An ongoing research in the field of medicine pertains to transient electronics, basically electrically-powered implants that dissolve inside the patient’s body once their job is done. Despite their many advantages, such devices run on power from external sources, thus limiting the range of their applications. In an attempt to overcome this drawback, a team of scientists is developing advanced biodegradable generators that produce energy using the same technique that results in static electricity.
At present, medical implants are used to treat (or manage) a variety of health problems, from impaired heart function to brain damage. Implantable devices, like pacemakers, help normalized heart rate in arrythmia patients, while specialized brain sensors look for potentially fatal swellings in people with traumatic injuries. Most of these contraptions are powered electrically, which means that they have to be surgically removed once they run out of power.
If left inside the patient’s body, the implants might eventually become sites of dangerous infection. Surgical removal of these devices often leads to other complications, especially in people with impaired health. Although still in the early stages of development, transient electronics are considered to be much better alternatives. These implantable contraptions, according to scientists, are programmed to dissolve naturally when no longer required, thus eliminating the need for surgery.
Like conventional implantable electronic devices, the transient varieties are driven by energy from external sources. As part of a new research, scientists have built an innovative biodegradable generator that can power medical implants via the process of triboelectricity. One of the most common causes of static electricity, the phenomenon produces electrical charge as a result of friction between two non-conductive materials.
When two objects are rubbed or pressed against each other repeatedly, there is usually an exchange of electrons between the two surfaces. Instances of triboelectricity include the build-up of electric charge when a comb is run through one’s hair, or when a glass is rubbed with fur. For the research, recently published in the Science Advances journal, the scientists used commonly-available, biodegradable polymers, like PCL and PLGA, to construct the generator.
According to the researchers, the device features two layers of varying thickness. Of the two, one is a thin, uniformly-flat film, while the other is a thicker layer covered with 300 nanometer-high rods. Separating the two layers are specially-designed sheets of biodegradable polymer, which in turn generate electricity when rubbed against each other. During lab testing, the team was able to produce around 32.6 milliwatts of power per square meter of the nanogenerator. Speaking about the study, Zhong Lin Wang of the Beijing Institute of Nanoenergy and Nanosystems said:
Our results open the gate to fully degradable electronic devices. A whole device can be absorbed in body and would not need to be removed through additional surgery.
As the team points out, the self-dissolving generator could easily power a neuron-stimulation implant, whose role is to control neuron growth. The scientists can program each of these devices to be functional for anywhere between a few hours to several years. At present, the team is working to develop a new technology that could harness the mechanical energy associated with respiration and heartbeats. Wang added:
We provide a potential power source by reclaiming biomechanical energy from the human body.
Via: IEEE Spectrum