Fiber-Templated 3D Calcium-Phosphate Scaffolds for Biomedical Applications: The Role of the Thermal Treatment Ambient on Physico-Chemical Properties

Abstract

A successful bone-graft-controlled healing entails the development of novel products with tunable compositional and architectural features and mechanical performances and is, thereby, able to accommodate fast bone in-growth and remodeling. To this effect, graphene nanoplatelets and Luffa-fibers were chosen as mechanical reinforcement phase and sacrificial template, respectively, and incorporated into a hydroxyapatite and brushite matrix derived by marble conversion with the help of a reproducible technology. The bio-products, framed by a one-stage-addition polymer-free fabrication route, were thoroughly physico-chemically investigated (by XRD, FTIR spectroscopy, SEM, and nano-computed tomography analysis, as well as surface energy measurements and mechanical performance assessments) after sintering in air or nitrogen ambient. The experiments exposed that the coupling of a nitrogen ambient with the graphene admixing triggers, in both compact and porous samples, important structural (i.e., decomposition of β-Ca3(PO4)2 into α-Ca3(PO4)2 and α-Ca2P2O7) and morphological modifications. Certain restrictions and benefits were outlined with respect to the spatial porosity and global mechanical features of the derived bone scaffolds. Specifically, in nitrogen ambient, the graphene amount should be set to a maximum 0.25 wt.% in the case of compact products, while for the porous ones, significantly augmented compressive strengths were revealed at all graphene amounts. The sintering ambient or the graphene addition did not interfere with the Luffa ability to generate 3D-channels-arrays at high temperatures. It can be concluded that both Luffa and graphene agents act as adjuvants under nitrogen ambient, and that their incorporation-ratio can be modulated to favorably fit certain foreseeable biomedical applications.

Modulated Laser Cladding of Implant-Type Coatings by Bovine-Bone-Derived Hydroxyapatite Powder Injection on Ti6Al4V Substrates—Part I: Fabrication and Physico-Chemical Characterization

“…The give-and-take behavior of the chemical elements was also reflected in the calculated Ca/P ratios, which ranged between 13.93-37.47 and 9.37-39.04 for samples deposited using BHA contents of 50 and 100 wt.%, respectively, and which were, overall, higher than the reported values [45,50]. Only the constituting elements (i.e., Ca, P, O, Ti, Al, V) of the ceramic (BHA) and metallic (Ti6Al4V) starting materials involved in laser the cladding processing were evidenced by EDS.…”

“…The give-and-take behavior of the chemical elements was also reflected in the calculated Ca/P ratios, which ranged between 13.93-37.47 and 9.37-39.04 for samples deposited using BHA contents of 50 and 100 wt.%, respectively, and which were, overall, higher than the reported values [45,50].…”

Polymer Sponge Replication Technology Derived Strontium-Substituted Apatite (Sr-HAP) Porous Scaffolds for Bone Tissue Engineering

“…The pore shape of a Sr-HAP scaffold for tissue regeneration should be restricted to facilitate proliferation and cell migration. Furthermore, the scaffold's pore size is likely to play an essential role in tissue engineering since they have a higher proclivity for providing room for cell uptake [28].…”

Selection Route of Precursor Materials in 3D Printing Composite Filament Development for Biomedical Applications

“…Graphene-based materials have recently attracted a significant interest in the biomedical field (e.g., as reinforcement components, due to their capacity to increase mechanical resistance, elasticity, and flexibility) [ 36 , 37 ]. Recently, studies have reported the possibility to incorporate such components into a ceramic or polymeric matrix [ 38 , 39 , 40 ]; however, it must be taken into account that the chemical, morphological, structural, architectural, and dimensional characteristics of graphene materials control the biological response of the products (cells viability is primarily size-dependent and better supported by materials with lower overall surface areas) [ 41 , 42 ].…”