Spatially Controlled Surface Immobilization of Nonmodified Peptides

Thomas Pauloehrl,†,◊ Alexander Welle,§ Michael Bruns, Katharina Linkert, Hans G. Börner, Martin Bastmeyer, ‡,◊ Guillaume Delaittre,†,‡,◊ and Christopher Barner-Kowollik †,◊,*.

Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Tech-nology (KIT), 76128 Karlsruhe, Germany
Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
§ Institute for Biological Interfaces (IBG-1), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
Institute for Applied Materials (IAM-WPT) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany
Laboratory for Organic Synthesis of Functional Systems, Department of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
Zoologisches Institut, Zell- und Neurobiologie, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany

ABSTRACT: A novel platform utilizing light as a facile means to provide spatio-temporal control for the direct covalent immobi-lization of peptides possessing exclusively natural aminoacid residues is presented. The strategy is based on the utilization of a phencyclone derivative acting as a potent diene for the highly efficient Diels–Alder formation of the photoactive precursor. The cycloadduct in turn can be activated at ambient temperature via a facile one-pot in situ decarbonylation/dehydrogenation reaction triggered by mild irradiation for 2 hours. The obtained triphenylene-imide is capable of undergoing ring-opening reac-tions with amines in analogy to the well-known phthalimide system. In contrast to previously reported phototriggered strate-gies, which require complex multi-step synthesis of surface an-chors functionalized with photochemically active moieties and individual modifications of (biologically) relevant substrates, the synthetic effort in the current approach is reduced to a minimum by employing a click reaction for the formation of the photoactive species and the inherent amine functionality of biomolecules for spatially controlled ligation. Successful patterning on surfaces with an amine-functionalized bromine marker and a native c(RGDfK) peptide was evidenced by imaging time-of-flight secondary-ion mass spectrometry (ToF-SIMS).