Comparison of photo- and Cu(I)-catalyzed "click" chemistries for the formation of carbohydrate SPR interfaces.

Understanding interactions of glycans with proteins in key biological events has seen the development of various analytical methods such as microarray techniques. Label-free approaches, such as surface plasmon resonance (SPR) techniques are particularly attractive and we explore here the potential of a novel interface composed of lamellar Ti/Au/silicon dioxide derivatized with sugars to probe lectin-sugar interactions by SPR. Two parallel surface functionalization strategies have been developed: one in which azide-functionalized surfaces are linked via a Cu(I) "click" method to alkynyl-derivatized glycan partners and another wherein perfluorophenyl azide-functionalized surfaces are reacted through a C-H insertion photocoupling reaction with underivatized glycans. The effectiveness of the two interfaces is assessed for their lectin-recognition abilities in an SPR format.