Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Author: search.filters.author.Göksel, YamanSubject: search.filters.subject.DOPA

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  • Master Thesis
    Adhesion of Dopa Functionalized Gels To Spin Labeled Surfaces
    (Izmir Institute of Technology, 2017) Göksel, Yaman; Akdoğan, Yaşar; Emrullahoğlu, Mustafa
    This study investigates the force free adhesive properties of synthetic polymer in aqueous media using electron paramagnetic resonance (EPR) spectroscopy. Due to poor performance of commercial adhesives in wet environments, scientists are interested in different types of adhesives to overcome this difficulty. On this context, mussels attract attention because of their versatile properties to adhere different types of surfaces from rocks to ship hulls underwater. Adhesion occurs when mussel secretes mussel foot proteins (MFPs) in order to form threads and plaques. Seven types of MFPs are unique in plaque contains high amount of L-3,4-dihydroxyphenylalanine (DOPA) amino acid which is reputed to be responsible for adhesion. In this research, branched polyethylene glycol (PEG) based polymers functionalized with DOPA were synthesized and their force-free adhesive properties to hydrophobic polystyrene and hydrophilic silica nanobeads were investigated in solution. These nanobead surfaces were conjugated with spin label molecules to probe adhesion dynamics using EPR spectroscopy. In addition, gel forms of polymers obtained using NaIO4, FeCl3 and Cr2O7 were used as adhesive materials for EPR measurements. All of these adhesive materials showed adhesion to spin labeled polystyrene (SL-PS) surface. However, non-DOPA containing PEG showed no indication of adhesion thus, demonstrating the importance of DOPA in wet adhesion. In addition, EPR results showed that DOPA based PEG polymers were unable to adhere to spin labeled silica (SL-SiO2) surface. This behavior was attributed to hydration layers around silica nanobeads. These layers formed around hydrophilic SiO2 surface prevent interaction between nanobead surface and polymeric material.