Mechanically Stable β-TCP Structural Hybrid Scaffolds for Potential Bone Replacement

Abstract

The authors report on the manufacturing of mechanically stable β-tricalcium phosphate (β-TCP) structural hybrid scaffolds via the combination of additive manufacturing (CerAM VPP) and Freeze Foaming for engineering a potential bone replacement. In the first step, load bearing support structures were designed via FE simulation and 3D printed by CerAM VPP. In the second step, structures were foamed-in with a porous and degradable calcium phosphate (CaP) ceramic that mimics porous spongiosa. For this purpose, Fraunhofer IKTS used a process known as Freeze Foaming, which allows the foaming of any powdery material and the foaming-in into near-net-shape structures. Using a joint heat treatment, both structural components fused to form a structural hybrid. This bone construct had a 25-fold increased compressive strength compared to the pure CaP Freeze Foam and excellent biocompatibility with human osteoblastic MG-63 cells when compared to a bone grafting Curasan material for benchmark.

A parametric study of ultra-short laser surface patterning of freeze foamed TCP-Zr: effects of laser parameters on surface morphology

“…The synthesis of the constructs was carried out at the Fraunhofer Institute for Ceramic Technologies and Systems by following an already established protocol [9]. In brief, tricalcium phosphate and ZrO2 (TZ-3YS-E; Co. TOSOH) were used as materials for obtaining a ceramic suspension containing additionally water, polyvinyl alcohol as a binder, Dolapix CE 64 as a dispersing agent (Co. Zschimmer & Schwarz Mohsdorf GmbH & Co. KG, Burgstädt, Germany), a rheological modifier (Tafigel AP15, Co. Münzing Chemie GmbH, Heil-bronn, Germany) and 2-Amino-2-methyl-1-propanol-AMP (Merck KGaA, 64271 Darmstadt, Germany) required for adjustment of pH.…”

Tailoring of Hierarchical Porous Freeze Foam Structures

“…This allows to combine the high biocompatibility of the Freeze Foams [21] with the constructional freedom of additive manufacturing approaches like lithography-based ceramic manufacturing (LCM) to create patient specific bone implants with improved compressive strength [18]. Recently, Ahlhelm et al used additively manufactured structures to be filled in green state with freeze foam and co-sintered both to a β-TCP hybrid structure that showed high biocompatibility [34]. In the ongoing BMBF-funded project "Hybrid-Bone" (03VP07633), this hybrid shaping method is used to develop compressive strength-enhanced, biodegradable jaw-bone replacements.…”

Investigation of the Damage Phenomenology with Dependence on the Macroporosity and Microporosity of Porous Freeze Foams

“…Hierarchical, porous ceramics can have remarkable multifunctionality [ 1 ] due to their different properties, such as the pore size distribution or connectivity, which offer a wide range of applications, such as filters, catalysts [ 2 , 3 , 4 ], or bone replacement material [ 5 ]. Meanwhile, the mechanical properties of these foams are dependent on their macroscopic and microscopic constitution.…”

“…Hierarchical foams are characterized by a bimodal distribution of microscopic and macroscopic pore sizes, as well as high interconnectivity [ 7 ] paired with good mechanical properties [ 8 ]. A high degree of open porosity in bioceramic foams results in a high specific surface area, allowing biological tissue to grow on and into the foam structure [ 5 ]. To manufacture such foams, several production technologies are available, e.g., partial sintering, freeze casting, sacrificial fugitives, replica templates, direct foaming, as well as certain 3D printing techniques [ 3 , 9 , 10 , 11 , 12 , 13 ].…”