Antimicrobial material for implanting in bones

Abstract

The invention relates to an antimicrobial material and method for inhibiting bacterial growth. The antimicrobial material may be used for implanting in bones and for coating or producing an implant or an implantable medical device, whereby particles formed from an antimicrobial material are remotely dispersed inside a matrix material that forms a matrix when hardened. In order to improve the compatibility of the antimicrobial material, the invention provides that the metal is formed from aggregates of primary particles having an average particle size ranging from 10 to 100 nm.

1 . A method of inhibiting bacterial growth comprising contacting a bacterial growth to be inhibited with an antimicrobial material comprising discrete aggregates formed of silver and releasing silver ions from said aggregates in an amount effective to inhibit bacterial growth, said aggregates having a porosity of about 70% to about 90% and being formed of primary particles connected together by sintering necks, said primary particles having an average size between 10 and 100 nm. 
     
     
         2 . The method of  claim 1 , wherein said aggregates have an average aggregate size of from 1 to 20 μm. 
     
     
         3 . The method of  claim 1  or  2 , wherein said aggregates have a surface area of from 3 to 6 m 2  per gram. 
     
     
         4 . The method of  claim 3 , wherein said primary particles have a generally spherical shape. 
     
     
         5 . The method of  claim 1 , wherein the step of releasing silver ions includes releasing silver ions at a rate which substantially eliminates cytotoxic effects. 
     
     
         6 . The method of  claim 5 , wherein said aggregates have an average aggregate size of from 1 to 20 μm and a surface area of from 3 to 6 m 2  per gram. 
     
     
         7 . The method of  claim 1 , wherein said antimicrobial material includes a matrix made of a polymer having said aggregates dispersed in the matrix. 
     
     
         8 . The method of  claim 7 , wherein said antimicrobial material contains from about 0.01% to about 2.0% of silver based on the total weight of the antimicrobial material. 
     
     
         9 . The method of  claim 8 , wherein said aggregates have an average aggregate size of from 1 to 20 μm and a surface area of from 3 to 6 m 2  per gram. 
     
     
         10 . The method of  claim 7 ,  8  or  9 , wherein the step of releasing silver ions includes releasing silver ions at a rate which substantially eliminates cytotoxic effects. 
     
     
         11 . The method of  claim 7 , wherein said aggregates are homogenously dispersed is said matrix. 
     
     
         12 . The method of  claim 7 , wherein said antimicrobial material is included in a medical device for contact with human tissue, and the step of releasing silver ions includes substantially eliminating cytotoxic effects on human tissue. 
     
     
         13 . The method of  claim 7 , wherein said polymer is substantially bioinert. 
     
     
         14 . In an antimicrobial system including an antimicrobial material and a bacterial growth to be inhibited, said antimicrobial material comprising discrete aggregates formed from silver, wherein the aggregates have a porosity of 70% to 95% and are formed of primary particles connected together by sintering necks, the primary particles having an average size between 10 and 100 nm. 
     
     
         15 . The system of  claim 14 , wherein the aggregates have an average aggregate size of from 1 to 20 μm. 
     
     
         16 . The system of  claim 14 , wherein said antimicrobial material releases silver ions in an amount effective to inhibit bacterial growth without cytotoxic effects. 
     
     
         17 . The system of  claim 14 ,  15  or  16 , wherein the aggregates have a surface area of from 3 to 6 m 2  per gram. 
     
     
         18 . The system of  claim 14 , wherein said primary particles have a generally spherical shape. 
     
     
         19 . An antimicrobial material that releases silver ions in an amount effective to inhibit bacterial growth without cytotoxic effects comprising discrete aggregates formed from silver, wherein the aggregates have a porosity of 70% to 90% and are formed of primary particles connected together by sintering necks, the primary particles having an average size between 10 and 100 nm. 
     
     
         20 . The antimicrobial material as in  claim 19 , wherein the aggregates have an average aggregate size of from 1 to 20 μm. 
     
     
         21 . The antimicrobial material as in  claim 20 , wherein the aggregates have an average aggregate size of from 10 to 20 μm. 
     
     
         22 . The antimicrobial material as in  claim 21 , wherein the aggregates have a surface area of from 3 to 6 m 2  per gram.