Synthesis and lectin recognition studies of glycosylated polystyrene microspheres functionalized via thiol-para-fluorine "click" reaction

The preparation of cross-linked polymeric micrometer sized particles of styrene and pentafluorostyrene functionalized at the surface with carbohydrate moieties is described. The particles were synthesized via precipitation polymerization consisting of the radical copolymerization of pentafluorostyrene, styrene and divinylbenzene. The amount of divinylbenzene is maintained constant for all the experiments whereas the proportion of the styrene and pentafluorostyrene was varied. Therefore, different fluorinated particles with high cross-linking density were obtained where the content of the active para-fluorine groups varies accordingly with the feed composition. Afterwards, the carbohydrate moieties were attached to the particles in two steps by the so-called thiol-para-fluorine "click" reaction based on the coupling of acetylated beta-D-thioglucopyranose onto pentafluorostyrene via a nucleophilic substitution of para-fluorine, followed by the deprotection of the acetate-protected thioglucose. The obtained glycoparticles were characterized by infrared spectroscopy and contact angle measurements, which confirmed the increasing amount of the glucose moieties in the particles as the composition of the feed on pentafluorostyrene comonomer increases. The synthesized glucose-modified particles are packed into cartridges and their binding abilities with specific proteins, such as Concanavalin A, are subsequently tested. Fluorescence spectroscopy and microscopy experiments evidenced that the glycoparticles packed into the columns are able to retain specifically Concanavalin A. Other proteins such as bovine serum albumin were tested and did not interact with the particle surface.