BSA-Sugar Conjugates as Ideal Building Blocks for SPR-Based Glycan Biosensors.

Controlled immobilization of sugar probes is of key importance for the development of glycan biosensors. To this end, a series of BSA-sugar conjugates with different numbers of mannose units are prepared via the squaric acid-mediated coupling reaction. The conjugates can absorb directly on gold substrate without any derivation reactions, thus providing a simple and effective method for the construction of SPR-based glycan biosensors. SPR measurements show that the BSA-mannose conjugate with 11 mannoses exhibit the highest affinity to the lectin concanavalin A with a limit of detection of ca. 1.8 nM. Regeneration and specificity of the obtained glycan biosensors are also investigated.