A novel fibrous conduit consisting of well-aligned nanofibers with longitudinal nanogrooves on the fiber surface was prepared by electrospinning and was subjected to an in vivo nerve regeneration study on rats using a sciatic nerve injury model. For comparison, a fibrous conduit having a similar fiber alignment structure without surface groove and an autograft were also conducted in the same test. The electrophysiological, walking track, gastrocnemius muscle, triple-immunofluorescence, and immunohistological analyses indicated that grooved fibers effectively improved sciatic nerve regeneration. This is mainly attributed to the highly ordered secondary structure formed by surface grooves and an increase in the specific surface area. Fibrous conduits made of longitudinally aligned nanofibers with longitudinal nanogrooves on the fiber surface may offer a new nerve guidance conduit for peripheral nerve repair and regeneration.

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Al3+ coagulated wet-spun graphene fibers show a large surface area and high electrical conductivity, resulting in large capacitance.

Flexible and pliable fiber electrodes with decent electrical conductivity and high capacitance density are crucial to fiber-shaped supercapacitors (FSCs) whose real-world applications include electronic textiles, miniaturized energy storage devices, and so on. Herein, we report a hybrid fiber structure made of reduced graphene oxide (rGO) and MXene, both of which are highly conductive two-dimensional (2D) materials, assembled into fibers via the scalable wet-spinning technique. By incorporation of 60 wt % MXene, the hybrid fibers can reach a balanced performance with conductivity up to 743.1 S cm −1 , meanwhile maintaining decent flexibility. To improve ion accessibility to inner pores within the fibers, nonvolatile electrolyte (H 2 SO 4 ) was preincorporated in between MXene and rGO layers. In addition, the size effect of MXene sheets on the overall performance of hybrid fibers was studied, favoring larger size of MXene in general. With these effective strategies, our optimal FSCs provide outstanding energy density (ca. 12 μWh cm −2 and 9.85 mWh cm −3 ) at a high power density (ca. 8.8 mW cm −2 and 7.1 W cm −3 ), showing great promise where high volumetric output is desired.

One-dimensional flexible fiber supercapacitors (FSCs) have attracted great interest as promising energy-storage units that can be seamlessly incorporated into textiles via weaving, knitting, or braiding. The major challenges in this field are to develop tougher and more efficient FSCs with a relatively easy and scalable process. Here, we demonstrate a wet-spinning process to produce graphene oxide (GO) fibers from GO dispersions in N-methyl-2-pyrrolidone (NMP), with ethyl acetate as the coagulant. Upon chemical reduction of GO, the resulting NMP-based reduced GO (rGO) fibers (rGO@NMP-Fs) are twice as high in the surface area and toughness but comparable in tensile strength and conductivity as that of the water-based rGO fibers (rGO@HO-Fs). When assembled into parallel FSCs, rGO@NMP-F-based supercapacitors (rGO@NMP-FSCs) offered a specific capacitance of 196.7 F cm (147.5 mF cm), five times higher than that of rGO@HO-F-based supercapacitors (rGO@HO-FSCs) and also higher than most existing wet-spun rGO-FSCs, as well as those FSCs built with metal wires, graphene/carbon nanotube (CNT) fibers, or even pseudocapacitive materials. In addition, our rGO@NMP-FSCs can provide good bending and cycling stability. The energy density of our rGO@NMP-FSCs reaches ca. 6.8 mWh cm, comparable to that of a Li thin-film battery (4 V/500 μAh).