Antimicrobial activity and biologic potential of silver-substituted calcium phosphate constructs produced with self-propagating high-temperature synthesis


There is significant demand for synthetic bone substitute materials that can decrease the incidence of implant-based bacterial infections. The intent of this research was to evaluate the antimicrobial activity and biologic potential of calcium phosphate (CaP) constructs substituted with silver (Ag) that were produced via self-propagating high-temperature synthesis (SHS). SHS is a combustion synthesis technique that has successfully generated porous CaP bioceramics intended for use in bone repair. SHS reactions are highly versatile; dopants can be added to the reactant powders to alter product chemistry and morphology. In this research, Ag powder was added to the reactants generating porous CaP constructs containing 0.5, 1, or 2 wt% Ag. Antibacterial performance of the constructs was assessed against Escherichia coli, a representative model for Gram-negative bacteria. Liquid solutions (1 μg/mL) of CaP–Ag particles to phosphate buffered saline were incubated with 105 cells/mL. After 24 h, 10 μL of solution were spread on an LB agar plate and cultured for 24 h at 37 °C. Samples cultured with CaP–Ag showed complete bacterial inhibition while the controls (E. coli only and CaP without Ag) exhibited significant colony formation. The effects of Ag concentration on cytotoxicity and biocompatibility were tested in vitro. At 7 days, osteoblasts uniformly enveloped the CaP–Ag particles and displayed a healthy flattened morphology suggesting the concentrations of Ag incorporated into constructs were not cytotoxic. CaP–Ag constructs produced via SHS represent a source of synthetic bone substitute materials that could potentially inhibit, or reduce the incidence of post-operative bacterial infections.

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The authors wish to acknowledge Dr. John Chandler and Gary Zito for their assistance during materials characterization. Additionally, the authors would like to thank Ryan Hort for his aseptic E. coli training, and Josh Cruz, Casey Davis, and Iris Vollmer for their assistance conducting this research. This work was accomplished under the Foundation for the National Institutes of Health Grant 1R15AR060011-01, and the Colorado Bioscience Discovery Evaluation Grant Program Grant 11BGF-48.

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Vollmer, N.L., Spear, J.R. & Ayers, R.A. Antimicrobial activity and biologic potential of silver-substituted calcium phosphate constructs produced with self-propagating high-temperature synthesis. J Mater Sci: Mater Med 27, 104 (2016).

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  • Contact Angle
  • Bone Replacement Material
  • Combustion Synthesis Technique
  • Bone Cell Attachment
  • Human Fetal Osteoblast Cell Line