Publications by Year: 2004

Marx G, Ben-Moshe M, Magdassi S, Gorodetsky R. Fibrinogen C-terminal peptidic sequences (Haptides) modulate fibrin polymerization. Thromb. HaemostasisThrombosis and Haemostasis. 2004;91 (1) :43 - 51.Abstract
We previously described synthetic peptides of 19-21 amino acid residues, homologous to the C-termini of fibrinogen Fib340 and Fib420, from the β-chain (Cβ), the extended αE chain (CαE) and near the end of the γ-chain (preCγ) which elicited attachment (haptotactic) responses from mesenchymal cells. We named these haptotactic peptides -Haptides. The effects of Haptides on fibrin clot formation was evaluated and their possible effects on platelet aggregation was examd. The Haptides Cβ, CαE and preCγ, (2-10 μM) increased fibrin clot turbidity and also decreased thrombin-induced clotting time. Higher concns. (>120 μM of Cβ or preCγ) induced fibrinogen pptn. even without thrombin. These ppts. exhibited different ultrastructure from thrombin-induced fibrin by scanning and transmission microscopy. C-terminal peptides of the other fibrinogen chains exerted no such effects. Sepharose beads covalently coated with either whole fibrinogen or Haptides (SB-Fib or SB-Haptide) highly adsorbed free FITCHaptides. In aq. soln., Haptides formed nano-particles with av. size of ∼150nm in diam. We suggest that such pos. charged aggregates could serve to nucleate and accelerate fibrin gel formation. These results also indicate that Cβ and preCγ sequences within fibrin(ogen) participate in the docking and condensation of fibrin(ogen) during its assembly into a fibrin clot. By contrast, Haptides up to 100μM did not bind to platelets, and had no effect on platelet aggregation. Our findings highlight the roles of the C-terminal sequences of the β and γ chains in fibrin(ogen) polymn. as well as in cell attachment. [on SciFinder(R)]
Magdassi S, Kahana F, Nini D, Zegerman C, Itach I.; 2004. Matrix with aroma for multiple openings of a package.Abstract
The invention concerns a method for providing a lasting aroma-impact of packaged goods which is sustained even after multiple open and closing cycles, by attaching to the package a solid or semi-solid matrix having the aroma fraction dispersed, entrapped, encapsulated or embedded in the matrix. The matrix in accordance with the invention is adapted to controlled ,slow release of the aroma fraction, e.g. a coffee aroma fraction. [on SciFinder(R)]
Nizri G, Magdassi S, Schmidt J, Cohen Y, Talmon Y. Microstructural Characterization of Micro- and Nanoparticles Formed by Polymer-Surfactant Interactions. LangmuirLangmuir. 2004;20 (11) :4380 - 4385.Abstract
We have studied the nano- and microparticles formed by complexation of poly(diallyldimethylammonium chloride) and SDS. The complexation phenomenon was characterized by light scattering and ζ-potential measurements. The nature of the complexes was revealed by direct-imaging cryogenic temp. transmission electron microscopy (cryo-TEM), showing nanometric details of the complexes formed around the point of neutralization. The images also reveal how those aggregates are solubilized by excess surfactant, first into faceted particles with threadlike micelles attached to their surfaces, prior to complete solubilization, then into lacelike aggregates, and finally into spheroidal micelles. The nanostructure of the complexes strongly suggests they are made of a hexagonal liq. cryst. phase. This was further supported by small-angle X-ray scattering (SAXS). [on SciFinder(R)]
Desai NP, Tao C, Yang A, Louie L, Yao Z, Soon-Shiong P, Magdassi S.; 2004. Protein stabilized pharmacologically active agents, methods for the preparation thereof, and methods for the use thereof.Abstract
In accordance with the present invention, there are provided compns. and methods useful for the in vivo delivery of substantially water insol. pharmacol. active agents (such as the anticancer drug paclitaxel) in which the pharmacol. active agent is delivered in the form of suspended particles coated with protein (which acts as a stabilizing agent). In particular, protein and pharmacol. active agent in a biocompatible dispersing medium are subjected to high shear, in the absence of any conventional surfactants, and also in the absence of any polymeric core material for the particles. The procedure yields particles with a diam. of less than about 1 μ. The use of specific compn. and prepn. conditions (e.g., addn. of a polar solvent to the org. phase), and careful election of the proper org. phase and phase fraction, enables the reproducible prodn. of unusually small nanoparticles of less than 200 nm diam., which can be sterile-filtered. The particulate system produced according to the invention can be converted into a redispersible dry powder comprising nanoparticles of water-insol. drug coated with a protein, and free protein to which mols. of the pharmacol. agent are bound. This results in a unique delivery system, in which part of the pharmacol. active agent is readily bioavailable (in the form of mols. bound to the protein), and part of the agent is present within particles without any polymeric matrix therein. [on SciFinder(R)]
Mumcuoglu KY, Magdassi S, Miller J, Ben-Ishai F, Zentner G, Helbin V, Friger M, Kahana F, Ingber A. Repellency of citronella for head lice: double-blind randomized trial of efficacy and safety. Isr Med Assoc JThe Israel Medical Association journal : IMAJ. 2004;6 (12) :756 - 9.Abstract
BACKGROUND: Head lice move easily from head to head. The lack of safe, effective repellents leads to reinfestation. OBJECTIVES: To test the efficacy of a slow-release citronella formulation as a repellent against the head louse. METHODS: During 4 months in 2003 a randomized, placebo-controlled double-blind clinical study was conducted in four elementary schools; 103 children were treated with the test formulation and 95 with a placebo. RESULTS: A significant difference was observed during the second examination 2 months later, when 12.0% of the children treated with the test repellent and 50.5% of those treated with placebo were infested with lice. A significant difference was also observed at the third examination 2 months later, when 12.4% of the children treated with the test repellent and 33.7% treated with placebo were infested. Overall, there were significant differences between those treated with the repellent and those treated with the placebo (15.4% and 55.1% respectively, P < 0.0001). Side effects were observed in 4.4% of children who disliked the odor of the formulation, and an additional 1.0% who complained of a slight itching and burning sensation. CONCLUSIONS: Use of an effective repellent could significantly lower the incidence of reinfestations, which would lower expenditure on lice control, including pediculicides, combs and products for nit removal, and the time spent on treatment and removal of the nits.[on SciFinder (R)]
Sommer AP, Ben-Moshe M, Magdassi S. Size-Discriminative Self-Assembly of Nanospheres in Evaporating Drops. J. Phys. Chem. BJournal of Physical Chemistry B. 2004;108 (1) :8 - 10.Abstract
Evapn. of liq. drops contg. nanospheres resulted in circular deposition patterns. The circularity of the patterns depended on the uniformity of the surface tension on the substrate. By employing binary suspensions, contg. two differently sized nanospheres, it was possible to modulate the fine structure of such rings. Slow evapn. on mirror-polished substrates resulted in well-ordered distributions, where larger particles self-assembled in dense hexagonal packages, forming apparently an external ring, deposited around the massive inner ring. Deposition started at the air/liq./solid-contact line. Results could inspire principles for the fabrication of optical devices and may be fruitfully used to design biomaterials with cell-selective properties. A simple model is employed to predict the radial arrangement of nanospheres in rings. Deviations from a std. order (predicted by the model) may be useful to detect biol. active nanoparticles. [on SciFinder(R)]
Ben Moshe M, Magdassi S, Cohen Y, Avram L. Structure of microemulsions with gemini surfactant studied by solvatochromic probe and diffusion NMR. J. Colloid Interface Sci.Journal of Colloid and Interface Science. 2004;276 (1) :221 - 226.Abstract
The structure of microemulsions prepd. by the anionic gemini surfactant didodecyl di-Ph ether disulfonate (C12-DADS) was investigated by a solvatochromic probe and NMR diffusion measurements. The NMR measurements indicate the presence of bicontinuous and oil-in-water microemulsions depending on microemulsion compn. The absorbance spectra of the solvatochromic probe, Nile red, indicate the solubilization of the probe in different sites, in agreement with the NMR findings. It was also found that the microemulsions were capable of dissolving the hydrophobic probe, Nile red, up to four times better than expected if it were simply dissolved in the toluene phase. [on SciFinder(R)]
Ben-Moshe M, Magdassi S. Surface activity and micellar properties of anionic gemini surfactants and their analogues. Colloids Surf., AColloids and Surfaces, A: Physicochemical and Engineering Aspects. 2004;250 (1-3) :403 - 408.Abstract
The properties of didodecyldiphenylether disulfonate gemini-type surfactants were studied and compared to mono-alkylated and monosulfonated analogous surfactants. Dynamic and equil. surface tension measurements indicate that the gemini surfactants have a higher surface activity compared to that of the monoalkyl analogs. The gemini-type surfactants have much larger surface area per mol., opposite effect of C no. on CMC and considerable swelling of the micelles upon increasing surfactant concn. Detn. of aggregation nos. by fluorescence measurements reveals that the longer chain gemini surfactants form micelles having <10 mols. per micelle. [on SciFinder(R)]
Hai M, Bernath K, Tawfik D, Magdassi S. Flow Cytometry: A New Method To Investigate the Properties of Water-in-Oil-in-Water Emulsions. LangmuirLangmuir. 2004;20 (6) :2081 - 2085.Abstract
A new and facile method is presented to evaluate w/o/w emulsions contg. fluorescent markers by flow cytometry. Flow cytometry allows simultaneous measurement of w/o/w emulsion droplets "marked" with a fluorescent marker or "blank" without the need for complicated sample prepn. The yield of prepn. of the w/o/w emulsion and the release rate of the fluorescent marker FITC-BSA were investigated by this new method. The release fraction (after 24 h) of FITC-BSA from the w/o/w emulsion decreased with increasing concn. of FITC-BSA inside the internal phase, just like the release fraction of NaCl as marker from the w/o/w emulsion. Flow cytometry results show that the yield and release behavior in w/o/w emulsions are in agreement with results reported by more complicated methods. [on SciFinder(R)]
Magdassi S. Fundamentals of Interface and Colloid Science: Interface Tension by J. Lyklema. Colloids Surf., AColloids and Surfaces, A: Physicochemical and Engineering Aspects. 2004;238 (1-3) :159.
Bernath K, Hai M, Mastrobattista E, Griffiths AD, Magdassi S, Tawfik DS. In vitro compartmentalization by double emulsions: sorting and gene enrichment by fluorescence activated cell sorting. Anal. Biochem.Analytical Biochemistry. 2004;325 (1) :151 - 157.Abstract
Water-in-oil (w/o) emulsions can be used to compartmentalize and select large gene libraries for a predetd. function. The aq. droplets of the w/o emulsion function as cell-like compartments in each of which a single gene is transcribed and translated to give multiple copies of the protein (e.g., an enzyme) it encodes. While compartmentalization ensures that the gene, the protein it encodes, and the products of the activity of this protein remain linked, it does not directly afford a way of selecting for the desired activity. Here the authors show that re-emulsification of w/o emulsions gives water-in-oil-in-water (w/o/w) emulsions with an external (continuous) water phase through which droplets contg. fluorescent markers can be isolated by fluorescence-activated cell sorting (FACS). These w/o/w emulsions can be sorted by FACS, while the content of the aq. droplets of the primary w/o emulsion remains intact. Consequently, genes embedded in these water droplets together with a fluorescent marker can be isolated and enriched from an excess of genes embedded in water droplets without a fluorescent marker. The ability of FACS instruments to sort up to 40,000 events per s may endow this technol. a wide potential in the area of high-throughput screening and the directed evolution of enzymes. [on SciFinder(R)]
Bernath K, Magdassi S, Tawfik DS. In vitro compartmentalization (IVC): A high-throughput screening technology using emulsions and FACS. Discov MedDiscovery medicine. 2004;4 (20) :49 - 53.Abstract
Extract: All screening approaches rely on ways of compartmentalizing assay reactions, and means of rapidly screening various molecules imbedded in these compartments. Miniaturization, which has become the hallmark of modern science and technology, has also been applied to screening, thus leading to a variety of high-throughput screening (HTS) technologies that aim at the smallest possible reaction volumes and the most sensitive and rapid means of detection. These demands are general and do not depend on the type of molecules (genes, proteins, small molecules, etc.) or activity (enzymatic, binding, inhibitory, etc.) that are being screened for, nor on the target of screening (functional genomics, directed evolution, drug discovery, etc.). Conventional HTS approaches use either robotic 2D-arrays (e.g., microtitre plates), or living cells. In vitro compartmentalization (IVC) is a newly developed technology that uses the aqueous droplets of water-in-oil (w/o) emulsions as cell-like compartments.[on SciFinder (R)]
Vaknin D, Dahlke S, Travesset A, Nizri G, Magdassi S. Induced crystallization of polyelectrolyte-surfactant complexes at the gas-water interface. Los Alamos Natl. Lab., Prepr. Arch., Condens. MatterLos Alamos National Laboratory, Preprint Archive, Condensed Matter [Internet]. 2004 :1-4, arXiv:cond-mat/0401194. Publisher's VersionAbstract
Synchrotron-x-ray and surface tension studies of a strong polyelectrolyte (PE) in the semi-dil. regime (∼O.1M monomer-charges) with varying surfactant concns. show that minute surfactant concns. induce the formation of a PE-surfactant complex at the gas/soln. interface. X-ray reflectivity and grazing angle x-ray diffraction (GIXD) provide detailed information of the top most layer, where the surfactant forms a 2-dimensional liq.-like monolayer, with a noticeable disruption of the structure of H2O at the interface. With the addn. of salt (NaCl) columnar-crystals with distorted-hexagonal symmetry are formed. [on SciFinder(R)]
Vaknin D, Dahlke S, Travesset A, Nizri G, Magdassi S. Induced Crystallization of Polyelectrolyte-Surfactant Complexes at the Gas-Water Interface. Phys. Rev. Lett.Physical Review Letters. 2004;93 (21) :218302/1 - 218302/4.Abstract
Synchrotron x-ray and surface-tension studies of a strong polyelectrolyte (PE) in the semidilute regime (∼0.1M monomer charges) with varying surfactant concns. show that minute surfactant concns. induce the formation of a PE-surfactant complex at the gas-soln. interface. X-ray reflectivity and grazing angle x-ray diffraction show the complex PE-surfactant resides at the interface and the alkyl chains of the surfactant form a two-dimensional liquidlike monolayer. With the addn. of salt (NaCl), columnar crystals with distorted-hexagonal symmetry are formed. [on SciFinder(R)]
Hai M, Magdassi S. Investigation on the release of fluorescent markers from w/o/w emulsions by fluorescence-activated cell sorter. [Erratum to document cited in CA141:265749]. J. Controlled ReleaseJournal of Controlled Release. 2004;97 (2) :383.Abstract
Some of the results shown in Figures 1, 2, 4a, and 6 were already reported in Langmuir 20 (2004) 2081-2085. Nevertheless, these earlier results do help in comprehending the full picture of this research project. [on SciFinder(R)]
Hai M, Magdassi S. Investigation on the release of fluorescent markers from w/o/w emulsions by fluorescence-activated cell sorter. J. Controlled ReleaseJournal of Controlled Release. 2004;96 (3) :393 - 402.Abstract
The mechanism of release of two fluorescent markers, fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) and fluorescein, from water-in-oil-in-water (w/o/w) emulsions was investigated using a rapid and sensitive method based on fluorescence-activated cell sorting (FACS). The release of FITC-BSA from a w/o/w emulsion was controlled by diffusion rather than by simple breakdown of the multiple droplets or by formation of reverse micelles in the oil phase. In contrast, the release of fluorescein from a double emulsion was controlled by formation of reverse micelles rather than by diffusion or simple breakdown of multiple droplets. A significant difference in the yield and fraction of FITC-BSA and fluorescein released from double emulsions was obsd. due to their different mol. structure and properties. The yield of FITC-BSA incorporation in a double emulsion increased with increasing FITC-BSA concn. in the internal water phase, while the yield of fluorescein decreased with increasing concn. The fraction of FITC-BSA released from a w/o/w emulsion after 24 h decreased with an increasing concn. of FITC-BSA in the internal phase. The w/o/w emulsion with internalized FITC-BSA was more stable than that with fluorescein, indicating its further application for sorting or enriching size-controlled double droplets that contained genes and water-sol. drugs. [on SciFinder(R)]
Gorodetsky R, Levdansky L, Vexler A, Shimeliovich I, Kassis I, Ben-Moshe M, Magdassi S, Marx G. Liposome transduction into cells enhanced by haptotactic peptides (Haptides) homologous to fibrinogen C-termini. J. Controlled ReleaseJournal of Controlled Release. 2004;95 (3) :477 - 488.Abstract
Haptides are 19-21mer cell-binding peptides equiv. to sequences on the C-termini of fibrinogen β chain (Cβ), γ chain (preCγ) and the extended αE chain of fibrinogen (CαE). In soln., Haptides accumulated in cells by non-saturable kinetics. This study describes Haptide interactions with liposomes and Haptide-mediated liposome uptake by cells. Haptides became incorporated into neg. charged liposomes, changing their zeta potential. At. force microscopy and particle sizing by light scattering showed that the liposomes dissolved Haptide nanoparticles and absorbed them from soln. Pre-mixing fluorescent rhodamine-contg. liposomes or "stealth" doxorubicin (DOX)-contg. liposomes (Doxil) with Cβ, preCγ or to a lesser degree CαE, significantly enhanced their uptake by fibroblasts and endothelial cells. Confocal microscopy showed Haptide-induced liposome uptake satd. above ∼40 μM Haptide. Cytotoxicity tests with lower concns. of Doxil liposomes indicated that premixing with ∼40 μM Cβ or preCγ increased their toxicity by one order of magnitude. It was evident that the liposomes complexed with an amphiphilic Haptide are transduced through cell membranes, probably by a non-receptor-mediated process. These results suggest that Cβ or pre-Cγ could be employed to augment the cellular uptake of drugs in liposomal formulations. [on SciFinder(R)]