Natural Batteries: Energy Harvesting in MedTech

July 5, 2019

The only certain thing in electronics is that active devices need power; the rest is optional. There are several ways to provide power. For small devices, the most common currently is batteries, and they require changing or recharging. A not overly onerous task, although some may disagree, if it involves attaching a USB-C cable and plugging the other end into a power supply. But for the growing field of implantable medical devices such as pacemakers, battery replacement involves an invasive surgical procedure risking internal bleeding, inflammation and infection, all of which would be unnecessary if the promise of energy harvesting is realised.

A rarely considered possibility for energy harvesting in the body is using the flow of blood. The heart pumps five litres of the red stuff every minute.

Simon Sherrington, MD

Get in touch on 07917 541246 to discuss what we can do for your business.

There are a number of options to power medical devices through harvesting ambient energy sources in the human body such as heat, movement, or pressure. Various research studies that we describe later show that the power that can be gleaned from energy harvesting devices is in the nanowatt to microwatt range, which would be enough to power a device. An increasing number of studies and experiments seem to confirm that energy harvesting can be a solution to provide that needed power.

The solutions being chased down

One solution is piezoelectric energy harvesting. In simple terms piezoelectric energy harvesting converts mechanical stress – such as a finger pushing on a piezoelectric material – into a current that can then power a device. It has been proposed as a harvesting method for example in road surfaces, shoes, or as we will see in pacemakers. A multi-university group of South Korean researchers demonstrated its potential in a live pig. The team attached a flexible energy harvester to a pig’s heart. The harvester used the contraction and relaxation of the heart’s muscles to power a radio frequency device which transmitted a signal to an external device to turn a light bulb on and off. The team reported a harvested current of 1.75uA (with a voltage of 17.8V). Furthermore, the researchers said that their device showed high biocompatibility. The impressive results of this in vivo demonstration suggest potential applications as implanted heart monitors for those with heart disease.

At the University of Michigan a similar idea was investigated. The researchers simulated a device that harvests energy from the reverberations of heartbeats through the chest. The electricity so generated can then be used to power a pacemaker or defibrillator. In simulations the device was shown to produce 10mW of power, which is eight time more than that required to run a pacemaker.

A rarely considered possibility for energy harvesting in the body is using the flow of blood. The heart pumps five litres of the red stuff every minute. Scientists at Shanghai’s Fudan University in China have developed a novel method to harvest electricity from blood flow using a nano-device. The device, called a fibre-shaped fluidic nanogenerator (FFNG), is a thin carbon nanotube filament that is wound round a fibre core with a half micron diameter. It uses the flow of salt solutions through it to build a harvestable charge. The scientists claim that the power conversion efficiency of the device is high at 20% – which is significantly more than other miniature energy harvesting devices. The device also has characteristics making it suitable in this application: elasticity tunability, light weight, and one dimensionality. The team produced positive results of blood flow energy harvesting from frogs.

If harvesting energy through the methods above doesn’t achieve results it is possible to hook devices up to natural batteries in the body. These biological batteries are located in the ear and usually convert the mechanical activity of the eardrum vibrating into electrochemical signals to send sound information to the brain. To exploit this battery several US institutes – MIT, Massachusetts Eye and Ear Infirmary (MEEI) and Harvard-MIT Division of Health Sciences and Technology – designed a device to harvest its power. The researchers developed a low-power chip that could utilise some of the power from the ‘battery’. The resulting device was then attached by wires to a guinea pig’s ear-battery. The chip itself rested outside the body of the guinea pig, but the team said that it is small enough to nestle in the cavity in the middle of the ear. The team believes that with further miniaturisation of the device it could be used for implanted self-powering hearing aids.

The prognosis is good

There is much research being carried out in the field with some positive results. New devices face a complex process before they can be used in medical practice, but the need is there and once the devices show themselves capable it should not be long before they are approved and implanted into real patients.

[Image licensed to Ingram Image]

Other Tech Stuff

Disruptive media manipulation

Such are the capabilities of AI to help improve the traditional ways of creating manipulated media that there is the potential to disrupt sectors of commerce – as well as presenting a challenge to news organisations and publishers.

VR: Regulation and side effects

VR is still in its early days and its impact on human body and mind is yet to be thoroughly assessed. However, various sources point out that immersive reality and pharmaceutical products may have a thing in common – side effects.

Impact of VR on Healthcare

No universal therapeutic tool is possible because no two medical conditions are the same. For instance, simple 3D images are required for dementia sufferers whose fading memory struggles with the complexity of the real world, while advanced and engaging virtual worlds must be created to distract cancer patients from the painful procedures they have to endure. VR for young children is a whole different story where a fairy-tale, cartoon-like approach is vital.

In Pain? Don a VR Headset

In Pain? Don a VR HeadsetSoftware developers and medics around the world are working to prove that Virtual Reality (VR) powers stretch far beyond gaming and entertainment and have the potential to aid thousands suffering from cancer, anxiety, personality disorders,...

Joseph’s technocapable coat: energy harvesting for smart clothes

Smart clothes are where style and science meet, giving garments a whole host of innovative applications, such as charging depots for personal electronic gadgets, fitness trackers for capturing biometric data and colour-changing fashionable assets that go with everything.

Could AI help spot a fake Donald Trump?

spotting a photograph or video where part of the image has been manipulated. Such a challenge faces news organisations on a regular basis: sensitivity over “fake news” means responsible publishers are on heightened alert to potential manipulation.

Telecom Industry Slices 5G

Network slicing, a key feature of 5G, lets operators automatically create separate, virtual end-to-end networks over the same physical infrastructure.

Industrial Internet of Things Dangers

Today’s industrial technology settings have more interfaces than ever before, making industrial systems some of the most attractive targets for malware and ransomware attacks.

Electric Vehicles: Charging Infrastructure Policy Stifling Adoption

Financial incentives are available to encourage EV drivers with access to off-street parking to install home-charging units. Local councils have access to funding to install on-street EV chargers. The former has been successful, the latter has so far failed.

FarmTech: Application of Drones

Drones are eyes in the sky helping farmers gain insight into crop growth and about microclimates within individual fields …