title: Bone regeneration in 3D printing bioactive ceramic scaffolds with improved tissue/material interface pore architecture in thin-wall bone defect.
abstract: Three-dimensional (3D) printing bioactive ceramics have demonstrated alternative approaches to bone tissue repair, but an optimized materials system for improving the recruitment of host osteogenic cells into the bone defect and enhancing targeted repair of the thin-wall craniomaxillofacial defects remains elusive. Herein we systematically evaluated the role of side-wall pore architecture in the direct-ink-writing bioceramic scaffolds on mechanical properties and osteogenic capacity in rabbit calvarial defects. The pure calcium silicate (CSi) and dilute Mg-doped CSi (CSi-Mg6) scaffolds with different layer thickness and macropore sizes were prepared by varying the layer deposition mode from single-layer printing (SLP) to double-layer printing (DLP) and then by undergoing one-, or two-step sintering. It was found that the dilute Mg doping and/or two-step sintering schedule was especially beneficial for improving the compressive strength (∼25-104 MPa) and flexural strength (∼6-18 MPa) of the Ca-silicate scaffolds. The histological analysis for the calvarial bone specimens in vivo revealed that the SLP scaffolds had a high osteoconduction at the early stage (4 weeks) but the DLP scaffolds displayed a higher osteogenic capacity for a long time stage (8-12 weeks). Although the DLP CSi scaffolds displayed somewhat higher osteogenic capacity at 8 and 12 weeks, the DLP CSi-Mg6 scaffolds with excellent fracture resistance also showed appreciable new bone tissue ingrowth. These findings demonstrate that the side-wall pore architecture in 3D printed bioceramic scaffolds is required to optimize for bone repair in calvarial bone defects, and especially the Mg doping wollastontie is promising for 3D printing thin-wall porous scaffolds for craniomaxillofacial bone defect treatment.
authors.affiliation: State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China. Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province, School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Shao
authors.forename: Xiurong
authors.initials: X
authors.lastname: Ke
authors.forename: An
authors.initials: A
authors.lastname: Liu
authors.forename: Miao
authors.initials: M
authors.lastname: Sun
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.forename: Xianyan
authors.initials: X
authors.lastname: Yang
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Fu
authors.forename: Yanming
authors.initials: Y
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Guojing
authors.initials: G
authors.lastname: Yang
authors.forename: Sanzhong
authors.initials: S
authors.lastname: Xu
authors.forename: Zhongru
authors.initials: Z
authors.lastname: Gou
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D002516:Ceramics / Q000494:pharmacology*; D019245:Compressive Strength; D004195:Disease Models, Animal; D008297:Male; D061848:Optical Imaging; D010012:Osteogenesis / Q000187:drug effects; D016062:Porosity; D066330:Printing, Three-Dimensional; D011817:Rabbits; D012886:Skull / Q000000981:diagnostic imaging / Q000473:pathology*; D054457:Tissue Scaffolds / Q000737:chemistry*; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials