الفهرس 
Theoretical AspectsOnly 14 pages are availabe for public view
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Abstract
Bone infection is the main source that triggers and initiates osteomyelitis. The patient suffering from such a brutal bone disease is usually subjected to long-term antibiotic treatment, which can lead to acute toxicity to other parts of body. To offer a solution for such condition, several materials scientists have designed localized targeting devices that can release controlled therapeutic doses of antibiotic directly at infected site, which maximize the benefit of treatment and reduce the toxic effect of the drug. Also, the removal of necrotic bone by surgeon creates large bone defects that need a bioactive material to regenerate and augment that defect. Therefore, the presented work focus on the design, synthesis and characterization of novel manganese doped calcium silicate ceramics for bone engineering and localized osteomyelitis treatment. Manganese is chosen in this study due to its known beneficial effect on bone regeneration.
The main objectives of the presented study were summarized by the following point:
1. Synthesis of novel manganese doped calcium silicate ceramics for bone treatment by employing the sol-gel technique. Variable manganese contents (0, 0.25, 0.5 mol. %) are added at the expense of calcium in calcium silicate structures. The samples are subjected to controlled heat treatment at various temperatures (1150, 1200, 1250 and 1300οC). Heating is highly essential for converting the amorphous dry gel in to well crystalline calcium silicate ceramics.
2. Characterization of fabricate manganese modified ceramics using the following characterization techniques.
• The Thermo-gravimetric analysis (TGA) and differential scanning calorimetric analysis (DSC) are employed to evaluate the thermal behavior of samples, and to find out the exact temperature for eliminating the organic residual, nitrate, ethanol as well as water from samples.
• The X-ray diffraction analysis is carried out for samples to identify the developed phases in those samples at various temperatures (1150, 1200, 1250 and 1300οC).
• The Transmission electron microscopy (TEM) is used to examine the effect of manganese addition on the morphology and microstructure of modified calcium silicate ceramic samples.
• The Fourier Transform Infrared (FTIR) spectroscopy is employed for structural analysis of samples and to distinguish the main characteristic absorption bands of calcium silicate ceramics.
• Textural analysis utilizing the high speed gas sorption analyzer is carried out for samples. The specific surface area, average pore diameter and total pore volume is determined for modified calcium silicate ceramics.
3. In vitro bioactivity evaluation in simulated body fluid is carried out for samples, and the effect of manganese addition on the ability of modified calcium silicate ceramics to induce hydroxyapatite layer over their surfaces is studied.
4. The ability of using manganese modified calcium silicate ceramics as localized ciprofloxacin delivery devices is addressed. The effect of manganese addition on drug loading and release profile is analyzed.
The main results and conclusions obtained from the study were summarized in the following point:
1. Manganese doped calcium silicate ceramics with variable manganese contents (0, 0.25 and 0.5 mol. %) are successfully prepared by the sol-gel method. They are given the code S1, S2 and S3, respectively.
2. Thermal analysis indicates that all the residuals of the prepared samples are eliminated before reaching 700 °C. In addition, the analysis shows that the addition of manganese at the expense of calcium has enhanced the crystallization process of amorphous gels, where less heating energy is needed to induce the growth of crystalline phases in both manganese modified samples (S2 and S3) relative to unmodified one (S1).
3. X-ray analysis indicates that samples S1 and S2, which are sintered at 1250⁰C, include the high temperature form of calcium silicate ceramic known as Pseudowollastonite or Cycllowollastonite as a single phase, while S3 consists of Pseudowollastonite as a major phase, beside negligible traces of Wollastonite. As the intension of the present work is to prepare high temperature form of calcium silicate, therefore, the sintered samples at 1250⁰C are chosen for further characterization and evaluation as bone engineering bioactive materials as well as drug carriers.
4. Transmission electron microscope images demonstrate the fibrous nature of sample S1 and S2. However, sample S2 shows a well-oriented fine fibrous microstructure than S1. In contrast, sample S3 has interlocked rod-like grains appearance.
5. The Fourier Transform Infrared spectra of samples S1, S2 and S3 show all the characteristic absorption bands of calcium silicate ceramics.
6. Textural analysis reveals that all samples have a porous structure with elevated specific surface areas. Also, the analysis shows that specific surface area and total pore volume of samples decreases by manganese addition. Specific surface areas of samples S1, S2 and S3 are found to be 427.89 and 293.2 and 265.6 m2.g-1, respectively. While their total pores volumes are 0.1160, 0.08123, and 0.07428 (cm3.g-1), respectively.
7. The in vitro bioactivity study in the simulated body fluid ensures that manganese addition has not affected the ability of modified samples S2 and S3 to induce hydroxyapatite layer on their surfaces, which implies the possibility of using those samples for bone regeneration.
8. The possibility of utilizing the novel fabricated calcium silicate samples (S1, S2 and S3) as controlled delivery vehicles for antibiotic ciprofloxacin was verified. Comparing between the drug releases patterns of all samples reveals that manganese modified samples S2 and S3 have more controlled release profiles than un-doped ceramic sample S1.
The study strongly recommends the novel manganese doped calcium silicate ceramic for bone engineering and localized osteomyelitis treatment