Biotinylated bi- and tetra-antennary glycoconjugates for Escherichia coli detection

Glycans cover the surface of all mammalian cells. Several toxins and pathogens use these glycans to bind and infect the cell. Using a versatile modular synthetic strategy, we have developed biotinylated bi- and tetraantennary glycoconjugates to capture and detect E. coli and compared the capturing ability of these molecules to commercial polyclonal antibodies. Magnetic beads were coated with biotinylated glycoconjugate or antibody, and these beads were used to capture, isolate, and quantify bacterial recovery by using a luminescence assay. The glycoconjugate-coated magnetic beads outperformed antibody-coated magnetic beads in sensitivity and selectivity when compared under identical experimental conditions. Glycoconjugates could capture Escherichia coli from stagnant water, and the ability of a panel of glycoconjugates to capture a selection of pathogenic bacteria was also evaluated. To the best of our knowledge, this study represents the first comprehensive study that compares synthetic glycoconjugates and antibodies for E. coli detection. The glycoconjugates are also very stable and inexpensive. The results presented here are expected to lead to an increased interest in developing glycoconjugate-based high affinity reagents for diagnostics.