Adding functionality with additive manufacturing: Fabrication of titanium-based antibiotic eluting implants

Sophie C. Cox, Parastoo Jamshidi, Neil M. Eisenstein, Mark A. Webber, Hany Hassanin, Moataz M. Attallah, Duncan E.T. Shepherd, Owen Addison, Liam M. Grover

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p = 0.01) improved the compressive strength (5.8 ± 0.7 MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6 hour period (< 28% of the total amount) were found to exceed the minimum inhibitory concentrations of Staphylococcus aureus (16 μg/mL) and Staphylococcus epidermidis (1 μg/mL); two bacterial species commonly associated with periprosthetic infections. Antibacterial efficacy was confirmed against both bacterial cultures using an agar diffusion assay. Interestingly, pore channel orientation was shown to influence the directionality of inhibition zones. Promisingly, this work demonstrates the potential to additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections.

Original languageEnglish
Pages (from-to)407-415
Number of pages9
JournalMaterials Science and Engineering C
Volume64
Early online date5 Apr 2016
DOIs
Publication statusPublished - 1 Jul 2016
Externally publishedYes

Keywords

  • Additive manufacturing
  • Antibiotic
  • Calcium phosphate cement
  • Drug delivery
  • Implant
  • Selective laser melting
  • Titanium

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