title: A novel route for synthesis of nanocrystalline hydroxyapatite from eggshell waste.
abstract: The eggshell waste has been value engineered to a nanocrystalline hydroxyapatite (HA) by microwave processing. To highlight the advantages of eggshell as calcium precursor in the synthesis of HA (OHA), synthetic calcium hydroxide was also used to form HA (SHA) following similar procedure and were compared with a commercially available pure HA (CHA). All the HAs were characterized by X-ray powder diffraction (XRD) method, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and specific surface area measurements. Nanocrystalline nature of OHA is revealed through characteristic broad peaks in XRD patterns, platelets of length 33-50 nm and width 8-14 nm in TEM micrograph and size calculations from specific surface area measurements. FT-IR spectra showed characteristic bands of HA and additionally peaks of carbonate ions. The cell parameter calculations suggest the formation of carbonated HA of B-type. The OHA exhibits superior sinterability in terms of hardness and density than both SHA and CHA may be due to larger surface area of its spherulite structure. The in vitro dissolution study shows longer stability in phosphate buffer and cell culture test using osteoblast cells establishes biocompatibility of OHA.
authors.affiliation: Department of Metallurgical & Materials Engineering, Indian Institute of Technology Madras, Chennai, India.
authors.forename: D
authors.initials: D
authors.lastname: Siva Rama Krishna
authors.forename: A
authors.initials: A
authors.lastname: Siddharthan
authors.forename: S K
authors.initials: SK
authors.lastname: Seshadri
authors.forename: T S
authors.initials: TS
authors.lastname: Sampath Kumar
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis*; D002460:Cell Line; D017886:Durapatite / Q000138:chemical synthesis*; D004528:Egg Shell / Q000737:chemistry / Q000648:ultrastructure; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000166:cytology; D033362:Powder Diffraction; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite