A Wireless Millimeter‐Scale Device for in Vivo Electromagnetic Brain Tumor Therapy by Ultrasound‐Responsive Ti₃C₂T_x Hydrogel

Implantable devices that integrate advanced nanomaterials with wireless energy systems represent a transformative approach to tackling brain tumors. Here, a millimeter-scale implantable device based on an MXene/polyvinyl alcohol (PVA) hydrogel is introduced, designed for precise and minimally invasive brain tumor therapy via tunable alternating electric fields. This device presents a novel approach by combining ultrasonic wireless energy transfer with triboelectric energy harvesting, eliminating the need for in vivo batteries and enabling continuous operation in a completely wireless manner. The system not only optimizes energy harvesting efficiency but also ensures the localized delivery of therapeutic electric fields directly to the tumor site. Its compact size and mechanical flexibility allow for precise implantation in the complex brain environment, offering a minimally invasive solution with enhanced safety and adaptability. Preclinical evaluations using U-87 MG orthotopic glioblastoma models demonstrate significant tumor growth inhibition and a marked improvement in survival rates, underscoring its therapeutic potential.