Innovations in medical technology through the blending of science and medicine have significantly enhanced patient care. Notably, the advent of implantable electronic devices, such as those used in the heart or brain, marks a major advancement, offering real-time monitoring and regulation of physiological signals. These developments present groundbreaking solutions for complex conditions like Parkinson’s disease. However, the durability of these devices remains a challenge. Typically, patients with implanted devices must undergo frequent surgeries to replace batteries, a process fraught with risks and burdens, both financial and physical. Current research is delving into implantable medical devices that function wirelessly, but the search for a safe and efficient energy source and compatible materials continues. Titanium (Ti) is commonly used for its biocompatibility and strength, but its inability to transmit radio waves requires an additional antenna for wireless power, increasing the device's size and discomfort for the patient.

In a groundbreaking development, a research team from Pohang University of Science and Technology (POSTECH, Gyeongbuk, Korea) has engineered electrostatic materials sensitive to even faint ultrasound signals, paving the way for permanently implantable electronic devices in biomedicine. The team chose ultrasound over radio waves due to its established safety record in medical diagnostics and treatments. They developed an electrostatic material that responds to weak ultrasound by combining high dielectric polymers (P(VDF-TrFE)) with calcium copper titanate (CCTO, CaCu3Ti4O12), a ceramic with a high dielectric constant. This material produces static electricity through interlayer friction, generating efficient electrical energy with exceptionally low output impedance, ensuring efficient electricity transmission.

The research team employed this innovative technology to develop an implantable neurological stimulator powered by ultrasound-based energy transmission, eliminating the need for batteries. This was substantiated through rigorous experimental validation. In trials using animal models, the device functioned at standard imaging ultrasound levels (500 mW/cm2) that place minimal strain on the human body. Additionally, it successfully alleviated symptoms associated with overactive bladder disorders by stimulating nerves, showcasing its potential to transform patient care with its cutting-edge, battery-free design.

“We have addressed the challenges in the field of implantable medical devices using ultrasound-based energy transmission technology that is harmless to the human body,” said Professor Sung-Min Park from POSTECH. “This research serves as a case of introducing advanced material technology into medical devices, and we anticipate that it will promote the emergence of a next-generation medical industry, including the treatment of intractable diseases using implantable devices.” 

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