Synthesis and characterization of multifunctional GdB3O6/Ca10(PO4)6(OH)2 core/shell particles for biomedical applications

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, KİMYA ANABİLİM DALI, Türkiye

Tezin Onay Tarihi: 2023

Tezin Dili: İngilizce

Öğrenci: MEHMET BURAK UZUN

Danışman: Ayşen Yılmaz

Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu

Özet:

Multifunctional particles with multiple properties are used in biomedical applications for cancer treatment. With the recently developing technology, particles with photoluminescent properties can perform real-time imaging. In this study, Ce3+/Tb3+ co-doped, Eu3+ doped GdB3O6 particles were synthesized, coated with hydroxyapatite (HAP) and polyethylene glycol (PEG). Then, particles were loaded with doxorubicin. Ce3+/Tb3+ co-doped and Eu3+ doped GdB3O6 particles were synthesized by the sol-gel process using different chelating agents and surfactant (Cetyltrimethylammonium bromide (CTAB), citric acid, glycine, ethylenediaminetetraacetic acid (EDTA), tartaric acid, phthalic acid) to see the effect of different chelating agents or surfactant on the structure. Ce3+/Tb3+ co-doped Gd0.95Ce0.025Tb0.025B3O6 compound with the highest crystallinity and luminescence intensity was obtained with CTAB. The Eu3+ ions were doped at different molar ratios in subsequent experiments. An increase in luminescence intensity was observed with increased amounts of Eu3+ ions, where the highest luminescence intensity was obtained in the Gd0.825Eu0.175B3O6 nanoparticle. GdBO3 particles doped with Eu3+ ions were also synthesized under the same conditions and the highest luminescence intensity was obtained in Gd0.80Eu0.20BO3 nanoparticles. The core was coated with hydroxyapatite to increase the drug loading efficiency. Hydroxyapatite was synthesized on the core by the wet precipitation method. The core had an average size of 458.65 nm and was analyzed with dynamic light scattering (DLS) as 616.85 nm after coating. The hydroxyapatite-coated core was then coated with non cytotoxic PEG 10000 to increase the liquid circulation time and colloidal stability. Gd0.825Eu0.175B3O6@HAP@PEG particles were mixed in doxorubicin for 24 hours and drug loading was completed. Drug releases were then studied at 37 °C in pH 7.4 phosphate buffered saline (PBS) and pH 5.5 acetate buffer solutions. During the release studies, the total number of moles of drug released versus luminescence intensity was measured and real-time imaging studies were completed. Finally, cytotoxicity experiments were performed on HCT-116 colon cancer cells.