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Development of artificial biomaterials by mimicking extracellular matrix of bone tissue is a promising strategy for bone regeneration. Hydrogel has emerged as a type of viable substitute, but its inhomogeneous networks and weak mechanics greatly impede clinical applications. Here, a dual crosslinked gelling system is developed with tunable architectures and mechanics to promote osteogenic capacity. Polyhedral oligomeric silsesquioxane (POSS) is designated as a rigid core surrounded by six disulfide-linked PEG shells and two 2-ureido-4[1H]-pyrimidinone (UPy) groups. Thiol-disulfide exchange is employed to fabricate chemical network because of the pH-responsive "on/off" function. While self-complementary UPy motif is capable of optimizing local microstructure to enhance mechanical properties. Taking the merits of biocompatibility and high-mechanics in periodontal ligament stem cells (PDLSCs) proliferation, attachment, and osteogenesis, hybrid hydrogel exhibits outstanding osteogenic potential both in vitro and in vivo. Importantly, it is the first time that a key epigenetic regulator of ten-eleven translocation 2 (Tet2) is discovered to significantly elevate the continuously active the WNT/β-catenin through Tet2/HDAC1/E-cadherin/β-catenin signaling cascade, thereby promoting PDLSCs osteogenesis. This work represents a general strategy to design the hydrogels with customized networks and biomimetic mechanics, and illustrates underlying osteogenic mechanisms that will extend the design rationales for high-functional biomaterials in tissue engineering., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Double‐network (DN) hydrogels consisting of noncovalent interacting networks are highly desired due to their well‐controlled compositions and environmental friendliness, but the low water resistance always impairs their mechanical strength. Here, an anti‐swelling hydrogel possessing the core/shell architecture through rational regulation of multiple weak noncovalent interactions is prepared. A composite hydrogel consists of chitosan (CS) and poly(N‐acryloyl 2‐glycine) (PACG), readily forming the shell‐structured DN hydrogel after soaking in a FeCl3 solution because of in situ formation of chain entanglements, hydrogen bonds, and ionic coordination. The produced DN hydrogels exhibit excellent anti‐swelling behaviors and mechanical durability for over half a year, even in some strict situations. Taking the merits of noncovalent bonds in adjustability and reversibility, the swelling property of these hydrogels can be easily customized through control of the ion species and concentrations. A dynamically reversible transition from super‐swelling to anti‐swelling is realized by breaking up and rebuilding the metal‐coordination complexes. This facile but efficient strategy of turning the noncovalent interactions and consequently the mechanics and anti‐swelling properties is imperative to achieve the rational design of high‐performance hydrogels with specific usage requirements and expand their applicability to a higher stage. [ABSTRACT FROM AUTHOR]