Electrical stimulation (ES) is widely used in physiological and medical sciences, while its application to treat inflammatory skin diseases (ISDs) remains a challenge owing to their natural pathological cuticle barrier and lack of an effective combination with chemotherapy to achieve specific immunomodulation. Here, a wearable, battery-free, multi-component drugloaded electronic microneedle (mD-eMN) system is developed by integrating remodeled metal microneedles loaded with multi-component chemical drugs and flexible triboelectric nanogenerators (TENGs). The system can rapidly release drugs into the site of ISDs and then realize an efficient penetration into cell body and specific immunomodulation under the synergism of pulsed electrons originating from the TENG. Also, the pulsed electrons can promote skin tissue homeostasis reconstruction to alleviate the inflammatory process of ISDs. Sufficient evidence shows that a significant skin inflammation regression of psoriasis (a typical ISDs model) is achieved using the mD-eMN system compared to traditional ES or chemotherapy alone. This innovative wearable mD-eMN system provides an effective flexible electronic and chemical drug joint technological platform for the treatment of ISDs, which is not only suitable for the treatment of psoriasis in this study but also maybe for other ISDs such as diabetic ulcers and skin tumors.

Invasive electrical stimulation (iES) is prone to cause neural stimulus-inertia owing to its excessive accumulation of exogenous charges, thereby resulting in many side effects and even failure of nerve regeneration and functional recovery. Here, a wearable neural iES system is well designed and built for bionic and long-lasting neural modulation. It can automatically yield biomimetic pulsed electrical signals under the driven of respiratory motion. These electrical signals are full of unique physiological synchronization can give biofeedback to respiratory behaviors, self-adjusting with different physiological states of the living body, and thus realizing a dynamic and biological self-matched modulation of voltage-gated calcium channels on the cell membrane. Abundant cellular and animal experimental evidence confirm an effective elimination of neural stimulus-inertia by these bioelectrical signals. An unprecedented nerve regeneration and motor functional reconstruction are achieved in long-segmental peripheral nerve defects, which is equal to the gold standard of nerve repair -- autograft. The wearable neural iES system provides an advanced platform to overcome the common neural stimulus-inertia and gives a broad avenue for personalized iES therapy of nerve injury and neurodegenerative diseases.

Peripheral nerve injury (PNI) remains an intractable challenge in regenerative medicine. Recently, physical cue-based strategies (e.g., electrical neurostimulation, acoustic radiation, electromagnetic bioregulation, as well as directional fiber guiding, etc.) have drawn increasing attention not only as a stimulator for cell functions modulation and fate determination, but also as a morphology-index for modulating cell phenotype, proliferation, and differentiation, especially for nerve cells. More importantly, the advanced percutaneous power transmission technology, self-power nanotechnology that leverages piezoelectrical/triboelectricity materials, and focused ultrasound and pulsed electromagnetic field technology exhibit the appealing practice potential for achieving low-invasive, wireless, and battery-free neuromodulation. In this review, recent advances of physical cue-based strategies including electrical, acoustic, magnetic, and morphology for PNI are systematically overviewed, and the open challenges for realizing scalable clinical/commercial transformation and future perspectives of these strategies for PNI are concluded.

Bioelectricity plays a significant role in major biological processes and electrical stimulation is an effective and non-invasive way to promote cellular growth, differentiation and tissue regeneration. In tissue engineering, piezoelectric...

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