title: Flow perfusion culture of MC3T3-E1 osteogenic cells on gradient calcium polyphosphate scaffolds with different pore sizes.
abstract: Calcium polyphosphate is a biodegradable bone substitute. It remains a challenge to prepare porous calcium polyphosphate with desired gradient porous structures. In this study, a modified one-step gravity sintering method was used to prepare calcium polyphosphate scaffolds with desired-gradient-pore-size distribution. The differences of porous structure, mechanical strength, and degradation rate between gradient and homogenous calcium polyphosphate scaffolds were evaluated by micro-computed tomography, scanning electron microscopy, and mechanical testing. Preosteoblastic MC3T3-E1 cells were seeded onto gradient and homogenous calcium polyphosphate scaffolds and cultured in a flow perfusion bioreactor. The distribution, proliferation, and differentiation of the MC3T3-E1 cells were compared to that of homogenous calcium polyphosphate scaffolds. Though no significant difference of cell proliferation was found between the gradient and the homogenous calcium polyphosphate scaffolds, a much higher cell differentiation and mineralization were observed in the gradient calcium polyphosphate scaffolds than that of the homogenous calcium polyphosphate scaffolds, as manifested by increased alkaline phosphatase activity (p < 0.05). The improved distribution and differentiation of cultured cells within gradient scaffolds were further supported by both (18)F-fluorine micro-positron emission tomography scanning and in vitro tetracycline labeling. We conclude that the calcium polyphosphate scaffold with gradient pore sizes enhances osteogenic cell differentiation as well as mineralization. The in vivo performance of gradient calcium polyphosphate scaffolds warrants further investigation in animal bone defect models.
authors.affiliation: Department of Biomedical Engineering, Wayne State University, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering, Wayne State University, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.affiliation: Detroit Medical Center & Providence Hospital Orthopaedic Residency, USA Department of Orthopaedic Surgery, Providence Hospital and Medical Centers, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Markel
authors.affiliation: Department of Biomedical Engineering, Wayne State University, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Shi
authors.affiliation: PET Center, Wayne State University, USA.
authors.forename: Otto
authors.initials: O
authors.lastname: Muzik
authors.affiliation: Department of Biomedical Engineering, Wayne State University, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Matthew
authors.affiliation: Department of Biomedical Engineering, Wayne State University, USA Department of Orthopaedic Surgery, Providence Hospital and Medical Centers, USA as7606@wayne.edu.
authors.forename: Weiping
authors.initials: W
authors.lastname: Ren
mesh_terms: D016475:3T3 Cells; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D019149:Bioreactors; D018786:Bone Substitutes / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D002454:Cell Differentiation; D049109:Cell Proliferation; D005462:Fluorine Radioisotopes / Q000737:chemistry; D051379:Mice; D010012:Osteogenesis; D010477:Perfusion; D016062:Porosity; D049268:Positron-Emission Tomography; D013314:Stress, Mechanical; D013752:Tetracycline / Q000737:chemistry; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D005462:Fluorine Radioisotopes; C020243:calcium phosphate; D000469:Alkaline Phosphatase; D013752:Tetracycline
keywords: 18F-fluorine micro-positron emission tomography; Calcium polyphosphate; gradient scaffold; perfusion flow bioreactor