The nerve guidance conduit (NGC) is a promising clinical strategy for regenerating the critical-sized peripheral nerve injury. In this study, the polysaccharide chitin is used to fabricate the hydrogel film for inducing the impaired sciatic nerve regeneration through incorporating the conductive poly­(3,4-ethylenedioxythiophene) nanoparticles (PEDOT NPs) and modifying with cell adhesive tetrapeptide Cys–Arg–Gly–Asp (CRGD) (ChT-PEDOT-p). The partial deacetylation process of chitin for exposing the amino groups is performed to (i) improve the electrostatic interaction between chitin and the negatively charged PEDOT for enhancing the composite hydrogel strength and (ii) offer the active sites for peptide modification. The as-prepared hydrogel remarkably promotes the in vitro RSC-96 cell adhesion and proliferation, as well as the Schwann cell activity-related gene S100, NF-200, and myelin basic protein (MBP) expression. Function of gastrocnemius muscle and thickness of myelinated axon in chitin/PEDOT groups are analogous to the autograft in 10 mm rat sciatic nerve defect. Immunofluorescence, immunohistochemistry, western blotting, and toluidine blue staining analyses on the regenerated sciatic nerve explain that the attachment and proliferation enhancement of Schwann cells and angiogenesis are the vital factors for the chitin/PEDOT composite to facilitate the nerve regeneration. This work provides an applicable chitin-based NGC material for accelerating the peripheral nerve restoration.

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Two-dimensional (2D) carbon nanosheets have been widely applied in many fields, and introduction of controllable N species and a wrinkled structure in 2D carbon is an appealing strategy to optimize their properties. Herein, we report a straightforward strategy for bifunctional regulation on the surface morphology (from a smooth to a wrinkled structure) and N doping of 2D carbon nanosheets by fast-pyrolyzing chitin nanosheets, which was obtained via a “top-down” exfoliation method. Our findings demonstrated that the heating rate was a key to determine the 2D wrinkled structure and type of N doping of the carbon nanosheets, and 2D wrinkled carbon nanosheets (PCNs-800-10) with hierarchical pores and enriched N species could be obtained under an optimized pyrolysis condition (ramp rate 10 °C min–1, at 800 °C for 2 h). When used as a metal-free electrocatalyst for the oxygen reduction reaction (ORR), PCNs-800-10 exhibits admirable activity, high selectivity, and excellent cycling durability of over 10 000 cycles. This was the first study to achieve the simultaneous regulation on both the wrinkled structure and the N species of 2D carbons by utilizing natural nitrogen-containing chitin without utilizing any substrates and nitrogen-containing additives, which can be extended to many other energy storage/conversion materials.

It is urgent to explore highly efficient and inexpensive electrocatalysts toward hydrogen evolution reaction (HER) for green hydrogen generation. Herein, ultrafine Ru nanoparticles (∼1.7 nm) anchored on chitin-derived porous nitrogen-doped carbon (Ru@NC) are constructed to promote the HER activity and stability via a strong metal−support interaction. Benefiting from the regulated electronic structure, Ru@NC delivers an HER overpotential of 39 mV at 10 mA cm −2 , less than that of common carbon-supported Ru/C (64 mV) and Pt/C (61 mV) catalysts in alkaline solution. Meanwhile, Ru@NC exhibits superior stability compared with Ru/C and Pt/C in both potential cycling and chronoamperometric tests. By tracking the structural evolution, Ru nanoparticles still disperse uniformly in Ru@NC with the particle size less than 2 nm, while for Ru/C, the particles go through severe aggregation after cyclic stability testing. This work provides a facile strategy for designing high-efficiency electrocatalysts via engineering the composition and morphology of supports.

A "green", low-cost, and efficient processing technology to spin regenerated cellulose multifilaments has attracted much attention in the textile field. Herein, robust cellulose filaments were produced from a cellulose solution in a NaOH/urea/ZnO aqueous system with a relatively high concentration (7.5 wt %) via the wet-spinning technique by coagulating in cheap and renewable 15 wt % citric acid/5 wt % trisodium citrate/40 wt % glycol at low temperature, followed by drawing in a 5% sulfuric acid bath. In our findings, the solubility and the solution stability were significantly improved by introducing 0.8 wt % ZnO, and the cellulose chains self-aggregated in parallel to form nanofibers through hydrogen bonding, as a result of the relatively slow exchange ratio between the coagulator and solvent. Moreover, the nanofibers with an average diameter of 30−50 nm were aligned to the fiber direction by stretching orientation in the second sulfuric acid coagulator, leading to the further enhancement of the filament strength. The nanofibril-structured cellulose fibers exhibited a high orientation degree of 0.85 and an excellent tensile strength of 2.92 cN dtex −1 . The wet-spinning process only took 8 h, and our production costs were as cheap as viscose, which was an efficient, low-cost, and "green" process without the discharge of toxic substances. Furthermore, the 80−160 nm ZnO nanoparticles could be generated into cellulose filaments for achieving ultraviolet and static resistance. This work provided a "green" and economical strategy for spinning robust cellulose filaments. Such a technology is being industrially trialed by cooperating with Yibin Grace Co. Ltd in China, showing potential impact on the sustainability in the industry, economy, and environment.