In particular, Dff gelled within a few seconds at both concentrations, while it took either enantiomer with His ~ 1 h to form stable hydrogels at 10 mM, thus highlighting the favourable role of Asp for gelation. At 25 mM, Dff yielded a hydrogel with G' = 75.1 ± 0.02 kPa and G" = 6.78 ± 1.11 kPa that underwent gel-to-sol transition at ~ 18 Pa in stress sweeps (Fig. and). For comparison, Hff yielded hydrogels with G' = 34.9 ± 3.4 kPa and hFF with G' = 34.3 ± 5.0 kPa, with both displaying moduli that dropped at ~ 70 Pa in stress sweeps. Having established that each peptide is a gelator under analogous conditions, we analysed the rheological behaviour of their co-assemblies (Fig. ).