Hydroxyapatite/polyamide66 porous scaffold with an ethylene vinyl acetate surface layer used for simultaneous substitute and repair of articular cartilage and underlying bone

In this paper, tissue scaffold made from polyamide66 (PA66) and hydroxyapatite (HA) was prepared by co-precipitation and thermal-induced phase inversion method, in which biomimetic HA crystals were uniformly distributed in PA66 matrix. The porosity of the scaffold is about 81% and the macropore size is from 50 to 500 μm. The ethylene vinyl acetate (EVA) layer was thermally molded on one surface of HA-PA66 scaffold to develop EVA/HA-PA66 composite for articular cartilage/bone substitute, i.e., upper EVA layer for cartilage substitute and underlying HA-PA66 scaffold for bone bonding and fixation. The physicochemical and mechanical properties of EVA were also investigated. The results indicate that the tensile and compressive strength of EVA is about 4.65 MPa and 9.44 MPa respectively, while its mean friction coefficient is very small, only about 0.23. The cell culture of EVA and HA-PA66 scaffold shows that these materials possess good cytocompatibility. The proposed preparation method is novel and effective, and the EVA/HA-PA66 composite has good potential for simultaneous substitute of articular cartilage and underlying bone.

The repaired process of HA/ polyamide66 porous scaffold with an ethylene vinyl acetate surface layer composite material [(a) TEM photograph of nHA crystals, (b) camera photo of EVA/HA-PA66 composite, (c) schematic diagram of the fabrication process, (d, f) SEM micrographs of HA-PA66 scaffold].Highlights
- EVA is used for substitute and repair of articular cartilage.
- Wettability, friction and wear properties of the surface of EVA were studied.
- Bilayered structure of EVA layer and nHA-PA66 porous scaffold was designed.
- Articular cartilage and underlying bone were repaired simultaneously.