title: Antimicrobial acrylic materials with in situ generated silver nanoparticles.
abstract: Polymethyl methacrylate (PMMA) is widely used to treat traumatic head injuries (cranioplasty) and orthopedic injuries (bone cement), but there is a problem with implant-centered infections. With organisms such as Acinetobacter baumannii and methicillin-resistant staphylococcus aureus developing resistance to antibiotics, there is a need for novel antimicrobial delivery mechanisms without risk of developing resistant organisms.
  
  
  OBJECTIVE
  To develop a novel antimicrobial implant material by generating silver nanoparticles (AgNP) in situ in PMMA.
  
  
  RESULTS
  All PMMA samples with AgNP's (AgNP-PMMA) released Ag(+) ions in vitro for over 28 days. In vitro antimicrobial assays revealed that these samples (even samples with the slowest release rate) inhibited 99.9% of bacteria against four different strains of bacteria. Long-term antimicrobial assay showed a continued antibacterial effect past 28 days. Some AgNP-loaded PMMA groups had comparable Durometer-D hardness (a measure of degree of cure) and modulus to control PMMA, but all experimental groups had slightly lower ultimate transverse strengths.
  
  
  CONCLUSIONS
  AgNP-PMMA demonstrated a tremendously broad-spectrum and long-intermediate-term antimicrobial effect with comparable mechanical properties to control PMMA. Current efforts are focused on further improving mechanical properties by reducing AgNP loading and assessing fatigue properties.
authors.affiliation: Department of Comprehensive Dentistry, Division of Research, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: James D
authors.initials: JD
authors.lastname: Oei
authors.forename: William W
authors.initials: WW
authors.lastname: Zhao
authors.forename: Lianrui
authors.initials: L
authors.lastname: Chu
authors.forename: Mauris N
authors.initials: MN
authors.lastname: DeSilva
authors.forename: Abishek
authors.initials: A
authors.lastname: Ghimire
authors.forename: H Ralph
authors.initials: HR
authors.lastname: Rawls
authors.forename: Kyumin
authors.initials: K
authors.lastname: Whang
mesh_terms: D040981:Acinetobacter baumannii / Q000254:growth & development*; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D053768:Metal Nanoparticles / Q000737:chemistry*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000254:growth & development*; D019904:Polymethyl Methacrylate / Q000737:chemistry / Q000494:pharmacology; D012834:Silver / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D019904:Polymethyl Methacrylate