Electronics have become widespread everywhere, and implantable devices are no exception. The microelectronic implantable medical device market, including advanced technologies such as “Implantable Medical Device Charging,” is expected to grow 30% faster than medical implants over the next five years, reaching $60 billion. by 2027. This growth is largely due to the increase in cardiovascular disease. , with the use of medical implants, such as pacemakers and defibrillators, constantly increasing.
However, one of the main challenges facing these devices is power, and charging implantable medical devices is becoming an increasingly important topic. Batteries are the energy source of choice, but they present several challenges:
- Bulky batteries are difficult to implant in compact areas of the body. For example, many brain implants must be implanted in the neck and connected to the target site via wires.
- The use of wire leads to an increased rate of infection, dislodgement, and fracture.
- The batteries in the device only last 5 years.
- Replacing a weak battery requires surgery, which increases the risk of mortality as well as billion in costs for the health system.
These limitations have created a clear need for a better solution to power implanted devices. Wireless charging has become a next-generation innovation.
Current wireless charging mechanisms:
There are about 10 types of wireless power mechanisms. The most common are radio frequency, magnetic induction and magnetic resonance charging systems. Figure 1 shows how these mechanisms work, from input power to transferring an alternating current (AC) signal to direct current (DC). Then, the frequencies are transferred wirelessly between the transmitting coils (e.g., a charging platform) and the receiving coils (e.g., a smartphone), and finally to the appropriate power supply for the battery.
- Radio frequency charging is being developed for use in smartphone chargers and tablet charging stands. These types of devices require the transmitter to generate radio frequency waves and allow a greater distance between the transmitter and receiver. Disadvantages include that this method is prone to interference and often requires precise and stable alignment. Additionally, RF is in its early stages and not yet deployed in commercial products.
- Magnetic induction, or near-field charging, sends an electric current via a transmitter coil through a charging station to generate a magnetic field whenever the receiver coil is placed on or near the charging station. This is often used for small wireless devices, such as an electric toothbrush, because it requires a shorter distance or direct contact between the receiver and transmitter coils. A major disadvantage is the longer charging time and the need for precise alignment.
- Magnetic resonance the load is the fastest growing segment in the wireless charging market. Magnetic resonance is primarily used for larger wireless devices that require greater power, such as electric vehicles. These large wireless devices use magnetic fields to transfer energy between two coupled coils when the receiver has the same generated frequency. Resonance allows greater alignment variation but has disadvantages such as low efficiency due to flux leakage and greater circuit complexity. High operating frequencies can also cause potential electromagnetic interference issues.
Recent advances in wireless charging for implantable medical devices:
Wireless charging is not new, but charging a small implantable medical device is much more difficult and requires much more review from regulatory agencies than charging a phone. Small wireless implantable medical devices require enough power between the transmitter and receiver to penetrate body tissues at various distances. Additionally, charging technology must be flexible enough to follow body movements, small enough to fit in the device, efficient enough to provide long power duration, and safe enough to avoid thermal injury. Here are 2 recent innovations that caught our attention in this particularly exciting and active field:
- NuCurrenta company specializing in wireless charging technology, launched a product called NuEva HF development platform in 2021. This device uses inductive and resonant power transfer to deliver power levels 1,000 times higher than radio frequency, and it shows the potential of high-frequency power transfer technology for charging implantable medical devices.
- In 2022, researchers at the Korea Institute of Science and Technology created an electronic device based on technology commonly used underwater. Researchers developed a triboelectric generator that transmits ultrasonic waves rather than electromagnetic waves to convert acoustic energy into electricity through water or tissue. This charging method has the potential to wirelessly charge implantable medical devices at a greater distance between transmitter and receiver with higher energy efficiency.
Future prospects:
Wireless charging is already well established in the consumer goods sector and it is only a matter of time before it makes the jump to medical devices. Implantable medical devices alone represent a significant and untapped opportunity, with an estimated 1.4 million devices implanted each year and a battery life of 6 to 10 years, we are looking at a burden on the healthcare system in the tens of billions of dollars per year in surgery costs alone, not to mention surgery costs. major complications occurring in 9% of replacement procedures.
While these numbers alone warrant a close look at promising technologies, we believe they are just the tip of the iceberg. Wireless charging technology will likely play a key role in the emerging field of implantable biosensors and smart implants, which are expected to revolutionize the way we diagnose and track diseases. Whoever successfully captures and integrates implantable medical device charging technology will be one step closer to this goal.
Featured image courtesy of Korea Institute of Science and Technology