Poly(dopamine acrylamide)-co-poly(propargyl acrylamide)-modified titanium surfaces for ‘click’ functionalization

Poly(dopamine acrylamide)-co-poly(propargyl acrylamide) (PDA-co-PPA) copolymers, containing alkyne- and catechol-functionalities, were prepared from reactive poly(pentafluorophenyl acrylate) (PPFA) via functionalization of the pentafluorophenyl-activated ester groups with dopamine hydrochloride and propargylamine. The bifunctional PDA-co-PPA copolymers were then coupled to the titanium (Ti) surface via coordination interaction of the catechol moieties, yielding a functionalizable Ti platform containing ‘clickable’ alkyne groups on the surface for the copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) of azide-labeled fluorescein, rhodamine, β-cyclodextrin, poly(ethylene glycol) (PEG), mannose and biotin. The functionalized Ti surfaces from the CuAAC reactions were characterized by fluorescence microscopy (for the rhodamine- and fluorescein-functionalized Ti surfaces), non-specific protein adsorption (for the PEG-grafted Ti surface), specific protein adsorption (for the mannose- and biotin-functionalized Ti surfaces) and host–guest interaction with antibiotics (for the β-cyclodextrin-functionalized Ti surface).