title: Gradient collagen/nanohydroxyapatite composite scaffold: development and characterization.
abstract: This paper reports an in situ diffusion method for the fabrication of compositionally graded collagen/nanohydroxyapatite (HA) composite scaffold. The method is diffusion based and causes the precipitation of nano-HA crystallites in situ. A collagen matrix acts as a template through which calcium ions (Ca(2+)) and phosphate ions (PO4(3-)) diffuse and precipitate a non-stoichiometric HA. It was observed that needle-like prismatic nano-HA crystallites (about 2 x 2 x 20 nm) precipitated in the interior of the collagen template onto the collagen fibrils. Chemical and microstructural analysis revealed a gradient of the Ca to P ratio across the width of the scaffold template, resulting in the formation of a Ca-rich side and a Ca-depleted side of scaffold. The Ca-rich side featured low porosity and agglomerates of the nano-HA crystallites, while the Ca-depleted side featured higher porosity and nano-HA crystallites integrated with collagen fibrils to form a porous network structure.
authors.affiliation: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK. DES6CL@YAHOO.COM
authors.forename: Chaozong
authors.initials: C
authors.lastname: Liu
authors.forename: Zhiwu
authors.initials: Z
authors.lastname: Han
authors.forename: J T
authors.initials: JT
authors.lastname: Czernuszka
mesh_terms: D000818:Animals; D002417:Cattle; D003094:Collagen; D017886:Durapatite; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D013057:Spectrum Analysis; D014057:Tomography, X-Ray Computed; D014965:X-Rays
chemical_list: D003094:Collagen; D017886:Durapatite