Raman-encoded, multivalent glycan-nanoconjugates for traceable specific binding and killing of bacteria.

Glycan recognition plays key roles in cell-cell and host-pathogen interactions, stimulating widespread interest in developing multivalent glycoconjugates with superior binding affinity for biological and medical uses. Here, we explore the use of Raman-encoded silver coated gold nanorods (GNRs) as scaffolds to form multivalent glycoconjugates. The plasmonic scaffolds afford high-loading of glycan density and their optical properties offer the possibilities of monitoring and quantitative analysis of glycan recognition. Using E. coli strains with tailored on/off of the FimH receptors, we have demonstrated that Raman-encoded GNRs not only allow for real-time imaging and spectroscopic detection of specific binding of the glycan-GNR conjugates with bacteria of interest, but also cause rapid eradication of the bacteria due to the efficient photothermal conversion of GNRs in the near-infrared spectral window. We envision that optically active plasmonic glycoconjugates hold great potential for screening multivalent glycan ligands for therapeutic and diagnostic applications.