title: Evaluation of silver-titanium implants activated by low intensity direct current for orthopedic infection control: An in vitro and in vivo study.
abstract: Silver is an alternative antimicrobial of interest for the prophylaxis of prosthetic infections and electrical activation is known to augment its oligodynamic efficacy. In this study, we evaluated the in vitro and in vivo efficacy of a silver (Ag)-titanium (Ti) implant activated by 30 µA direct current compared with three controls - passive Ag-Ti, active Ti-Ti, and passive Ti-Ti. We hypothesized that the experimental group would provide better resistance to pathogenic colonization on the implant. Modified Kirby-Bauer technique was used to evaluate in vitro efficacy of the four groups against five bacteria and one fungus. For in vivo evaluation, forty-eight rats were divided into four groups. The implant was secured in a wound cavity along the posterior margin of the femur. The wound was inoculated with 7.5 × 10(5) CFU of Staphylococcus aureus. Rats were euthanized 14 days postsurgery and quantitative cultures were performed on the implant segments and the wound cavity tissue. In vitro tests showed that the growth of all six pathogens was inhibited around the active Ag anodes of the experimental group. In vivo, none of the four groups were able to prevent wound infection, but the experimental group resulted in reduced colonization. The mean bacterial loads on Ti segments were significantly lower in the implants which also had an Ag segment (p = 0.0007), and this effect was more pronounced with electrical activation (p = 0.0377). The results demonstrate the antimicrobial potential of LIDC-activated Ag-Ti implants. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1023-1031, 2016.
authors.affiliation: Department of Orthopaedics, University of North Carolina, Chapel-Hill, North Carolina.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Cavanaugh
authors.affiliation: Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina.
authors.forename: Zhuo George
authors.initials: ZG
authors.lastname: Tan
authors.affiliation: Department of Orthopaedics, University of North Carolina, Chapel-Hill, North Carolina.
authors.forename: James P
authors.initials: JP
authors.lastname: Norris
authors.affiliation: Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina.
authors.forename: Amelia
authors.initials: A
authors.lastname: Hardee
authors.affiliation: Department of Orthopaedics, University of North Carolina, Chapel-Hill, North Carolina.|Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, North Carolina.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Weinhold
authors.affiliation: Department of Orthopaedics, University of North Carolina, Chapel-Hill, North Carolina.
authors.forename: Laurence E
authors.initials: LE
authors.lastname: Dahners
authors.affiliation: Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Orndorff
authors.affiliation: Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina.|Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, North Carolina.
authors.forename: Rohan A
authors.initials: RA
authors.lastname: Shirwaiker
mesh_terms: D000818:Animals; D005260:Female; D005269:Femur / Q000382:microbiology / Q000601:surgery; D020007:Implants, Experimental; D051381:Rats; D017207:Rats, Sprague-Dawley; D012834:Silver / Q000737:chemistry / Q000494:pharmacology; D013203:Staphylococcal Infections / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000254:growth & development*; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology
chemical_list: D012834:Silver; D014025:Titanium
keywords: antimicrobial implant; electrical activation; oligodynamic silver; prosthetic infection