A General Approach to the Covalent Immobilization of Single Polymers

Abstract

Stuck fast: The covalent immobilization of polymeric single molecules is achieved by the photochemically induced CH/NH insertion reaction of perfluorophenylazides (see picture). When the concentration of the surface azido groups is decreased, isolated polymeric single molecules are observed. This technique is especially suited for materials that do not possess functional groups and are difficult to be immobilized by other means.

Stereocontrolled 1-S-glycosylation and comparative binding studies of photoprobe-thiosaccharide conjugates with their O-linked analogs

“…Solid-supported techniques are thus playing crucial roles for studies of various carbohydrate–protein interactions, and as a result, methods for immobilization of carbohydrates on surfaces and resins have become an important research topic. In this context, the well-established perfluoro-phenylazide (PFPA) chemistry enables one-step, facile, and robust attachment of organic molecules on solid surfaces, by either thermal- or photo-activation, resulting in versatile surface modification for a wide range of applications [41,49,52–56,61–64]. …”

Photogenerated Carbohydrate Microarrays

“…Furthermore, the technique is applicable to a variety of polymers. [11,12,[14][15][16] In this study, PFPA chemistry was first used to covalently attach poly(ethylene oxide) (PEO) to amino-functionalized glass slides. By treating the amino groups on the array glass slide with N-hydroxylsuccinimide-derivatized PFPA (NHS-PFPA), [17] a monolayer of PFPA was formed on the surface (Scheme 1).…”

Photochemically Initiated Single Polymer Immobilization

“…Using this approach, covalently immobilized polystyrene molecules of various molecular weights were obtained by treating silicon wafers with PFPA-silane at very low concentrations. [46] We found that the higher the molecular weight of the polymer, the lower the concentration of PFPA-silane needed to achieve single molecule immobilization (see caption in Figure 6). This is consistent with the immobilization chemistry.…”

“…Indeed, by reducing the density of the azido groups on the substrate, covalently immobilized polymer single molecules were obtained. [46] The immobilized polymer molecules appear as "dots" in the AFM images, corresponding to the pancake-like collapsed conformation that is commonly observed with isolated flexible polymers grafted on a surface. Results shown in Figure 5 were obtained by treating silicon wafers with a mixture of PFPA-silane and octadecyltrimethoxysilane (ODTMS).…”

“…Once the PFPA-functionalized substrate is prepared, it could be used as a universal surface to covalently immobilize polymers by a simple and fast irradiation procedure. Using this approach, we have already successfully immobilized single molecules of poly(2-ethyloxazoline) (PEOX) [46] and poly (4-vinylpyridine). [47] In comparison with other covalent immobilization methods, this approach uses a photochemically initiated process to facilitate the attachment of single polymers.…”