Coaxial micro-extrusion of a calcium phosphate ink with aqueous solvents improves printing stability, structure fidelity and mechanical properties

Bagnol, Romain; Sprecher, Christoph M.; Peroglio, Marianna; Chevalier, Jérôme; Mahou, Redouan; Büchler, Philippe; Richards, Geoff; Eglin, David

doi:10.1016/j.actbio.2021.02.022

Cited by 8 publications

(6 citation statements)

References 56 publications

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“…This would enable an intrinsic hardening by diffusion of water into the paste and—by adjusting stoichiometry—would also help to increase the degree of conversion into struvite. Furthermore, the hardening of such pastes might be directly initiated during printing, e.g., by actively mixing with water or by using a coaxial printing approach as recently described for calcium phosphate cements [ 28 ]. This would be beneficial for the fabrication of larger implants, which otherwise might collapse during printing due to their own weight.…”

Section: Discussionmentioning

confidence: 99%

Extrusion-Based 3D Printing of Calcium Magnesium Phosphate Cement Pastes for Degradable Bone Implants

et al. 2021

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This study aimed to develop printable calcium magnesium phosphate pastes that harden by immersion in ammonium phosphate solution post-printing. Besides the main mineral compound, biocompatible ceramic, magnesium oxide and hydroxypropylmethylcellulose (HPMC) were the crucial components. Two pastes with different powder to liquid ratios of 1.35 g/mL and 1.93 g/mL were characterized regarding their rheological properties. Here, ageing over the course of 24 h showed an increase in viscosity and extrusion force, which was attributed to structural changes in HPMC as well as the formation of magnesium hydroxide by hydration of MgO. The pastes enabled printing of porous scaffolds with good dimensional stability and enabled a setting reaction to struvite when immersed in ammonium phosphate solution. Mechanical performance under compression was approx. 8–20 MPa as a monolithic structure and 1.6–3.0 MPa for printed macroporous scaffolds, depending on parameters such as powder to liquid ratio, ageing time, strand thickness and distance.

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Section: Discussionmentioning

confidence: 99%

Extrusion-Based 3D Printing of Calcium Magnesium Phosphate Cement Pastes for Degradable Bone Implants

et al. 2021

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“…More importantly, unlike the high temperature used in melt printing, solvent printing is usually performed under mild temperature, allowing the use of low thermally stable materials such as natural polymers and biomolecules. [ 8 , 11 ] However, extrudate distortion is more likely to occur during solvent extrusion due to the lubricant effect of the solvents, thus causing wall slip, especially in unfilled polymer solutions. [ 52 , 53 ] As shown in Figure 1a , the melt‐printed scaffolds show more uniform and regular shape than the solvent‐printed PCL scaffolds, which present an irregular cross‐section and groove or flake‐like surface morphology.…”

Section: Discussionmentioning

confidence: 99%

“…[ 6 ] Solution/solvent‐based extrusion 3D printing is a more recent alternative allowing to print inks, based on a range of natural and synthetic polymers and suitable solvents, at low/room temperatures. [ 7 , 8 , 9 , 10 , 11 ] This technique allows the incorporation of temperature‐sensitive biomolecules and a high loading of bioactive particles. [ 9 , 12 , 13 ] However, a limited number of articles reported a comparative study between melt and solvent printing.…”

Section: Introductionmentioning

confidence: 99%

Crystal Growth of 3D Poly(ε‐caprolactone) Based Bone Scaffolds and Its Effects on the Physical Properties and Cellular Interactions

et al. 2022

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Extrusion additive manufacturing is widely used to fabricate polymer-based 3D bone scaffolds. However, the insight views of crystal growths, scaffold features and eventually cell-scaffold interactions are still unknown. In this work, melt and solvent extrusion additive manufacturing techniques are used to produce scaffolds considering highly analogous printing conditions. Results show that the scaffolds produced by these two techniques present distinct physiochemical properties, with melt-printed scaffolds showing stronger mechanical properties and solvent-printed scaffolds showing rougher surface, higher degradation rate, and faster stress relaxation. These differences are attributed to the two different crystal growth kinetics, temperature-induced crystallization (TIC) and strain-induced crystallization (SIC), forming large/integrated spherulite-like and a small/fragmented lamella-like crystal regions respectively. The stiffer substrate of melt-printed scaffolds contributes to higher ratio of nuclear Yes-associated protein (YAP) allocation, favoring cell proliferation and differentiation. Faster relaxation and degradation of solvent-printed scaffolds result in dynamic surface, contributing to an early-stage faster osteogenesis differentiation.

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“…The discs are sterilized using a cold ethylene oxide gas protocol, degassed under vacuum for at least 5 days, and press-fit into the cell-culture wells under sterile conditions prior to use. 3D-printed Osteoink ® scaffolds are hardened post-printing using a steam autoclave (Belimed Infection Control, Belimed Sauter AG) as previously described [ 26 ].…”

Section: Methodsmentioning

confidence: 99%

Micro-porous PLGA/β-TCP/TPU scaffolds prepared by solvent-based 3D printing for bone tissue engineering purposes

Hatt,

Wirth,

Ristaniemi

et al. 2023

Regenerative Biomaterials

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The 3D printing process of fused deposition modelling (FDM) is an attractive fabrication approach to create tissue engineered bone substitutes to regenerate large mandibular bone defects, but often lacks desired surface porosity for enhanced protein adsorption and cell adhesion. Solvent-based printing leads to the spontaneous formation of micropores on the scaffold’s surface upon solvent removal, without the need for further post processing. Our aim is to create and characterise porous scaffolds using a new formulation composed of mechanically stable poly(lactic-co-glycol acid) (PLGA) and osteoconductive β-tricalcium phosphate (β-TCP) with and without the addition of elastic thermoplastic polyurethane (TPU) prepared by solvent-based 3D-printing technique. Large scale regenerative scaffolds can be 3D-printed with adequate fidelity and show porosity at multiple levels analysed via micro-computer tomography, scanning electron microscopy and N2 sorption. Superior mechanical properties compared to a commercially available CaP ink are demonstrated in compression, bending, and screw pull out tests. Biological assessments including cell activity assay and live-dead staining prove the scaffold's cytocompatibility. Osteoconductive properties are demonstrated by performing an osteogenic differentiation assay with primary human bone marrow mesenchymal stromal cells. We propose a versatile fabrication process to create porous 3D-printed scaffolds with adequate mechanical stability and osteoconductivity, both important characteristics for segmental mandibular bone reconstruction.

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Coaxial micro-extrusion of a calcium phosphate ink with aqueous solvents improves printing stability, structure fidelity and mechanical properties

Cited by 8 publications

References 56 publications

Extrusion-Based 3D Printing of Calcium Magnesium Phosphate Cement Pastes for Degradable Bone Implants

Extrusion-Based 3D Printing of Calcium Magnesium Phosphate Cement Pastes for Degradable Bone Implants

Crystal Growth of 3D Poly(ε‐caprolactone) Based Bone Scaffolds and Its Effects on the Physical Properties and Cellular Interactions

Micro-porous PLGA/β-TCP/TPU scaffolds prepared by solvent-based 3D printing for bone tissue engineering purposes

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