Colloids magnetic particles

Separate nanometer- to micron-sized colloidal magnetic particles, often dispersed in solutions they are usually stabilized by polyions or polymers. 

Physically interconnected colloidal magnetic particles supported by a monolayer, a BLM, or a solid substrate. 

Pastor-Satorras R, Rubi R (1998) Fractal properties of cluster of colloidal magnetic particles. Prog Colloid Polym Sci 110 29-33... 

Particularly attractive for numerous bioanalytical applications are colloidal metal (e.g., gold) and semiconductor quantum dot nanoparticles. The conductivity and catalytic properties of such systems have been employed for developing electrochemical gas sensors, electrochemical sensors based on molecular- or polymer-functionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzyme-based electrodes, immunosensors, and DNA sensors. Advances in the application of molecular and biomolecular functionalized metal, semiconductor, and magnetic particles for electroanalytical and bio-electroanalytical applications have been reviewed by Katz et al. [142]. 

Papell, S.S.Low viscosity magnetic fluid obtained by the colloidal suspension of magnetic particles. US Patent (1965) 3,215,572. 

Unilamellar vesicles have been used as a reactor for the synthesis of nanos-meter-scale magnetic particles (13,14). By adding alkaline solution to vesicles containing intravesicular solutions of Fe2+ and Fe3+, the Fe /Fe resulted in the formation of membrane-bound discrete particles of different ion oxide particles. These results together with the particle formation in microemulsion are not only of interest in colloid chemistry but also have significance in mineralization in biosystems, such as magnetotactic bacteria, where particles are formed within enclosed organic compartments. 

Kantor, A. B., Gibbons, I., Miltenyi, S., and Schmitz, J. (1998) Magnetic cell sorting with colloidal superparamagnetic particles, in Cell Separation Methods and Applications (Recktenwald, D., and Radbruch, A., eds.), Marcel Dekker, Inc., New York, pp. 153. 

If the sonolysis is done in the presence of a support or porous host, then colloidal metal particles are formed. These powders have a surface area over a hundred times greater than powders commercially available and are amorphous. Such materials are generally considered for catalytic reactions and not for magnetic applications. 

N.M.R. STUDIES of ADSORBED ETHYLENE We have also investigated the reaction of C ethylene with colloidal palladium. Our initial intent was to attempt to observe the formation of ethylidyne from ethylene on the surface of the colloidal palladium particles, a reaction which is known to occur readily on the surface of supported palladium and on palladium single crystals (17). Such a reaction has been identified for ethylene on supported platinum by magnetic resonance experiments in which spin echo double resonance techniques were used to characterize the organic species (18,19), but direct observation of resonances for adsorbed ethylene or ethylidyne was not possible in the highly inhomogeneous solid samples used. The chemical shift differences... 

Since the field related to magnetic particles is broad, this article is written from a colloid chemistry point of view. Readers should refer to the articles by Privman et al., Sngimoto, and Matijevic for information on the formation of monodispersed particles. 

Thomas, J.R., Preparation and magnetic properties of colloidal cobalt particles, J. Appl. Phys., 37, 2914, 1966. 

Ozaki, M., Egami, T., Sugiyama, N., and Matijevic, E., Agglomeration in colloidal hematite particles due to weak magnetic interactions, J. Colloid Interface Sci., 126, 212, 1988. 

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