**Master’s Thesis Defense of the Student (Lama Mohammed Hussein Hadi) in the Department of Physiology and Medical Physics at the College of Medicine, Al-Nahrain University**
"Evaluation of Green Synthesized of Magnesium Oxide and Magnesium Oxide- Fullerene Composite Nanoparticles Antibacterial Activities against Pseudomonas aeruginosa and Staphylococcus aureus Multidrug Resistant Isolates."
Conduct green synthesis and detailed analysis of the structural (XRD), morphological (FESEM and TEM), and optical (UV-Vis) characteristics of magnesium oxide nanoparticles (MgO NPs).
Evaluate the antibacterial activity of the green synthesized MgO nanoparticles against Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa.
Assess the impact of adding C60 (fullerene) to MgO nanoparticles in terms of enhancing their antibacterial activity.
The formation of MgO nanoparticles as fine nano-sheets, a morphology not previously reported, which increased their effective surface area and enhanced their antibacterial activity.
The biological activity was tested against Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive), where both the nanoparticles and the composite demonstrated inhibitory effects on bacterial growth.
The minimum inhibition zone diameter for MgO was 10.2 mm, increasing to 21 mm at a concentration of 5 µg/mL.
The C60–MgO composite showed a significant synergistic effect, achieving a 14 mm inhibition zone at a low concentration (1.25 µg/mL), reaching up to 20 mm against both bacterial strains.
The half-maximal inhibitory concentration (IC50) values were determined: for Pseudomonas aeruginosa, 41.45 µg/mL for MgO and 20.27 µg/mL for C60–MgO, indicating enhanced activity with fullerene incorporation.
For Staphylococcus aureus, the IC50 of MgO was approximately 24.456 µg/mL, which decreased to 15.64 µg/mL with the composite, reflecting a potent synergistic antibacterial effect.
Finally, a molecular docking study was conducted to explore the mechanism of inhibition. Results showed that fullerene molecules interact with active binding sites in bacterial proteins, with binding energies of –2.41 kcal/mol against Staphylococcus aureus and –1.96 kcal/mol against Pseudomonas aeruginosa.