Publications by Year: 2003

Magdassi S, Kamyshny A, Vinetsky Y, Bassa A, Abo Mokh R.; 2003. Ink-jet inks containing metal nanoparticles useful for conductive patterns.Abstract
Compns. for use in ink jet printing onto a substrate comprise a water based dispersion including metallic nanoparticles and appropriate stabilizers. Also disclosed are methods for the prodn. of said compns. and methods for their use in ink jet printing onto suitable substrates. Thus, an ink comprised 99.75% nanoparticle dispersion comprising 0.18% silver nanoparticle and 0.2% CM-cellulose sodium salt and 0.25% BYK 154 wetting agent. [on SciFinder(R)]
Magdassi S, Ben-Moshe M, Berenstein L, Zaban A. Microemulsion based ink-jet ink: Properties and performance. J. Imaging Sci. Technol.Journal of Imaging Science and Technology. 2003;47 (4) :357 - 360.Abstract
Oil-in-water microemulsions which contain a hydrophobic colorant were evaluated as water based ink-jet inks. These microemulsion based ink-jet inks are thermodynamically stable, have the features of dye based inks prior to printing, and the features of pigment based inks after printing. The microemulsion was prepd. and printed, as described recently by Magdassi et al. using the gemini-type surfactant, didodecyldiphenylether disulfonate, toluene, 1-propanol, water as the continuous phase and Nile Red or Sudan IV as the hydrophobic dye. Microemulsion av. droplet size was measured by dynamic light scattering and found to be ∼8 nm. The authors found by AFM imaging that the printed 20 - 60 μm droplets are composed of nanoparticles with av. size of 130 nm. The printing process was evaluated by a fluorescence microscope, while images of the droplets were viewed as a function of time after impact with the substrate. It was found that the microemulsion droplets formed distorted spheres on ink-jet paper, more perfectly shaped spheres on Forbo paper substrate and perfect round spheres on vinyl slides. When printed on glass, a "bagel like" shape was obtained. The droplet size varied, depending on the surface energy of the substrate, being at least 20 μm for low energy surfaces and growing larger for higher energy substrates. It was noticed that the time scales for spreading on paper was less than tens of milliseconds accompanied and followed by fixation and drying of the droplets in less than 3 - 5 s. [on SciFinder(R)]
Magdassi S, Ben Moshe M, Talmon Y, Danino D. Microemulsions based on anionic gemini surfactant. Colloids Surf., AColloids and Surfaces, A: Physicochemical and Engineering Aspects. 2003;212 (1) :1 - 7.Abstract
Oil in water microemulsions were prepd. using didodecyldiphenylether disulfonate gemini-type surfactant (C12-DADS), water, oil (toluene) and a co-solvent (short chain alc. such as 1-propanol). The phase diagrams for microemulsions with gemini surfactants were detd. and compared to those of structurally related surfactants, monododecyldiphenylether disulfonate (C12-MADS) and monododecyldiphenylether monosulfonate (C12-MAMS). Cond. measurements and direct imaging by cryo-TEM were performed to characterize the phases. [on SciFinder(R)]
Kamyshny A, Relkin P, Lagerge S, Partyka S, Magdassi S. Native and hydrophobized human IgG: enthalpies of heat-induced structural changes and adsorption onto silica. J. Therm. Anal. Calorim.Journal of Thermal Analysis and Calorimetry. 2003;71 (1) :263 - 272.Abstract
Differential scanning calorimetry (DSC) and isothermal calorimetric batch technique were used to monitor the heat-induced structural changes and adsorption properties of human IgG, in native and hydrophobized states. The transition temp. (Tmax) and enthalpy of heat-induced conformational changes (ΔcalH) of IgG in soln. as well as the enthalpy change accompanying the adsorption of IgG onto hydrophilic silica (ΔadsH), were shown to depend on the degree of the protein hydrophobicity (no. of covalently attached alkyl chains). The adsorption enthalpy for all forms of IgG at all surface concns. was found to be endothermic, that is the process is entropy driven. Factors affecting the IgG adsorption onto silica are discussed. [on SciFinder(R)]
Magdassi S, Ben Moshe M. Patterning of Organic Nanoparticles by Ink-jet Printing of Microemulsions. LangmuirLangmuir. 2003;19 (3) :939 - 942.Abstract
Direct ink-jet printing of water-insol. org. materials may provide a new route for low-cost fabrication of various products that require fine patterning of functional mols. However, printing by water-based, environmentally friendly inks requires significant research and development efforts aimed at achieving a dispersion of nanoparticles of the specific mol. in water. We demonstrate a concept for direct patterning of water-insol. org. mols. in the form of nanoparticles, which can be easily adapted to a large variety of mols. such as conducting polymers and org. light-emitting diodes. The method is based on formation of a thermodynamically stable oil-in-water microemulsion in which volatile "oil" droplets contain the dissolved org. mols. The microemulsion droplets are converted into org. nanoparticles upon impact with the substrate surface due to evapn. of the volatile solvent. [on SciFinder(R)]
Cohen E, Joseph T, Kahana F, Magdassi S. Photostabilization of an entomopathogenic fungus using composite clay matrices. Photochem. Photobiol.Photochemistry and Photobiology. 2003;77 (2) :180 - 185.Abstract
To provide photostabilization for entomopathogenic fungi by anionic dyes, composite matrixes based on clay-biopolymer combinations were prepd. In the first step, the neg. surface charge of various clays (montmorillonite, attapulgite, bentonite and kaolinite) was reversed to pos. by adsorption to the polycationic biopolymer chitosan. The second step involved adsorption of the toxicol. safe anionic dyes fast green (FG) and naphthol yellow S (NYS) to the clay complexes. Compared with cytotoxic photoprotectants like berberine, palmatine and acriflavine, the anionic dyes have no adverse effects up to a concn. of 1 M. In assays using various clay-chitosan-dye matrixes and UV irradn. from a lamp source, it was evident that both FG and NYS provided considerable photostabilization for conidia of the entomopathogenic fungus Aschersonia spp. that served as a model biocontrol agent. Because of the light-dispersing property, bentonite and attapulgite per se provided significant photoprotection. All clay matrixes contg. FG provided a substantial photostabilization effect. [on SciFinder(R)]
Magdassi S, Yang A, Tao C, Desai NP, Yao Z, Soon-Shiong P.; 2003. Preparation of total nutrient admixtures as stable multicomponent liquids or dry powders.Abstract
Stabilized total nutrient admixt. (TNA) compns., useful for the in vivo parenteral delivery of pharmacol. acceptable lipids or fats, as well as methods for their prepn. are described. In particular, the pharmacol. acceptable lipid or fat is contained within a biocompatible polymer, e.g., a protein, walled shell. In a particular embodiment of the invention, a TNA compn. using human serum albumin (HSA) as a stabilizer has been prepd. as a convenient three-in-one formulation (i.e., contg. a fat emulsion, dextrose, and amino acids plus electrolytes). This "three-in-one" formulation can be prepd. in liq. form or in dry form (comprising submicron-sized nanoparticles). The dried material is stable, even under long term storage, and is easily reconstituted immediately before use by simply adding sterile water (with or without vitamin supplementation). This serves to rehydrate the powder into a TNA suitable for injection. The long shelf life, ease of reconstitution, and single-component injectability of invention compns. provide significant cost savings, as such compns. can be reconstituted and administered safely, even at home. In addn., HSA, the stabilizing agent of choice for use in the practice of the present invention, has been shown to improve survival and wellness when given as a supplement to patients receiving conventional forms of total nutrient admixts. [on SciFinder(R)]
Izmailova VN, Kamyshny A, Levachev SM, Magdassi S, Kharlov AE, Yampol'skaya GP. Rheological Properties of the Interfacial Layers of Hydrophobized Gelatins. Colloid J.Colloid Journal (Translation of Kolloidnyi Zhurnal). 2003;65 (6) :784 - 785.Abstract
Rheol. properties of the interfacial layers of gelatins chem. modified with N-hydroxysuccinimide ester of caprylic acid (the degree of modification is 10, 30, and 85%) are studied. Interfacial layers are spontaneously formed at the aq. gelatin soln.-toluene interface. Rheol. characteristics (yield strength, modulus of elastic deformation, Schwedoff and Bingham viscosities) increase in proportion to the degree of modification (hydrophobization) of gelatin. [on SciFinder(R)]
Magdassi S, Bassa A, Vinetsky Y, Kamyshny A. Silver Nanoparticles as Pigments for Water-Based Ink-Jet Inks. Chem. Mater.Chemistry of Materials. 2003;15 (11) :2208 - 2217.Abstract
Stabilized concd. citrate-reduced silver nanocolloids for use as pigments in ink-jet inks were prepd. CM-cellulose was used as a polymeric stabilizer providing both electrostatic and steric stabilization. X-ray diffraction pattern, optical properties (UV-visible spectroscopy), size (TEM and dynamic light scattering), and zeta potentials of the nanoparticles were studied. It was shown that the product is silver with cubic symmetry. Absorption spectra are characterized, as a rule, by asym. absorption bands with maxima at 417-440 nm and shoulders at 350-352 and 380-382 nm. TEM images of unstabilized and stabilized colloids indicate the formation of nanoparticles of different shapes (spheres, hexagons, cubes, and rods) with rather wide size distribution in the range from several nanometers (spheres) up to several hundreds of nanometers (rods). CMC was found to be an effective stabilizer of silver nanoparticles, and the av. particle size at CMC concns. from 0.025 to 0.2 wt. % does not exceed 50 nm. Both unstabilized and stabilized silver nanoparticles display neg. zeta potentials in the pH range from 2 to 9; the maximal neg. values are obsd. at pH 6-8 (-27 ± 5 mV for unstabilized and -33 ± 5 mV for CMC-stabilized colloids, resp.). Concd. dispersions of silver nanoparticles (1.1 wt. % of silver), which were stable for at least 7 mo, were prepd. by exhausted lyophilization of the freshly prepd. colloids followed by redispersion. These nanoparticles in the presence of proper wetting agent, such as Disperbyk, can be used as pigments in ink-jet ink formulations for printing on various substrates (paper, glass, and transparencies). The stabilizing agent, CM-cellulose, also acts as a binder, providing good adhesion of ink to the substrates. [on SciFinder(R)]
Kamyshny A, Magdassi S, Avissar Y, Almog J. Water-soaked evidence: detectability of explosive traces after immersion in water. J. Forensic Sci.Journal of Forensic Sciences. 2003;48 (2) :312 - 317.Abstract
Various factors governing the detectability of explosive traces after being soaked in water were studied. The variables are: the type of the surface (surfaces liable to be found in aircraft were chosen), the type of explosive, the type of water (tap or seawater), and movement of the immersed surface in the water. The maximal immersion times (tmax) after which explosive detection was possible were evaluated. This datum was found to depend on the type of explosive (one of the important factors is soly. in water), the surface material and the environmental conditions (tap or seawater movement). Detection of PETN on high-d. polyethylene, linoleum, glass and aluminum, by the chem. Explosive Testing Kit (ETK), was possible even after a month of soaking in seawater. In addn., it was found that movement of bulk water around the samples with deposited explosives considerably decreases tmax values. It is, therefore, recommended to retrieve samples for explosive anal. as soon as possible and in areas where the currents of water is minimal. [on SciFinder(R)]
Lagerge S, Kamyshny A, Magdassi S, Partyka S. Calorimetric methods applied to the investigation of divided systems in colloid science. J. Therm. Anal. Calorim.Journal of Thermal Analysis and Calorimetry. 2003;71 (1) :291 - 310.Abstract
A review. A new batch titrn. microcalorimeter has been used for estn. of thermodn. properties in various investigated colloidal systems. As examples, we present enthalpic and kinetic data obtained from this calorimetric device for four different processes widely encountered in colloid science: (i) the diln./micellization process of cationic gemini surfactants in aq. soln.; (ii) the hydration process of non ionic surfactants in org. soln., i.e. the mechanism of micellar solubilization of water in the aggregates; (iii) the complexation of calcium ions by polyacrylates sodium salts (PaNa); (iv) the adsorption phenomenon of PaNa mols. on the calcium carbonate surface. [on SciFinder(R)]
Kamyshny A, Magdassi S, Mishirqi S.; 2003. Diagnostic beads for the detection of blood in animal excreta and a method for production thereof.Abstract
Diagnostic beads are disclosed for the detection of occult blood in animal excreta, esp. for use in a cat litter. The beads comprise a particulate material and a detection compn. attached to the particulate material. The detection compn. comprises a chromogen, a peroxide, an enhancer, a stabilizer, and a binder, the chromogen being selected to react with occult blood in the animal excreta so as to produce a visible and immediate color change when excreta contg. blood comes into contact with the diagnostic beads. [on SciFinder(R)]
Steinberg D, Kamyshny A, Magdassi S.; 2003. Edible compositions capable of removing oral biofilm.Abstract
An edible and/or chewable article contg. at least one food grade substance having adsorption affinity towards at least one dental plaque (biofilm) constituent and capable of reducing and/or removing the oral biofilm while present in the mouth is described. Particular articles are chewing gums, sweets, candies, candy- and other nutritional bars, ice creams, chocolates, confectionery and bakery/pastry products, honey, dairy products and beverages, and oral hygiene products such as tooth pastes, oral gels and mouthwashes. A chewing gum comprises a conventional gum base and at least one food grade active substance having adsorption affinity towards at least one dental plaque (biofilm) constituent (bacteria and proteins and bacterial cell-free enzymes) and capable of reducing and/or removing the oral biofilm while present in the mouth. Typical active substances are polysaccharides and non-toxic salts thereof, such as alginates, chitosan, CM-cellulose, agar and carrageenan, inorg. substances such as silica, hydroxyapatite and calcium carbonate, and proteins, particularly gelatin and lectin. The chewing gum and other articles are particularly intended for removing and/or for preventing or reducing dental plaque (biofilm), and controlling oral, dental and periodontal diseases. For example, chewing gum base contg. sodium alginate exhibited high binding properties for Streptococcus mutans, av. of 2000% compared to the gum base without the alginate (control = 100% adhesion). Other polysaccharides, such as carrageenan, agar, sodium CM-cellulose and chitosan also exhibited higher adsorption than the control chewing gum base, but less than the alginate (500%, 510%, 600%, and 400%, resp.). [on SciFinder(R)]