Sustainable Nanocellulose–Collagen Hybrid Hydrogels From Agro‐Marine Waste with Enhanced Biomechanical Properties for Cartilage Regeneration

ABSTRACT Hydrogels are widely used in regenerative medicine due to their biocompatibility and tissue‐like properties; however, many rely on non‐renewable resources and exhibiting limited functionality. This study presents a sustainable hydrogel composite derived from agro‐marine waste, addressing both environmental and biomedical challenges. The composite integrates nanocellulose (NCs) extracted from date fruit pomace with collagen methacryloyl (ColMA) obtained from fish skin. The extracted NCs exhibited an average length of 529 nm, diameter of 63 nm, and crystallinity index of 40.2%. Incorporating 6% NCs into ColMA significantly improved the hydrogel's mechanical strength, increasing the bulk and nano‐elastic moduli to 31 and 24 kPa, respectively. The NC‐ColMA hydrogels displayed excellent shear‐thinning behavior, recovery ability, and UV crosslinking potential, alongside reduced pore size and swelling ratio with enhanced enzymatic and hydrolytic stability. Moreover, the hydrogels supported >95% hMSC viability, promoted proliferation, and upregulated chondrogenic markers (SOX‐9, ACAN, ELN) without elevating pro‐inflammatory cytokines, while modestly increasing TGF‐β1 expression. The composite also demonstrated superior injectability and printability, enabling precise 3D bioprinting. Overall, this NC‐ColMA hydrogel, with its tunable mechanical characteristics and biological compatibility, shows great potential for diverse medical applications while also contributing to waste reduction efforts in the date and fishing industries.