Nature is well known to create strong and tough materials, usually two mutually exclusive mechanical properties in synthetic materials. These properties are achieved through hierarchical physical or chemical reinforcement over several length scales. The reinforcement concepts found in nature can be abstracted and used in a bio-inspired manner to make man-made materials better, stronger, and more sustainable. For example, strong and tough hydrogels are needed to withstand the load requirements of different applications such as contact lenses, biomaterials, and drug delivery materials. The mechanical properties of hydrogels can be enhanced, e.g., by increasing the cross-linking densities through chain entanglements, by applying various coupling chemistry, tailoring the network architecture, or combining ionic physical crosslinks with covalent crosslinks in a polymer network. A very versatile method to enhance the mechanical properties of polymers is to physically incorporate a filler into the materials, which is usually characterized by high mechanical properties and a high aspect ratio. Suitable fillers include metal nanoparticles, glass fibers, carbon nanotubes, cellulose whiskers, cellulose fibers (CNF), and cellulose nanocrystals (CNCs). CNCs, in particular, are good reinforcing fillers for polymeric materials due to their remarkable properties, such as large surface area, high aspect ratio, controllable surface chemistry, renewability and biodegradability. CNCs are obtained from renewable resources including cotton, wood, or other cellulosic materials, and typically have a very high tensile strength, around 2 to 6 GPa, and a Young´s modulus of 20 to 150 GPa. Depending on their source and preparation method, CNCs have a diameter that ranges between 5-70 nm and a length of 100-250 nm, i.e. their aspect ratio is high. Amphiphilic polymer conetworks (APCNs) are a type of hydrogel with superior mechanical properties over conventional gels because the hydrophobic component strengthens the material when swollen in water. Their most prominent everyday application is as extended-wear soft contact lenses, which are called silicone hydrogels. Moreover, they have been explored, e.g., as implant materials, biocatalyst supports, separation membranes, self-sealing breathable membranes, and microcapsules. Even though APCNs are stronger and tougher than most other hydrogels, applications of APCNs would benefit from improved stiffness and toughness, especially when swollen. Studies that aim to enhance the mechanical properties of APCNs are limited. Dynamic covalent bonds and triblock copolymer micelles have allowed for high stretchability. Another recent example is the use of a mechanical "fuse link" consisting of aggregated hydrophobic chain segments in a hydrophilic polymer network matrix. We have previously shown that poly-β-benzyl-l-aspartate (PBLA) peptide segments adjacent to the crosslinking points in APCNs can also be used to improve the mechanical properties of APCNs. Depending on the peptide length, they either form α-helices or β-sheets as secondary structure and efficiently reinforce polymeric materials. The peptides strengthened the mechanical properties of poly(2-hydroxyethyl acrylate)-linked by-poly(dimethylsiloxane) (PHEA-l-PDMS) APCNs, inducing an up to a 40-fold increase in maximal stress and 340% increase in strain when dry relative to base APCNs.