Fluorogenic affinity gels constructed from clickable boronic acids

Boronate affinity gel was prepared by immobilizing azide-functionalized boronic acid on alkyne-modified Sepharose. Different azide-functionalized boronic acids were synthesized from 2-, 3-, and 4-aminophenylboronic acids. One of the azide-functionalized boronic acids, 3BII, displayed weak and unexpected fluorescence emission. Using Cu(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) reaction (click chemistry), the azide-functionalized boronic acid could be immobilized on alkyne-modified Sepharose 4B under very mild reaction condition. Immobilization of boronic acid 3BII also led to a new fluorogenic affinity gel, which displayed dose-dependent fluorescence intensity change upon binding fructose and glucose at physiological pH. The clickable boronic acids may be used as simple and modular building blocks to construct molecular recognition materials and surfaces for different applications including bioseparation, sensing and controlled drug delivery. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 201