Determination of α2,3-sialylated glycans in human serum using a glassy carbon electrode modified with carboxylated multiwalled carbon nanotubes, a polyamidoamine dendrimer, and a glycan-recognizing lectin from Maackia Amurensis

α2,3-Sialylated glycans (α2,3-sial-Gs) are crucial molecular targets for cancer diagnosis and clinical research. We describe a biosensor for detecting α2,3-sial-Gs that is based on the specific recognition by the Maackia amurensis lectin (MAL). A glassy carbon electrode was modified with carboxy-modified MWCNTs and a polyamidoamine dendrimer (PAMAM). The PAMAM is highly branched and contains many amino groups. MAL was immobilized on the modified electrode to create a sensor capable of detecting α2,3-sial-Gs (at a working voltage of 0.2 V vs. SCE) in the 10 fg⋅mL⁻¹ to 50 ng⋅mL⁻¹ concentration range and with a detection limit as low as 3 fg⋅mL⁻¹ (at an S/N ratio of 3). This approach may pave the way to detection schemes for other proteins and glycans if appropriate affinity binding pairs are available. (author)