Ultrasound-Driven Injectable and Fully Biodegradable Triboelectric Nanogenerators.

Implantable medical devices (IMDs) provide practical approaches to monitor physiological parameters, diagnose diseases, and aid treatment. However, device installation, maintenance, and long-term implantation increase the risk of infection with conventional IMDs. Therefore, medical devices with biocompatibility, controllability, and miniaturization are highly demandable. An ultrasound-driven, biodegradable, and injectable triboelectric nanogenerator (I-TENG) is demonstrated to reduce the risks of implant-related injuries and infections. The injection can be given by subcutaneous injection with a needle to minimize the implantation incision. The stable output of I-TENG is driven by ultrasound (20 kHz, 1 W cm -2 ), with a voltage of 356.8 mV and current of 1.02 µA during in vivo studies and an electric field of about 0.92 V mm -1 during ex vivo experiments. The cell scratch and proliferation assays showed that the delivered electric field effectively increased cell migration and proliferation, indicating a significant potential to accelerate healing with electricity.