Selective carbohydrate recognition by synthetic receptors in aqueous solution

The molecular recognition of carbohydrates in water is an intriguing subject in view of the important role of saccharides in biological activities, such as intercellular recognition, signal transduction or as targets of bacterial/viral infection of cells. Considerable efforts have been directed toward understanding and mimicking such recognition processes, and developing effective agents to control these events. Driven by the need to create very efficient methods to combine a detectable signal with the recognition process, the past few years have seen a major push towards practically useful synthetic carbohydrate sensors. This review summarizes the recent achievements upon the preparation of synthetic receptors for carbohydrate recognition in water. Single molecule sensors based on boronic acids as well as polymeric receptors for saccharide sensing are discussed. Current research efforts are summarized, which address the development of operational sugar sensors for online monitoring and for long-term stability. Special emphasis is given to sugar sensing probes with a signal detection system, which is based on ligand exchange. The discussion in this review further includes polymeric carbohydrate receptors, which generate the sensing signal by altering the surrounding matrix property of the saccharide recognition site. Also, the recent developments to prepare carbohydrate recognition sites with high chiral discrimination ability are highlighted.