Modification of pore-wall in direct ink writing wollastonite scaffolds favorable for tuning biodegradation and mechanical stability and enhancing osteogenic capability

FASEB J. 2020 Apr;34(4):5673-5687. doi: 10.1096/fj.201903044R. Epub 2020 Mar 1.

Abstract

Surface chemistry and mechanical stability determine the osteogenic capability of bone implants. The development of high-strength bioactive scaffolds for in-situ repair of large bone defects is challenging because of the lack of satisfying biomaterials. In this study, highly bioactive Ca-silicate (CSi) bioceramic scaffolds were fabricated by additive manufacturing and then modified for pore-wall reinforcement. Pure CSi scaffolds were fabricated using a direct ink writing technique, and the pore-wall was modified with 0%, 6%, or 10% Mg-doped CSi slurry (CSi, CSi-Mg6, or CSi-Mg10) through electrostatic interaction. Modified CSi@CSi-Mg6 and CSi@CSi-Mg10 scaffolds with over 60% porosity demonstrated an appreciable compressive strength beyond 20 MPa, which was ~2-fold higher than that of pure CSi scaffolds. CSi-Mg6 and CSi-Mg10 coating layers were specifically favorable for retarding bio-dissolution and mechanical decay of scaffolds in vitro. In-vivo investigation of critical-size femoral bone defects repair revealed that CSi@CSi-Mg6 and CSi@CSi-Mg10 scaffolds displayed limited biodegradation, accelerated new bone ingrowth (4-12 weeks), and elicited a suitable mechanical response. In contrast, CSi scaffolds exhibited fast biodegradation and retarded new bone regeneration after 8 weeks. Thus, tailoring of the chemical composition of pore-wall struts of CSi scaffolds is beneficial for enhancing the biomechanical properties and bone repair efficacy.

Keywords: additive manufacture; bioceramic scaffold; electrostatic interaction; foreign-ion doping; pore-wall modification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biocompatible Materials / chemistry*
  • Bone and Bones / cytology*
  • Calcium Compounds / chemistry*
  • Ceramics / chemistry
  • Femoral Fractures / etiology
  • Femoral Fractures / pathology
  • Femoral Fractures / therapy*
  • Mechanical Phenomena
  • Osteogenesis*
  • Porosity
  • Rabbits
  • Silicates / chemistry*
  • Tissue Engineering*
  • Tissue Scaffolds*

Substances

  • Biocompatible Materials
  • Calcium Compounds
  • Silicates
  • calcium silicate