The Production of Porous Hydroxyapatite Scaffolds with Graded Porosity by Sequential Freeze-Casting

Abstract

Porous hydroxyapatite (HA) scaffolds with porosity-graded structures were fabricated by sequential freeze-casting. The pore structures, compressive strengths, and biocompatibilities of the fabricated porous HA scaffolds were evaluated. The porosities of the inner and outer layers of the graded HA scaffolds were controlled by adjusting the initial HA contents of the casting slurries. The interface between the dense and porous parts was compact and tightly adherent. The porosity and compressive strengths of the scaffold were controlled by the relative thicknesses of the dense/porous parts. In addition, the porous HA scaffolds showed good biocompatibility in terms of preosteoblast cell attachment and proliferation. The results suggest that porous HA scaffolds with load-bearing parts have potential as bone grafts in hard-tissue engineering.

Functionally graded ceramics for biomedical application: Concept, manufacturing, and properties

“…Inspired by those examples of natural tissues, the development of artificial implants with graded structures and functionalities is nowadays increasing . Table gives an overview of different FGCs developed in the biomedical field with their main applications …”

“…In addition, by modulating the density from layer to layer, a better mimicking of the natural bone is achieved, with the result of coupling the necessary mechanical strength to biological functions. A common approach is to develop a graded structure, but inverse as compared to natural bone, with a dense core and a porous surface . In fact, the macropores in the outer layer provide access for cells and blood vessels and enhance the formation of new bone, whereas the inner denser structure improve the strength of the implant …”

“…Functionally Graded Ceramics (FGCs) are designed to withstand a variety of severe operative conditions, including high temperatures, corrosive environments, abrasion, mechanical, and thermal‐induced stresses . An overview of the FGC structures already developed and their main application fields is proposed in Table .…”

Impact and biocompatibility studies on Mg2+‐substituted Apatite‐derived 3D porous scaffolds for hard tissue engineering

“…[2][3][4] An ideal synthetic scaffold should possess suitable physiochemical properties, bioactivity, biodegradability, osteoconductivity, osteoinductivity, and suitable interconnected porous structure to promote cell proliferation and suitable surface morphology for cell attachment. [10][11][12][13][14] Apatite is one of the inorganic component for guided hard tissue regeneration owing to its chemical composition closely resembles to the natural human bone. Bioceramic materials have been widely used in bone tissue engineering due to its excellent biocompatibility, biodegradability, and osteoconductivity.…”

“…8,9 Different phases of bioceramic biomaterials (including calcium phosphate, Apatite, biphasic calcium phosphate, α and β calcium phosphate) were utilized to fabricate the scaffolds to accommodate tissue regeneration functions of in vitro or in vivo. [10][11][12][13][14] Apatite is one of the inorganic component for guided hard tissue regeneration owing to its chemical composition closely resembles to the natural human bone. 15,16 Bioactivity and biodegradability of the Apatite material are based on the crystallinity.…”