High-performance, breathable and flame-retardant moist-electric generator based on asymmetrical nanofiber membrane assembly.

Moist-electric generators (MEGs), which are capable of spontaneously generating energy from ubiquitous moisture, are considered as a potential power supply candidate for wearable electronics. However, the application of the MEGs in the wearable field is still challenging due to the low electric output and the lack of wearable attributes such as breathability and flame retardancy. Herein, we demonstrated a wearable MEG with high power-output, breathability and flame retardancy, which was fabricated by designing an asymmetrical nanofiber assembly using hydrophilic polyvinyl alcohol/phytic acid (PVA/PA) and hydrophobic polyvinylidene difluoride (PVDF) nanofiber membranes. Owing to the synergistic effects of strong water absorption, enhanced ion release and numerous micro-nano transport channels, a single MEG of 1 cm2 could constantly generate high direct-current (DC) power, i.e., a voltage of 1.0 V, a current of 15.5 µA, and a power density of 3.0 µW cm-2, outperforming other reported nanofiber-based MEGs. More importantly, the asymmetric nanofiber structure ensured the moisture circulation inside MEG and thus produced a sustained voltage output for 7 days without any deterioration. The MEG also showed good flexibility, air/moisture permeability and flame retardancy, which give it necessary wearable attributes. Furthermore, large-scale integration of MEG units could be readily realized to fabricate a power source device for driving different portable electronics, while the moisture sensitivity made the MEG well used for sensing applications (e.g., respiration monitoring, fire warning).

Bioactive microgel-coated electrospun membrane with cell-instructive interfaces and topology for abdominal wall defect repair.

Current mesh materials used for the clinical treatment of abdominal defects struggle to balance mechanical properties and bioactivity to support tissue remodeling. Therefore, a bioactive microgel-coated electrospinning membrane was designed with the superiority of cell-instructive topology in guiding cell behavior and function for abdominal wall defect reconstruction. The electrostatic spinning technique was employed to prepare a bioabsorbable PLCL fiber membrane with an effective mechanical support. Additionally, decellularized matrix (dECM)-derived bioactive microgels were further coated on the fiber membrane through co-precipitation with dopamine, which was expected to endow cell-instructive hydrophilic interfaces and topological morphologies for cell adhesion. Moreover, the introduction of the dECM into the microgel promoted the myogenic proliferation and differentiation of C2C12 cells. Subsequently, in vivo experiments using a rat abdominal wall defect model demonstrated that the bioactive microgel coating significantly contributed to the reconstruction of intact abdominal wall structures, highlighting its potential for clinical application in promoting the repair of soft tissue defects associated with abdominal wall damage. This study presented an effective mesh material for facilitating the reconstruction of abdominal wall defects and contributed novel design concepts for the surface modification of scaffolds with cell-instructive interfaces and topology.