Publications

2012
Meital Gavriel Aviv, Amit, Boaz , Yayon, Avner , Garti, Nissim , and Milhofer, Helga Furedi. . 2012. Gradient Organic Inorganic Nanocomposites For Tissue Repair At The Cartilage/Bone Interface.. Key Engineering Materials, 493-494, Bioceramics 23, Pp. 577–581. doi:10.4028/www.scientific.net/KEM.493-494.577.
Damages to articular cartilage that are caused by trauma, age-related diseases (arthritis, arthrosis) and/or phys. stress pose major medical problems. A possible soln. is to introduce a biodegradable sponge-like scaffold contg. cartilage-forming cells. In the current work we developed a model for a partially calcified functional biomedical membrane with a gradient of calcium phosphate crystal d. to form the interface between bone and a sponge-like cell contg. scaffold for cartilage regeneration. The membrane consists of a biocompatible, biodegradable, partially calcified hydrogel, in our case gelatin was used. One part is an org.-inorg. nanocomposite consisting of nanocryst. calcium phosphate particles, formed in situ within the hydrogel, while the other part is the hydrogel without inorg. crystals. The exptl. method used was one-dimensional single diffusion. Gelatin gels contg. calcium or phosphate ions, resp., were exposed from the upper side to a soln. of the other constituent ion (i.e. a sodium phosphate soln. was allowed to diffuse into a calcium contg. gel and vice versa). SEM (E-SEM), EDX, XRD and ATR-FTIR spectroscopy confirmed the existence within the gel of a d. gradient of carbonate apatite crystals, with a dense top layer extending several microns into the gel. Ca/P at. ratios were in the range characteristic of calcium deficient apatites. The effect of different exptl. parameters on the calcification process within the gelatin membranes is discussed. [on SciFinder(R)]
Chandrashekhar V Kulkarni and Glatter, Otto. . 2012. Hierarchically Organized Systems Based On Liquid Crystalline Phases.. In Self-Assem. Supramol. Archit., Pp. 157–191. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch6.
A review. Presented are hierarchically organized nanostructures formed from lyotropic liq. cryst. (LC) phases. The nano-, micro-, and macroscopic structural hierarchy arises from the kinetic stability of various lyotropic phases dispersed in oil-in-water (O/W) or water-in-oil (W/O) emulsions. When an O/W emulsion consists of a dispersion of LC nanoparticles stabilized by certain stabilizers, it is called an ISAsome, i.e., an internally self-assembled particle. In contrast, when the water droplets are dispersed in a continuous film of LC nanostructures, they are called W/O-nanostructured emulsions, which do not require a stabilizing agent. Both emulsions exhibit fascinating properties that can be tuned to a great extent. Such tunability proliferates their performance in various applications. Herein, the formation, multiscale structure, properties, and their modulation for the aforementioned superstructures formed from LC phases are discussed. Focusing further on ISAsomes Pickering emulsions stabilized by various nanoparticles are presented, including synthetic clay laponite and silica nanoparticles. The transfer of hydrophobic components among several differently nanostructured ISAsomes was studied by time-resolved x-ray scattering; the effects of Isasome-forming components are also illustrated. The continuous aq. region of ISAsome dispersions can be loaded with water-sol. polymers that form thermo-reversible hydrogels. This enables the entrapment of ISAsome systems into such hydrogel networks. Subsequent drying of these loaded systems facilitates immobilization of ISAsomes, which can be easily restored by rehydration of the loaded dry films. The formation of hydrogels in the aq. reservoirs of W/O-nanostructured emulsions also proved advantageous in terms of tuning their viscosity and, in some cases, enhancing their stability. The current contribution covers systems with diverse structural hierarchy, ranging from equil. liq. cryst. nanostructures to the systems with multiple orders of length scales in their structure. [on SciFinder(R)]
Nissim Garti, Libster, Dima , and Aserin, Abraham. . 2012. Lipid Polymorphism In Lyotropic Liquid Crystals For Triggered Release Of Bioactives.. Food & Function, 3, 7, Pp. 700–713. doi:10.1039/c2fo00005a.
In this review the authors present recent progress on lyotropic liq. crystals (LLC) as delivery vehicles for cosmetoceuticals, nutraceuticals, and drugs. LLC were known for decades and their potential as delivery vehicles is well recognized. Yet, the 2 major mesophases, reverse hexagonal (HII) and bicontinuous cubic (primitive, gyroid, and diamond), are relatively hard gels with very slow release kinetics of the bioactives. In recent years a discontinuous cubic micellar mesophase (QL) was characterized and studied, showing significant potential as a delivery vehicle. In addn., the HII mesophase formed could be much more fluid and produced at room temp. Recent studies concd. on establishing methods to evaluate solubilization capacity and relationship between the diam. and length of the cylinders and the nature of the solubilizates. Special attention was given to finding methods to target the vehicles to the lumen and to trigger the release of the bioactives. This review summarizes the efforts of the authors' group along with work by numerous other scientists in this area. All these efforts suggest that the lyotropic mesophases and the corresponding dispersed soft particles (cubosomes, hexosomes, micellosomes) are now more than ever ready to become drug delivery vehicles for transport across the skin and the gut. [on SciFinder(R)]
Nissim Garti, Hoshen, Geut , and Aserin, Abraham. . 2012. Lipolysis And Structure Controlled Drug Release From Reversed Hexagonal Mesophase.. Colloids And Surfaces, B: Biointerfaces, 94, Pp. 36–43. doi:10.1016/j.colsurfb.2012.01.013.
The present work investigates a system composed of a ternary reversed hexagonal mesophase (HII) loaded with a lipase for modulating drug delivery capabilities of the system. Thermomyces lanuginosa lipase was solubilized into HII mesophase for the benefits of continuing lipolysis of the lipids, consequently disordering and decompg. the hexagonal mesophase and thereby enhancing the diffusion of the encapsulated drug. A single transition from the HII structure to a random micellar phase was detected during the lipolysis. In the first lipolysis stage the hexagonal system (glycerol monooleate, tricaprylin, and water) preserved its symmetry within ca. 200 min. During this step about 40-60% molar of the lipids were hydrolyzed, and a gradual shrinking of the HII cylinders (decrease of 8 \AA in lattice parameter) was detected. In the second lipolysis stage, the HII mesophase gradually disintegrated (faster rate) and the release of a model drug (sodium diclofenac) was significantly enhanced, which was assumed to be lipolysis rate-controlled. After about 15 h the HII mesophase was disintegrated into two dispersed immiscible phases. The release obeyed two-step Higuchi kinetics with two consecutive linear correlations of the drug release. [on SciFinder(R)]
Massimo Bonini and Lo Nostro, Pierandrea. . 2012. Micelle Formation: Thermodynamic Aspects And Characterization.. In Nanotechnol. Solubilization Delivery Foods, Cosmet. Pharm., Pp. 31–49. DEStech Publications, Inc.
A review. The most prominent feature of surfactants is their ability to self-assoc. and form discrete aggregates in aq. dispersions. Among the various self-assembled structures that are produced (vesicles, membranes, liq. crystals, etc.), micelles represent the simplest class of assocn. colloids, and are widely used as nano-architectures for different applications. In spite of the vast literature, a complete understanding of all the exptl. evidences related to the micellization process is still a work in progress. In particular, the thermodn. and kinetics of micellization provide the crucial concepts for the control of dissocn. and reconstruction of micelles, such as in the solubilization, stabilization and delivery of active ingredients, and in cosmetics, detergents, food technol., and in pharmaceutical formulations. In this contribution, we offer an overview of the various structures formed by self-assembling amphiphilic mols. in water. The basic thermodn. involved in self-assembly is described, and an overview of the exptl. techniques used in the characterization of the structure and properties of these nanostructures is given. [on SciFinder(R)]
N Garti and Aserin, A. 2012. Micelles And Microemulsions As Food Ingredient And Nutraceutical Delivery Systems.. Woodhead Publishing Series In Food Science, Technology And Nutrition, 239, Encapsulation Technologies and Delivery Systems for Food Ingredients and Nutraceuticals, Pp. 211–251.
A review. Microemulsions are considered excellent delivery vehicles for bioactives, food additives and food supplements. They offer the advantages of spontaneous formation, ease of manuf., thermodn. stability, very low viscosity and Newtonian properties, full transparency (clear solns.) and improved solubilization capacities of bioactive materials. This chapter explores some of the new trends in microemulsion research, including many carried out in our lab, through anal. of some representative studies. The solubilization of different food additives such as flavoring agents, aromas, antioxidants, and colorants, as well as peptides and nutraceuticals, in various microemulsion compns. and microstructures are reviewed. [on SciFinder(R)]
Vesselin Kolev, Ivanova, Anela , Madjarova, Galia , Aserin, Abraham , and Garti, Nissim. . 2012. Molecular Dynamics Approach To Water Structure Of Hii Mesophase Of Monoolein.. Journal Of Chemical Physics, 136, 7, Pp. 074509/1–074509/11. doi:10.1063/1.3685509.
The goal of the present work is to study theor. the structure of water inside the water cylinder of the inverse hexagonal mesophase (HII) of glyceryl monooleate (monoolein, GMO), using the method of mol. dynamics. To simplify the computational model, a fixed structure of the GMO tube is maintained. The nonstd. cylindrical geometry of the system required the development and application of a novel method for obtaining the starting distribution of water mols. A predictor-corrector schema is employed for generation of the initial d. of water. Mol. dynamics calcns. are performed at const. vol. and temp. (NVT ensemble) with 1-dimensional periodic boundary conditions applied. During the simulations the lipid structure is kept fixed, while the dynamics of water is unrestrained. Distribution of hydrogen bonds and d. as well as radial distribution of water mols. across the water cylinder show water structure deep in the cylinder (∼6 \AA below the GMO heads). The obtained results may help understanding the role of water structure in the processes of insertion of external mols. inside the GMO/water system. The present work has a semi-quant. character and it should be considered as the initial stage of more comprehensive future theor. studies. (c) 2012 American Institute of Physics. [on SciFinder(R)]
Claire Geral, Angelova, Angelina , Lesieur, Sylviane , Angelov, Borislav , and Nicolas, Valerie. . 2012. Multicompartment Lipid Nanocarriers For Targeting Of Cells Expressing Brain Receptors.. In Self-Assem. Supramol. Archit., Pp. 319–355. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch11.
A review. Neurotrophic factors, such as the brain-derived neurotrophic factor (BDNF), are essential for the development and survival of human neurons. Their encapsulation in carrier lipid systems is anticipated to overcome the problems resulting from the pharmacokinetics of peptides in the cerebral circulation. Lipid nanocarriers contg. an omega-3 polyunsatd. fatty acid [eicosapentaenoic acid] (EPA), showing neuroprotective effects, should trigger the BDNF activity. The purpose of this study is to design and characterize self-assembled lipid systems suitable for encapsulation and potentiation of neurotrophic peptide activity and study of multicompartment liq. cryst. formulations in vitro on a human neuronal cell line expressing BDNF receptors. Sterically stabilized nanodispersed lipid systems are prepd. from a PEGylated (polyethylene glycol) liq. cryst. phase in excess water. Such lipid nanovectors, derived by self-assembly, are of ongoing interest thanks to their biocompatible compns. and the relatively low energy input required for their manuf. The latter is an essential factor for the encapsulation of fragile and temp.-sensitive peptide mols. Having induced the differentiation of a human neuroblastoma cell line SH-SY5Y, as a model of neurodegeneration, we examine in vitro the expression of the TrkB brain receptor of neurotrophins and the cytotoxicity of the designed multicompartment lipid nanocarriers to neuronal cells. [on SciFinder(R)]
Patrick G Hartley and Shen, Hsin-Hui. . 2012. Nanocharacterization Of Lyotropic Liquid Crystalline Systems.. In Self-Assem. Supramol. Archit., Pp. 97–127. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch4.
A review. The development of techniques for the characterization of the nanostructure of lyotropic liq. cryst. systems were crucial in enabling increased understanding of fundamental properties and efficacy in technol. applications. Provided is a review of a no. of commonly used and emerging nanocharacterization techniques, with a view to providing a resource for academic and industrial researchers joining the field. [on SciFinder(R)]
Roy E Hoffman, Aserin, Abraham , and Garti, Nissim. . 2012. New Insights Into The Microemulsion-Based Chromatographic Nmr Resolution Mechanism And Its Application To Fragrance/Flavor Molecules.. Journal Of Magnetic Resonance, 220, Pp. 18–25. doi:10.1016/j.jmr.2012.05.002.
The NMR chromatog. method is applied to a class of mols. with similar phys. properties. We correlate the sepn. ability of microemulsions to the phys. properties of the analyzed mols. Flavor and aroma compds. are very widespread. Compositional anal. is in many cases tedious. Any new method of anal. is always useful and challenging. Here we show a new application to a class of fragrance mols., with only a moderate variation in their chem. and phys. characteristics. Up to 11 selected compds. in one mixt. are resolved in one spectrum by NMR chromatog., despite the similarity of the compds. The differences between O/W and W/O microemulsions and their resoln. mechanism as applied to fragrance mols. are explained in terms of hydrophilicity and lipophilicity and effective crit. packing parameters of the microemulsions. The obsd. diffusion rates are shown to correlate with solvation parameters. These results can be used to est. the diffusion rates of mols. to be sepd., allowing selection of the microemulsion or NMR chromatog. solvent appropriate for each specific application. [on SciFinder(R)]
Debby P Chang and Nylander, Tommy. . 2012. Nonlamellar Lipid Liquid Crystalline Structures At Interfaces.. In Self-Assem. Supramol. Archit., Pp. 289–318. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch10.
A review. Nonlamellar lipid-based liq. cryst. structures, such as cubic, hexagonal, and sponge phases, have potential as delivery systems in pharmaceutical, food, and cosmetic applications. This is due to the space-dividing nature of these phases, which features mono- or bicontinuous networks of both hydrophilic and hydrophobic domains. To utilize these nonlamellar liq. cryst. structures as delivery vehicles, it is crucial to understand how they interact with and respond to different types of interfaces. The progress in the area of liq. cryst. lipid-based nanoparticles opens up new possibilities for prepn. of well-defined surface films with well-defined nanostructure. Apart from the relevance to drug delivery, such studies create opportunities for new applications for functionalized and tunable surface coatings as well. This review will focus on recent progress in the formation of nonlamellar dispersion and its interfacial properties at the solid-liq. and biol. relevant interfaces. Various exptl. techniques on the study of interfacial interactions of these cryst. structures will be discussed. [on SciFinder(R)]
Marganit Cohen-Avrahami, Libster, Dima , Aserin, Abraham , and Garti, Nissim. . 2012. Penetratin-Induced Transdermal Delivery From Hii Mesophases Of Sodium Diclofenac.. Journal Of Controlled Release, 159, 3, Pp. 419–428. doi:10.1016/j.jconrel.2012.01.025.
Penetratin, a cell penetrating peptide is embedded within a reversed hexagonal (HII) mesophase for improved transdermal delivery of sodium diclofenac (Na-DFC). The HII mesophase serves as the solubilization reservoir and gel matrix whereas penetratin is the transdermal penetration enhancer for the drug. The systems were characterized and the interactions between the components were detd. by SAXS, ATR-FTIR and SD-NMR. High affinity of Na-DFC to glycerol monooleate (GMO) was revealed, assocd. with increasing the order within the water channels. This affinity is enhanced upon heating and seems to be assocd. with GMO dehydration. Penetratin (PEN) is entrapped at the hydrophilic region of the HII mesophase, between the GMO headgroups, reducing the order of the system and decreasing the size of the hexagonal domains. The transdermal delivery rate of Na-DFC through porcine skin, from the HII mesophases, was enhanced by PEN and so also the cumulative transport crossing the skin. PEN induced accelerated drug diffusion through the stratum corneum, towards the different skin layers. The transdermal delivery enhancement is explained from the results of the ATR-FTIR anal. It seems that PEN accelerates the structural transition of skin lipids from hexagonal to liq. The disordering results in enhanced diffusion of Na-DFC through the stratum corneum, followed by enhanced overall penetration of the drug. [on SciFinder(R)]
Raffaele. Mezzenga. 2012. Physics Of Self-Assembly Of Lyotropic Liquid Crystals.. In Self-Assem. Supramol. Archit., Pp. 1–20. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch1.
A review. Reviewed are recent advances in the understanding of self-assembly principles in lipid-based lyotropic lipid crystals, from the original rationalization achieved using the crit. packing parameter up to recent, more sophisticated thermodn. approaches, such as the SCF theory, which can be efficiently used to minimize the total free energy of a lipid-water system and identify stable mesophases. Highlighted is the importance of reversible hydrogen bonding as one of the key parameters ruling the self-assembly in these systems and examine the implications this may have also in real applications. The current understanding on the dynamics of phase transitions are finally discussed and the status of the art on current atomistic approaches to investigate the relaxation dynamics in these systems is reviewed. [on SciFinder(R)]
Perla Relkin and Anton, Marc. . 2012. Protein- And Lipid-Based Nano- And Mirco-Capsules, As Food Micronutrient Carriers.. In Nanotechnol. Solubilization Delivery Foods, Cosmet. Pharm., Pp. 125–149. DEStech Publications, Inc.
A review. Com. available food ingredients, such as proteins, satd. or polyunsatd. lipids and polysaccharides have nutritional and structure-forming properties at different scale levels. They belong to classes of biodegradable and biocompatible biomaterials which are the focus of intensive research studies thanks to their potentiality to be used as bioactive matrix carriers. This chapter will be concerned with physicochem. and structural properties of protein and lipoprotein assemblies naturally present in food or induced by thermomech. treatments; and with the description of exptl. design and formulation of nutrient-rich products. In the first part, we will focus on the structural properties, from nano- to microsize level, of casein micelle heat-induced proteins aggregates, and of natural egg lipoproteins in relation to their property of protecting nutrients or bioactive compds. (vitamins, unsatd. fatty acids, antioxidants, aroma compds.) and stabilizing emulsions. In the second part we will draw attention to the relation between their protective and carrying properties with the structure and dynamics, at different scales, of such complex food matrixes. In conclusion, the trends in research concerning the delivery of nutrients in complex food will be debated. [on SciFinder(R)]
Anan Yaghmur and Rappolt, Michael. . 2012. Recent Advances In The Characterization Of Lipid-Based Nanocarriers.. In Nanotechnol. Solubilization Delivery Foods, Cosmet. Pharm., Pp. 187–208. DEStech Publications, Inc.
A review. Soft self-assembled lipidic systems with well-defined nanostructures have become increasingly important in the development of pharmaceutical, food, and cosmetic delivery systems. They have key roles in overcoming the insufficiency of bioavailability and other obstacles in drug delivery systems, such as severe side effects and the toxicity of poorly water-sol. bioactive mols. In particular, self-assembled nanostructures of naturally occurring surfactant-like lipids represent an interesting family of nanocarriers. This family of biodegradable and biocompatible materials displays structures closely related to those obsd. in biol. membranes and enables the formation of efficient delivery systems. The optimal utilization of these nanostructured objects requires a full understanding of their physicochem. properties and detailed characterization of their structures. Their stability after administration is a key issue in the development of excipients with a good performance and a significant redn. of unwanted side effects. This chapter summarizes recent studies of the possibility of utilizing soft lipidic self-assembled systems as drug and food nanocarriers. The scope covers recent investigations that have attempted to shed light on the formation of delivery systems based on microemulsions, and different nanostructured aq. dispersions. It highlights also some recent advances in the characterization of these complex soft nanoobjects. The main focus is placed on the recent developments in the field of small-angle scattering methods, dynamic light scattering (DLS), electron microscopy (tilt-angle cryo-TEM, and cryo-FESEM), and NMR (NMR) techniques. [on SciFinder(R)]
Dima Libster, Aserin, Abraham , and Garti, Nissim. . 2012. Recent Developments In Lyotropic Liquid Crystals As Drug Delivery Vehicles.. In Self-Assem. Supramol. Archit., Pp. 219–256. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch8.
A review. Recently, self-assembled lyotropic liq. crystals (LLCs) of lipids and water have attracted the attention of both the scientific and the applied research communities due to the remarkable structural complexity and practical potential of these nanostructures in diverse applications. The phase behavior of mixts. of glycerol monooleate (monoolein, GMO) was particularly well studied due to the potential utilization of these systems in drug delivery systems, food products, and encapsulation and crystn. of proteins. The present chapter summarizes structural features of LLCs and recent systematic efforts to utilize these for solubilization and the potential release of drugs and biomacromols. One of the most interesting applications is the implementation of cell-penetrating peptides in the reversed hexagonal mesophase to enhance the skin-penetrating pattern of a model drug (sodium diclofenac). Liq. crystal vehicles were shown to allow "on demand" targeted release, based on controlling the polymorphism of lyotropic liq. cryst. mesophases. Novel liq. cryst. matrix-gold nanorod hybrid materials were reported to induce light-triggered phase transition of liq. cryst. phases. Hydrophobized gold nanorods (GNRs) have been incorporated within the LLCs, composed of phytantriol and water, to provide remote heating, and trigger the phase transitions on irradn. at close to their resonant wavelength. A new pathway to pH-responsive LLCs, enabling the controlled release of hydrophilic drugs diffusing through the water channels of the mesophases, was also investigated. The system is capable of self-assembling into a reverse bicontinuous cubic phase of Im3m symmetry at pH 7 and transforming into a reverse columnar hexagonal phase at pH 2. Lyotropic liq. crystals were shown to entrap several nucleotides into cubic and lamellar monoolein-based mesophases in order to protect them and enable their release. DNA (DNA) within two types of reverse columnar hexagonal mesophases was studied, one based on pure nonionic lipids and the other decorated by cationic lipids to induce opposite charges at the surfaces of the water channels of the mesophases. This provided new opportunities in the design technologies for DNA transfection and for gene delivery. The main outcomes of the described research demonstrated that control of the phys. properties of hexagonal LLC on different length scales is key for rational design of these systems as delivery vehicles for both low-mol.-wt. therapeutics and biomacromols. [on SciFinder(R)]
Alejandro D Rey and Herrera-Valencia, EE. 2012. Rheological Theory And Simulation Of Surfactant Nematic Liquid Crystals.. In Self-Assem. Supramol. Archit., Pp. 21–77. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch2.
Presented a comprehensive review of rheol. theory, modeling, and simulation of surfactant nematic liq. cryst. phases, including calamitic and discotic micellar solns. and wormlike micelles. A review of verifiable rheol. liq. crystal models for lyotropic nematics highlighting the mechanisms that control orientation behavior under shear, anisotropic viscoelasticity, and non-Newtonian behavior. Since defects and textures are essential characteristics of these materials that affect the flow properties, an in-depth review of phys. and rheophys. defects is presented, including defect nucleation and coarsening processes. The theory for micellar nematics is applied to textures, flow birefringence, phase transition under shear, orientation fluctuations, and flow alignment, and the predictions are compared with exptl. data. The theory is finally applied to transient shear flows of wormlike micellar nematic solns., and the predicted banded textures and transient stress responses are compared to rheol. expts. The predictions provide a new way to ext. addnl. information from exptl. rheol. data and allow to distinguish the role of liq. cryst. properties such as viscoelastic anisotropy, flow alignment, coupling between orientation kinematics, and flow kinematics. The rheol. predictions show a strong similarity with other nematic materials, including low-molar-mass thermotropes and lyotropic nematic polymers. [on SciFinder(R)]
Anan Yaghmur and Glatter, Otto. . 2012. Self-Assembly In Lipidic Particles.. In Self-Assem. Supramol. Archit., Pp. 129–155. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch5.
A review. The present contribution summarizes our previous investigations on the formation of emulsions, whose particles consist of a self-assembled inverted-type liq. cryst. phase or an inverted-type microemulsion. In this context, the main focus was on replacing either the dispersed oil droplets in normal O/W emulsions, or the kinetically stabilized internal W/O emulsion in double W/O/W emulsions, by an inverted-type liq. cryst. phase or an inverted-type microemulsion system. Owing to the physico-chem. properties of their internal nanostructures, these unique aq. dispersions are superior to conventional emulsions and double emulsions. They are attractive as nanonreactors and as host systems for solubilizing active mols. (drugs, flavors, and vitamins) in the cosmetics, pharmaceutical, and food industries. This chapter describes the effect of varying temp. and solubilizing oil on the reversible structural transitions of the internal nanostructures of these lipidic dispersions. [on SciFinder(R)]
Idit Amar-Yuli, Aserin, Abraham , and Garti, Nissim. . 2012. Synthesis And Alignment Of Nanostructured Materials Using Liquid Crystals.. In Self-Assem. Supramol. Archit., Pp. 193–218. John Wiley & Sons, Inc. doi:10.1002/9781118336632.ch7.
A review. Liq. crystal (LC) science and technol. have made important contributions to nanoscience and nanotechnol. in areas such as medical diagnostics, drug delivery, and in high-tech devices. The major nanotechnol. contribution is their capability to provide new preparative procedures, self-assembly, and alignment of nanoscale materials with controlled uniform size, shape, and dimensionality. The self-assembly of the liq. cryst. systems, particularly the lyotropic LC type, enables the integration of lipophilic and hydrophilic reagents that meet to react at the interface. Therefore the reaction and the products properties are governed by the host liq. cryst. medium and by the external conditions (e.g., light, heat, chem. environment, and elec. and magnetic field), which directly affect the LC hosting system. This review attempts to give an overview of current research in the fields of prepn., self-assembly, and alignment of nanomaterials using mainly lyotropic LCs and partially thermotropic LCs as direct and reverse templates. [on SciFinder(R)]
Shifra Rokach, Ottaviani, Maria Francesca , Shames, Alexander I, Nir, Ido , Aserin, Abraham , and Garti, Nissim. . 2012. W/O Microemulsions As Dendrimer Nanocarriers: An Epr Study.. Journal Of Physical Chemistry B, 116, 41, Pp. 12633–12640. doi:10.1021/jp307616b.
A complex system, based on a dendrimer solubilized in the aq. core of water-in-oil microemulsion, may combine the advantages of both dendrimers and microemulsions to provide better control of drug release. We report for the first time the use of EPR technique to det. the effect of solubilized dendrimer on the structure of the microemulsion. The solubilized poly(propyleneimine) (PPI-G2) interacts with sodium bis(2-ethylhexyl) sulfosuccinate (AOT). EPR anal. provided information on polarity, microviscosity, and mol. order of the systems. Polarity and microviscosity increased from unloaded water-in-oil microemulsion to the system loaded with 0.2 wt. % PPI-G2, but remained unchanged with higher PPI-G2 loads. The degree of order also increased with 0.2 wt. % PPI-G2 with only minor addnl. increase with larger quantities (25 wt. %) of PPI-G2. Variations in pH only slightly affected the structure of microemulsion in the absence and presence of the loaded dendrimers. Aliph. oils with longer lipophilic chains enhanced the structural order of the microemulsion. On increasing water content, polarity and degree of order increased. PPI-G2 dendrimer in small loads is attracted by the neg. charged AOT and thus intercalates in the interface of the droplets. Yet, at higher PPI-G2 loads, the excess mols. are solubilized in the water core. [on SciFinder(R)]

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