New synthetic PEKK/bioceramic hybrids and their surface sulfonation counterparts have increased cellular osteogenic capacity and promoted osseointegration

Abstract

PEKK has good biocompatibility as an implantable material, but its mechanical properties and osseointegration are not satisfied enough. Aluminum oxide (Al2O3) is highly wear-resistant, while hydroxyapatite (HA) is a biologically active. However all previous biocomposites made via mechanical mixing of these two bioceramic materials have not been able to meet clinical standards. The aim of this work is to resolve these problems by using newly synthesized bioceramic hybrids. In vitro and in vivo experiments have demonstrated that these new biomaterials have significantly improved biocompatibility and biomechanical properties when compared to neat PEKK. Surface sulfonation of the hybrids also leads to further improvements of these two properties. S-PEKK/Al2O3 and S-PEKK/HA promote MC3T3-E1 adhesion. PEKK/HA and S-PEKK/HA significantly promote cell proliferation by upregulating both mRNA and protein levels of cell cycle genes to facilitate cells shift from G0/G1 phase to S phase. PEKK/HA hybrids and S-PEKK/Al2O3 promote cell differentiation by upregulating the expression of osteogenic differentiation genes and proteins. PEKK/HA, S-PEKK/Al2O3 and S-PEKK/HA are able to strongly bind to the new bone and exhibit good in vivo osseointegration properties. We conclude that PEKK/HA, S-PEKK/Al2O3 and S-PEKK/HA show good osteogenic ability, especially S-PEKK/HA, and could be promising materials for bone implants.

Keywords

• PEKK
• Hydroxyapatite
• Alumina
• Bioceramic hybrids
• Osseointegration