Enzyme immobilization onto magnetic nanoparticles prepared via biomimetic coating

Thesis Type: Post Graduate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2014




Immobilization of cholesterol oxidase on solid supports in good way to improve their stability and activity, and can be reused for large scale applications. In this study, polidopamine coated magnetic nanoparticles used for cholesterol oxidase immobilization. Firstly, magnetic nanoparticles were synthesized by co-precipitation of Fe2+ and Fe3+ salts with NaOH. Subsequently, polydopamine layer was deposited on the surface of magnetic nanoparticles. Finally, cholesterol oxidase was immobilized onto Fe3O4 nanoparticles modified with polydopamine. All of the the magnetic nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Under optimum conditions, 98% of the available cholesterol oxidase was immobilized on polydopamine coated magnetic nanoparticles. Enzyme assays revealed that cholesterol oxidase on polydopamine coated magnetic nanoparticles demonstrated enhanced pH and thermal stability compared to free enzyme. As a result, immobilization of cholesterol oxidase onto magnetic nanoparticles via polydopamine layer is economical, facile and efficient. In addition, the study may be useful in improving the stability and activity of cholestrol oxidase, and may contribute to more efficient use of this enzyme.