Robocasting of biomimetic hydroxyapatite scaffolds using self-setting inks

Abstract

Low temperature self-setting ceramic inks have been scarcely investigated for solid freeform fabrication processes. This work deals with the robocasting of alpha-tricalcium phosphate/gelatine reactive slurries as a bioinspired self-setting ink for the production of biomimetic hydroxyapatite/gelatine scaffolds. A controlled and totally interconnected pore network of $300 mm was obtained after ink printing and setting, with the struts consisting of a micro/nanoporous matrix of needle-shaped calcium deficient hydroxyapatite crystals, with a high specific surface area. Gelatine was effectively retained by chemical crosslinking. The setting reaction of the ink resulted in a significant increase of both the elastic modulus and the compressive strength of the scaffolds, which were within the range of the human trabecular bone. In addition to delaying the onset of the setting reaction, thus providing enough time for printing, gelatine provided the viscoelastic properties to the strands to support their own weight, and additionally enhanced mesenchymal stem cell adhesion and proliferation on the surface of the scaffold. Altogether this new processing approach opens good perspectives for the design of hydroxyapatite scaffolds for bone tissue engineering with enhanced reactivity and resorption rate.

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

“…[5][6][7] The fabrication of an artificial scaffold similar to the natural bone still remains a challenging task. 15,16 Bioactivity and biodegradability of the Apatite material are based on the crystallinity. 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.…”

Biological functionality of extracellular matrix‐ornamented three‐dimensional printed hydroxyapatite scaffolds

“…Considering the aforementioned viewpoint, additive manufacturing such as robocasting (3D plotting) can be used to fabricate patient specific implantable biomaterials. 10 Robocasting involves the extrusion of high solid content, loaded in a polymeric matrix using air pressure controlled syringe. 11 Furthermore, 3D plotted (also called 3D printing) scaffolds can be sintered to improve the strength.…”

Biological functionality and mechanistic contribution of extracellular matrix‐ornamented three dimensional Ti‐6Al‐4V mesh scaffolds

“…The non‐porous implants are characterized by higher elastic modulus than the bone tissue, which may delay bone healing or reduce the expected life of the implant in extreme cases, because of stress shielding effect and consequent resorption of bone surrounding the implant . From this perspective, additive manufacturing methods such as electron beam melting (EBM) is being explored to fabricate patient specific implants of titanium (Ti) and titanium alloy (Ti‐6Al‐4V) . The foam, mesh, or open‐cellular structures of titanium alloy are envisaged to reduce stress shielding effect without compromising the impact energy absorption capability of the implant .…”

“…1,2 From this perspective, additive manufacturing methods such as electron beam melting (EBM) is being explored to fabricate patient specific implants of titanium (Ti) and titanium alloy (Ti-6Al-4V). 3 The foam, mesh, or open-cellular structures of titanium alloy are envisaged to reduce stress shielding effect without compromising the impact energy absorption capability of the implant. 4 In load-bearing orthopedic applications, Ti-6Al-4V, Co-Cr alloy (29Cr-6Mo-0.22C), and stainless steel (316 L) are widely used because of their high strength together with good corrosion resistance in physiological environment.…”