title: The synergic role of collagen and citrate in stabilizing amorphous calcium phosphate precursors with platy morphology.
abstract: Bioinspired in vitro collagen mineralization experiments have been performed in the presence of citrate and the combined role of the two bone organic matrix components in controlling mineral formation was investigated for the first time. Mineralized and non-mineralized collagen fibrils have been in depth characterized by combining small- and wide-angle X-ray scattering (SAXS/WAXS) techniques with Atomic Force Microscopy (AFM) imaging. A synergic effect of collagen and citrate in driving the formation of long-term stable amorphous calcium phosphate (ACP) nanoparticles with platy morphology was found. AFM images on mineralized collagen fibrils revealed that some of the ACP nanoparticles were deposited on the intramolecular nanoscopic holes of collagen fibrils.
  
  
  
  Citrate is an important component of the bone organic matrix but its specific role in bone mineralization is presently unclear. In this work, bioinspired in vitro collagen mineralization experiments in the presence of citrate have been carried out and the combined role of collagen and citrate in controlling mineral formation has been addressed for the first time. Through X-ray scattering and Atomic Force Microscopy characterizations on mineralized and non-mineralized collagen fibrils, we have found that citrate in synergy with collagen stabilizes an amorphous calcium phosphate (ACP) phase with platy morphology over one week and controls its deposition on collagen fibrils.
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia and To.Sca.Lab, Università dell'Insubria, Como, Italy; Instituto Andaluz de Ciencias de la Tierra (IACT, CSIC-UGR), Armilla (Granada), Spain. Electronic address: jmdl@iact.ugr-csic.es.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Delgado-López
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia and To.Sca.Lab, Università dell'Insubria, Como, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Bertolotti
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Aarhus C, Denmark.
authors.forename: Jeppe
authors.initials: J
authors.lastname: Lyngsø
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Aarhus C, Denmark.
authors.forename: Jan Skov
authors.initials: JS
authors.lastname: Pedersen
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cervellino
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia and To.Sca.Lab, Università dell'Insubria, Como, Italy.
authors.forename: Norberto
authors.initials: N
authors.lastname: Masciocchi
authors.affiliation: Istituto di Cristallografia and To.Sca.Lab, CNR, Como, Italy. Electronic address: antonella.guagliardi@ic.cnr.it.
authors.forename: Antonietta
authors.initials: A
authors.lastname: Guagliardi
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic; D002130:Calcium Phosphates / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry*; D006736:Horses; D018625:Microscopy, Atomic Force; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; C519480:amorphous calcium phosphate; D019343:Citric Acid; D003094:Collagen
keywords: ACP; AFM; Biomaterials; Bone mineralization; Citrate; Collagen; Nanoapatite; SAXS/WAXS