Processing and Properties of Bioactive Surface-Porous PEKK

Abstract

Bioactive surface-porous polyetherketoneketone materials (PEKK-BSP) were prepared by first leaching hydroxyapatite (HA) microsphere templates from compression molded PEKK/HA composites (i.e., PEKK-P) followed by sulfonation with 80% sulfuric acid for 3 h (i.e., PEKK-SP) and then soaking in a simulated body fluid (SBF) for 5 days. The combination of both physical and chemical processes created a surface-porous PEKK material (PEKK-SP) that had both structurally interconnected and open macropores (200–600 μm) because of templating of HA microspheres, and micropores (<10 μm) due to effects of the sulfonation. The in vitro bioactivity of PEKK-SP was demonstrated by the development of a dense layer of bone-like apatite inside and on the surfaces after SBF treatment. The sulfonation process followed SBF treatment also significantly reduced the water contact angle of PEKK material. Mechanical tests showed that both PEKK-BSP and PEKK-P were a little better than PEKK-SP in terms of compressive strength and modulus. In vitro cell culture using rabbits’ mesenchymal stem cells (MSCs) demonstrated that PEKK-BSP promoted better cell growth and proliferation than other groups of PEKK materials. Moreover, compared to PEKK material alone, PEKK-BSP elevated gene expressions of osteocalcin (OCN), Type I collagen (Col-I), alkaline phosphatase (ALP), and runt-related transcription factor 2 (Runx2). This bioactive PEKK-BSP material has potential application for spinal interbody fusion devices to enhance their in vivo osseointegration.

Positive role of calcium phosphate ceramics regulated inflammation in the osteogenic differentiation of mesenchymal stem cells

“…The bioactivity of Ca‐P ceramics was also evaluated through the bone‐like apatite formation tests. Briefly, simulated body fluid (SBF) was prepared according to previously described (Yuan et al, ). After immersed in SBF for 3 days at 37°C, the samples were taken out and washed gently in deionized water, and then dried at room temperature for bone‐like apatite observation by SEM.…”

High‐Performance Polymer Foams by Thermally Induced Phase Separation

“…Most other examples of porous high performance polymer foams were produced by chemical or physical (gas) blowing [ 13,14 ] or particulate leaching. [ 15,16 ] However, the bulk production of PEEK and PEKK foams, and to a lesser degree PEI foams [ 17,18 ] is still a huge challenge. Gas blowing and particulate leaching methods have limitations restricting their suitability for high performance polymers, because of the small processing window for semicrystalline polymers [ 19 ] and high temperature and pressure requirements.…”

“…So far porous PEKK has only been produced by particulate leaching. [ 15,33,34 ] Reported porosities for porous PEKK obtained by porogen leaching were around 75≈90%, [ 33,34 ] which are close to that achieved by us (77 ± 2%). Converse et al [ 33 ] reported compression properties of porous PEKK produced by porogen leaching, the E‐moduli reported are of the same order of magnitude as those measured by us while the compression strength is identical within error (for a comparison see Figure S4, Supporting Information).…”

Implantable PEKK/tantalum microparticles composite with improved surface performances for regulating cell behaviors, promoting bone formation and osseointegration

“…Compared with PEEK, PEKK has some advantages such as better mechanical performances, higher thermal stability and structural variation between semi-crystalline and amorphous phase as well as versatile chemistry because of two ketone bonds [ 23 ]. Furthermore, PEKK implantable materials have received acceptance by medical implant manufacturers who had gained permit from the U.S. Food and Drug Administration [ 24 ].…”