In vivo liberation of silver ions from metallic silver surfaces

Abstract

In vivo liberation of electrically charged silver atoms/silver ions from metallic silver pellets, silver grids and silver threads placed in the brain, skin and abdominal cavity was proved by way of the histochemical technique autometallography (AMG). A bio-film or "dissolution membrane" inserted between the metallic surface and macrophages was recognized on the surface of the implanted silver after a short period of time. Bio-released silver ions bound in silver-sulphur nanocrystals were traced within the first 24 h in the "dissolution membrane" and the "dissolucytotic" macrophages. In animals that had survived 10 days or more, silver nanocrystals were detected both extra- and intracellularly in places far away from the implant including regional lymph nodes, liver, kidneys and the central nervous system (CNS). The accumulated silver was always confined to lysosome-like organelles. Dissolucytotic silver was extracellularly related to collagen fibrils and fibres in connective tissue and basement membranes. Our study demonstrates that (1) the number of bio-released silver ions depends on the size of the surface of the implanted silver, (2) the spread of silver ions throughout the body takes place primarily not only through the vascular system, but also by retrograde axonal transport. It is concluded that implantation of silver or silver-plated devices is not recommendable.