Controllable construction of carbohydrate microarrays by site-directed grafting on self-organized porous films

Carbohydrate-protein interactions are critical in many biological processes. However, the interactions between individual carbohydrates and proteins are often of low affinity and difficult to study. Recent development of carbohydrate microarrays provides an effective tool to explore the interaction. In this work, carbohydrate microarrays were controllably constructed by grafting of a carbohydrate-containing monomer on self-organized honeycomb-patterned films. The films were prepared from an amphiphilic block copolymer, poly(styrene-block-(2-hydroxyethyl methacrylate)), by a breath figure method. Three-dimensional fluorescence results demonstrate that the hydroxyl groups aggregate mainly inside the pores, which afford a chance of site-directed surface modification. 2-(2,3,4,6-Tetra-O-acetyl-beta-D-glucosyloxy)ethyl methacrylate was selectively grafted in the pores by a surface-initiated atom transfer radical polymerization. Characterization by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, and contact angle measurements confirms the site-directed growth of the glycopolymer chains. Further specific recognition of the carbohydrate microarrays to lectin (concanavalin A) leads to an organized microarray of protein, and hence this approach also opens a new route to fabricating other functional microarrays such as protein-patterned surfaces.