Here, the synthesis of linear polyglycerols bearing multiple copies of mono and dimannosides (LPG(40)Man(0.60) and LPG(40)(Man alpha 1,2Man)(0.60)) is demonstrated. A method based on label-free microscale thermophoresis is optimized to determine the direct binding affinity of multivalent mannosides for Escherichia coli (E. coli) strain ORN178 that produces the fimbriae protein FimH. It is observed that the LPG(40)(Man alpha 1,2Man)(0.60) exhibits only a modest onefold improvement in binding as compared to LPG(40)Man(0.60). Nevertheless, both the multivalent mannosides display remarkably very low nm binding constant (K-d) in contrast to the high mu m K-d of the single alpha-d-methylmannoside for intact E. coli ORN178 particles. Furthermore, in an adhesion-inhibition assay, both multivalent mannosides show 50% inhibition of bacteria adhesion to the HT-29 colon cells at low mu m concentrations.