High‐strength petroleum‐based materials like plastics have been widely used in various fields, but their nonbiodegradability has caused serious pollution problems. Cellulose, as the most abundant sustainable polymer, has a great chance to act as the ideal substitute for plastics due to its low cost, wide availability, biodegradability, etc. Herein, the recent achievements for developing cellulose “green” solvents and regenerated cellulose materials with high strength via the “bottom‐up” route are presented. Cellulose can be regenerated to produce films/membranes, hydrogels/aerogels, filaments/fibers, microspheres/beads, bioplastics, etc., which show potential applications in textiles, biomedicine, energy storage, packaging, etc. Importantly, these cellulose‐based materials can be biodegraded in soil and oceans, reducing environmental pollution. The cellulose solvents, dissolving mechanism, and strategies for constructing the regenerated cellulose functional materials with high strength and performances, together with the current achievements and urgent challenges are summarized, and some perspectives are also proposed. The near future will be an exciting era for high‐strength biodegradable and renewable materials. The hope is that many environmentally friendly materials with good properties and low cost will be produced for commercial use, which will be beneficial for sustainable development in the world.

The regeneration of bone tissue is regulated by both osteogenic and angiogenic growth factors which are expressed in a coordinated cascade of events. The aim of this study was to create a dual growth factor-release system that allows for time-controlled release to facilitate bone regeneration. We fabricated core−shell SF/PCL/PVA nanofibrous mats using coaxial electrospinning and layer-by-layer (LBL) techniques, where bone morphogenetic protein 2 (BMP2) was incorporated into the core of the nanofibers and connective tissue growth factor (CTGF) was attached onto the surface. Our study confirmed the sustained release of BMP2 and a rapid release of CTGF. Both in vitro and in vivo experiments demonstrated improvements in bone tissue recovery with the dual-drug release system. In vivo studies showed improvement in bone regeneration by 43% compared with single BMP2 release systems. Time-controlled release enabled by the core−shell nanofiber assembly provides a promising strategy to facilitate bone healing.

Cost-effective chitosan/REC/cellulose hydrogels with high-strength are used for highly efficient dye adsorption.

The environment-friendly fibers fabricated from natural polysaccharides have attracted much attention in the development of sustainable materials, owing to the global pollution caused by fibers and textiles fabricated from petroleum-based polymers. Chitin derived from seafood wastes possesses excellent biocompatibility and biodegradability, but it is still far from being fully explored. Here, we designed and prepared, for the first time, chitin fibers with nanofibril structures from the chitin solution in the NaOH/urea aqueous system by cooling on a lab-scale wet-spinning machine. Because of the slow diffusion of phytic acid into the chitin dope, the stiff chitin chains could self-aggregate sufficiently in a parallel manner to form the nanofibers via a "bottom-up" approach and then be bundled into the gel-state fibers. The dried chitin fibers were demonstrated to be composed of nanofibers with a mean diameter of 27 nm and exhibited a tensile strength of 2.33 cN/dtex, which is higher than those reported in the literature. Interestingly, with an increase of the draw ratio from 1.0 to 1.8, the crystal index (χ c ) and degree of orientation (Π) increased very slightly, whereas the tensile strength and Young's modulus of the chitin fibers enhanced significantly, suggesting that a relatively perfect nanofibrous structure existed in all of the chitin fibers with and without drawing. Moreover, the chitin fibers were validated to support the adhesion and growth of ventricular myocytes as a cardiac tissue scaffold showing good biocompatibility. Furthermore, the complete biodegradation time of the chitin fibers in soil and in vitro could be extrapolated from experimental data to be approximately 22 and 34 days, respectively, indicating good biodegradability. This work would lead to a great potential of chitin in the applications including absorbable surgical suture, hemostasis and fixation medical device, and so forth, where biodegradability is required.

Anisotropic structure is key for exploring the biomimetic functions of anisotropic hydrogels. However, the anisotropic hydrogel study should not be limited to its architecture design but must include the understanding and improvement of the internal interaction among their components. Herein, a noncovalent mediated assembly strategy is proposed to simultaneously improve the chitin chain mobility and enhance the interfacial interaction, for achieving anisotropic chitin/2D material (molybdenum disulfide and brushite as example) hydrogels via mechanical deformation. Tannic acid (TA) is used to i) introduce the dynamic noncovalent crosslinking structure among the chitin chains for affording considerable molecular mobility to allow chitin chains alignment under mechanical deformation; ii) enhance chitin–2D interfacial interaction for benefiting 2D materials orientation under the chitin chains driving. The design concept achieves multiple noncovalent assembly crosslinks (chitin–chitin, chitin–TA, and chitin–TA–2D) and biomimetic anisotropic nanofibrous morphology, leading to the superior mechanical performance. The anisotropic chitin–TA/brushite hydrogel effectively accelerates bone regeneration by promoting cell osteogenic differentiation and directional migration, showing potential in tissue engineering. It is anticipated that the noncovalent mediated assembly concept could be used to fabricate other polymer based composite anisotropic hydrogels for diverse applications.