Immobilized silver colloids

Silver in the metallic state is not readily eliminated from the body. Following intramuscular implantation, silver will complex with sulfur-containing amino acids or proteins and may remain permanently immobilized at the site of the implant (Luckey and Venugopal 1997). Implantation of silver foil has been demonstrated to induce fibrosarcoma in rats at the implant site, particularly when implanted subcutaneously (Oppenheimer etal. 1956). Subcutaneous injection of colloidal silver has likewise been shown to induce tumor formation. Autometallography is used to highlight... 

Silver, gold and copper are the most commonly used metals for SERS and the variety of substrates include, among others, roughened surfaces, nanoparticle colloidal suspensions, island films and nanostmctured surfaces (4). Current trends in SERS and Raman spectroscopy include the development of new substrates which includes immobilized particles, functionalized nanoparticles and nanolayered films. These recent development have created new opportunities for chemical and biological sensing. 

Control of the evaporation conditions also allows the preparation of polymer-immobilized nanoparticles. For example, colloidal silver was obtained with the particle size of 1.0-20 nm (the colloidal Ag particles less than 40 nm in diameter absorb light at -400 nm). The dispersion of gold nanoparticles (mean particle size 2nm) in poly(diphenylbutadiyne) has been obtained by cocondensation of vapor of Au and diacetylene on a support at 77K. ... 

The radiation-chemical and photo-induced reduction is preferred to the reduction by hydrogen when it is necessary to prepare small particles with a narrow size distribution. A characteristic example is the preparation of blue silver in the process of y-irradiation of shghtly alkaline aqueous solutions of AgC104 containing 2-propanol and PAA. - The blue silver is a linear Ag cluster stabilized on a polymer molecule. In the course of radiation-chemical reduction, the Ag clusters are transformed through a number of successive stages into a polymer-immobilized colloidal silver. 

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