A Multimaterial Scaffold With Tunable Properties: Toward Bone Tissue Repair

TLDR

PEEK/β‑TCP scaffolds aim to combine PEEK’s strength with β‑TCP’s bioactivity, but the nearly inert PEEK membrane limits exposure of β‑TCP to body fluid. The study proposes blending a biodegradable polymer with PEEK and β‑TCP and fabricating the composite via selective laser sintering to create a multi‑material scaffold. In the scaffold, poly(l‑lactide) degrades first, forming caverns in the PEEK membrane that expose the wrapped β‑TCP to physiological fluids. The resulting caverns enable ion exchange, giving the scaffold bioactivity, biodegradability, and cytocompatibility, and in vivo bone‑defect repair shows new bone growth from the margin to the center and full integration with host bone after eight weeks.

Abstract

Abstract Polyetheretherketone (PEEK)/β‐tricalcium phosphate (β‐TCP) scaffolds are expected to be able to combine the excellent mechanical strength of PEEK and the good bioactivity and biodegradability of β‐TCP. While PEEK acts as a closed membrane in which β‐TCP is completely wrapped after the melting/solidifying processing, the PEEK membrane degrades very little, hence the scaffolds cannot display bioactivity and biodegradability. The strategy reported here is to blend a biodegradable polymer with PEEK and β‐TCP to fabricate multi‐material scaffolds via selective laser sintering (SLS). The biodegradable polymer first degrades and leaves caverns on the closed membrane, and then the wrapped β‐TCP is exposed to body fluid. In this study, poly( l ‐lactide) (PLLA) is adopted as the biodegradable polymer. The results show that large numbers of caverns form on the membrane with the degradation of PLLA, enabling direct contact between β‐TCP and body fluid, and allowing for their ion‐exchange. As a consequence, the scaffolds display the bioactivity, biodegradability and cytocompatibility. Moreover, bone defect repair studies reveal that new bone tissues grow from the margin towards the center of the scaffolds from the histological analysis. The bone defect region is completely connected to the host bone end after 8 weeks of implantation.