Dendrimer biocide-silver nanocomposites: their preparation and applications as potent antimicrobials

Abstract

A novel cationic dendrimer biocide-silver nanocomposite and methods for its use as a biocide. The biocidal nanocomposites of the present invention are effective against a variety of microbial species, including anthrax. The invention is also highly stable and safe for exposure to human skin. The invention has applications as an antibiological warfare agents, antimicrobial agent for surface coatings and as a general biocide that is safe for human exposure.

What is claimed is:  
     
         1 . A dendrimer biocide-silver nanocomposite composition comprising a quaternary ammonium dendrimer biocide and silver ions associated with said dendrimer biocide.  
     
     
         2 . The dendrimer biocide-silver nanocomposite composition of  claim 1  wherein greater than 1 percent stoichiometric amount of a silver compound is used to prepare the dendrimer biocide-silver nanocomposite.  
     
     
         3 . The dendrimer biocide-silver nanocomposite composition of  claim 1  wherein from about 200 to 500 percent stoichiometric amount of a silver compound is used to prepare the dendrimer biocide-silver nanocomposite.  
     
     
         4 . The dendrimer biocide-silver nanocomposite composition of  claim 1  wherein a 200 percent stoichiometric amount of a silver compound is used to prepare the dendrimer biocide-silver nanocomposite.  
     
     
         5 . The dendrimer biocide-silver nanocomposite composition of  claim 1  wherein a 500 percent stoichiometric amount of a silver compound is used to prepare the dendrimer biocide-silver nanocomposite.  
     
     
         6 . The dendrimer biocide-silver nanocomposite composition of  claim 1  wherein the dendrimer biocide is a D3ClNC8 dendrimer biocide.  
     
     
         7 . A dendrimer biocide-silver nanocomposite prepared by a process comprising: 
 (a) adding excess AgNO 3  to a dendrimer biocide solution to convert the chloride ion of the dendrimer biocide to a nitrate ion;    (b) removing any precipitated AgCl;    (c) removing any remaining AgNO 3  in the solution by adding excess NaCl to the supernatant liquid; and    (d) diafiltering to remove remaining NaCl.    
     
     
         8 . A method of controlling the growth of a microorganism comprising exposing said microorganism to a dendrimer biocide-silver nanocomposite composition comprising a quaternary ammonium dendrimer biocide and silver ions associated with said dendrimer biocide.  
     
     
         9 . A method of controlling the growth of a microorganisms according to  claim 8  wherein said microorganism is selected from the group consisting essentially of acidogenic gram-positive cocci, Gram-negative anaerobic oral bacteria, Group A streptococci, enteric bacteria, Gram-negative rods, and Gram-positive cocci.  
     
     
         10 . A method of controlling the growth of a microorganisms according to  claim 8  wherein said microorganism is selected from the group consisting essentially of  streptococcus, staphylococci, haemophilus influenzae, escherichia coli, P. aeruginosa, burkholderia cepacia, Pseudomonas pseudomallei, C. albicansm, staphylococcus epidermidis , and  S. aureus.    
     
     
         11 . A method of controlling the growth of a microorganism according to  claim 8  wherein said microorganism is a spore.  
     
     
         12 . A method of controlling the growth of a microorganism according to  claim 11  wherein said spore corresponds to  B. anthracis  or anthrax.  
     
     
         13 . A method of controlling the growth of a microorganism according to  claim 8  wherein said dendrimer biocide-silver nanocomposite is immobilized on a surface.  
     
     
         14 . A method of controlling the growth of a microorganism according to  claim 13  wherein said surface is comprised of a polymer, or glass, or metal.  
     
     
         15 . A method of controlling the growth of a microorganism according to  claim 14  wherein said surface polymer is selected from the group consisting of polyurethane, polystyrene, polyethylene, and polypropylene.  
     
     
         16 . A method of controlling the growth of a microorganism according to  claim 8  wherein said dendrimer biocide-silver nanocomposite is applied as a spray.  
     
     
         17 . A method of controlling the growth of a microorganism according to  claim 8  wherein said dendrimer biocide-silver nanocomposite is incorporated into a coating.