Immobilization of Poly(Ethylene Glycol) Terminated with Amine to Titanium Surface by Electrodeposition

In many applications such as catheters, artificial blood vessels and diagnostic sensors, blood compatibility or prevention of adhesion of platelet is required. The preferred way to control these purposes is to eliminate or drastically reduce the adsorption of proteins. Surface modification with Poly(ethylene glycol), PEG has long been known to reduce undesirable protein adsorption. No technique for the immobilization of PEG to base metal has been developed. In this study, PEG terminated at both terminals or one terminal with amine bases was immobilized onto titanium surface by immersion or electrodeposition. The bonding manners of PEG onto titanium, which involve directionality of terminated amines and chemical bonding states of interface between the deposited PEG layer and TiO2, were characterized using X-ray photoelectron spectroscopy, XPS. As a result, terminated amines locate inside of the PEG layer and combine mainly with TiO2 as stable NHO by electrodeposition, while amines randomly exist and show mainly unstable bonding with TiO2 by immersion. Moreover, the difference of amine termination leads to different bonding manners, U-shape in PEG terminated both terminals and brush in PEG terminated one terminal. This immobilization process is one-stage convenient technique and useful for all electroconductive and morphological materials.