Surface functionalization of cross-linked polystyrene microspheres via thiol-ene "click" reaction and assembly in honeycomb films for lectin recognition

Patterned porous films prepared by the breath figure method have received considerable interests because of the potential applications. This paper reports a top-down method to fabricate functional patterned films. Cross-linked polystyrene microspheres were synthesized by a two-stage dispersion polymerization using divinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDMA) as cross-linkers, which provide free vinyl groups on the microspheres surface. The amounts of residual vinyl groups were determined by potentiometric titration. Glucose was then bound to the microspheres via thiol-ene reaction, which was confirmed by x-ray photoelectron spectroscopy and water contact angle measurements. Results indicate that vinyl groups of EGDMA show relatively higher reactivity than that of DVB. Microspheres with glucose were assembled into the pores of honeycomb films prepared by the breath figure method, forming functional arrays for recognizing a lectin, Con A. This top-down method is useful in preparing patterned films with various functional moieties, which may act as a platform, such as, for investigating carbohydrate-lectin interactions and for sensing.