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

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 sintered porous structures exhibited an average compressive strength of similar to 236 MPa. After some preliminary coating experiments, an ethanol slurry of fine bioactive glass (BG) particles (10 wt.%) stabilized with polyvinylpyrrolidone was used to deposit a uniform surface coating onto the filaments, followed by glazing at 850 degrees C. The functionalized scaffolds showed a relatively uniform surface coverage by the bioactive glass. The results of in vitro testing by immersing the scaffolds in simulated body fluid (SBF) showed remarkable morphological surface changes and an extensive deposition of hydroxyapatite layer. The overall results demonstrate the viability of producing porous YSZ scaffolds with excellent bioactivity, which are promising for bone tissue engineering under load bearing applications.

Automated summary

This study demonstrates the fabrication of YSZ scaffolds with 70% macro porosity using robocasting, with inks containing 48% solids volume fraction proving to be the most reliable. The sintered porous structures showed a high compressive strength of around 236 MPa. After coating with bioactive glass and immersion in simulated body fluid, the scaffold exhibited excellent bioactivity and deposition of hydroxyapatite.