Project Title: Additive Manufacturing of Ceramic Parts Reinforced with a Ductile Core 

Acronym: TOUGHCORE (RTI2018-095566-B-I00)

Funding Entity: Ministerio de Ciencia, Innovación y Universidades (MCIU) – Agencia Estatal de Investigación (AEI)

Participating Entities:  University of Extremadura

Duration: 01/01/2019 – 31/12/2021

Budget: 96.800,00 €

Principal Investigator (PI): Pedro Miranda

Number of researchers: 3

Abstract:

The TOUGHCORE project developed new hybrid biomaterials with a controlled pore architecture based on biopolymer/bioceramic composite bars with a core/cortex structure that gives them improved mechanical and osseointegration properties. In particular, scaffolds (porous structures) with controlled pore architecture wa additively manufactured by robocasting (DIW) or digital light processing (DLP). The bars of these scaffolds are formed by biphasic composite materials, consisting of a bioceramic shell (bioactive or bioinerte) with a ductile and tenacious biopolymer core. The manufacture of materials with these new architectures was carried out, first of all, by 3D printing a preform of ceramic material with two independent networks of interconnected porosity. The interior porosity was then infiltrated into the hollow bioceramic bars with the liquid phase biopolymer. This configuration allows the characteristics of each material to be optimally combined: the bioceramic housing provides the necessary rigidity, high strength (bioinert ceramics) and/or excellent osteoconductivity (bioactive ceramics), while the biopolymer provides toughness and ductility. In addition, in this way the interconnected functional porosity necessary for cell colonization that leads to the fixation of the implant, in the case of bioinerte polymers and ceramics, and to the complete regeneration of bone tissue, in the case of bioactive and biodegradable materials, is preserved.

Although the strength of the structures does not improve with respect to the corresponding structures with dense ceramic bars, the incorporation of intra-bar holes does not imply a significant reduction in the resistance of the structure once the infiltration with polymers occurs, the scaffolds developed does exhibit, as pursued, greatly improved mechanical performance (up to more than an order of magnitude) in terms of toughness,  both under compression stresses and, especially, under bending. Therefore, the novel microarchitecture of the scaffolds that this project has developed will allow the regeneration of large bone defects even in regions of the skeleton until now prohibited to bioactive ceramic structures that are conventionally used in bone tissue engineering. Thanks to the great versatility of the additive methods used in their manufacture, these implants can be adapted to the injury of each patient in a personalized way by generating a digital model of the implant from medical scanners of the patient. In addition, they will exhibit an accelerated fixation and osseointegration capacity, with respect to dense materials or where the polymeric material is applied as a coating of the bioceramic scaffolding, being able to maintain the mechanical integrity of the implant-tissue system during bone regeneration.