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The proper axial length of the eye is crucial for achieving emmetropia. In this study, we present a wireless battery-free eye modulation patch designed to correct high myopia and prevent relapse. The patch consists of piezoelectric transducers, an electrochemical micro-actuator, a drug microneedle array, μ-LEDs, a flexible circuit, and biocompatible encapsulation. The system can be wirelessly powered and controlled using external ultrasound. The electrochemical micro-actuator plays a key role in precisely shortening the axial length by driving the posterior sclera inward. This ensures accurate scene imaging on the retina for myopia eye. The drug microneedle array delivers riboflavin to the posterior sclera, and μ-LEDs' blue light induces collagen cross-linking, reinforcing sclera strength. In vivo experiments demonstrate that the patch successfully reduces the rabbit eye's axial length by ~1217 μm and increases sclera strength by 387%. The system operates effectively within the body without the need for batteries. Here, we show that the patch offers a promising avenue for clinically treating high myopia. The proper axial length of the eye is crucial for achieving emmetropia. Here, authors introduce a wireless battery-free eye modulation patch designed to correct high myopia and prevent relapse. [ABSTRACT FROM AUTHOR]

Peripheral nerve stimulators have emerged as a crucial instrument in the realm of neurological disease, capable of modulating nerve activity through precisely targeted electrical stimulation to specific sites within the nervous system. Herein, a new wireless battery‐free peripheral nerve stimulation device for remote muscle activation is developed. The device with conch‐inspired bionic design can be wirelessly powered and controlled by a mobile phone playing audio via the piezoelectric effect. The device consists of two parts: a conch‐like signal‐intensifying piezoelectric resonator for converting acoustic wave into electrostimulation signal; and a pedestal with stimulation electrodes for transmitting the electrostimulation signal to a peripheral nerve. For remote nerve intervention, a programmed audio tone from one mobile phone can be tele‐transmitted from other phones according to the desired stimulation protocols. In‐vivo experiments in stimulating the sciatic nerve in mice showed that the device can activate muscles (e.g., 1 Hz 920 mV for 26 degree of leg movement), and the neuron‐muscle interaction has been confirmed by electromyogram (EMG). The wireless peripheral nerve stimulation conch achieves feasible remote muscle activation without batteries, and can extend the scope of self‐powered techniques for telemedicine and limb/trunk rehabilitation. [ABSTRACT FROM AUTHOR]

Softening of piezoelectric materials facilitates the development of flexible wearables and energy harvesting devices. However, as one of the most competitive candidates, piezoelectric ceramic-polymer composites inevitably exhibit reduced power-generation capability and weak mechanical strength due to the mismatch of strength and permittivity between the two phases inside. Herein a flexible, air-permeable, and high-performance piezoceramic textile composite with a mechanically reinforced hierarchical porous structure is introduced. Based on a template-assisted sol-gel method, a three-order hierarchical ceramic textile is constructed by intertwining submillimeter-scale multi-ply ceramic fibers that are further formed by twisting micrometer-scale one-ply ceramic fibrils. Theoretical analysis indicates that large mechanical stress can be easily induced in the multi-order hierarchical structure, which greatly benefits the electrical output. Fabricated samples generate an opencircuit voltage of 128 V, a short-circuit current of 120 μA, and an instantaneous power density of 0.75 mW cm-2, much higher than the previously reported works. The developed multi-order and 3D-interconnected piezoceramic textile shows satisfactory piezoelectricity (d33 of 190 pm V-1), air permeability (45.1 mm s-1), flexibility (Young's modulus of 0.35 GPa), and toughness (0.125 MJ m-3), collectively. The design strategy of obtaining balanced properties promotes the practicality of smart/functional materials in wearables and flexible electronics. [ABSTRACT FROM AUTHOR]