  Soft stretchable materials are key for arising technologies such as
stretchable electronics or batteries, smart textiles, biomedical devices,
tissue engineering and soft robotics. Recent attempts to design such materials,
via e.g. micro-patterning of wavy fibres on soft substrates, polymer
engineering at the molecular level or even kirigami techniques, provide
appealing prospects but suffer drawbacks impacting the material viability:
complexity of manufacturing, fatigue or failure upon cycling, restricted range
of materials or biological incompatibility. Here, we report a universal
strategy to design highly stretchable, self-assembling and fatigue-resistant
synthetic fabrics. Our approach finds its inspiration in the mechanics of
living animal cells that routinely encounter and cope with extreme
deformations, e.g. with the engulfment of large intruders by macrophages,
squeezing and stretching of immune cells in tiny capillaries or
shrinking/swelling of neurons upon osmotic stimuli. All these large instant
deformations are actually mediated and buffered by membrane reserves available
in the form of microvilli, membrane folds or endomembrane that can be recruited
on demand. We synthetically mimicked this behavior by creating nanofibrous
liquid-infused tissues spontaneously forming surface reserves whose unfolding
fuels any imposed shape change. Our process, relying only on geometry,
elasticity and capillarity, allows to endow virtually any material with high
stretchability and reversibility, making it straightforward to implement
additional mechanical, electrical or chemical functions. We illustrate this
with proof-of-concept activable capillary muscles, adaptable slippery liquid
infused porous surfaces and stretchable basic printed electronic circuits.
