Piezoelectric materials possess intrinsic mechanoelectric coupling properties, allowing efficient bidirectional conversion between acoustic and electrical energy. This unique characteristic has opened transformative avenues in biomedical fields, particularly in brain science. Piezoelectric acoustic-electric conversion technology provides a powerful alternative, enabling non-invasive, precise, and wireless neural modulation and stimulation, which are essential for developing advanced brain-computer interface (BCI), neurological treatments, and neural regeneration strategies. This technology holds significant potential for treating challenging neurological disorders including Parkinson’s disease, epilepsy, and depression and for facilitating neural repair. Additionally, the integration of piezoelectric materials can enhance real-time diagnostics and therapeutic strategies, providing significant benefits in terms of patient safety, procedural efficacy, and reduced healthcare costs. The adoption of these materials can significantly enhance the quality of life for patients with chronic neurological conditions, enabling improved management, monitoring, and treatment outcomes.

Significant advancements have been achieved in applying piezoelectric materials within neuroscience, driven by continuous innovations in material science, device engineering, and biointerface design. In the inverse piezoelectric pathway, where electrical signals are converted into ultrasound, transcranial focused ultrasound stimulation (tFUS) has emerged as a leading non-invasive neuromodulation technique. Owing to its millimeter-scale spatial precision, controllable penetration depth, and highly tunable acoustic parameters, tFUS enables both targeted therapeutic interventions and the fine, reversible regulation of neuronal excitability and network activity (Fig. 4). To address the limitations posed by skull-induced acoustic scattering and energy attenuation, researchers have developed implantable piezoelectric ultrasound stimulators that integrate ultra-thin, flexible microprobes with localized stimulation capability. In animal models, these devices have been shown to precisely activate dopaminergic neurons and achieve on-demand dopamine release, offering new strategies for neuromodulation in deep brain regions (Fig. 5). Conversely, the direct piezoelectric effect, where ultrasound is converted into electrical signals, forms the foundation for wireless ultrasound-powered stimulation electrodes. For instance, advanced energy harvesters based on Sm-doped PMN?PT single crystals can provide stable, high-efficiency power delivery to chronically implanted electrodes, thereby eliminating infection risks, mechanical constraints, and frequent maintenance associated with percutaneous leads or battery replacements (Fig. 6). At the microscale, the advent of “neural dust” platforms, which are ultra-miniaturized wireless devices powered and interrogated by piezoelectric transducers, has enabled chronic, bidirectional neural recording and stimulation with minimal invasiveness, paving the way for long-term untethered neural interfaces (Fig. 7). At the nanoscale, ultrasonically activated piezoelectric nanoparticles (e.g., BaTiO?-based systems) can generate localized electric fields that modulate ion-channel dynamics, whereas piezoelectric nanostickers have demonstrated the ability to direct neural stem cell differentiation and accelerate tissue repair in traumatic brain injury (TBI) models via precise site-specific electrical stimulation (Figs. 8?9). The bidirectional acoustic?electric interconversion technology, enabled by both the direct and inverse piezoelectric effects, supports mutual transformation between ultrasound and electrical signals, with broad applications in cutting-edge fields such as ultrasonic medical imaging, ultrasonic biosensing, and ultrasonic brain?computer interfaces (BCIs). In imaging, flexible piezoelectric composite arrays allow high-resolution, real-time ultrasound visualization of cerebral vasculature and blood flow, while maintaining intimate conformal contact with the complex topography of biological tissue surfaces (Fig. 10). Building on these imaging capabilities, functional ultrasound (fUS) has been seamlessly integrated with brain?computer interface systems, enabling accurate non-invasive decoding of motor intentions with high spatiotemporal resolution and reliable multiday performance (Fig. 11). Furthermore, the development of injectable and biodegradable ultrasonic sensors has provided a wireless, real-time solution for monitoring critical intracranial physiological parameters such as pressure, pH, and temperature, significantly improving biosafety by reducing long-term implantation risks while maintaining high sensitivity and biocompatibility (Fig. 12). Collectively, these advancements underscore the versatile and transformative potential of piezoelectric acoustic?electric interconversion technologies, which encompass neuromodulation, wireless energy transfer, high-definition neural imaging, and precision biosensing, for both fundamental neuroscience research and the development of next-generation clinical therapies.

Piezoelectric materials represent a paradigm shift in brain science technology by enabling non-invasive neural imaging, wireless energy transfer, and precise neural modulation and stimulation. However, several challenges must be addressed to fully realize their clinical and practical potential. These include the neurotoxicity of lead-based piezoelectric ceramics, which must be mitigated by developing and optimizing lead-free or biodegradable piezoelectric materials to ensure biocompatibility and long-term stability in biological environments. Enhancing the acoustic energy coupling efficiency and power output of ultrasound-based wireless energy harvesting systems is also crucial to overcome limitations imposed by acoustic safety thresholds and improve operational effectiveness. Furthermore, improving the neural targeting efficiency and reducing invasiveness of nanoparticle-based stimulation systems through sophisticated surface modification techniques, optimized nanoparticle size, and alternative delivery methods such as intravenous or intranasal administration will be necessary. Future research directions will likely emphasize interdisciplinary collaboration, leveraging advancements in nanotechnology, materials science, electronics, and neural engineering to enhance system performance, targeting precision, and safety profiles. Integration with advanced computational modeling and artificial intelligence may further refine device performance and therapeutic accuracy. Continued innovation in these domains promises to facilitate the translation of piezoelectric acoustic-electric technologies from experimental stages to mainstream clinical applications, thereby significantly impacting neural modulation strategies, treatments for brain diseases, and the development of intelligent, minimally invasive neural interface devices.