title: Immobilization of phosphate monomers on collagen induces biomimetic mineralization.
abstract: BACKGROUND
  Immobilization of phosphoproteins on type-I collagen via covalent binding may induce extra- and intrafibrillar mineralization.
  
  
  OBJECTIVE
  This study tested the hypothesis that methacrylate phosphate esters immobilized on reconstituted type-I collagen can mimic the nucleating role of phosphoproteins.
  
  
  METHODS
  Three functional monomers (MDP, GPDM and Phenyl-P) that differed in chemical structure and steric hindrances around the phosphate moiety were evaluated. Reconstituted type-I collagen was either left untouched (control) or treated by 5% monomer/ethanol for 20 s. All samples were incubated in simulated dentinal fluid as mineralizing medium at 37°C for 7 or 14 days. The extra- and intrafibrillar mineralization were examined by SEM and TEM/SAED crystallography, respectively.
  
  
  RESULTS
  FT-IR spectroscopy showed that the phosphate groups were incorporated on reconstituted collagen, irrespective of their chemical structure. MDP immobilization induced dense growth of extrafibrillar mineral over time, while with GPDM- and Phenyl-P-immobilized collagen, mineralization was moderate and sparse, respectively. TEM/SAED evidence disclosed that intrafibrillar minerals exclusively occurred in MDP-immobilized collagen.
  
  
  CONCLUSIONS
  Immobilization of MDP, which had the lowest steric hindrance, could induce significant biomimetic extra- and intrafibrillar mineralization; resembling the lowest level of hierarchy organization of dentin.
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Hamid
authors.initials: H
authors.lastname: Nurrohman
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Syozi
authors.initials: S
authors.lastname: Nakashima
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Takagaki
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nikaido
authors.affiliation: Advanced Biomaterials, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Asakawa
authors.affiliation: Advanced Biomaterials, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Uo
authors.affiliation: Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Sally J
authors.initials: SJ
authors.lastname: Marshall
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
mesh_terms: D000818:Animals; D001031:Apatites / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry; D032701:Biomimetics; D002417:Cattle; D003094:Collagen / Q000737:chemistry; D024042:Collagen Type I / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D004952:Esters / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010710:Phosphates / Q000737:chemistry*; D010750:Phosphoproteins / Q000737:chemistry; D010766:Phosphorylation; D011485:Protein Binding; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D024042:Collagen Type I; D004952:Esters; D008689:Methacrylates; D010710:Phosphates; D010750:Phosphoproteins; D003094:Collagen
keywords: Functional monomer; biomimetic mineralization; chemical structure; steric hindrance; type-I collagen