Wear your health on your sleeve

Medical wearables push for innovation

By Catherine Bischofberger

New flexible and organic printing technologies are revolutionizing the medical wearable device market and the IEC is establishing the key relevant International Standards.

medical patch Smaller and more flexible medical patches are being produced thanks to printed electronics

The craze for wearables could be waning in the consumer market, according to some of the latest figures published in the trade press. A report published by US-based marketing consultancy eMarketer estimates that by 2020 only one in five US adults will use a wearable device on an ongoing basis. As the US is one of the biggest markets for wearables in the world, the report caused quite a flurry of concern when it was published in March 2017. One of the reasons for this rather lacklustre growth prospect is the disappointing take-up of Apple watches, according to the same press reports. They also blame a lack of new consumer-based applications.

In the world of healthcare, it is quite the opposite. New applications seem to be found on a daily basis, most of which relate directly to printed electronics. The technology enables the creation of numerous electronic devices and components using various printing methods. Among these, a host of wearable devices help medical staff keep track of their patients’ health. The most ubiquitous are self-monitoring devices for diabetes patients, one of the success stories of the printed electronics industry in recent years.

A host of new technologies are emerging which push the envelope even further. Looking towards the future, scientists envisage the arrival of self-powered devices created by using nanotechnology. The idea is for wearable sensors to be powered by body heat or movement and do away with chargeable batteries which are cumbersome and power hungry.

Body heat power

In the US, the centre for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), a state-funded university-based research hub, is working in such a field. The wearables its students are seeking to develop are expected to indicate levels of pollution and inform asthma sufferers of potential dangers. The aim is to prevent illness rather than cure it, which will be of a lesser cost to the taxpayer.

ASSIST has recently teamed up with a leading US start-up in the bio-integrated sensor market to develop an ultrathin flexible patch reader worn on the skin. The patch is expected to monitor oxygen levels in patients undergoing treatment for peripheral artery disease. The joint research project has recently been awarded a USD 1,5 million state-funded grant.

Sweat and (no) tears

Another US-based medical university has created a device that adheres to the skin and analyzes key biomarkers from the person’s sweat, enabling him or her to see whether something is medically amiss. It can detect cystic fibrosis, for example.

In other parts of the world, the wearable medical device market is predicted to go through the roof. According to the report Wearable Medical Devices published by Indian-based B2B research consultancy Markets and Markets, Asia is poised to be the fastest-growing region in the wearable medical device market from 2016 to 2021. The growth will be driven in part by technological breakthroughs in medical devices. The market is also expected to grow at a rapid pace in Europe, in line with the increase of chronic illnesses in an aging population, according to similar reports. Many of the leading companies in the wearable medical device market are based in Europe, some of the better-known in Switzerland and in the Netherlands.

Clever clothes

Researchers at the Holst Centre at Eindhoven University in the Netherlands, working with colleagues from Belgium’s Ghent campus, have been at the forefront of the European drive to develop the latest printed electronics technology for the wearable medical devices market. For instance, they have come up with a thin-film printing technology which enables the development of more complex medical wearables. These stretch and conform to the body but also integrate various types of sensor-based measurements in a smaller and therefore less intrusive body patch. The technology combines cheap organic and large area electronics (OLAE), already used for glucose diagnostic devices for example, with thin-film technologies such as thin-film metallization, which makes the layering of multiple electronic circuits possible.

Ultimately sensors will be integrated in our clothing. Automated production techniques will allow manufacturers to integrate electronics and sensors directly into the yarn during the production of smart textiles. In the future, the garment itself is expected to become the sensor. Other researchers, also based on the Eindhoven campus and in Ghent, together with imec, a Belgian innovation hub in nanoelectronics and digital technologies, have demonstrated one of the first stretchable and body-conformable thin-film transistor (TFT) driven LED displays to be laminated into textiles, paving the way for wearable displays in textiles to provide users with feedback.

Standards are key

As these new technologies prepare for mass production, the requirement for International Standards gets more pressing. The IEC has already paved the way in some of these new fields of research. IEC Technical Committee (TC) 47: Semiconductor devices, produces International Standards for the design, use and reuse of sensors as well as their testing and certification. Internet of things (IoT) and human body communication (HBC) are two of the new application areas the TC is involved with. The IEC 62951 series of International Standards, in particular, covers the field of flexible substrates and thin film. IEC 62951-1Semiconductor devices - Flexible and stretchable semiconductor devices - Part 1: Bending test method for conductive thin films on flexible substrates, was published in April 2017. Parts 2 to 6 of the series are currently under development.

Another all-important TC is IEC TC 62: Electrical equipment in medical practice, and its subcommittees, for instance IEC SC 62B: Diagnostic imaging equipment. The IEC 60601 family of International Standards provides the essential foundation for the work carried out in that area.

IEC TC 100: Audio, video and multimedia systems and equipment, and IEC TC 110: Electronic display devices, cover all areas related to display technology. Electronics related to printing technologies are standardized under the remit of IEC TC 119: Printed electronics. The IEC 62899 family of International Standards encompasses a huge raft of technologies, including the latest flexible substrates. One of the most recent TCs to have been set up is IEC TC 124: Wearable electronic devices and technologies. Its scope is to prepare International Standards for applications such as patchable, implantable, electronic textile and even edible materials and devices.

The wide-ranging and increasingly all-encompassing IoT is being standardized under the umbrella of IEC and the International Organization for Standardization (ISO) in a Subcommittee, ISO/IEC JTC 1/SC 41, of the Joint Technical Committee ISO/IEC JTC 1: Information Technology. Health and safety issues are crucial in anything that relates to medical applications and a number of TCs are involved in those areas, including IEC TC 108: Safety of electronic equipment within the field of audio/video, information technology and communication technology.

IECEE, the IEC System of Conformity Assessment Schemes for Electrotechnical Equipment and Components, which offers global testing and certification based on International Standards, is also doing essential work in providing medical equipment with the right safety, quality, efficiency and overall performance verification. 

IECQ, the IEC Quality Assessment System for Electronic Components, plays a major role in the testing and certification of the electronic components, notably sensors, that are essential parts of any wearable device.

Gallery
medical patch Smaller and more flexible medical patches are being produced thanks to printed electronics
wearable injector A wearable injector allows the patient to go about his/her normal routine while being administered the drugs he/she needs (Photo: Unilife)