title: Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces.
abstract: Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation.
authors.affiliation: School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH, UK.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Smith
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT, UK.
authors.forename: Jennifer Z
authors.initials: JZ
authors.lastname: Paxton
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT, UK.
authors.forename: Yi-Pei
authors.initials: YP
authors.lastname: Hung
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT, UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Hadley
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT, UK.
authors.forename: James
authors.initials: J
authors.lastname: Bowen
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT, UK.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Williams
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT, UK. Electronic address: l.m.grover@bham.ac.uk.
authors.forename: Liam M
authors.initials: LM
authors.lastname: Grover
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry; D002448:Cell Adhesion; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003460:Crystallization; D017886:Durapatite / Q000737:chemistry; D006622:Hip Prosthesis; D051379:Mice; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology; D010006:Osteoblasts / Q000166:cytology*; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D017886:Durapatite; C020243:calcium phosphate
keywords: Calcium phosphate; Coating; Crystallinity; Hydroxyapatite; Prosthesis