In vitro cytotoxicity of silver nanoparticles on osteoblasts and osteoclasts at antibacterial concentrations

Abstract Nanoparticulate silver coatings for orthopaedic implants promise to decrease postoperative infection rates. However, silver-induced cytotoxicity on bone cells has not been investigated in detail. This study investigated the cytotoxic effects of silver nano- and microparticles and Ag(+) on osteoblasts (OBs) and osteoclasts (OCs) and correlated their effects with the antibacterial efficacy on Staphylococcus epidermidis. Silver nanoparticles (50 nm) exhibited strong cytotoxic effects on OBs and OCs. Weak cytotoxic effects were observed for silver microparticles (3 μm). The cytotoxicity was primarily mediated by a size-dependent release of Ag(+). Antibacterial effects occurred at Ag(+) concentrations that were 2-4 times higher than those inducing cytotoxic effects. Such adverse effects on OB and OC survival may have deleterious effects on the biocompatibility of orthopaedic implants. Our study represents an important step toward the detailed investigation of orthopaedic implant with nanoparticulate silver coatings prior to their widespread clinical usage.

Acid, Silver, and Solvent-Free Gold-Catalyzed Hydrophenoxylation of Internal Alkynes

A range of arylgold compounds have been synthesized and investigated as single-component catalysts for the hydrophenoxylation of unactivated internal alkynes. Both carbene and phosphine-ligated compounds were screened as part of this work, and the most efficient catalysts contained either JohnPhos or IPr/SIPr. Phenols bearing either electron-withdrawing or electron-donating groups were efficiently added using these catalysts. No silver salts, acids, or solvents were needed for the catalysis, and either microwave or conventional heating afforded moderate to excellent yields of the vinyl ethers.

The Rate of Precipitation of Copper Aluminide in the Silver Rich Silver-Copper-Aluminum Alloys

In order to determine the best annealing temperature at which to age-harden the alloys, hardness tests on speci­men annealed for different lengths of time at different temperatures were made.

Precipitation of Gold, Silver, and Copper from Cyanide Solutions on Activated Charcoal.

Charcoal has been known for a considerable length of time to have the property of recovering gold, silver, and copper from cyanide solutions of these metals. Quantita­tive data that may shed light on the mechanism of the re­moval of these metals is very limited except that char­coal in a form known as activated has the power to abstract gold and silver in considerable quantities from the above solutions.

Supergene Enrichment of Silver Ores with Special Reference to those from Neihart, Montana.

In the development of a technique it was necessary to learn the fundamentals of ore microscopy as applied to the various minerals of silver, which included the use of reflected polarized light, etch reactions, micro­chemical analysis, and sight recognition of mineral. In addition it was necessary to become familiar with the accepted criteria of sequence, replacement, and other textural phenomena.

Microscopic Study of Montana Silver Ores.

A microscopic investigation of the Montana silver minerals was conducted. This study consisted mainly of identifying the silver and silver-bearing minerals and of determining their paragenetic rela­tionships. The increasing amount of research in which the reflecting microscope is employed is evidence of the great value of this method of approach in the solution of problems of paragenesis of the opaque minerals.

A Study and Application of the Process of Supergene Enrichment of Silver Ores.

In many deposits of silver ores the grade of the ore de­creases considerably a few hundred feet below the surface. It is believed that in many cases the better ores owe their richness in part to the process of sulphide enrichment. It is recognized, however, that many rich silver ores are hypogene deposits that have been affected very little, if any, by processes of enrichment.

Secondary Enrichment of Copper at the Madison Gold Skarn Deposit, Silver Star District, Montana

Secondary Enrichment of Copper at the Madison Gold Skarn Deposit, Silver Star District, Montana. This paper focuses on the chemical reactions responsible for secondary enrichment of copper...we argue that most of the secondary Cu enrichment occurred during a late hydrothermal event that replaced the high temperature skarn mineral assemblage with hematitic jasperoid. Evidence favoring this "hypogene" Cu enrichment hypothesis is presented.

Age Hardening of Silver-Platinum Alloys

The alloy system selected for study was the binary alloy of platinum and silver. An examination of the various silver alloy diagrams revealed that of several possible alloys, the silver platinum was the most suit­able with regard to solubility.