Dual-energy device unlocks potential for wireless medical implants

This first-of-a-kind device can efficiently harvest energy from both magnetic fields and ultrasound sources at the same time. 

“Our device may unlock next-generation biomedical applications because it can generate 300 percent higher power than the current state-of-the-art devices,” said Bed Poudel, research professor at Penn State and co-author of the study. 

“By combining two energy sources in a single generator, power generated from a given volume of the device can be significantly improved which can unlock many applications that were not possible before,” Poudel added. 

This technique increases medical implant lifespan

This wireless charging technology offers the potential for developing tiny, millimeter-sized, battery-free bioelectronic devices. 

Traditional implants, such as pacemakers, are often powered by batteries and charged via wires, which presents issues such as limited lifespan and the need for surgical replacements. This may result in unwanted infection or medical consequences in some circumstances. 

The new wireless charging technique can enhance implant lifespan while reducing surgical risks.

“The problem is that as you make these implants less invasive by making them smaller and smaller, the efficiency of wireless charging becomes much lower,” said Mehdi Kiani, associate professor of electrical engineering at Penn State and co-author of the study. 

“To address this, you need to increase the power. But the problem is that high frequency electromagnetic waves could be harmful to the body,” Kiani added. 

The magnetic field and ultrasound energy often work at lower frequencies and might be used to charge implants wirelessly.

How does this dual-energy device work?

The devices employ a sophisticated two-step process to convert magnetic field energy into electricity. The first layer, magnetostrictive, plays a crucial role by transforming a magnetic field into stress.

Simultaneously, the second layer, piezoelectric, converts this stress or vibrations into an electric field. This combined mechanism allows the device to turn energy from a magnetic field into an electric current.

Furthermore, the piezoelectric layer exhibits a dual capability. In addition to converting stress into an electric field, it can simultaneously convert ultrasound energy into an electric current. 

This novel feature increases the device’s adaptability by allowing it to use magnetic field and ultrasound energy sources with great efficiency and efficacy.

“Now we can combine two modalities in a single receiver. This can exceed any of the individual modalities because we now have two sources of energy. We can increase the power by a factor of four, which is really significant,” said Sumanta Kumar Karan, the study’s lead author, in the press release.

Beyond medical applications, this technology has implications for powering wireless sensor networks in smart buildings. 

The findings were published in the journal Energy & Environmental Science.