, Gyeongyun; Park, Seon-Min; Kim, Si Hyun; Shin, Jeong Hwan; Chang, Chulhun L; Gho, Yong Song

    2015-10-01

    The release of extracellular vesicles, also known as outer membrane vesicles, membrane vesicles, exosomes, and microvesicles, is an evolutionarily conserved phenomenon from bacteria to eukaryotes. It has been reported that Mycobacterium tuberculosis releases extracellular vesicles harboring immunologically active molecules, and these extracellular vesicles have been suggested to be applicable in vaccine development and biomarker discovery. However, the comprehensive proteomic analysis has not been performed for M. tuberculosis extracellular vesicles. In this study, we identified a total of 287 vesicular proteins by four LC-MS/MS analyses with high confidence. In addition, we identified several vesicular proteins associated with the virulence of M. tuberculosis. This comprehensive proteome profile will help elucidate the pathogenic mechanism of M. tuberculosis. The data have been deposited to the ProteomeXchange with identifier PXD001160 (http://proteomecentral.proteomexchange.org/dataset/PXD001160). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Enzymatic degradation of polymer covered SOPC-liposomes in relation to drug delivery

    DEFF Research Database (Denmark)

    Davidsen, Jesper; Vermehren, C.; Frøkjær, S.

    2001-01-01

    Polyethylenoxide (PEG) covered liposomes are used as lipid-based drug-delivery systems. In comparison to conventional liposomes the polymer-covered liposomes display a long circulation half-life in the blood stream. We investigate the influence of polyethyleneoxide-distearoylphosphatidylethanolam......Polyethylenoxide (PEG) covered liposomes are used as lipid-based drug-delivery systems. In comparison to conventional liposomes the polymer-covered liposomes display a long circulation half-life in the blood stream. We investigate the influence of polyethyleneoxide......-distearoylphosphatidylethanolamine (DSPE-PEG$-750$/) lipopolymer concentration on phospholipase A$-2$/ (PLA$-2$/) catalyzed hydrolysis of liposomes composed of stearoyloleoylphosphatidylcholine (SOPC). The characteristic PLA$-2$/ lag-time was determined by fluorescence and the degree of lipid hydrolysis was followed by HPLC analysis...

  18. CREATING AND INVESTIGATION OF ADENOSINE-5-TRIPHOSPHATE LIPOSOMAL FORMS FOR ORAL APPLYING

    Directory of Open Access Journals (Sweden)

    O. V. Khrobatenko

    2013-06-01

    Full Text Available Liposomal form of adenosine-5-triphosphate (ATP for oral applying was studied. The methods of obtaining and determining the size of the liposomes, the definition of ATP percentage content in liposomes were proposed. The effect of liposomal form of ATP on physical performance of laboratory animals by swimming to the limit of exhaustion was studied. It was shown that using of the liposomal form as compared with free ATP (in a similar dose promoted the increased efficiency of laboratory animals. Application of liposomal form occurring at single administration for 6 days at a dose of 30 mg/kg facilated a 62% increase of efficiency, and 60 mg/kg did 76%, while consumption of liposomal form of ATP for 12 days did 64% and 93%, respectively.

  19. DNA-mediated self-assembly of artificial vesicles.

    Science.gov (United States)

    Hadorn, Maik; Eggenberger Hotz, Peter

    2010-03-26

    Although multicompartment systems made of single unilamellar vesicles offer the potential to outperform single compartment systems widely used in analytic, synthetic, and medical applications, their use has remained marginal to date. On the one hand, this can be attributed to the binary character of the majority of the current tethering protocols that impedes the implementation of real multicomponent or multifunctional systems. On the other hand, the few tethering protocols theoretically providing multicompartment systems composed of several distinct vesicle populations suffer from the readjustment of the vesicle formation procedure as well as from the loss of specificity of the linking mechanism over time. In previous studies, we presented implementations of multicompartment systems and resolved the readjustment of the vesicle formation procedure as well as the loss of specificity by using linkers consisting of biotinylated DNA single strands that were anchored to phospholipid-grafted biotinylated PEG tethers via streptavidin as a connector. The systematic analysis presented herein provides evidences for the incorporation of phospholipid-grafted biotinylated PEG tethers to the vesicle membrane during vesicle formation, providing specific anchoring sites for the streptavidin loading of the vesicle membrane. Furthermore, DNA-mediated vesicle-vesicle self-assembly was found to be sequence-dependent and to depend on the presence of monovalent salts. This study provides a solid basis for the implementation of multi-vesicle assemblies that may affect at least three distinct domains. (i) Analysis. Starting with a minimal system, the complexity of a bottom-up system is increased gradually facilitating the understanding of the components and their interaction. (ii) Synthesis. Consecutive reactions may be implemented in networks of vesicles that outperform current single compartment bioreactors in versatility and productivity. (iii) Personalized medicine. Transport and

  20. Cellular phenotype and extracellular vesicles: basic and clinical considerations.

    Science.gov (United States)

    Quesenberry, Peter J; Goldberg, Laura R; Aliotta, Jason M; Dooner, Mark S; Pereira, Mandy G; Wen, Sicheng; Camussi, Giovanni

    2014-07-01

    Early work on platelet and erythrocyte vesicles interpreted the phenomena as a discard of material from cells. Subsequently, vesicles were studied as possible vaccines and, most recently, there has been a focus on the effects of vesicles on cell fate. Recent studies have indicated that extracellular vesicles, previously referred to as microvesicles or exosomes, have the capacity to change the phenotype of neighboring cells. Extensive work has shown that vesicles derived from either the lung or liver can enter bone marrow cells (this is a prerequisite) and alter their fate toward that of the originating liver and lung tissue. Lung vesicles interacted with bone marrow cells result in the bone marrow cells expressing surfactants A-D, Clara cell protein, and aquaporin-5 mRNA. In a similar vein, liver-derived vesicles induce albumin mRNA in target marrow cells. The vesicles contain protein, mRNA, microRNA, and noncoding RNA and variably some DNA. This genetic package is delivered to cells and alters the phenotype. Further studies have shown that initially the altered phenotype is due to the transfer of mRNA and a transcriptional modulator, but long-term epigenetic changes are induced through transfer of a transcriptional factor, and the mRNA is rapidly degraded in the cell. Studies on the capacity of vesicles to restore injured tissue have been quite informative. Mesenchymal stem cell-derived vesicles are able to reverse the injury to the damaged liver and kidney. Other studies have shown that mesenchymal stem cell-derived vesicles can reverse radiation toxicity of bone marrow stem cells. Extracellular vesicles offer an intriguing strategy for treating a number of diseases characterized by tissue injury.

  1. Spin State As a Probe of Vesicle Self-Assembly

    OpenAIRE

    Kim, Sanghoon; Bellouard, Christine; Eastoe, Julian; Canilho, Nadia; Rogers, Sarah E; Ihiawakrim, Dris; Ersen, Ovidiu; Pasc, Andreea

    2016-01-01

    A novel system of paramagnetic vesicles was designed using ion pairs of iron-containing surfactants. Unilamellar vesicles (diameter ≈ 200 nm) formed spontaneously and were characterized by cryogenic transmission electron microscopy, nanoparticle tracking analysis, and light and small-angle neutron scattering. Moreover, for the first time, it is shown that magnetization measurements can be used to investigate self-assembly of such functionalized systems, giving information on the vesicle compo...

  2. Spin State As a Probe of Vesicle Self-Assembly.

    Science.gov (United States)

    Kim, Sanghoon; Bellouard, Christine; Eastoe, Julian; Canilho, Nadia; Rogers, Sarah E; Ihiawakrim, Dris; Ersen, Ovidiu; Pasc, Andreea

    2016-03-02

    A novel system of paramagnetic vesicles was designed using ion pairs of iron-containing surfactants. Unilamellar vesicles (diameter ≈ 200 nm) formed spontaneously and were characterized by cryogenic transmission electron microscopy, nanoparticle tracking analysis, and light and small-angle neutron scattering. Moreover, for the first time, it is shown that magnetization measurements can be used to investigate self-assembly of such functionalized systems, giving information on the vesicle compositions and distribution of surfactants between the bilayers and the aqueous bulk.

  3. [Seminal vesicle cystadenoma as the cause of a retrovesical tumor].

    Science.gov (United States)

    Kaminsky, A; Kania, U; Ortloff, P; Sperling, H

    2014-04-01

    Tumors of the seminal vesicle are rare. Malignant tumors are more common than benign tumors. A seminal vesicle cystadenoma is a rarity. We report on a 41-year-old man with the incidental finding of an asymptomatic retrovesical tumor. The tumor, the seminal vesicle, and the abdominal part of the ductus deferens were surgically removed. The operative access is variable and surgical treatment is the method of choice. The patient's prognosis is good and there are no signs of recurrence.

  4. Dynamic properties of the alkaline vesicle population at hippocampal synapses.

    Directory of Open Access Journals (Sweden)

    Mareike Röther

    Full Text Available In compensatory endocytosis, scission of vesicles from the plasma membrane to the cytoplasm is a prerequisite for intravesicular reacidification and accumulation of neurotransmitter molecules. Here, we provide time-resolved measurements of the dynamics of the alkaline vesicle population which appears upon endocytic retrieval. Using fast perfusion pH-cycling in live-cell microscopy, synapto-pHluorin expressing rat hippocampal neurons were electrically stimulated. We found that the relative size of the alkaline vesicle population depended significantly on the electrical stimulus size: With increasing number of action potentials the relative size of the alkaline vesicle population expanded. In contrast to that, increasing the stimulus frequency reduced the relative size of the population of alkaline vesicles. Measurement of the time constant for reacification and calculation of the time constant for endocytosis revealed that both time constants were variable with regard to the stimulus condition. Furthermore, we show that the dynamics of the alkaline vesicle population can be predicted by a simple mathematical model. In conclusion, here a novel methodical approach to analyze dynamic properties of alkaline vesicles is presented and validated as a convenient method for the detection of intracellular events. Using this method we show that the population of alkaline vesicles is highly dynamic and depends both on stimulus strength and frequency. Our results implicate that determination of the alkaline vesicle population size may provide new insights into the kinetics of endocytic retrieval.

  5. Floating Escherichia coli by expressing cyanobacterial gas vesicle genes

    Science.gov (United States)

    Wang, Tianhe; Kang, Li; Li, Jiaheng; Wu, Wenjie; Zhang, Peiran; Gong, Minghao; Lai, Weihong; Zhang, Chunyan; Chang, Lei; Peng, Yong; Yang, Zhongzhou; Li, Lian; Bao, Yingying; Xu, Haowen; Zhang, Xiaohua; Sui, Zhenghong; Yang, Guanpin; Wang, Xianghong

    2015-02-01

    Gas vesicles are hollow, air-filled polyprotein structures that provide the buoyancy to cells. They are found in a variety of prokaryotes. In this study, we isolated a partial gas vesicle protein gene cluster containing gvpA and gvpC20Ψ from Planktothrix rubescens, and inserted it into an expression vector and expressed it in E. coli. The gas vesicle was developed in bacterial cells, which made bacterial cells to float on medium surface. We also amplified gvpA and gvpC20Ψ separately and synthesized an artificial operon by fusing these two genes with the standardized gene expression controlling elements of E. coli. The artificial operon was expressed in E. coli, forming gas vesicles and floating bacteria cells. Our findings verified that the whole set of genes and the overall structure of gas vesicle gene cluster are not necessary for developing gas vesicles in bacteria cells. Two genes, gvpA and gvpC20Ψ, of the gas vesicle gene cluster are sufficient for synthesizing an artificial operon that can develop gas vesicles in bacteria cells. Our findings provided a wide range of applications including easing the harvest of cultured microalgae and bacteria, as well as enriching and remediating aquatic pollutants by constructing gas vesicles in their cells.

  6. Antibacterial Activities of Nisin Z Encapsulated in Liposomes or Produced In Situ by Mixed Culture during Cheddar Cheese Ripening

    Science.gov (United States)

    Benech, R.-O.; Kheadr, E. E.; Lacroix, C.; Fliss, I.

    2002-01-01

    This study investigated both the activity of nisin Z, either encapsulated in liposomes or produced in situ by a mixed starter, against Listeria innocua, Lactococcus spp., and Lactobacillus casei subsp. casei and the distribution of nisin Z in a Cheddar cheese matrix. Nisin Z molecules were visualized using gold-labeled anti-nisin Z monoclonal antibodies and transmission electron microscopy (immune-TEM). Experimental Cheddar cheeses were made using a nisinogenic mixed starter culture, containing Lactococcus lactis subsp. lactis biovar diacetylactis UL 719 as the nisin producer and two nisin-tolerant lactococcal strains and L. casei subsp. casei as secondary flora, and ripened at 7°C for 6 months. In some trials, L. innocua was added to cheese milk at 105 to 106 CFU/ml. In 6-month-old cheeses, 90% of the initial activity of encapsulated nisin (280 ± 14 IU/g) was recovered, in contrast to only 12% for initial nisin activity produced in situ by the nisinogenic starter (300 ± 15 IU/g). During ripening, immune-TEM observations showed that encapsulated nisin was located mainly at the fat/casein interface and/or embedded in whey pockets while nisin produced by biovar diacetylactis UL 719 was uniformly distributed in the fresh cheese matrix but concentrated in the fat area as the cheeses aged. Cell membrane in lactococci appeared to be the main nisin target, while in L. casei subsp. casei and L. innocua, nisin was more commonly observed in the cytoplasm. Cell wall disruption and digestion and lysis vesicle formation were common observations among strains exposed to nisin. Immune-TEM observations suggest several modes of action for nisin Z, which may be genus and/or species specific and may include intracellular target-specific activity. It was concluded that nisin-containing liposomes can provide a powerful tool to improve nisin stability and availability in the cheese matrix. PMID:12406756

  7. The International Society for Extracellular Vesicles launches the first massive open online course on extracellular vesicles

    Science.gov (United States)

    Lässer, Cecilia; Théry, Clotilde; Buzás, Edit I.; Mathivanan, Suresh; Zhao, Weian; Gho, Yong Song; Lötvall, Jan

    2016-01-01

    The International Society for Extracellular Vesicles (ISEV) has organised its first educational online course for students and beginners in the field of extracellular vesicles (EVs). This course, “Basics of Extracellular Vesicles,” uses recorded lectures from experts in the field and will be open for an unlimited number of participants. The course is divided into 5 modules and can be accessed at www.coursera.org/learn/extracellular-vesicles. The first module is an introduction to the field covering the nomenclature and history of EVs. Module 2 focuses on the biogenesis and uptake mechanisms of EVs, as well as their RNA, protein and lipid cargo. Module 3 covers the collection and processing of cell culture media and body fluids such as blood, breast milk, cerebrospinal fluid and urine prior to isolation of EVs. Modules 4 and 5 present different isolation methods and characterisation techniques utilised in the EV field. Here, differential ultracentrifugation, size-exclusion chromatography, density gradient centrifugation, kit-based precipitation, electron microscopy, cryo-electron microscopy, flow cytometry, atomic-force microscopy and nanoparticle-tracking analysis are covered. This first massive open online course (MOOC) on EVs was launched on 15 August 2016 at the platform “Coursera” and is free of charge. PMID:27989272

  8. The International Society for Extracellular Vesicles launches the first massive open online course on extracellular vesicles.

    Science.gov (United States)

    Lässer, Cecilia; Théry, Clotilde; Buzás, Edit I; Mathivanan, Suresh; Zhao, Weian; Gho, Yong Song; Lötvall, Jan

    2016-01-01

    The International Society for Extracellular Vesicles (ISEV) has organised its first educational online course for students and beginners in the field of extracellular vesicles (EVs). This course, "Basics of Extracellular Vesicles," uses recorded lectures from experts in the field and will be open for an unlimited number of participants. The course is divided into 5 modules and can be accessed at www.coursera.org/learn/extracellular-vesicles. The first module is an introduction to the field covering the nomenclature and history of EVs. Module 2 focuses on the biogenesis and uptake mechanisms of EVs, as well as their RNA, protein and lipid cargo. Module 3 covers the collection and processing of cell culture media and body fluids such as blood, breast milk, cerebrospinal fluid and urine prior to isolation of EVs. Modules 4 and 5 present different isolation methods and characterisation techniques utilised in the EV field. Here, differential ultracentrifugation, size-exclusion chromatography, density gradient centrifugation, kit-based precipitation, electron microscopy, cryo-electron microscopy, flow cytometry, atomic-force microscopy and nanoparticle-tracking analysis are covered. This first massive open online course (MOOC) on EVs was launched on 15 August 2016 at the platform "Coursera" and is free of charge.

  9. The International Society for Extracellular Vesicles launches the first massive open online course on extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Cecilia Lässer

    2016-12-01

    Full Text Available The International Society for Extracellular Vesicles (ISEV has organised its first educational online course for students and beginners in the field of extracellular vesicles (EVs. This course, “Basics of Extracellular Vesicles,” uses recorded lectures from experts in the field and will be open for an unlimited number of participants. The course is divided into 5 modules and can be accessed at www.coursera.org/learn/extracellular-vesicles. The first module is an introduction to the field covering the nomenclature and history of EVs. Module 2 focuses on the biogenesis and uptake mechanisms of EVs, as well as their RNA, protein and lipid cargo. Module 3 covers the collection and processing of cell culture media and body fluids such as blood, breast milk, cerebrospinal fluid and urine prior to isolation of EVs. Modules 4 and 5 present different isolation methods and characterisation techniques utilised in the EV field. Here, differential ultracentrifugation, size-exclusion chromatography, density gradient centrifugation, kit-based precipitation, electron microscopy, cryo-electron microscopy, flow cytometry, atomic-force microscopy and nanoparticle-tracking analysis are covered. This first massive open online course (MOOC on EVs was launched on 15 August 2016 at the platform “Coursera” and is free of charge.

  10. Role of extracellular vesicles in autoimmune diseases.

    Science.gov (United States)

    Turpin, Delphine; Truchetet, Marie-Elise; Faustin, Benjamin; Augusto, Jean-François; Contin-Bordes, Cécile; Brisson, Alain; Blanco, Patrick; Duffau, Pierre

    2016-02-01

    Extracellular vesicles (EVs) consist of exosomes released upon fusion of multivesicular bodies with the cell plasma membrane and microparticles shed directly from the cell membrane of many cell types. EVs can mediate cell-cell communication and are involved in many processes including inflammation, immune signaling, angiogenesis, stress response, senescence, proliferation, and cell differentiation. Accumulating evidence reveals that EVs act in the establishment, maintenance and modulation of autoimmune processes among several others involved in cancer and cardiovascular complications. EVs could also present biomedical applications, as disease biomarkers and therapeutic targets or agents for drug delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Antimony to Cure Visceral Leishmaniasis Unresponsive to Liposomal Amphotericin B

    Science.gov (United States)

    Morizot, Gloria; Jouffroy, Romain; Faye, Albert; Chabert, Paul; Belhouari, Katia; Calin, Ruxandra; Charlier, Caroline; Miailhes, Patrick; Siriez, Jean-Yves; Mouri, Oussama; Yera, Hélène; Gilquin, Jacques; Tubiana, Roland; Lanternier, Fanny; Mamzer, Marie-France; Legendre, Christophe; Peyramond, Dominique; Caumes, Eric; Lortholary, Olivier; Buffet, Pierre

    2016-01-01

    We report on 4 patients (1 immunocompetent, 3 immunosuppressed) in whom visceral leishmaniasis had become unresponsive to (or had relapsed after) treatment with appropriate doses of liposomal amphotericin B. Under close follow-up, full courses of pentavalent antimony were administered without life-threatening adverse events and resulted in rapid and sustained clinical and parasitological cure. PMID:26735920

  12. Modulation of enzymatic PS synthesis by liposome membrane composition.

    Science.gov (United States)

    Pinsolle, Alexandre; Roy, Philippe; Cansell, Maud

    2014-03-01

    Phosphatidylserine (PS) is a phospholipid known to exert important physiological roles in humans. However, this phospholipid (PL) is poorly available as a natural source and hardly produced by the chemical route. In this work, PS was obtained by transphosphatidylation using phospholipase D (PLD) and PL self-assembled into liposomes as the substrates. The aim was to better understand how the liposome membrane composition could modulate PS yield. Three lecithins were used as PL substrates, one originated from a marine source providing a high amount of n-3 polyunsaturated fatty acids, and two issued from soya differing in their phosphatidylcholine (PC) content. Different parameters such as Ca(2+) content, enzyme and L-serine concentrations modulated PS synthesis. The presence of Ca(2+) increased PS conversion yield. The alcohol acceptor (L-serine) concentration positively acted on PL conversion, by governing the equilibrium between transphosphatidylation and hydrolysis. Beside these specific reaction conditions, it was demonstrated that the membrane composition of the liposomes modulated PS synthesis. A direct correlation between PS accumulation and the amount of cholesterol or α-tocopherol incorporated into the soya lecithins was observed. This result was interpreted in terms of "head" spacers promoting PLD transphosphatidylation. On the whole, this work provided key parameters for the formulation of liposomes using enzymatic PLD technology, to produce lecithins enriched in different proportions of PS and esterified with various types of fatty acids depending on the initial lecithin source. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Emerging roles of liposomal bupivacaine in anesthesia practice

    Directory of Open Access Journals (Sweden)

    Obaid Malik

    2017-01-01

    Full Text Available Despite advances in drug technology and improvements in technology, including peripheral nerve catheters and ultrasound, postoperative pain is still a significant problem in the clinical setting worldwide. Postoperative pain can have a critical negative impact with regard to physiological consequences to the body and therefore, the role of liposomal bupivacaine as an extended release bupivacaine with approximately 72 h of duration may have far-reaching and significant impact in clinical practice. Liposomal bupivacaine has a DepoFoam multivesicular liposome technology with particle suspension in an isotonic aqueous solution and consists of tiny lipid-based particles, which contain discrete water-filled chambers dispersed through a lipid matrix. Other advantages include a reduction in opioid consumption, while not requiring a catheter or any other device, as well as easy dilution with saline. This review summarizes current research with this novel agent in postsurgical pain, and discusses potential roles in chronic pain states. Further studies are warranted for its use in epidural and intrathecal administration. Moreover, this review will explore the expansion of liposomal bupivacaine's current clinical role.

  14. Biomolecular Interactions of Tannin Isolated from Oenothera gigas with Liposomes.

    Science.gov (United States)

    Sekowski, Szymon; Ionov, Maksim; Dubis, Alina; Mavlyanov, Saidmukhtar; Bryszewska, Maria; Zamaraeva, Maria

    2016-04-01

    We have examined the interaction between hydrolysable tannin 1-O-galloyl-4,6-hexahydroxydiphenoyl-β-D-glucose (OGβDG) with neutral liposomes as a model of cell membranes composed of three lipids: lecithin, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) at different mass ratios. OGβDG in the concentration range 0.5-15 µg/ml (0.4-12 µM) strongly interacts with liposomal membranes by changing their structure, surface charge and fluidity. Used OGβDG molecules decrease and increase the rigidity of hydrophilic surface and hydrophobic parts of liposomes, respectively. At higher concentrations of tannin (>15 µM), liposomes are aggregated. Fourier Transform Infra-Red (FTIR) analysis showed that mainly -OH groups from OGβDG and also PO(2-) groups from phospholipids are responsible for the interaction. Obtained data indicate the importance of membrane lipid composition in interactions between tannins and cells.

  15. Effect of Cytotoxicity of Pegylated Liposomal Recombinant Human ...

    African Journals Online (AJOL)

    Veronese FM, Pasut G. PEGylation, successful approach to drug delivery. Drug Discov Today 2005; 10: 1451-. 1458. 13. Matteucci ML, Anyarambhatla G, Rosner G, Azuma C,. Fisher PE, Dewhirst MW, Needham D, Thrall DE. Hyperthermia increases accumulation of technetium-. 99m-labeled liposomes in feline sarcomas.

  16. Assembly of Liposomes Controlled by Triple Helix Formation

    DEFF Research Database (Denmark)

    Vogel, Stefan; Jakobsen, Ulla

    2013-01-01

    sequences (G or C-rich) to explore the applicability of the method for different triple helical assembly modes. We demonstrate advantages and limitations of the approach and proof the reversible and reproducible formation of liposome aggregates during thermal denaturation cycles. Nanoparticle tracking...

  17. Rapid Quantification and Validation of Lipid Concentrations within Liposomes

    Directory of Open Access Journals (Sweden)

    Carla B. Roces

    2016-09-01

    Full Text Available Quantification of the lipid content in liposomal adjuvants for subunit vaccine formulation is of extreme importance, since this concentration impacts both efficacy and stability. In this paper, we outline a high performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD method that allows for the rapid and simultaneous quantification of lipid concentrations within liposomal systems prepared by three liposomal manufacturing techniques (lipid film hydration, high shear mixing, and microfluidics. The ELSD system was used to quantify four lipids: 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC, cholesterol, dimethyldioctadecylammonium (DDA bromide, and ᴅ-(+-trehalose 6,6′-dibehenate (TDB. The developed method offers rapidity, high sensitivity, direct linearity, and a good consistency on the responses (R2 > 0.993 for the four lipids tested. The corresponding limit of detection (LOD and limit of quantification (LOQ were 0.11 and 0.36 mg/mL (DMPC, 0.02 and 0.80 mg/mL (cholesterol, 0.06 and 0.20 mg/mL (DDA, and 0.05 and 0.16 mg/mL (TDB, respectively. HPLC-ELSD was shown to be a rapid and effective method for the quantification of lipids within liposome formulations without the need for lipid extraction processes.

  18. Soft Interaction in Liposome Nanocarriers for Therapeutic Drug Delivery

    Directory of Open Access Journals (Sweden)

    Domenico Lombardo

    2016-06-01

    Full Text Available The development of smart nanocarriers for the delivery of therapeutic drugs has experienced considerable expansion in recent decades, with the development of new medicines devoted to cancer treatment. In this respect a wide range of strategies can be developed by employing liposome nanocarriers with desired physico-chemical properties that, by exploiting a combination of a number of suitable soft interactions, can facilitate the transit through the biological barriers from the point of administration up to the site of drug action. As a result, the materials engineer has generated through the bottom up approach a variety of supramolecular nanocarriers for the encapsulation and controlled delivery of therapeutics which have revealed beneficial developments for stabilizing drug compounds, overcoming impediments to cellular and tissue uptake, and improving biodistribution of therapeutic compounds to target sites. Herein we present recent advances in liposome drug delivery by analyzing the main structural features of liposome nanocarriers which strongly influence their interaction in solution. More specifically, we will focus on the analysis of the relevant soft interactions involved in drug delivery processes which are responsible of main behaviour of soft nanocarriers in complex physiological fluids. Investigation of the interaction between liposomes at the molecular level can be considered an important platform for the modeling of the molecular recognition processes occurring between cells. Some relevant strategies to overcome the biological barriers during the drug delivery of the nanocarriers are presented which outline the main structure-properties relationships as well as their advantages (and drawbacks in therapeutic and biomedical applications.

  19. Chiral recognition of bilirubin and biliverdin in liposomes and micelles.

    Science.gov (United States)

    Novotná, Pavlína; Králík, František; Urbanová, Marie

    2015-10-01

    The structural formula of biologically important chiral pigments bilirubin and biliverdin differs only by one double bond. We showed that this results in dissimilar interactions with two models of membranes: cationic liposomes composed of 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol and zwitterionic micelles from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). While the liposomes recognized the P-form of bilirubin, the micelles recognized its M-form. Both recognized the P-form of biliverdin. Our study also comprised ternary systems consisting of the pigments, model membranes and serum albumin (human and bovine). Bilirubin preferentially interacted with the albumins even in the presence of the liposomes. On the other hand, biliverdin preferred the liposomes. Remarkably, the presence of CHAPS completely changed the biliverdin binding to the protein. Because our study was oriented on different chiral interactions, a chiroptical method of electronic circular dichroism was chosen as the principal method to study our systems. As complementary methods, UV-vis absorption and fluorescence emission were used. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Liposome functionalization with copper-free "click chemistry"

    NARCIS (Netherlands)

    Oude Blenke, Erik; Klaasse, Gruson; Merten, Hannes; Plückthun, Andreas; Mastrobattista, Enrico|info:eu-repo/dai/nl/228061105; Martin, Nathaniel I.|info:eu-repo/dai/nl/314123083

    2015-01-01

    The modification of liposomal surfaces is of interest for many different applications and a variety of chemistries are available that makes this possible. A major disadvantage of commonly used coupling chemistries (e.g. maleimide-thiol coupling) is the limited control over the site of conjugation in