The establishment of nano-objects/hydrogel chains interactions that can easily break and rearrange also facilitated energy dissipation and consequently material stretchability. For instance, the stretchability of GO/HA hybrids, crosslinked through oxidative coupling, reached values between 94% and 200%, and PPy-PDA NPs embedded in a PAA matrix facilitated elongation up to 8 times the original length. These values exceeded that of human skin (typically 60-75%), making these materials highly resistant to external forces without fracturing (Figure ). In terms of size, given that interacting polymer chains can untangle with greater difficulty from smaller particles than from larger ones, the former have proved better suited for enhancing internal stress conductivity and, consequently, increasing stretchability. Another crucial factor influencing the mechanical properties is the uniform distribution of nano-objects. For instance, aggregation of GO nanosheets (for concentrations above 0.5%) within a PAA matrix and excessive accumulation of PDA-coated Ag NPs only in localized areas of a PVA-based hydrogel, coupled to irregular crosslinking, resulted in a material more prone to rupture when stretched and a significant decrease in tensile strength was measured. Incorporating catechol moieties by functionalizing polymer backbones with DA, pyrogallol or using PDA as a coating or in form of NPs conferred and/or improved hydrogel adhesiveness (Figure ). Commercially available fibrin sealants generally exhibit values in the 5 kPa range, and the obtention of a material with similar properties makes it suitable for wound closure and healing. Illustration of the adhesion to different substrates and resistance to deformation without detachment. Adapted with permission. Copyright 2021 The Royal Society of Chemistry.