Revolutionary biodegradable power system developed by Chinese scientists for implantable bioelectronics

    AI generated image for illustration purpose only.

    20th November 2023 – (Beijing) A team of Chinese scientists has devised a novel biodegradable, wireless energy receiving and storage device that could power bioelectronic implants, such as completely biodegradable drug delivery systems. These implantable bioelectronic systems, including monitoring sensors and drug delivery implants, offer minimally invasive, reliable techniques to accurately monitor and treat patients.

    According to a paper published in the journal Science Advances by researchers from Lanzhou University, the development of power modules for these devices has been lagging, despite advancements in biocompatible and biodegradable sensors and circuit units.

    Existing biodegradable power supply units, although usable, often lack the necessary power generation for biomedical applications and are typically single-use. Power supply units connected to transdermal chargers can cause inflammation, and those powered by non-rechargeable batteries may necessitate surgical replacement, potentially leading to complications.

    In response to this challenge, the researchers have introduced a wireless implantable power system that boasts high energy storage performance and favourable tissue interfacing properties due to its soft and flexible design. This allows it to adapt to the shape of tissues and organs.

    The wireless power supply device is composed of a magnesium coil, which charges the device when an external transmitting coil is placed on the skin above the implant. The power received by the magnesium coil then passes through a circuit before entering an energy storage module comprised of zinc-ion hybrid supercapacitors. Unlike batteries that store power as chemical energy, supercapacitors store power as electrical energy.

    Although supercapacitors store less energy per unit, they possess high power density, enabling them to consistently discharge a significant amount of energy.

    The prototype power supply system, enclosed in a flexible biodegradable chip-like implant, combines energy harvesting and storage into a single device. Power can flow through the circuit directly into an attached bioelectronic device and into the supercapacitor where it is stored to ensure a constant, reliable power output once charging is complete.

    Both zinc and magnesium are essential to the human body, and the amounts contained in the device are below daily intake levels, ensuring the biocompatibility of the dissolvable implants. The entire device is encapsulated in polymer and wax, allowing it to bend and twist according to the structure of the tissue it is placed in.

    Tests on rats indicated that the device can operate effectively for up to 10 days and fully dissolve within two months. The device’s operation duration can be modified by adjusting the thickness and chemistry of the encapsulation layer.

    The researchers also demonstrated the power supply’s functionality by connecting stacked supercapacitors with a receiving coil and a biodegradable drug delivery device, and implanting it into rats. The drug delivery device, containing an anti-inflammatory medicine, was implanted into rats with yeast-induced fever. During a 12-hour monitoring period, the temperatures of the group without implants were significantly higher than those with the implant.

    The researchers acknowledged the need to address the issue of controlling the device’s on and off duration through controlled triggering of charging. Nevertheless, they affirmed that the prototype represents an important step forward in advancing a broad range of transient implantable bioelectronic devices by providing effective and reliable energy solutions.