title: A simple and effective approach to prepare injectable macroporous calcium phosphate cement for bone repair: Syringe-foaming using a viscous hydrophilic polymeric solution.
abstract: In this study, we propose a simple and effective strategy to prepare injectable macroporous calcium phosphate cements (CPCs) by syringe-foaming via hydrophilic viscous polymeric solution, such as using silanized-hydroxypropyl methylcellulose (Si-HPMC) as a foaming agent. The Si-HPMC foamed CPCs demonstrate excellent handling properties such as injectability and cohesion. After hardening the foamed CPCs possess hierarchical macropores and their mechanical properties (Young's modulus and compressive strength) are comparable to those of cancellous bone. Moreover, a preliminary in vivo study in the distal femoral sites of rabbits was conducted to evaluate the biofunctionality of this injectable macroporous CPC. The evidence of newly formed bone in the central zone of implantation site indicates the feasibility and effectiveness of this foaming strategy that will have to be optimized by further extensive animal experiments.
  
  
  CONCLUSIONS
  A major challenge in the design of biomaterial-based injectable bone substitutes is the development of cohesive, macroporous and self-setting calcium phosphate cement (CPC) that enables rapid cell invasion with adequate initial mechanical properties without the use of complex processing and additives. Thus, we propose a simple and effective strategy to prepare injectable macroporous CPCs through syringe-foaming using a hydrophilic viscous polymeric solution (silanized-hydroxypropyl methylcellulose, Si-HPMC) as a foaming agent, that simultaneously meets all the aforementioned aims. Evidence from our in vivo studies shows the existence of newly formed bone within the implantation site, indicating the feasibility and effectiveness of this foaming strategy, which could be used in various CPC systems using other hydrophilic viscous polymeric solutions.
authors.affiliation: Université de Nantes, INSERM UMRS 791, Laboratoire d'Ingénierie Ostéo-Articulaire et Dentaire, 1 place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1, France; Université de Nantes, Polytech Nantes, Institut des Matériaux Jean Rouxel, CNRS UMR 6502, Rue Christian Pauc, BP 50609, 44306 Nantes Cedex 3, France.
authors.forename: Jingtao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Université de Nantes, INSERM UMRS 791, Laboratoire d'Ingénierie Ostéo-Articulaire et Dentaire, 1 place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1, France; Université de Nantes, Polytech Nantes, Institut des Matériaux Jean Rouxel, CNRS UMR 6502, Rue Christian Pauc, BP 50609, 44306 Nantes Cedex 3, France.
authors.forename: Weizhen
authors.initials: W
authors.lastname: Liu
authors.affiliation: ONIRIS - Ecole Nationale Veterinaire de Nantes, Atlanpole-La Chantrerie, BP 40706, 44307 Nantes cedex 3, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Gauthier
authors.affiliation: Université de Nantes, INSERM UMRS 791, Laboratoire d'Ingénierie Ostéo-Articulaire et Dentaire, 1 place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Sourice
authors.affiliation: Université de Nantes, INSERM UMRS 791, Laboratoire d'Ingénierie Ostéo-Articulaire et Dentaire, 1 place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1, France; CHU de Nantes, Nantes University Hospital, PHU 4 OTONN, 1 Pl A. Ricordeau Nantes, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Pilet
authors.affiliation: Université de Nantes, INSERM UMRS 791, Laboratoire d'Ingénierie Ostéo-Articulaire et Dentaire, 1 place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1, France; CHU de Nantes, Nantes University Hospital, PHU 4 OTONN, 1 Pl A. Ricordeau Nantes, France.
authors.forename: Gildas
authors.initials: G
authors.lastname: Rethore
authors.affiliation: Université de Nantes, INSERM UMRS 791, Laboratoire d'Ingénierie Ostéo-Articulaire et Dentaire, 1 place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1, France.
authors.forename: Khalid
authors.initials: K
authors.lastname: Khairoun
authors.affiliation: Université de Nantes, CEISAM, CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Bouler
authors.affiliation: Université de Nantes, Polytech Nantes, Institut des Matériaux Jean Rouxel, CNRS UMR 6502, Rue Christian Pauc, BP 50609, 44306 Nantes Cedex 3, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Tancret
authors.affiliation: Université de Nantes, INSERM UMRS 791, Laboratoire d'Ingénierie Ostéo-Articulaire et Dentaire, 1 place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1, France; CHU de Nantes, Nantes University Hospital, PHU 4 OTONN, 1 Pl A. Ricordeau Nantes, France. Electronic address: pierre.weiss@univ-nantes.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Weiss
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001843:Bone Cements / Q000737:chemistry*; D001861:Bone Regeneration; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D019245:Compressive Strength; D065347:Hypromellose Derivatives / Q000737:chemistry; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D011208:Powders; D011817:Rabbits; D013314:Stress, Mechanical; D013594:Syringes; D014783:Viscosity
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D018786:Bone Substitutes; D002130:Calcium Phosphates; D011108:Polymers; D011208:Powders; D065347:Hypromellose Derivatives; C020243:calcium phosphate
keywords: Bone regeneration; Calcium phosphate cements; Macropores; Si-HPMC hydrogel; Silated polymer