Document Details
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Document Type |
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Thesis |
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Document Title |
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Antifungal activity of mycoendophytic silver nanoparticles encapsulated with chitosan النشاط المضاد للفطريات لجسيمات الفضة النانوية الفطرية والمغلفة بالكیتوزان |
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Subject |
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Faculty of Science |
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Document Language |
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Arabic |
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Abstract |
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This study aimed to improve the biosynthesis of silver nanoparticles (AgNPs) using endophytic fungi and encapsulate them with chitosan. Endophytic fungi isolated from different plants: Juniperus procera, Dodonaeae viscosa, Ficus carica, Lavandula dentate, and Ziziphus spina-christi. The chosen isolates were identified as Bipolaris sorokiniana, Curvularia kusanoi, Amesia atrobrunnea, Alternaria destruens, and Aspergillus alabamensis. Mycosynthesis influencing parameters such as incubation temperature, culture media, pH, and silver nitrate (AgNO3) molarity were optimized to produce high-quality AgNPs and analyzed using ultraviolet-visible (UV–Vis) spectroscopy. Then, AgNPs were encapsulated with chitosan (Ch-AgNPs) under microwave heating at 650 W for 90s. The results of this study indicated that Potato Dextrose Broth (PDB) with 1 mM AgNO3, an acidic pH, and a temperature of 25–30°C was the optimum for AgNPs synthesis. UV–Vis showed the highest peak at 420–450 nm, whereas Ch-AgNPs showed one peak for AgNPs at 400–415 nm and another peak for chitosan at 220–230nm. Fourier transform infrared (FTIR) spectroscopy confirmed that encapsulation with chitosan was successfully incorporated and interacted with AgNPs through amide functionalities. Dynamic light scattering (DLS) and Z-potential were around -11.6 mV and -17.8 mV for AgNPs and between +38.9 and +59 mV for Ch-AgNPs, which confirmed the significant stability enhancement after encapsulation with chitosan. Field emission scanning electron microscope (FES-SEM) showed spherical Ch-AgNPs and an increase in the nanoparticle size to 18.62–44.65 nm due to encapsulation with chitosan. Anti-fungal evaluation results of Ch-AgNPs (50, 25, 12.5, and 6.25 mg/L) showed significant mycelial growth reduction in vitro against Aspergillus fumigatus, A. niger, A. terreus, Cladosporium sp., Curvularia lunata, and Fusarium oxysporum using the mycelial growth inhibition method (MGI).
Keywords: Silver nanoparticles, Endophytic fungi, Chitosan, Antifungal, Biosynthesis |
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Supervisor |
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Prof. Dr. Saleh Mohammad Al-Garni |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1445 AH
2023 AD |
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Added Date |
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Friday, December 1, 2023 |
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Researchers
| ساميه سعيد الزهراني | Alzahrani, Samiyah Saeed | Researcher | Doctorate | |
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