Surface modulation of single-walled carbon nanotubes for selective bacterial cell agglutination

Elena Romero-Ben,1 Juan José Cid,1 Mohyeddin Assali,1 Elisabeth Fernández-García,2 Ralf Erik Wellinger,2 Noureddine Khiar1 1Asymmetric Synthesis and Functional Nanosystems Group, Institute of Chemical Research-Universidad de Sevilla, Avda. Américo Vespucio, 41092 Seville, Spain; 2Genome Stability Department, Andalusian Center for Molecular Biology and Regenerative Medicine Centre, Universidad de Sevilla-CSIC, Avda. Américo Vespucio, 41092 Seville, Spain Background: Bacterial resistance to antibiotics is one of the biggest challenges facing medicine today. Anti-adhesive therapy, using inhibitors of bacterial adhesion to epithelial cells, one of the first stages of infection, is a promising approximation in this area. The size, shape, number of sugar and their placement are variables that have to be taken into account in order to develop multivalent systems able to inhibit the bacterial adhesion based on sugar-lectin interaction. Materials and methods: In the present work we report a modular approach for the synthesis of water-soluble 1D-carbon nanotube-sugar nanoconstructs, with the necessary flexibility to allow an efficient sugar-lectin interaction. The method is based on the reaction of aryl diazonium salts generated in situ from aniline-substituted mannose and lactose derivatives with single wall carbon nanotubes (SWCNTs) sidewalls. Results: Two hybrid nanosystems, I-II, exposing mannose or lactose and having a tetraethylene glycol spacer between the sugar and the nanotube sidewall were rapidly assembled and adequately characterized. The sweet nano-objects were then tested for their ability to agglutinate and selectively inhibit the growth of uropathogenic Escherichia coli. These studies have shown that nanosystem I, exposing mannose on the nanotube surface is able to agglutinate and to inhibit the bacterial growth unlike nano-objects II exposing lactose.Conclusion: The results reported constitute a proof of principle in using mannose-coated 1D-carbon nanotubes as antiadhesive drugs that compete for FimH binding and prevent the uropathogenic bacteria from adhering to the urothelial surface. Keywords: single-walled carbon nanotubes, carbohydrates, bacterial resistance, antiadhesive therapy, multivalency, aryl diazonium salts chemistry