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

Abstract

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.