Layer-by-layer deposition of tannic acid and poly(2-isopropyl-2-oxazoline) onto iron oxide nanoparticles

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: MAJID AKBAR

Danışman: İREM EREL GÖKTEPE

Özet:

Layer-by-layer (LbL) technique is a simple and unique technique for fabrication of thin films. It is possible to control the film properties during assembly and post-assembly steps. Stimuli responsive polymers are important building blocks for LbL assembly, especially for drug delivery applications of LbL films. Iron oxide nanoparticles have been of interest for biomedical applications such as bioimaging and/or drug delivery via magnetothermal trigger. This thesis study aimed to develop strategies for layer-by-layer assembly of neutral polymers onto iron oxide nano particles. Iron oxide nano particles were synthesized by ultrasound based co-precipitation method and characterized by dynamic light scattering, FTIR spectroscopy and transmission electron microscopy techniques. Multilayers of poly(2-isopropyl-2-oxazoline) (PIPOX) and Tannic Acid (TA) were deposited onto iron oxide nano particles using LbL technique. The driving force for multilayer assembly was found to be hydrogen bonding interactions among PIPOX and TA. Film deposition onto iron oxide nanoparticles was characterized using zeta potential and hydrodynamic size measurements. A model anti-cancer drug, doxorubicin (DOX) was loaded into LbL coated iron oxide nanoparticles at pH 7.5. It was shown that DOX could be released from the surface of LbL coated iron oxide nanoparticles via both pH and temperature-trigger. DOX released from the surface at moderately acidic conditions due to protonation of TA and loss in electrostatic interactions among TA and DOX. On the other hand, DOX was released from the surface via temperature-trigger due to lower critical solution temperature (LCST)-type phase behavior of PIPOX and conformational transition in PIPOX chains within the multilayers resulting in release of DOX molecules. Considering the temperature and pH response of multilayer and potential of iron oxide nanoparticles for biomedical applications, results obtained in this thesis are important to develop strategies for LbL coating of iron oxide nanoparticles and release of drug molecules from surfaces.