Commercial or clinical tissue adhesives are currently limited due to their weak bonding strength on wet biological tissue surface, low biological compatibility, and slow adhesion formation. Although catechol-modified hyaluronic acid (HA) adhesives are developed, they suffer from limitations: insufficient adhesiveness and overfast degradation, attributed to low substitution of catechol groups. In this study, we demonstrate a simple and efficient strategy to prepare mussel-inspired HA hydrogel adhesives with improved degree of substitution of catechol groups. Because of the significantly increased grafting ratio of catechol groups, dopamine-conjugated dialdehyde–HA (DAHA) hydrogels exhibit excellent tissue adhesion performance (i.e., adhesive strength of 90.0 ± 6.7 kPa), which are significantly higher than those found in dopamine-conjugated HA hydrogels (∼10 kPa), photo-cross-linkable HA hydrogels (∼13 kPa), or commercially available fibrin glues (2–40 kPa). At the same time, their maximum adhesion energy is 384.6 ± 26.0 J m–2, which also is 40–400-fold, 2–40-fold, and ∼8-fold higher than those of the mussel-based adhesive, cyanoacrylate, and fibrin glues, respectively. Moreover, the hydrogels can gel rapidly within 60 s and have a tunable degradation suitable for tissue regeneration. Together with their cytocompatibility and good cell adhesion, they are promising materials as new biological adhesives.

In this study, dynamic imine covalent bonds were introduced into vanillin-based vitrimers networks, endowing thermosets with hot-reprocessing ability and chemical recyclability under acid hydrolysis. First, dialdehyde monomer, which was synthesized from lignin-derived vanillin monomer, was reacted with conventional amine cross-linkers to form dynamic imine bond networks. Even after three hot-processing cycles, the tensile strength and elongation at break of polyschiff vitrimers could be recovered at least up to 71.2 and 72.8%, respectively, through the imine metathesis reaction. Importantly, the dialdehyde monomers showed enhanced recyclability under strong acid solution and could be reused to regenerate polyschiff vitrimers. These characteristics of reprocessablility, recyclablility, and biobased monomer present a feasible way to satisfy the demands of sustainability.

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The conductive hydrogels have found large application prospects in fabricating flexible multifunctional electronic devices for future-generation wearable human-machine interactions. However, the inferior mechanical strength, low temperature resistance, and non-recyclability induced...

Although regenerated silk fibroin (SF), which has excellent biocompatibility, biodegradability, and a low inflammatory response in vivo, has promising applications in tissue engineering, the mechanical properties and biofunctionality must be further improved to satisfy tissue-engineering applications. Cellulose nanofibrils (CNFs) are promising candidates for bionanocomposite production due to their ultrahigh strength and excellent biocompatibility. In this study, CNFs were extracted directly from microcrystalline cellulose using an aqueous lithium bromide solution, a typical solvent for dissolving SF fibers. As a result, SF/cellulose nanocomposite films with improved tensile strength were fabricated using aqueous lithium bromide solution as a novel solvent system for the dissolution and blending of SF and cellulose. The extracted CNFs were homogeneously dispersed within the composite films through the rapid gelation of cellulose. The degradability of the composite films in a protease XIV solution was strongly dependent upon the SF component, which significantly promoted the degradation rate of composite films. Adhesion and proliferation results showed that SF/cellulose nanocomposite films promoted cell viability. Our work suggests a facile and effective approach for designing SF/cellulose nanocomposites that may have wide potential applications in tissue engineering.