title: Influence of pore size of porous titanium fabricated by vacuum diffusion bonding of titanium meshes on cell penetration and bone ingrowth.
abstract: The present work assesses the potential of three-dimensional (3D) porous titanium (pore size of 188-390 μm and porosity of 70%) fabricated by vacuum diffusion bonding of titanium meshes for applications in bone engineering. Rat bone marrow mesenchymal stem cells were used to investigate the proliferation and differentiation of cells on titanium scaffolds with different pore sizes at day 7, day 14 and day 21 based on DNA contents, alkaline phosphatase (ALP) activity, collagen (COL) secretion and osteogenic gene expressions including ALP, COL-1, bone morphogenetic protein-2 (BMP-2), osteopontin (OPN), runt-related transcription factor 2 (RUNX2), using smooth solid titanium plate as reference material. The rabbit models with distal femoral condyles defect were used to investigate the bone ingrowth into the porous titanium. All samples were subjected to Micro-CT and histological analysis after 4 and 12 weeks of healing. A one-way ANOVA followed by Tukey post hoc tests was used to analyze the data. It was found that the differentiation stage of cells on the porous titanium delayed compared with the smooth solid titanium plate and Ti 188 was more inclined to promote cell differentiation at the initial stage (day 14) while cell proliferation (day 1, 4, 7, 10, 14 and 21) and bone ingrowth (4 and 12 weeks) were biased to Ti 313 and Ti 390. The study indicates that the hybrid porous implant design which combines the advantages of different pore sizes may be meaningful and promising for bone defect restoration.
  
  
  CONCLUSIONS
  One of the significant challenges in bone defect restoration is the integration of biomaterials and surrounding bone tissue. Porous titanium may be a promising choice for bone ingrowth and mineralization with appropriate mechanical and biological properties. In this study, based on porous titanium fabricated by vacuum diffusion bonding of titanium meshes, we have evaluated the influence of various pore sizes on rat bone marrow mesenchymal stem cells (rBMMSCs) penetration in vitro and bone ingrowth in vivo. It was interesting that we found the proliferation and differentiation abilities of rBMMSCs, as well as bone ingrowth were related to different pore sizes of such porous scaffolds. The results may provide guidance for porous titanium design for bone defect restoration.
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Prosthetic Dentistry, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, PR China.
authors.forename: Bei
authors.initials: B
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Prosthetic Dentistry, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, PR China.
authors.forename: Wen
authors.initials: W
authors.lastname: Song
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Prosthetic Dentistry, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, PR China.
authors.forename: Tianxiao
authors.initials: T
authors.lastname: Han
authors.affiliation: The Second Artillery Engineering University, No. 2 Tongxin Road, Xi'an 710025, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, PR China.
authors.forename: Fuping
authors.initials: F
authors.lastname: Li
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, PR China.
authors.forename: Lingzhou
authors.initials: L
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, PR China. Electronic address: hchkou@nwpu.edu.cn.
authors.forename: Hongchao
authors.initials: H
authors.lastname: Kou
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Prosthetic Dentistry, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, PR China. Electronic address: wqtzym@fmmu.edu.cn.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001846:Bone Development / Q000187:drug effects*; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects* / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D004058:Diffusion; D005456:Fluorescent Dyes / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D010316:Particle Size; D016062:Porosity; D019919:Prosthesis Implantation; D011817:Rabbits; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000187:drug effects; D014025:Titanium / Q000494:pharmacology*; D014618:Vacuum; D014867:Water / Q000737:chemistry; D055114:X-Ray Microtomography
chemical_list: D005456:Fluorescent Dyes; D014867:Water; D004247:DNA; D014025:Titanium
keywords: Bone defect; Mesenchymal stem cells; Osteogenesis; Pore size; Porous titanium