Exciton Technologies Inc.

Nucryst Pharmaceuticals Corp.

N.v. Union Miniere S.a.

Smith + Nephew

Stojan Djokic

Robert Edward Burrell

Hua Qing Yin

Rita Johanna Mary Langford

Maurice Dubois

Ross H Lepard

Rita Johanna Langford

Rita Johannna Mary Langford

A method for preparing a concentrated solution containing water, citrate ions and silver ions, including providing an amount of trisilver citrate, providing an amount of citric acid, wherein the amount of the citric acid is at least 19 times the amount of the trisilver citrate by weight, and mixing the trisilver citrate and the citric acid in an amount of water to produce the concentrated solution, wherein the amount of water is selected so that the concentrated solution has a citrate ion concentration which is at least 300 grams per liter. A concentrated solution containing water, citrate ions and silver ions, wherein the concentrated solution has a silver ion concentration which is at least 10 grams per liter. A diluted solution prepared by adding water to a concentrated solution containing water, citrate ions and silver ions.

Antimicrobial silver solutions

A composite material comprising a substrate and a deposition product and the use of a deposition product for providing an antimicrobial effect. The substrate of the composite material is a medical device. Further, in each of the composite material and the use, the deposition product consists essentially of at least one oxidized silver species and wherein the deposition product is comprised of a compound having the formula AgOX, where X is an anion.

Deposition products, composite materials and processes for the production thereof

A method for producing a deposition product includes providing a deposition solution having a pH below 7 and comprising an aqueous solution of a silver salt comprised of silver ions and an oxidizing agent. The silver salt is comprised of silver nitrate and has a concentration in the deposition solution between about 1 and 20 grams per liter. The oxidizing agent is comprised of a persulfate and has a concentration in the deposition solution between about 1 and 50 grams per liter. The method further includes producing the deposition product by facilitating a chemical reaction between the silver ions and the oxidizing agent while maintaining the deposition solution at a temperature of between about 2 and 40 degrees Celsius. The deposition product consists essentially of at least one oxidized silver species, and is comprised of a compound having the formula AgOX, where X is an anion.

Methods for the production of deposition products including an oxidized metal species under both acidic and alkaline conditions, methods for the production of composite materials including a substrate and the deposition product, and products in the nature of deposition products and composite materials. The methods are particularly suited for depositing a very thin layer of a deposition product on a substrate and may be used to produce composite materials for use in many applications, including but not limited to electronics, materials engineering and medical applications. In a preferred embodiment, the metal is silver, the substrates are medical devices or components of medical devices and the deposition product includes an antimicrobially active oxidized silver species.

The invention provides bioabsorbable materials with antimicrobial coatings or powders which provide an effective and sustainable antimicrobial effect. Specifically, this invention provides bioabsorbable materials comprising a bioabsorbable substrate associated with one or more antimicrobial metals being in a crystalline form characterized by sufficient atomic disorder, such that the bioabsorbable material in contact with an alcohol or water based electrolyte, releases atoms, ion, molecules, or clusters of at least one antimicrobial metal at a concentration sufficient to provide an antimicrobial effect. The one or more antimicrobial metals do not interfere with the bioabsorption of the bioabsorbable material, and do not leave behind particulates larger than 2 &mgr;m, as measured 24 hours after the bioabsorbable material has disappeared. Most preferably, the particulate sizing from the coating or powder is sub-micron that is less than about 1 &mgr;m, as measured 24 hours after the bioabsorbable material has disappeared. Particulates are thus sized to avoid deleterious immune responses or toxic effects. Such antimicrobial metals are in the form of a continuous or discontinuous coating, a powder, or a coating on a bioabsorbable powder. The antimicrobial coating is thin, preferably less than 900 nm or more preferably less than 500 nm, and very fine grained, with a grain size (crystallite size) of preferably less than 100 nm, more preferably less than 40 nm, and most preferably less than 20 nm. The antimicrobial coating is formed of an antimicrobial metal, which is overall crystalline, but which is created with atomic disorder, and preferably also having either or both of a) a high oxygen content, as evidenced by a rest potential greater than about 225 mV, more preferably greater than about 250 mV, in 0.15 M Na CO against a SCE (standard calomel electrode), or b) discontinuity in the coating. The antimicrobial metal associated with the bioabsorbable substrate may also be in the form of a powder, having a particle size of less than 100 &mgr;m, or preferably less than 40 &mgr;m, and with a grain size (crystallite size) of preferably less than 100 nm, more preferably less than 40 nm, and most preferably less than 20 nm. Such powders may be prepared as a coating preferably of the above thickness, onto powdered biocompatible and bioabsorbable substrates; as a nanocrystalline coating and converted into a powder; or as a powder of the antimicrobial metal which is cold worked to impart atomic disorder. Methods of preparing the above antimicrobial bioabsorbable materials are thus also provided.

Antimicrobial bioabsorbable materials

A process for the preparation of silver coated particles useful as polymer fillers is provided. Copper coated, or copper particles are dispersed in an alkaline ammoniacal solution to remove impurities and activate the surfaces thereof. A combined completing and reducing agent is added. Finally, a solution containing silver ions is used to coat the particles with a uniform layer of silver.

Growing community of inventors

Edmonton, Canada

Stojan Djokic