# All Publications

Orit Amsalem, Abraham Aserin, and Nissim. Garti. 2010. “Phospholipids-embedded fully dilutable liquid nanostructures. Part 2: The role of sodium diclofenac.” Colloids and Surfaces, B: Biointerfaces, 81, 2, Pp. 422–429. Abstract
Complex pseudo-ternary phase diagrams based on sucrose monolaurate (SE), propylene glycol (PG), and phosphatidylcholine (PC) as the "surfactant phase"; triacetin (TA) and decaglycerol ester (10G1CC) as the "oil phase"; and water as the aq. phase were constructed, into which the authors solubilized the water-insol. drug (sodium diclofenac, Na-DFC). In the authors' previous study the authors demonstrated that the solubilization of Na-DFC in the oil + surfactant phases (prior to dilg. it with water), was 90-fold greater than its dissoln. in water, and that the system was pH-dependent. The greatest Na-DFC solubilization capacity was obtained at pH 7.2. In this study the authors examd. the effect of the solubilization of Na-DFC in a phosphatidylcholine system using DLS, viscosity, elec. cond., SAXS, SD-NMR, and cryo-TEM measurements. It was found that: (1) the system remains micellar after aq. diln. but with greater polydispersity and greater variety of shapes. The authors concluded that the structures in the absence of water (but in the presence of PG) were of direct spherical micelles (∼4 nm) mixed with elongated cylindrical micelles (12-140 nm); (2) the aq. diln. causes fragmentation of the cylinders into smaller spherical micelles; (3) solubilization of Na-DFC behaving like a kosmotropic agent or "structure maker" yields mostly spherical swollen micelles and more ordered systems than in its absence; and (4) Na-DFC is solubilized at the interface of the micelles without swelling the droplets. [on SciFinder(R)]
Ishai Paul Ben, Dima Libster, Abraham Aserin, Nissim Garti, Yuri. Feldman, Paul Ben Ishai, Dima Libster, Abraham Aserin, Nissim Garti, and Yuri. Feldman. 2010. “Influence of Cyclosporine A on Molecular Interactions in Lyotropic Reverse Hexagonal Liquid Crystals.” Journal of Physical Chemistry B, 114, 40, Pp. 12785–12791. Abstract
We present a dielectric study of H(II) mesophases (H(II)) based on a GMO/tricaprylin/phosphatidylcholine/water system seeded with the peptide Cyclosporine A (CSA). The study covers a frequency range 0.01 Hz to 1 MHz and a temperature range of 293 to 319 K, with a 3 K temperature step. Three dielectric relaxation processes are observed and discussed. This picture is further elucidated by comparison with a dielectric study of the empty H(II) mesophase system, previously published, where the same three processes were involved. A complex picture emerges whereby the CSA is intercalated between the surfactant tails yet protrudes into the interface as well. Whereas the CSA remains hydrophobic, it still influences the relaxation behavior of the GMO head and counterion movement along the interface in a nontrivial manner. The third dipolar species, the tricaprylin molecule, is also influenced by the presence of CSA. A critical temperature T(0) = 307 K is recognized and identified as the dehydration temperature of the surfactant heads. This induces a conformal transition in the CSA, drastically changing its effect on the three dielectric processes evident in the raw data. The implications of this behavior are discussed in detail.[on SciFinder (R)]
Liron Bitan-Cherbakovsky, Idit Yuli-Amar, Abraham Aserin, and Nissim. Garti. 2010. “Solubilization of Vitamin E into HII LLC Mesophase in the Presence and in the Absence of Vitamin C.” Langmuir, 26, 5, Pp. 3648–3653. Abstract
The synergistic solubilization of two major hydrophilic (vitamin C, ascorbic acid, AA) and lipophilic (vitamin E, D-$\alpha$-tocopherol, VE) antioxidants within reverse hexagonal (HII) mesophases is reported. The HII mesophases are composed of monoolein (GMO)/VE/AA/water. A wide range of VE concn. was examd. (on the expense of GMO concns.) while the AA and water concns. remained const. (4 and 12.5 wt %, resp.) in order to expand the HII mesophase. SAXS and DSC combined with ATR-FTIR techniques were utilized to study the interactions between each solubilizate and the HII component that enabled the synergistic accommodation of the hydrophilic and hydrophobic mols. It was revealed that up to 27 wt % VE solubilized within the HII mesophase. This hydrophobic additive localized at the lipophilic GMO tail region solvating the surfactant tails, thereby enabling the formation of the HII structure. As a result, the lattice parameter and the m.p. of the hydrophobic tails decreased. Above 27 wt % VE (up to 33 wt %), once the GMO lipophilic region was homogeneously solvated, addnl. VE mols. located closer to the interface. At this range of concns., new hydrogen bonds between O-H groups of VE and O-H groups of GMO were formed. Once 35 wt % VE was introduced, the HII structure transformed to face-centered reverse micellar cubic phase (Fd3m, Q227). [on SciFinder(R)]
Marganit Cohen-Avrahami, Abraham Aserin, and Nissim. Garti. 2010. “HII mesophase and peptide cell-penetrating enhancers for improved transdermal delivery of sodium diclofenac.” Colloids and Surfaces, B: Biointerfaces, 77, 2, Pp. 131–138. Abstract
This study develops a novel transdermal delivery vehicle for the enhanced delivery of sodium diclofenac (Na-DFC). The system utilizes the advantages of reversed hexagonal lyotropic liq. crystals (HIILC), combined with a peptide cell penetration enhancer (CPE), creating together an adaptable system that provides versatile options in the field of transdermal delivery. This enhancer peptide is based on a family of amphipathic peptides that exhibit improved membrane permeability. Franz permeation cell expts. revealed that the peptide enhancer (RALA) improved Na-DFC skin penetration of the liq. crystal 2.2-fold. The authors studied the structural effects of RALA solubilization on the HII mesophase. RALA acts as a chaotropic agent, interfering in the structure of the water, and causes a measurable swelling of the aq. cylinders by 5 \AA. Small angle x-ray scattering (SAXS) and attenuated total reflectance-Fourier transform IR (ATR-FTIR) measurements reveal enhanced hydration of the glycerol monooleate (GMO) headgroups and a 6.5% increase in the fraction of non-freezable water resulting from RALA incorporation. RALA caused a gradual increase in the GMO effective headgroup area due to the hydration, leading eventually to a transform of the hexagonal structure towards a lamellar one. CD and ATR-FTIR measurements showed a conservation of the peptide structure when incorporated into the HII mesophase. The combined HIILC-CPE systems can serve as high potential vehicles for a variety of drugs, as they can easily be modified by varying the compn. and temp., according to the required dose and delivery features. [on SciFinder(R)]
Rivka Efrat, Zoya Abramov, Abraham Aserin, and Nissim. Garti. 2010. “Nonionic-Anionic Mixed Surfactants Cubic Mesophases. Part I: Structural Chaotropic and Kosmotropic Effect.” Journal of Physical Chemistry B, 114, 33, Pp. 10709–10716. Abstract
We prepd. and investigated cubic bicontinuous (V) phase from mixts. of nonionic monoolein (GMO) and anionic oleyl lactate (OL) surfactants in the presence of ethanol and water. The isotropic region and the compn. of the V phase in the pseudoternary phase diagram vary with the nature of the hydrophilic headgroups and their charge. We examd. three anionic species, acidic (HOL), partially neutralized (OL), and totally ionized (NaOL) forms. The largest swollen V region within the phase diagram was formed from the partially neutralized form. The V formation is dependent on the GMO/OL ratio. The largest isotropic region in the phase diagrams was found with GMO/OL at a 70:30 wt % ratio and in the presence of 5.0 and 38.5 wt % ethanol and water, resp. The structural effect of OL was detd. by small-angle X-ray spectroscopy, differential scanning calorimetry, and Fourier transform IR. The results revealed that the structure is curvature-dependent. Mesophases made from 90:10 wt % GMO/OL showed phase transition from gyroid (G) to diamond (D) symmetry. Prepns. made from 30:70 wt % GMO/OL exhibited coexistence of two mesophases, one (of low order) cubic and the other lamellar. Because of the overall gauche deformation growth, the hydrocarbon order decreased with the OL content increase. The GMO, sn2 and sn3 headgroups, and water structure vibration bands indicate a chaotropic effect as a result of the interdigitation of OL anions and Na+ and H+ counterions. [on SciFinder(R)]
Nissim Garti, Abraham Aserin, Dima Libster, Tehil Mishraki, Idit Amar-Yuli, and Liron. Bitan-Chervkovsky. 2010. “Reverse hexagonal mesophase liquid crystals and uses thereof.” United States of America (WO2010150262A2). Abstract
Reverse hexagonal mesophase (HII) liq. crystals are provided and relating therapeutic and non-therapeutic applications are demonstrated. [on SciFinder(R)]
The patent describes novel and modified lyotropic liquid crystals with hexagonal symmetry for enhanced solubilization of bioactives
Roy Hoffman, Nissim Garti, Abraham Aserin, and Chava. Pemberton. 2010. “Liquid compositions and uses thereof for generating diffusion ordered NMR spectra of mixtures.” United States of America (WO 2010023673). Abstract
There is claimed a liq. medium capable of giving a resolved diffusion ordered NMR spectra of mixts. of compds. that is both stable and less susceptible to magnetic susceptibility effects. The present invention relates to homogeneous liq. systems substantially 1H- NMR inactive and/or devoid of protons and are capable of enhancing the diffusion sepn. of a mixt., wherein said system is substantially devoid of at least one NMR active nucleus present in said mixt. The invention further discloses methods of using said homogeneous liq. systems for enhancing the diffusion sepn. of a mixt. and/or generating a diffusion ordered spectrum of a mixt. and/or minimizing the peak width in a liq. state diffusion ordered spectrum of a mixt. [on SciFinder(R)]
Miri Klein, Abraham Aserin, Inna Svitov, and Nissim. Garti. 2010. “Enhanced stabilization of cloudy emulsions with gum Arabic and whey protein isolate.” Colloids and Surfaces, B: Biointerfaces, 77, 1, Pp. 75–81. Abstract
Cloudy emulsions are oil-in-water (O/W) emulsions normally prepd. as concs., further dild., per request, into the final beverage. The cloudy emulsion provides flavor, color, and cloud (turbidity) to the soft drink. These systems are stabilized by emulsifiers and/or amphiphilic polysaccharides. Cloudy emulsions based on naturally occurring food grade emulsifiers were studied in the present work. Two charged natural biopolymers, whey protein isolate (WPI) and gum arabic (GA), are interacted in aq. soln. to form charge-charge interactions improving the emulsion stability. The emulsions were high sheared (Microfluidizer) and characterized by particle size distribution anal. (DLS), optical centrifugation (LUMiFuge), optical microscopy observations, and turbidity measurements. Emulsions obtained from 10 wt% of 3:1 wt. ratio WPI:GA, at pH 7 (10 wt% canola oil) show better stability than emulsions stabilized by GA or WPI alone. The droplet sizes were smaller than 1 $μ$m and did not grow significantly during 1 mo of incubation at 25 °C. The D-limonene-based emulsion droplets were larger (\textgreater2 $μ$m) than those made with vegetable oils immediately after prepn. and underwent significant droplet size increase (coalescence) within 1 mo (\textgreater8 $μ$m). The emulsion with turbidity suitable as a cloudy emulsion was composed of 3 wt% WPI:GA (3:1) and 20 wt% canola oil. [on SciFinder(R)]
Miri Klein, Abraham Aserin, Paul Ben Ishai, and Nissim. Garti. 2010. “Interactions between whey protein isolate and gum Arabic.” Colloids and Surfaces, B: Biointerfaces, 79, 2, Pp. 377–383. Abstract
In this study we have attempted to understand the nature of "charge interactions" between two neg. charged biopolymers (whey protein isolate, WPI and gum Arabic, GA) and, consequently, why their mixt. exhibits better interfacial activity. Surface tension ($\gamma$0) measurements indicated that at ca. 1 wt.% of the biopolymer mixt. (3:1 wt. ratio) the air/water surface is satd. At 5 wt.% the $\gamma$0 of the mixt. is lower than the calcd. co-operative value. The $\zeta$-potential measurements revealed that the isoelec. point of the WPI:GA 3:1 wt. ratio mixt. is 3.8. The $\zeta$-potential values up to pH 6 are below those calcd. Similarly, the elec. conductivities of the mixt. are lower than those calcd. All these measurements indicate: (1) partial charge neutralization in spite of the fact that both biopolymers are neg. or (2) partial charge-charge interactions between the two biopolymers. The thermal heating behavior of the frozen water in the aq. mixt. studied by DSC (heating cycle of the frozen sample) clearly indicates that the two biopolymers are interacting. We calcd. the enthalpy, the free energy and the chem. potential of the interactions. We found that the interactions of the biopolymers are rather weak. They are likely derived from some local pos. charged domains (pH 7) on the protein that neutralize some of the neg. charged GA. These interactions form weak charge adducts. These charge adducts are sufficient to improve its adsorption into the oil-water interface and enhance the emulsion stability. [on SciFinder(R)]
Dima Libster, Abraham Aserin, Idit Amar-Yuli, Tehila Mishraki, Yael Domovich-Eisenberg, Oded Livnah, and Nissim. Garti. 2010. “Crystallization of cyclosporin A in lyotropic reverse hexagonal liquid crystals.” CrystEngComm, 12, 7, Pp. 2034–2036. Publisher's Version Abstract
In this communication we demonstrate for the first time that lyotropic reverse hexagonal mesophase can serve as a crystn. medium for a hydrophobic peptide, resulting in high quality single crystals suitable for crystallog. anal. The obtained crystals of cyclosporin A enabled excellent X-ray data collection, diffracting to a resoln. limit of 1.0 \AA. Current findings open a new perspective in the field of crystn. of biol. macromols. in lyotropic mesophases. [on SciFinder(R)]
Tehila Mishraki, Dima Libster, Abraham Aserin, and Nissim. Garti. 2010. “Temperature-dependent behavior of lysozyme within the reverse hexagonal mesophases (HII).” Colloids and Surfaces, B: Biointerfaces, 75, 2, Pp. 391–397. Abstract
This manuscript is the second part of a study on the structural behavior of lysozyme-loaded reverse hexagonal mesophases. In the current paper, th focus was mainly on the mutual temp.-dependency relationship between the protein and the mesophase. The conformational stability of the enzyme and the structural effects on the host system were characterized using small-angle X-ray scattering (SAXS), ATR-FTIR spectroscopy, fluorescence, and rheol. measurements. It was found that the mesophase does not change the solubilized lysozyme (LSZ) active site conformation. The obtained data suggested that LSZ embedment within the HII mesophase improved its thermal stability by hampering its helical structure destruction, apparently due to hydrogen bonding of the protein with monoolein polar heads. Examn. of the structural parameters of the hexagonal carrier revealed a strong thermal dependency. The lattice parameter of both empty and LSZ-loaded systems had a similar temp.-dependent behavior. However, comparing the domain size of the LSZ-loaded system to the empty system showed different trends. LSZ incorporation induced a decrease in crystal size and lower order at room temp. Nevertheless, an increase in domain size was triggered by the enzyme at elevated temps., in contrast to its decrease in the empty carriers. Rheol. measurements showed concn.-dependent elasticity in the presence of LSZ compared to the empty system, which took place in a concn.-dependent manner at all examd. temps. Up to 60 °C, the elasticity of the LSZ-loaded hexagonal systems decreased with temp. increase. This finding was interpreted in the context of weakening and/or cleaving of the monoolein hydroxyls' interactions with the protein, leading to partial reconstitution of the initially low domain size and elasticity decrease. However, in the range of 60-75 °C (in most systems), the prevailing effect was thermally induced dehydration of the monoglyceride hydrophilic heads, which imposed elasticity increase, owing to enhanced flow ability of the liq. cryst. structure. [on SciFinder(R)]
Tehila Mishraki, Dima Libster, Abraham Aserin, and Nissim. Garti. 2010. “Lysozyme entrapped within reverse hexagonal mesophases: Physical properties and structural behavior.” Colloids and Surfaces, B: Biointerfaces, 75, 1, Pp. 47–56. Abstract
A model protein (lysozyme) was incorporated into monoolein-based reverse hexagonal (HII) mesophase and its structure effects were characterized by small angle X-ray scattering, ATR-FTIR spectroscopy, and rheol. measurements. Modifications in mol. organization of the HII mesophases as well as the conformational stability of lysozyme (LSZ) as a function of pH and denaturing agent (urea) were clarified. Up to 3 wt. % LSZ can be solubilized into the HII. The vibration FTIR anal. revealed that LSZ interacted with OH groups of glycerol monooleate (GMO) in the outer interface region, resulting in strong hydrogen bonding between the surfactant and its environment. Simultaneously, the decrease in the hydrogen-bonded carbonyl population of GMO was monitored, indicating dehydration of the monoolein carbonyls. These mol. interactions yielded a minor decrease in the lattice parameter of the systems, as detected by small angle X-ray scattering. Furthermore, LSZ was crystd. within the medium of the hexagonal structures in a single crystal form. The $\alpha$-helix conformation of lysozyme was stabilized at high pH conditions, demonstrating greater helical structure content, compared to D2O soln. Moreover, the hexagonal phase decreased the unfavorable $\alpha$ → $\beta$ transition in lysozyme, thereby increasing the stability of the protein under chem. denaturation. The rheol. behavior of the hexagonal structures varied with the incorporation of LSZ, reflected in stronger elastic properties and pronounced solid-like response of the systems. The hydrogen bonding enhancement in the interface region of the structures was most likely responsible for these phenomena. The results of this study provided valuable information on the use of hexagonal systems as a carrier for incorporation and stabilization of proteins for various applications. [on SciFinder(R)]
Ido Nir, Abraham Aserin, Dima Libster, and Nissim. Garti. 2010. “Solubilization of a Dendrimer into a Microemulsion.” Journal of Physical Chemistry B, 114, 50, Pp. 16723–16730. Abstract
The present work investigates, for the first time, a system comprising a dendrimer incorporated into the water core of water-in-oil (W/O) microemulsion (ME). A second generation (G-2) poly(propyleneimine) dendrimer (PPI) was solubilized into W/O ME composed of AOT (sodium bis(2-ethylhexyl)sulfosuccinate), heptane, and water. Such a model system possessing the benefits of both dendrimers and ME, can potentially offer superior control of drug administration. The localization of PPI within the system, its specific interactions with the components of the carrier, and its effect on the ME structure was explored by SAXS, DSC, ATR-FTIR, and elec. cond. measurements. Considerable water binding by PPI, accompanied by partial dehydration of AOT polar heads, was detected by ATR-FTIR and DSC anal., suggesting that PPI acted as a "water pump". In addn., SAXS measurements showed periodicity increase and disordering of the droplets. Hence, localization of PPI within the core and interfacial regions of the droplets was assumed. Direct electrostatic interactions between PPI and the sulfonate group were not noticed, since the dendrimer mols. were mostly not protonated in the current basic environment at pH 12. However, slight hydrogen bonding between PPI and the S=O groups allowed the dendrimer to behave as a "spacer" between sodium and sulfonate ions. This affected the elec. cond. behavior of the system, revealing that PPI favored the percolation process. Most likely, PPI decreased the rigidity of the interfacial layer, facilitating the diffusion of sodium ions through the channels. The characterized model system can be advantageously utilized to design specific delivery vehicles, allowing administration of dendrimers as a therapeutic agent from host MEs. [on SciFinder(R)]
Shoshana Rozner, Deborah E Shalev, Alexander I Shames, Maria Francesca Ottaviani, Abraham Aserin, and Nissim. Garti. 2010. “Do food microemulsions and dietary mixed micelles interact?” Colloids and Surfaces, B: Biointerfaces, 77, 1, Pp. 22–30. Abstract
Using microemulsions (ME) as delivery vehicles requires understanding whether water-insol. mols. are delivered by an interaction of the ME system with the dietary mixed micelles (DMM) in the small intestine to give new mixed micelles, or by alternate paths. Dild. DMM and ME systems were mixed at various wt. ratios to address this question. The individual and mixed systems were characterized by phys. techniques that address this interaction from different aspects. This research showed that increased DMM concn. in ME/DMM mixed systems caused: (1) increased conformational order of the acyl chains and perturbed hydrogen bonds between the ethoxylate headgroups (based on ATR-FTIR results); (2) significant increase in microviscosity (from 1.7 to 3.3 ns) (based on EPR results); (3) increased diffusivity of the surfactant mols. compared to their diffusivity in pure ME droplets, and decreased diffusivity of the taurochenodeoxycholate mols. compared to their diffusivities in pure DMM micelles (based on PGSE-NMR results); (4) formation or modification of intramol. interactions (based on NOESY-NMR results); (5) decreased av. droplet diam. and increased droplet d. per unit area compared to pure ME systems (based on DLS and cryo-TEM results); and (6) fluorescence resonance energy transfer between two dyes (diphenylhexatriene and Nile Red), which were solubilized in each system sep. (based on fluorescence resonance energy transfer results). These results show that DMM and ME interact to create ME-DMM mixed micelles, providing a potential pathway for delivering solubilized mols. [on SciFinder(R)]