title: Characterizing inorganic crystals grown on organic self-assembled bilayers with scanning probe and electron microscopies.
abstract: Combined microscopy techniques are used to establish the usability of phosphonic acid layers as promoters of hydroxyapatite (HAp) growth. Using spread coating, octadecylphosphonic acid (OPA) self-assembled bilayers are delivered to the thin natural oxide layer of a titanium film surface with no prior treatment. These bilayers aggregate two major advantages of phosphonic moieties to titanium surfaces: nucleation of hydroxyapatite crystals from ionic solution and affinity for both titanium oxide surface and HAp crystals. The functionalized substrates and bare titanium (control) samples are immersed in an aqueous solution containing calcium and phosphorus ions. Over a 4-week immersion time, OPA-functionalized substrates present numerous large agglomerates of inorganic crystals, in contrast to control samples, with no significant amount of deposits. Initial sample characterization was performed with atomic force microscopy (AFM). Compositional and structural characterization of these agglomerates (using TEM, EDS, and electron diffraction), revealed that they are indeed HAp, the main component of the inorganic bone matrix.
authors.affiliation: Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, 30123-970, Brazil.
authors.forename: Mariana C
authors.initials: MC
authors.lastname: Prado
authors.forename: Braulio S
authors.initials: BS
authors.lastname: Archanjo
authors.forename: Thiago L
authors.initials: TL
authors.lastname: Vasconcelos
authors.forename: Luiz O
authors.initials: LO
authors.lastname: Ladeira
authors.forename: Bernardo R A
authors.initials: BR
authors.lastname: Neves
mesh_terms: D001857:Bone Matrix / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003460:Crystallization; D017886:Durapatite / Q000737:chemistry* / Q000378:metabolism; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D020527:Microscopy, Scanning Probe; D010757:Phosphorous Acids / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D020099:Coated Materials, Biocompatible; D010757:Phosphorous Acids; C570063:phosphonic acid; D010758:Phosphorus; D017886:Durapatite; D014025:Titanium; D002118:Calcium
keywords: AFM; EDS; SEM; hydroxyapatite; phosphonic acids; self-assembled bilayers