Biocompatible small peptide super-hydrogelators bearing carbazole functionalities

For the first time we have introduced carbazole capping groups onto two short peptide sequences, namely a diphenylalanine dipeptide and a glycine–diphenylalanine tripeptide, giving compounds 1 and 2, respectively. Both molecules form hydrogels at low concentrations, as low as 0.03% (w/v) for 1 – well within the range of supergelators. Both gelators are composed of small ca. 2 nm thick molecular fibres, as elucidated by AFM and are non-cytotoxic towards HeLa cells at concentrations which are at or above their minimum gelation concentration.