  Hydrogels are widespread soft materials, which can serve a wide range of
applications. The control over the viscoelastic properties of the gel is of
paramount importance. Ongoing environmental issues have raised the consumer's
concern towards the use of more sustainable materials, including hydrogels.
However, are greener materials compatible with high functionality? In a
safe-by-design approach, this work demonstrates that functional hydrogels with
in situ responsivity of their elastic properties by external stimuli can be
developed from entirely ``sustainable'' components, a biobased amphiphile and
biopolymers (gelatin, chitosan and alginate). The bioamphiphile is a
stimuli-responsive glycolipid obtained by microbial fermentation, which can
self-assemble into fibers, but also micelles or vesicles, in water under high
dilution and by a rapid variation of the stimuli. The elastic properties of the
bioamphiphile/biopolymer interpenetrated hydrogels can be modulated by
selectively triggering the phase transition of the glycolipid and/or the
biopolymer inside the gel by mean of temperature or pH.
