Implantable and ingestible (edible) electronic devices that stay inside your body pose unique engineering challenges. These should not only use the best processor but also be minimal in size, biocompatible, safe and extremely reliable. Reliability is all the more important as it often turns out to be a case of life or death!
Despite so many risks and challenges, it is awesome to see how implants have developed since the days of the first pacemaker in 1958. From cardiac pacemakers to cochlear implants, from brain interfaces to retinal implants, there are numerous implantable medical electronic devices available today. Even more exciting is the emerging field of edibles—tiny, capsule-sized electronic devices that are consumed orally for diagnosis and treatment of diseases. Some edibles are designed to remain inside the body for some time, while others do their job and get disposed of within minutes.
Today, we have reached a state where inventions like these no longer surprise us because our minds have become tuned to a sci-fi future, and we have started expecting such developments. So let us put aside the wow-factor, and instead look at the current and future state of implants and edibles.
Painless diabetes testing, drug delivery and more
With improvements in quality and reliability, there is now a reasonably good demand for cochlear, retinal and cardiovascular implants. Cardiovascular implants have evolved much in recent years, and have overcome past constraints regarding compatibility with imaging systems such as magnetic resonance imaging (MRI). Interestingly, the rise in lifestyle diseases like diabetes has also led to an increased demand for implantable devices like implantable continuous glucose monitoring and implantable infusion pumps. There are also implantable devices for phrenic nerve stimulation to restore breathing function in patients, and sacral nerve stimulation for patients with bladder disorders. Implantable neuro-stimulators, on the other hand, help those with neurological disorders like Parkinson’s disease.
With the availability of better biocompatible materials that minimise the possibility of infections, there is greater faith in implants. Researchers at the Graeme Clark Institute have developed an implant that is fitted under the scalp to diagnose and treat epilepsy, and even forecast a likely seizure. They are also developing an implantable drug pump for patients with drug-resistant epilepsy.
Cochlear implants are used when hearing aids don’t work well—that is, when the patient has severe sensorineural hearing loss due to absent or reduced cochlear hair cell function. The implant basically carries out the function of the cochlea or inner ear, stimulating the auditory nerve directly.
Retinal implants are giving vision to the impaired around the world. Going one step further, the Monash Vision Group is developing Gennaris—a bionic vision system that bypasses damage to the eye and optic nerve to restore functional vision for people who have injured both these or lost sight due to glaucoma and acquired retinal disease. This system interfaces directly with the brain, bypassing the retina and optic nerve.
Elsewhere, researchers are also exploring biocompatible, implantable photonic devices that can improve health monitoring, diagnostics and light-activated therapies. Consider the possibility of biocompatible and wirelessly-powered light-emitting diodes (LEDs) and miniature lasers implanted inside the body. Advances in biotechnology, such as optogenetics, will enable these photonic implants to be integrated tightly with neurological or physiological circuits.
A good interface between implanted devices and the brain can help in great ways—for example, it can return motor function to amputees and people paralysed due to stroke or spinal cord injury. A minimally invasive electrode called the Stentrode developed at the University of Melbourne might be a step in this direction. Implanted into a blood vessel adjoining the area of the brain that controls movement, it may help control an exoskeleton, enabling crippled or paralysed people to move. The implant can apparently be installed without opening the skull, which is what makes it attractive!
Neuralink, a company funded by Elon Musk, is also working on implantable brain-computer interfaces. They are developing syringe-injectable, flexible, sub-micron-thickness substrates that can be used in implantable electronics. The substrate is soft enough to sit harmlessly in the brain, and has electrical properties that enable only the targeted part of the brain to receive the electrical stimulus.
Brain-computer interface is the future of implantable systems. It can help people with degenerative brain diseases and neurological disorders. However, it must be handled with care because an electrode implanted in the brain can be used both for good and bad purposes!
Rise of edibles for diagnostics and drug delivery
When the electronic device needs to stay inside the body forever or for a reasonably long time, it is worth operating on a patient to implant the device. However, if you just want it to stay inside for a few minutes, hours or even days, for the purpose of monitoring a health condition or temporarily dispensing some medicines, operating on the patient doesn’t make sense. This requirement led to the development of ingestible or edible electronics, which industry-watchers expect to create huge waves like wearables did.
