Chinese scientists have created a biodegradable wireless charger they claim can be safely implanted into the human body and used to power bioelectronic devices such as drug delivery systems and sensory devices.
Although bioelectronic devices like pacemakers and cochlear implants have been used in medicine for several decades, they require external energy sources that ultimately run out and need frequent replacement over the course of the patient’s lifetime.
Now, researchers at Gansu province’s Lanzhou University claim to have developed a wearable energy storage and supply unit that does not require removal or replacement once its function is complete.
Current biodegradable power supply units are not suited for medical applications as their service life is too short and often causes inflammation and irritation at the site when applied transdermally, according to the team’s paper, published in the peer-reviewed journal, Science Advances.
To improve upon this, the research unit hypothesised a wireless implantable power system that they described as possessing high-energy storage performance and a soft and flexible texture that allowed it to adapt to the shape of both tissue and internal organs.
The postage-stamp-sized implant consists of a magnesium coil, zinc-ion capacitors, a rectifying module, and a magnesium interconnect coated in a polymer and wax skin.
Power is harvested by the magnesium coil, which passes through the circuit before being stored within the zinc-ion supercapacitors. Unlike batteries that store their power in the form of chemical energy, supercapacitors hold electrical energy.
While supercapacitors have less storage potential than batteries, they possess a higher energy density, making them well-suited for the team’s application.
Initially trialled on lab rodents, the researchers observed that the biodegradable implant functioned for up to 10 days, completely dissolving within 60 days.
Both zinc and magnesium are essential micronutrients for human health, and the paper noted the implant contained less than the recommended daily intake levels, making the implant’s dissolvable components entirely safe within the human system.
To prove the implant’s functionality of the power supply unit, the team connected it to a drug delivery device containing anti-inflammatory medicine implanted into the rodents with yeast-induced pyrexia.
After 12 hours of close observation, the researchers saw the temperatures of the subjects that received the implant were significantly lower, indicating that the fever had broken.
Although successful, the paper said some kinks still needed ironing out. Notably, turning the device on or off remained an issue – the implant remained on until the capacitors had discharged completely.
Satisfied with their early triumph, the team said the prototype represented an important step forward in the field of bioelectronic devices.
https://interestingengineering.com/innovation/bioimplantable-wireless-charger-china
