Here, we demonstrate the synthesis of linear polyglycerols bearing multiple copies of mono and dimannosides [LPG40Man0.60 and LPG40(Manα1,2Man)0.60]. A method based on label-free microscale thermophoresis (MST) has been optimized to determine the direct binding affinity of multivalent mannosides for Escherichia coli (E. coli) strain ORN178 that produces the fimbriae protein FimH. We observed that the LPG40(Manα1,2Man)0.60 exhibited only a modest one-fold improvement in binding as compared to LPG40Man0.60. Nevertheless, both the multivalent mannosides displayed remarkably very low nM binding constant (Kd) in contrast to the high μM Kd of the single α-D-methylmannoside for intact E. coli ORN 178 particles. Furthermore, in an Adhesion-Inhibition Assay, both multivalent mannosides showed 50% inhibition of bacteria adhesion to the HT-29 colon cells at low μM concentrations.
