الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 131 |  |  |
| | | from | 131 | | |
Abstract
Biomaterials can be defined as materials intended to interface with biological systems to treat, augment or replace any tissue, organ or a function of the body. Biomaterials could provide a solution to most of problems that developed for all bone grafting procedures.
Hydroxy apatite HA [Ca10(PO4)6(OH)2] is a biomaterial for substituting human hard tissues, due to its excellent biocompatibility and osteoconductivity as well as close similarity to the human bone structure.
The aim of the present work is to use HA as a carrier for the chromium ions which can improve the production of insulin which may help in treatment of diabetes. Through preparing pure HA apatite (S1) and Cr loaded HA (S2,S3,S4 and S5) of different chromium concentrations [0.005,0.01,0.02,0.03 mole] respectively by wet precipitation method .Diamonium hydrogen phosphate[(NH4)2HPO4] is added in droplet manner(1-3 mL per min.) to a mixture of calcium nitrate [Ca(nO3)2.4h2o] and chromium nitrate [Cr(NO3)2.9H 2O] with magnetic stirring and constant temp. 60 C0 .The pH of the mixture was kept at 10 during chemical reaction process.
The XRD (X-Ray Diffraction) and FTIR (Fourier Transforms Infrared spectroscopy) were used as analytical techniques for the prepared HA and Cr loaded HA samples. The rate of their degradation was followed to assess biocompatibility by Simulated Body Fluid (SBF) up to 24 day, through the elemental and chemical analysis of Ca, P and Cr. The differential thermal analysis was used to determine the onset crystallization temperatures (Tc). pH of the samples also was measured at the first period of immersion time in (SBF) .
It was noted that chromium ions can be incorporated into HA crystal during mineralization and affect the crystal lattice parameters as well as the size of the crystal .
The crystal growth of HA is strongly promoted on doping Cr+3 ions by the co precipitation method with basic solutions. During the immersion of the samples in SBF, Ca and P ions concentrations was lowered, indicating that carbonated bone like apatite layer is formed on the surface of calcium phosphate bioceramic samples . Hydroxy apatite acts as a carrier for the Cr+3 ions, where the Ca+2 ions substituted by the Cr+3 ions. from the chemical analysis of Cr loaded HA samples after immersion in SBF for 24 day, the dissolution rate of Cr+3 ions are considered to be a safe dose for human and this lead to improve the production of insulin which may help in the treatment of diabetes.