Magnesium alloy AZ91 exhibits antimicrobial properties in vitro but not in vivo

Emily K. Brooks, Richard Ahn, Menachem E. Tobias, Lisa A. Hansen, Nicole R. Luke-Marshall, Linda Wild, Anthony A. Campagnari, Mark T. Ehrensberger*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


Magnesium alloys hold great promise for developing orthopedic implants that are biocompatible, biodegradable, and mechanically similar to bone tissue. This study evaluated the in vitro and in vivo antimicrobial properties of magnesium–9%aluminum–1%zinc (AZ91) and commercially pure titanium (cpTi) against Acinetobacter baumannii (Ab307). The in vitro results showed that as compared to cpTi, incubation with AZ91 significantly reduced both the planktonic (cpTi = 3.45e8, AZ91 = 8.97e7, p < 0.001) colony forming units (CFU) and biofilm-associated (cpTi = 3.89e8, AZ91 = 1.78e7, p = 0.01) CFU of Ab307. However, in vivo results showed no significant differences in the CFU enumerated from the cpTi and AZ91 implants following a 1-week implantation in an established rodent model of Ab307 implant associated infection (cpTi = 5.23e3, AZ91 = 2.46e3, p = 0.29). It is proposed that the in vitro results were associated with an increased pH in the bacterial culture as a result of the AZ91 corrosion process. The robust in vivo buffering capacity likely diminished this corrosion associated pH antimicrobial effect.

Original languageEnglish
Pages (from-to)221-227
Number of pages7
JournalJournal of Biomedical Materials Research - Part B Applied Biomaterials
Issue number1
StatePublished - Jan 2018
Externally publishedYes


  • antimicrobial
  • biodegradable
  • in vivo
  • infection
  • magnesium


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