title: Macrotopographic closure promotes tissue growth and osteogenesis in vitro.
abstract: While the impact of substrate topographies at nano- and microscale on bone cell behavior has been particularly well documented, very few studies have analyzed the role of substrate closure at a tissular level. Moreover, these have focused on matrix deposition rather than on osteoblastic differentiation. In the present work, mouse calvaria cells were grown for 15days on hydroxyapatite (HA) ceramics textured with three different macrogrooves shapes (**100µm): 1 sine and 2 triangle waveforms. We found that macrotopography favors cell attachment, and that bone-like tissue growth and organization are promoted by a tight "closure angle" of the substrate geometry. Interestingly, while Flat HA controls showed little marker expression at the end of the culture, cells grown on macrogrooves, and in particular the most closed (triangle waveform with a 517µm spatial period) showed a fast time-course of osteoblast differentiation, reaching high levels of gene and protein expression of osteocalcin and sclerostin, a marker of osteocytes.
  
  
  
  Many in vitro studies have been conducted on topography at nano and microscale, fewer have focused on the influence of macrotopography on osteoblasts. Ceramics with a controlled architecture were obtained throught a 3D printing process and used to assess osteoblast behavior. Biocompatible, they allowed the long-terme survival of osteoblast cells and the laying of an important bone matrix. V-shaped grooves were found to accelerates osteoblast differentiation and promote bone-like tissue deposition and maturation (osteocyte formation), proportionately to angle closure. Such macrostructures are attractive for the design of innovative implants for bone tissue engineering and in vitro models of osteogenesis.
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France. Electronic address: laura.juignet@univ-st-etienne.fr.
authors.forename: Laura
authors.initials: L
authors.lastname: Juignet
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France; Ecole des Mines de Saint-Etienne, Centre Ingénierie Santé, Campus Santé Innovations, Saint-Etienne F-42023, France. Electronic address: charbonnier@emse.fr.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Charbonnier
authors.affiliation: Ecole Nationale d'Ingénieurs de Saint Etienne, LTDS, UMR 5513 CNRS, Saint-Etienne F-42023, France. Electronic address: virginie.dumas@enise.fr.
authors.forename: Virginie
authors.initials: V
authors.lastname: Dumas
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France. Electronic address: wafa.bouleftour@univ-st-etienne.fr.
authors.forename: Wafa
authors.initials: W
authors.lastname: Bouleftour
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France. Electronic address: mireille.thomas@univ-st-etienne.fr.
authors.forename: Mireille
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France; Ecole des Mines de Saint-Etienne, Centre Ingénierie Santé, Campus Santé Innovations, Saint-Etienne F-42023, France. Electronic address: laurent@emse.fr.
authors.forename: Coralie
authors.initials: C
authors.lastname: Laurent
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France. Electronic address: vico@univ-st-etienne.fr.
authors.forename: Laurence
authors.initials: L
authors.lastname: Vico
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France; Ecole des Mines de Saint-Etienne, Centre Ingénierie Santé, Campus Santé Innovations, Saint-Etienne F-42023, France. Electronic address: douard@emse.fr.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Douard
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France; Ecole des Mines de Saint-Etienne, Centre Ingénierie Santé, Campus Santé Innovations, Saint-Etienne F-42023, France. Electronic address: marchat@emse.fr.
authors.forename: David
authors.initials: D
authors.lastname: Marchat
authors.affiliation: Laboratoire de Biologie des Tissus Ostéoarticulaires, INSERM, U1059, Université de Lyon, Université Jean Monnet, Saint-Etienne F-42023, France. Electronic address: luc.malaval@univ-st-etienne.fr.
authors.forename: Luc
authors.initials: L
authors.lastname: Malaval
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry*; D002448:Cell Adhesion / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology*; D002478:Cells, Cultured; D017886:Durapatite / Q000737:chemistry*; D008422:Materials Testing; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology*; D013499:Surface Properties
chemical_list: D018786:Bone Substitutes; D017886:Durapatite
keywords: Bioceramics; Macrotopography; Osteoblast differentiation; Substrate closure