title: Nanocrystalline hydroxyapatite coatings on titanium: a new fast biomimetic method.
abstract: We obtained a fast biomimetic deposition of hydroxyapatite (HA) coatings on Ti6Al4V substrates using a slightly supersaturated Ca/P solution, with an ionic composition simpler than that of simulated body fluid (SBF). At variance with other fast deposition methods, which produce amorphous calcium phosphate coatings, the new proposed composition allows one to obtain nanocrystalline HA. Soaking in supersaturated Ca/P solution results in the deposition of a uniform coating in a few hours, whereas SBF, or even 1.5SBF, requires 14 days to deposit a homogeneous coating on the same substrates. The coating consists of HA globular aggregates, which exhibit a finer lamellar structure than those deposited from SBF. The extent of deposition increases on increasing the immersion time. Transmission electron microscope (TEM) images recorded on the material detached from the coating show that the deposition is constituted of thin nanocrystals. Electron diffraction (ED) patterns recorded from most of the crystals exhibit the presence of rings, which can be indexed as reflections characteristic of HA. Furthermore, several HA single-crystal spot ED images were obtained from individual crystals.
authors.affiliation: Department of Chemistry "G. Ciamician", University of Bologna, via Selmi, 2, 40126 Bologna, Italy. adriana.bigi@unibo.it
authors.forename: Adriana
authors.initials: A
authors.lastname: Bigi
authors.forename: Elisa
authors.initials: E
authors.lastname: Boanini
authors.forename: Barbara
authors.initials: B
authors.lastname: Bracci
authors.forename: Alessandro
authors.initials: A
authors.lastname: Facchini
authors.forename: Silvia
authors.initials: S
authors.lastname: Panzavolta
authors.forename: Francesco
authors.initials: F
authors.lastname: Segatti
authors.forename: Luigina
authors.initials: L
authors.lastname: Sturba
mesh_terms: D000497:Alloys; D032701:Biomimetics / Q000379:methods*; D001826:Body Fluids / Q000737:chemistry*; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D017886:Durapatite / Q000032:analysis / Q000737:chemistry*; D008422:Materials Testing; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000032:analysis / Q000737:chemistry*
chemical_list: D000497:Alloys; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; C519480:amorphous calcium phosphate; C031462:titanium alloy (TiAl6V4); D017886:Durapatite; D014025:Titanium