The precise design of bioactive surfaces, essential for the advancement of many biomedical applications, depends on achieving control of the surface architecture as well as on the ability to attach bioreceptors to antifouling surfaces. Herein, we report a facile avenue toward hierarchically structured antifouling polymer brushes of oligo(ethylene glycol) methacrylates via surface-initiated atom transfer radical polymerization (SI-ATRP) presenting photoactive tetrazole moieties, which permitted their functionalization via nitrile imine-mediated tetrazole-ene cyclocloaddition (NITEC). A maleimide-functional ATRP initiator was photoclicked to the side chains of a brush enabling a subsequent polymerization of carboxybetaine acrylamide to generate a micropatterned graft-on-graft polymer architecture as evidenced by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Furthermore, the spatially resolved biofunctionalization of the tetrazole-presenting brushes was accessed by the photoligation of biotin-maleimide and subsequent binding of streptavidin. The functionalized brushes bearing streptavidin were able to resist the fouling from blood plasma (90% reduction with respect to bare gold). Moreover, they were employed to demonstrate a model biosensor by immobilization of a biotinylated antibody and subsequent capture of an antigen as monitored in real time by surface plasmon resonance.

§Institut für Biologische Grenzflächen Karlsruhe Institute of Technology Hermann von Helmholtz Platz 1 76344 Eggenstein Leopoldshafen Germany

†Institute of Macromolecular Chemistry Academy of Sciences of the Czech Republic v v i Heyrovsky sq 2 162 06 Prague Czech Republic

‡Institut für Angewandte Materialien Hermann von Helmholtz Platz 1 76344 Eggenstein Leopoldshafen Germany

∥Preparative Macromolecular Chemistry Institut für Technische Chemie und Polymerchemie Karlsruhe Institute of Technology Engesserstr 18 76131 Karlsruhe Germany

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