Robocasting and surface functionalization with highly bioactive glass of ZrO₂ scaffolds for load bearing applications

Abstract

This work is a proof of concept for making load bearing implants with osseointegration and bone bonding ability. Yttria-stabilized zirconia (YSZ) scaffolds with a percentage of macro porosity of about 70% were fabricated by robocasting. Although a maximum solids volume fraction of 50 vol.% could be achieved, the 3D-printing process revealed to be more reliable when using inks with 48 vol.% solids. The sin-

Robocasting of advanced ceramics: ink optimization and protocol to predict the printing parameters - A review

“…Porous zirconia scaffolds for load-bearing bone implants were reliably produced by Gaddam et al. [ 60 ] using robocasting. Highly concentrated inks with 48 vol.% solid loading enabled to obtain porous zirconia scaffolds with strut density of 6.04 ± 0.06 g cm −3 , which was close to the theoretical density of YSZ (ρ = 6.05 g cm −3 ).…”

“… De-binding: 600 °C, with a soaking time of 1 h. Sintering: 1450 °C for 1 h in air. [ 60 ] B 4 C - PEI - Deionised water - Stearic acid - Pluronic F-127 (10–17 wt%) 46 to 50 Planetary centrifugal mixer: - 2000 rpm for 1 min, once at the beginning of each powder batch addition, and then twice with a 15 s cool-off break. Relative density: 94–97 % TD.…”

“…Second, the medium in which the printing operation is performed also plays a role: in this regard, Feilden et al. [ 66 ] pointed out that while robocasting of porous scaffolds is often carried out in paraffin oil bath [ 31 , 45 , 53 , 60 , 64 ], it is not suitable for monolith manufacture as pockets of oil tend to get trapped in-between densely packed ceramic rods, thus leading to printing defects and unwanted porosity.

Figure 10 Optical photographs of Si 3 N 4 green parts (cuboidal or beam geometries) with porous grid-like or solid architectures; adapted with permission from [ 69 ].

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“…First, the direct effect on the interstrut distance during deposition should be taken into account as dense parts require ceramic rods to merge together to prevent the formation of inter-strut porosity, while porous scaffolds need a user-defined spacing between rods to create designed macropores. Second, the medium in which the printing operation is performed also plays a role: in this regard, Feilden et al [66] pointed out that while robocasting of porous scaffolds is often carried out in paraffin oil bath [31,45,53,60,64], it is not suitable for monolith manufacture as pockets of oil tend to get trapped in-between densely packed ceramic rods, thus leading to printing defects and unwanted porosity. Buj-Corral et al [95] investigated the role of robocasting printing parameters on the surface roughness and dimensional accuracy of the lateral walls of porous prismatic zirconia parts.…”

Bioactive Ceramic Scaffolds for Bone Tissue Engineering by Powder Bed Selective Laser Processing: A Review

“…The bioinert or traditional ceramics usually possess sufficient flexural strength and can be used for load-bearing implants; however, they do not promote angiogenesis and direct bonding to the bone in the same way as bioactive ceramics [78][79][80]. Bioactive ceramics used for critical open bone defect treatments generally experience compressive and traction forces.…”