Formulation of a covalently bonded hydroxyapatite and poly(ether ether ketone) composite.

ABSTRACT: Spinal fusion devices can be fabricated from composites based on combining hydroxyapatite and poly(ether ether ketone) phases. These implants serve as load-bearing scaffolds for the formation of new bone tissue between adjacent vertebrae. In this work, we report a novel approach to covalently bond hydroxyapatite and poly(ether ether ketone) to produce a novel composite formulation with enhanced interfacial adhesion between phases. Compared to non-linked composites (HA_PEEK), covalently linked composites (HA_L_PEEK), loaded with 1.25?vol% hydroxyapatite, possessed a greater mean flexural strength (170?±?5.4 vs 171.7?±?14.8?MPa (mean?±?SD)) and modulus (4.8?±?0.2 vs 5.0?±?0.3?GPa (mean?±?SD)). Although the mechanical properties were not found to be significantly different (p?>?0.05), PEEK_L_HA contained substantially larger hydroxyapatite inclusions (100-1000?µm) compared to HA_PEEK (50-200?µm), due to the inherently agglomerative nature of the covalently bonded hydroxyapatite and poly(ether ether ketone) additive. Larger inclusions would expectedly weaken the HA_L_PEEK composite; however, there is no significant difference between the flexural modulus of poly(ether ether ketone) with respect to HA_L_PEEK (p?=?0.13). In addition, the flexural modulus of HA_PEEK is significantly lower compared to poly(ether ether ketone) (p?=?0.03). Ultimately, covalent linking reduces hydroxyapatite particulate de-bonding from the polymeric matrix and inhibits micro-crack development, culminating in enhanced transfer of stiffness between hydroxyapatite and poly(ether ether ketone) under loading.

SUBMITTER: Hughes EA 

PROVIDER: S-EPMC6299303 | biostudies-literature | 2018 Jan-Dec

REPOSITORIES: biostudies-literature