title: The Orientation of Nanoscale Apatite Platelets in Relation to Osteoblastic-Osteocyte Lacunae on Trabecular Bone Surface.
abstract: The orientation of nanoscale mineral platelets was quantitatively evaluated in relation to the shape of lacunae associated with partially embedded osteocytes (osteoblastic-osteocytes) on the surface of deproteinised trabecular bone of adult sheep. By scanning electron microscopy and image analysis, the mean orientation of mineral platelets at the osteoblastic-osteocyte lacuna (Ot.Lc) floor was found to be 19° ± 14° in the tibia and 20° ± 14° in the femur. Further, the mineral platelets showed a high degree of directional coherency: 37 ± 7% in the tibia and 38 ± 9% in the femur. The majority of Ot.Lc in the tibia (69.37%) and the femur (74.77%) exhibited a mean orientation of mineral platelets between 0° and 25°, with the largest fraction within a 15°-20° range, 17.12 and 19.8% in the tibia and femur, respectively. Energy dispersive X-ray spectroscopy and Raman spectroscopy were used to characterise the features observed on the anorganic bone surface. The Ca/P (atomic %) ratio was 1.69 ± 0.1 within the Ot.Lc and 1.68 ± 0.1 externally. Raman spectra of NaOCl-treated bone showed peaks associated with carbonated apatite: ν1, ν2 and ν4 PO4(3-), and ν1 CO3(2-), while the collagen amide bands were greatly reduced in intensity compared to untreated bone. The apatite-to-collagen ratio increased considerably after deproteinisation; however, the mineral crystallinity and the carbonate-to-phosphate ratios were unaffected. The ~19°-20° orientation of mineral platelets in at the Ot.Lc floor may be attributable to a gradual rotation of osteoblasts in successive layers relative to the underlying surface, giving rise to the twisted plywood-like pattern of lamellar bone.
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden. furqan.ali.shah@biomaterials.gu.se.|BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden. furqan.ali.shah@biomaterials.gu.se.
authors.forename: Furqan A
authors.initials: FA
authors.lastname: Shah
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, Göteborg, Sweden.
authors.forename: Ezio
authors.initials: E
authors.lastname: Zanghellini
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, Göteborg, Sweden.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Matic
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden.|BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Thomsen
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden.|BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Palmquist
mesh_terms: D000818:Animals; D001031:Apatites / Q000378:metabolism*; D001842:Bone and Bones / Q000502:physiology* / Q000648:ultrastructure*; D002113:Calcification, Physiologic / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D034561:Sheep, Domestic; D013052:Spectrometry, X-Ray Emission; D013059:Spectrum Analysis, Raman
chemical_list: D001031:Apatites
keywords: Biomineralisation; Bone; Electron microscopy; Lacuna; Osteoblastic–osteocyte; Raman spectroscopy; Trabecular bone