title: Nanoscale surface characterization of biphasic calcium phosphate, with comparisons to calcium hydroxyapatite and β-tricalcium phosphate bioceramics.
abstract: OBJECTIVE
  It is our aim to understand the mechanisms that make calcium phosphates, such as bioactive calcium hydroxyapatite (HA), and biphasic calcium (BCP) and β-tricalcium (β-TCP) phosphates, desirable for a variety of biological applications, such as the filling of bone defects.
  
  
  METHODS
  Here, we have characterized these materials by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and laser granulometry.
  
  
  RESULTS
  SEM shows clearly that BCP is a matrix made of macro-organized microstructure, giving insight to the specially chosen composition of the BCP that offers both an adequate scaffold and good porosity for further bone growth. As revealed by laser granulometry, the particles exhibit a homogeneous size distribution, centered at a value somewhat larger than the expected 500 μm. XPS has revealed the presence of adventitious carbon at all sample surfaces, and has shown that Ca/P and O/Ca ratios in the outer layers of all the samples differ significantly from those expected. A peak-by-peak XPS comparison for all samples has revealed that TCP and BCP are distinct from one another in the relative intensities of their oxygen peaks. The PO3(-)/PO2(-) and CaOH+/Ca+ TOF-SIMS intensity ratios were used to distinguish among the samples, and to demonstrate that the OH- fragment, present in all the samples, is not formed during fragmentation but exists at the sample surface, probably as a contaminant.
  
  
  CONCLUSIONS
  This study provides substantial insight into the nanoscale surface properties of BCP, HA and β-TCP. Further research is required to help identify the effect of surfaces of these bioceramics with proteins and several biological fluids.
  
  
  CONCLUSIONS
  The biological performance of implanted synthetic graft bone biomaterials is strongly influenced by their nanosurface characteristics, the structures and properties of the outer layer of the biomaterial.
authors.affiliation: Laboratoire d'Innovation et d'Analyse de Bioperformance, École Polytechnique de Montréal, C.P. 6079, Succursale Centre-ville, Montréal, Québec H3C 3A7, Canada; Dental Biomaterials Research Laboratory, Department of Restorative Dentistry, Faculty of Dentistry, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, Manitoba R3E 0W2, Canada. Electronic address: Rodrigo.Franca@umanitoba.ca.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: França
authors.affiliation: Laboratoire d'Innovation et d'Analyse de Bioperformance, École Polytechnique de Montréal, C.P. 6079, Succursale Centre-ville, Montréal, Québec H3C 3A7, Canada.
authors.forename: Taraneh Djavanbakht
authors.initials: TD
authors.lastname: Samani
authors.affiliation: Laboratoire d'Innovation et d'Analyse de Bioperformance, École Polytechnique de Montréal, C.P. 6079, Succursale Centre-ville, Montréal, Québec H3C 3A7, Canada.
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Bayade
authors.affiliation: Laboratoire d'Innovation et d'Analyse de Bioperformance, École Polytechnique de Montréal, C.P. 6079, Succursale Centre-ville, Montréal, Québec H3C 3A7, Canada.
authors.forename: L'Hocine
authors.initials: L
authors.lastname: Yahia
authors.affiliation: Laboratoire d'Innovation et d'Analyse de Bioperformance, École Polytechnique de Montréal, C.P. 6079, Succursale Centre-ville, Montréal, Québec H3C 3A7, Canada; Regroupement Québecois de Matériaux de Pointe, Département de Génie Physique, École Polytechnique de Montréal, C.P. 6079, Succursale Centre-ville, Montréal, Québec H3C 3A7, Canada.
authors.forename: Edward
authors.initials: E
authors.lastname: Sacher
mesh_terms: D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D006882:Hydroxyapatites / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D006882:Hydroxyapatites; C485817:beta-tricalcium phosphate; C074950:hydroxyapatite-beta tricalcium phosphate; D017886:Durapatite
keywords: Bioceramic; Biphasic calcium phosphate; FTIR; Hydroxyapatite; Porosity; SEM; TOF-SIMS; XPS; XRD; β-tricalcium phosphate