Yassine Maazouz

Bio: Yassine Maazouz is an academic researcher from Polytechnic University of Catalonia. The author has contributed to research in topics: Bone regeneration & Mathematics. The author has an hindex of 9, co-authored 20 publications receiving 442 citations. Previous affiliations of Yassine Maazouz include University of Minnesota.

Osteoinduction by Foamed and 3D-Printed Calcium Phosphate Scaffolds: Effect of Nanostructure and Pore Architecture.

Abstract: Some biomaterials are osteoinductive, that is, they are able to trigger the osteogenic process by inducing the differentiation of mesenchymal stem cells to the osteogenic lineage. Although the underlying mechanism is still unclear, microporosity and specific surface area (SSA) have been identified as critical factors in material-associated osteoinduction. However, only sintered ceramics, which have a limited range of porosities and SSA, have been analyzed so far. In this work, we were able to extend these ranges to the nanoscale, through the foaming and 3D-printing of biomimetic calcium phosphates, thereby obtaining scaffolds with controlled micro- and nanoporosity and with tailored macropore architectures. Calcium-deficient hydroxyapatite (CDHA) scaffolds were evaluated after 6 and 12 weeks in an ectopic-implantation canine model and compared with two sintered ceramics, biphasic calcium phosphate and β-tricalcium phosphate. Only foams with spherical, concave macropores and not 3D-printed scaffolds with c...

Bioceramics and bone healing.

Abstract: Calcium phosphates have long been used as synthetic bone grafts. Recent studies have shown that the modulation of composition and textural properties, such as nano-, micro- and macro-porosity, is a...

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 μm 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

Bioactive calcium phosphate materials and applications in bone regeneration

Abstract: Bone regeneration involves various complex biological processes. Many experiments have been performed using biomaterials in vivo and in vitro to promote and understand bone regeneration. Among the many biomaterials, calcium phosphates which exist in the natural bone have been conducted a number of studies because of its bone regenerative property. It can be directly contributed to bone regeneration process or assist in the use of other biomaterials. Therefore, it is widely used in many applications and has been continuously studied. Calcium phosphate has been widely used in bone regeneration applications because it shows osteoconductive and in some cases osteoinductive features. The release of calcium and phosphorus ions regulates the activation of osteoblasts and osteoclasts to facilitate bone regeneration. The control of surface properties and porosity of calcium phosphate affects cell/protein adhesion and growth and regulates bone mineral formation. Properties affecting bioactivity vary depending on the types of calcium phosphates such as HAP, TCP and can be utilized in various applications because of differences in ion release, solubility, stability, and mechanical strength. In order to make use of these properties, different calcium phosphates have been used together or mixed with other materials to complement their disadvantages and to highlight their advantages. Calcium phosphate has been utilized to improve bone regeneration in ways such as increasing osteoconductivity for bone ingrowth, enhancing osteoinductivity for bone mineralization with ion release control, and encapsulating drugs or growth factors. Calcium phosphate has been used for bone regeneration in various forms such as coating, cement and scaffold based on its unique bioactive properties and bone regeneration effectiveness. Additionally, several studies have been actively carried out to improve the efficacy of calcium phosphate in combination with various healing agents. By summarizing the properties of calcium phosphate and its research direction, we hope that calcium phosphate can contribute to the clinical treatment approach for bone defect and disease.

Printability and Shape Fidelity of Bioinks in 3D Bioprinting.

Abstract: Three-dimensional bioprinting uses additive manufacturing techniques for the automated fabrication of hierarchically organized living constructs. The building blocks are often hydrogel-based bioinks, which need to be printed into structures with high shape fidelity to the intended computer-aided design. For optimal cell performance, relatively soft and printable inks are preferred, although these undergo significant deformation during the printing process, which may impair shape fidelity. While the concept of good or poor printability seems rather intuitive, its quantitative definition lacks consensus and depends on multiple rheological and chemical parameters of the ink. This review discusses qualitative and quantitative methodologies to evaluate printability of bioinks for extrusion- and lithography-based bioprinting. The physicochemical parameters influencing shape fidelity are discussed, together with their importance in establishing new models, predictive tools and printing methods that are deemed instrumental for the design of next-generation bioinks, and for reproducible comparison of their structural performance.