title: Development of a morphogenetically active scaffold for three-dimensional growth of bone cells: biosilica-alginate hydrogel for SaOS-2 cell cultivation.
abstract: Polymeric silica is formed from ortho-silicate during a sol-gel formation process, while biosilica is the product of an enzymatically driven bio-polycondensation reaction. Both polymers have recently been described as a template that induces an increased expression of the genes encoding bone morphogenetic protein 2 (BMP-2) and osteoprotegerin in osteoblast-related SaOS-2 cells; simultaneously or subsequently the cells respond with enhanced hydroxyapatite formation. In order to assess whether the biocompatible polymeric silica/biosilica can serve as a morphogenetically active matrix suitable for three-dimensional (3D) cell growth, or even for 3D cell bioprinting, SaOS-2 cells were embedded into a Na-alginate-based hydrogel. Four different gelatinous hydrogel matrices were used for suspending SaOS-2 cells: (a) the hydrogel alone; (b) the hydrogel with 400 μM ortho-silicate; (c) the hydrogel supplemented with 400 μM ortho-silicate and recombinant silicatein to allow biosilica synthesis to occur; and (d) the hydrogel with ortho-silicate and BSA. The SaOS-2 cells showed an increased growth if silica/biosilica components were present in the hydrogel. Likewise intensified was the formation of hydroxyapatite nodules in the silica-containing hydrogels. After an incubation period of 2 weeks, cells present in silica-containing hydrogels showed a significantly higher expression of the genes encoding the cytokine BMP-2, the major fibrillar structural protein collagen 1 and likewise of carbonic anhydrase. It is concluded that silica, and to a larger extent biosilica, retains its morphogenetic/osteogenic potential after addition to Na-alginate-based hydrogels. This property might qualify silica hydrogels to be also used as a matrix for 3D cell printing.
authors.affiliation: ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Centre, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
authors.affiliation: ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Centre, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Heinz C
authors.initials: HC
authors.lastname: Schröder
authors.affiliation: School of Materials Science and Engineering, Tsinghua University, Beijing, People's Republic of China.
authors.forename: Qingling
authors.initials: Q
authors.lastname: Feng
authors.affiliation: ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Centre, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Schlossmacher
authors.affiliation: ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Centre, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Thorben
authors.initials: T
authors.lastname: Link
authors.affiliation: ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Centre, Johannes Gutenberg University, Mainz, Germany.|National Research Centre for Geoanalysis, Chinese Academy of Geological Sciences, Beijing, People's Republic of China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
mesh_terms: D000464:Alginates / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D062028:Bioprinting; D055396:Bone Morphogenetic Protein 2 / Q000737:chemistry; D001842:Bone and Bones / Q000502:physiology*; D002256:Carbonic Anhydrases / Q000737:chemistry; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D003094:Collagen / Q000737:chemistry; D016207:Cytokines / Q000378:metabolism; D017886:Durapatite / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis; D011108:Polymers / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D000464:Alginates; C525718:BMP2 protein, human; D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D016207:Cytokines; D020100:Hydrogels; D011108:Polymers; D011994:Recombinant Proteins; D017640:Silicates; D012822:Silicon Dioxide; D003094:Collagen; D017886:Durapatite; D002256:Carbonic Anhydrases
keywords: BMP-2; SaOS-2 cells; alginate; biosilica; carbonic anhydrase 1; collagen 1; hydrogel; silica