title: Antibacterial efficacy of silver-impregnated polyelectrolyte multilayers immobilized on a biological dressing in a murine wound infection model.
abstract: OBJECTIVE
  To investigate the antibacterial effect of augmenting a biological dressing with polymer films containing silver nanoparticles.
  
  
  BACKGROUND
  Biological dressings, such as Biobrane, are commonly used for treating partial-thickness wounds and burn injuries. Biological dressings have several advantages over traditional wound dressings. However, as many as 19% of wounds treated with Biobrane become infected, and, once infected, the Biobrane must be removed and a traditional dressing approach should be employed. Silver is a commonly used antimicrobial in wound care products, but current technology uses cytotoxic concentrations of silver in these dressings. We have developed a novel and facile technology that allows immobilization of bioactive molecules on the surfaces of soft materials, demonstrated here by augmentation of Biobrane with nanoparticulate silver. Surfaces modified with nanometer-thick polyelectrolyte multilayers (PEMs) impregnated with silver nanoparticles have been shown previously to result in in vitro antibacterial activity against Staphylococcus epidermidis at loadings of silver that are noncytotoxic.
  
  
  METHODS
  We demonstrated that silver-impregnated PEMs can be nondestructively immobilized onto the surface of Biobrane (Biobrane-Ag) and determined the in vitro antibacterial activity of Biobrane-Ag with Staphylococcus aureus. In this study, we used an in vivo wound infection model in mice induced by topical inoculation of S aureus onto full-thickness 6-mm diameter wounds. After 72 hours, bacterial quantification was performed.
  
  
  RESULTS
  Wounds treated with Biobrane-Ag had significantly (P < 0.001) fewer colony-forming units than wounds treated with unmodified Biobrane (more than 4 log10 difference).
  
  
  CONCLUSIONS
  The results of our study indicate that immobilizing silver-impregnated PEMs on the wound-contact surface of Biobrane significantly reduces bacterial bioburden in full-thickness murine skin wounds. Further research will investigate whether this construct can be considered for human use.
authors.affiliation: School of Veterinary Medicine, Department of Surgical Sciences, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Guthrie
authors.forename: Ankit
authors.initials: A
authors.lastname: Agarwal
authors.forename: Dana S
authors.initials: DS
authors.lastname: Tackes
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Johnson
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Abbott
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Murphy
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Czuprynski
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Kierski
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Schurr
authors.forename: Jonathan F
authors.initials: JF
authors.lastname: McAnulty
mesh_terms: D000818:Animals; D001684:Biological Dressings; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000627:therapeutic use*; D004195:Disease Models, Animal; D053768:Metal Nanoparticles; D051379:Mice; D009779:Occlusive Dressings; D011108:Polymers / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D023822:Tissue Engineering / Q000379:methods*; D014945:Wound Healing
chemical_list: C042816:Biobrane; D020099:Coated Materials, Biocompatible; D011108:Polymers; D012834:Silver