A microporous surface containing Si₃N₄/Ta microparticles of PEKK exhibits both antibacterial and osteogenic activity for inducing cellular response and improving osseointegration.

Abstract

As an implantable biomaterial, polyetherketoneketone (PEKK) exhibits good mechanical strength but it is biologically inert while tantalum (Ta) possesses outstanding osteogenic bioactivity but has a high density and elastic modulus. Also, silicon nitride (SN) has osteogenic and antibacterial activity. In this study, a microporous surface containing both SN and Ta microparticles on PEKK (STP) exhibiting excellent osteogenic and antibacterial activity was created by sulfonation. Compared with sulfonated PEKK (SPK) without microparticles, the surface properties (roughness, surface energy, hydrophilicity and protein adsorption) of STP significantly increased due to the SN and Ta particles presence on the microporous surface. In addition, STP also exhibited outstanding antibacterial activity, which inhibited bacterial growth <i>in vitro</i> and prevented bacterial infection <i>in vivo</i> because of the presence of SN particles. Moreover, the microporous surface of STP containing both SN and Ta particles remarkably induced response (e.g., proliferation and differentiation) of rat bone mesenchymal stem (rBMS) cells <i>in vitro</i>. Furthermore, STP significantly improved new bone regeneration and osseointegration <i>in vivo</i>. Regarding the induction of cellular response <i>in vitro</i> and improvement of osseointegration <i>in vivo</i>, the microporous surface containing Ta was better than the surface with SN particles. In conclusion, STP with optimized surface properties activated cellular responses <i>in vitro</i>, enhanced osseointegration and prevented infection <i>in vivo</i>. Therefore, STP possessed the dual biofunctions of excellent osteogenic and antibacterial activity, showing great potential as a bone substitute.