الفهرس 
IntroductionOnly 14 pages are availabe for public view
Abstract
In the present project, two phosphatic/ silk/ nanosilver/ chitosan composites were successfully achieved maintaining the normal ratios between inorganic/organic ratios to be 70/30 mimicking, therefore, natural bone mineral structures.
• Silk fibroin protein and chitosan amide groups acted as organic matrices to provide the active sites available for nucleation and growth of HA and OCP phases.
• Intimately, the organic matrices in the suitable amount (30%) provided a larger number of active sites, which promoted the self-assembly of HA and OCP crystallites on silk fibroin/ chitosan surface in synthesis and in vitro assessment.
• The two developed composites showed thermal stability up to 200 °C with total weight loss of 6.444 and 8.566 % corresponding to HA and OCP composites respectively. Therefore, assessing the difference in their specific formulae of each with five water molecules for the later.
• The high crystallinity features were confirmed by XRD in parallel with the definite Debye Scherrer rings within the TEM. Intimate cross linking between silk fibroin and the phosphatic phases was proved by FTIR results with minor differences between both. The calculated (CI)XDR and (CI)FTIR for both phases in either composites are in high conformity having a slightly higher values for HA composite.
Chapter Four Results and
Discussion
136
• An adequate porosity required for the deposition process of newly phosphatic phases was recorded for OCP/ SF/NS/Cs composite relative to HA/ SF/NS/Cs. Post-immersion, the trimodal pore system was achieved in OCP.
• The percentage change of the total porosity post immersion amounted to 20 and 5% for HA/ SF/NS/Cs and OCP/SF/NS/Cs respectively. A more leachable configuration of the later is thus confirmed since the OCP is more resorbable it affected earlier deposition of newly apatitic layer. The exchanged ions influenced the electric field inside the pores as well as pore volume and provided a convenient way for tuning the adsorptive properties.
• The release of Ca and Pi ions followed by a deposition with a higher rate for OCP composite relative to HA one was achieved in D-MEM. The biolayer formation was associated by the dissolution of some phosphatic phases especially for OCP leaving a rougher surface which should affect more adherence to the host site.
• Similar trend of sequential adsorption/ release of protein was recorded for both composites with higher values of OCP matrices due to their adequate pore size distribution. Therefore, more bio layer formation is developed.
• FESEM and FTIR both revealed biolayer deposition on the composite surfaces 48 hours post immersion through the deposition of phosphatic phases. The crystallinity indices of the phosphatic phases were slightly lower denoting precipitation following the initial dissolution.
Chapter Four Results and
Discussion
137
• The inclusion of silver nanoparticles enveloped by chitosan fragments would be expected to have more beneficial bactericidal activity for OCP composite. Since both composites contain similar initial nanosilver concentrations, OCP composite is still holding more SN on its surface as confirmed by its EDAX.
• A bottom up approach, in the present work, controlled the achieved configuration by arranging elementary chemical motifs into the system displaying intricate pattern by in situ formation. Biophysical and biochemical manipulation of 3D polymer network was achieved for controlling interface.
• Conclusively, the fabricated composites combined the benefits of phosphatic phases, silk fibroin, silver nanoparticles enveloped by chitosan and, therefore, hold a great promise for the biomedical applications in the near future for hard tissue repair