Electroconductive hydrogels are very attractive candidates for accelerated spinal cord injury (SCI) repair because they match the electrical and mechanical properties of neural tissue. However, electroconductive hydrogel implantation can potentially aggravate inflammation, and hinder its repair efficacy. Bone marrow stem cell‐derived exosomes (BMSC‐exosomes) have shown immunomodulatory and tissue regeneration effects, therefore, neural tissue‐like electroconductive hydrogels loaded with BMSC‐exosomes are developed for the synergistic treatment of SCI. These exosomes‐loaded electroconductive hydrogels modulate microglial M2 polarization via the NF‐κB pathway, and synergistically enhance neuronal and oligodendrocyte differentiation of neural stem cells (NSCs) while inhibiting astrocyte differentiation, and also increase axon outgrowth via the PTEN/PI3K/AKT/mTOR pathway. Furthermore, exosomes combined electroconductive hydrogels significantly decrease the number of CD68‐positive microglia, enhance local NSCs recruitment, and promote neuronal and axonal regeneration, resulting in significant functional recovery at the early stage in an SCI mouse model. Hence, the findings of this study demonstrate that the combination of electroconductive hydrogels and BMSC‐exosomes is a promising therapeutic strategy for SCI repair.

Hydrogels, because of their water-rich nature and soft mechanical characteristics that resemble those of skin tissues, are promising materials for artificial skin. Existing piezoresistive hydrogels combine unique tissue-like and sensory properties, but these materials are often plagued by problems such as poor mechanical properties and the requirement of an external power supply or batteries. Here, a tough and self-powered hydrogel based on a tough polyacrylonitrile hydrogel incorporating ferroelectric poly(vinylidene fluoride) (PAN-PVDF) is reported. The dipolar interactions between the PVDF and PAN chains cause an increase in the best electroactive β-phase PVDF percentage in the composites from 0 to 91.3%; thus, a maximum piezoelectric coefficient d 33 , 30 pC N −1 , was achieved for the hydrogels. Skin-like Young's modulus values (1.33− 4.24 MPa), stretchability (90−175%), and high toughness (1.23 MJ/m 2 ) were achieved simultaneously for the hydrogels. This tough gel is capable of generating an electrical signal output (≈30 mV and ≈2.8 μA) with a rapid response (≈31 ms) due to the stress-induced poling effect. Moreover, the gel can also precisely detect physiological signals (e.g., gesture, pulse, and words). This study provides a simple and efficient method for artificial skin with high toughness, self-power generation capability, fast response, low cost, and tissue-like properties.

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