Wear it well

While wearable textile products have been around for at least ten years, Markus Strecker, ceo and founder of garment producer Teiimo, pointed out that a US patent was filed in 1942 for a jacket with integrated telephone and antenna. Teiimo applied the same techniques with its MP3 Infineon jacket, which had earphones and microphone designed into the jacket along with a keypad incorporated in the fabric, and a hermetically encapsulated audio module, all powered by a removable battery and multimedia card. Other jackets followed from other manufacturers, including Motorola, Philips/Levi and O’Neill, with its fully washable Hub, incorporating a textile keypad, cable harness, and integrated microphone and docking station. More recently, clothing incorporating LED lights and heating elements have been introduced.

As Strecker emphasised, with the most recent developments ‘we know where you are, and much more’, achieved through the advances in microelectromechanical sensors (MEMS), including accelerometers, gyroscopes and magnetometers; optical sensors and actuators, epaper and touch screens; flexible and stretchable circuits, and new interconnects and textile components; although washability remains a challenge.

Aksell Reho, ceo of Clothing +, outlined his vision of making sensors and electronics ‘disappear’ into textiles. ‘Wearable should be things we are already wearing... but we need new technology to overcome the problems offered by existing electronics. Clothing doesn’t have much of a history of innovation despite being a massive and long term industry.’ He also doesn’t see clothing disappearing in the future!

Sensing-Tex, for example, has developed a range of pressure sensitive textiles, which can act like a stretchable second skin, with high resolution spatial and sensing capabilities, as well as proximity capacitive sensors and illuminating LED textiles and thin film and stretchable optical fibre fabrics. As Miguel Ridao,  at Sensing-Tex demonstrated, these technologies can be used for a wide range of applications, for example, from personal lighting solutions for cycling clothing to doormats in building entrances, recording both ingress and exit.

Keith McMillen, ceo of BeBop, described the development in collaboration with Eeonyx of multilayer printed fabric sensors that can be used, for example, as skull caps to monitor head impacts or pressure mats for baseball.

Apart from personal sports and health monitoring, wearables are also making inroads into traditional pharma and medical care as part of digital health. According to Dirk Schapeler, director, digital health, at Bayer, $3bn of funding is going into digital health in the US, with a CAGR of 23%, resulting in funding climbing to an estimated $6.5bn by 2017. Globally, he says that this research by Accenture also shows that there are around 5000 start-up companies involved in the sector.

Schapeler believes this digitisation of the healthcare industry will produce new types of services and products, as well as disruptive business models, as the customer base will change with the growth of the ‘informed patient’, bringing threats to some companies and opportunities for others.

As he pointed out, if a Jawbone sleep tracker can detect the epicentre of an earthquake in California, through its data pooling, then pharmaceutical companies need to look at how to leverage this disruption through the adoption of digital health.

In the textile sensor area, Reho pointed out that his company Clothing + began with what it claims was the first heart rate monitor in the form of a strap in 2002, but has more recently been working on sensor vests with Phillips to monitor water accumulation in the lungs and predict the need for hospitalisation. The company has also developed shorts with EMG sensors to show the muscle load in the legs of the wearer.

True mobile health, or wearable mHealth, is becoming a reality, according to Guilherme de Palma, ceo and founder of Pancreum, who pointed out that remote monitoring after a patient has left hospital, for example, can avoid re-hospitalisation, lowering the cost of medical care, both private and public. ‘This is achievable with low-power wearable devices, attached to sensors, connected to a mobile device via Bluetooth Smart, the internet and the care provider,’ he added.

One potential hurdle for pharma wearables could be the US Food & Drug Administration’s wearable guidance that distinguishes between wearable medical devices and ‘general wellness’ devices. The latter are considered low risk products, and defined as maintaining or encouraging a general state of health – or claim to reduce the impact of certain chronic diseases or conditions.

For medical applications, although the benefits of building data in the form of unified electronic health records, the regulatory environment may restrict the medical and pharmaceutical developers in their selection of technology partners developing the devices. Partnerships are being formed, for example, between Novartis and Qualcomm to use wearable technology in clinical trials, while GSK is working with clinical trial designer Medidata on a cloud-based trial data tool.

The Scripps Translational Science Institute is working in a consortium with four partners to develop the use of wearable, wireless health sensors to offer what it describes as a ‘precision medicine’ approach designed to improve the health outcomes for Ebola patients, increase the safety of health workers and reduce the risk of further spread of the virus. Funded by the US Agency for International Development, the Sensor Technology and Analytics to Monitor, Predict and Protect Ebola Patients project (STAMP2) also involves a wireless vital signs monitor developer, Sotera Wireless; a sensor developer, Rhythm Diagnostics Systems, and personalised predictive analytics technology specialist PhysIQ.

Battery life is a key issue, particularly if the battery is incorporated into the device, and extremely important if a wearable device is to be used to monitor patients in a clinical trial. While the devices developed by Jawbone and Fitbit, for example, require recharging on a weekly basis, Garmin’s vivofit lasts for up to 12 months without recharging. Medidata has collaborated with Garmin to offer its clients the use of these activity trackers for clinical research projects as a way to overcome compliance issues and ensure participants wear the device 24/7 thereby providing continuous data collection.

Flexibility is the key to garment design but a major stumbling block as far as electrical circuits are concerned, and that is apart from washability and general water resistance. Michael Burrows, business development manager at Microcircuit Materials, part of DuPont, says the company has introduced a new range of printable conductive inks to connect sensors to a central control device in ‘digitally enhanced clothing’ that can be washed up to 100 times, while still delivering stable performance.

The issue of supplying power for wearables was addressed by Christian Dalsgaard, founder of Ohmatex. In addition to developing sensor technology for measuring muscle activity for the astronauts of the European Space Agency, Ohmatex is also working on connectors suitable for integration into textiles but also power textiles through Powerweave, an EU-funded FP7 project  bringing together academic organisations such as Brunel University in London, UK, with industrial concerns like Ohmatex and Peerless Plastics & Coatings.

The power textile fibres under development are based on a conductive core, surrounded by an electrode material, an electrolyte layer, another electrode and a current collector, all in a protective jacket. The same approach can also be used to produce photovoltaic fibres as well as ‘supercapacitors’, Dalsgaard explains. These fibres can be woven into textiles, offering the potential to both produce and store electric power.

Another approach to power harvesting is to use the human body to provide the power, either thermally or mechanically through movement, something under development through the US ASSIST programme, which is a consortium of US universities, including Florida International, North Carolina State, Michigan and PennState. The research focuses on nanocomposites, such as (Bi,Sb)₂(Se,Te)₃, with improved thermoelectric performance, and using piezoelectrics to harvest mechanical energy.

Batteries that can be printed and manufactured roll-to-roll also offer a thin and flexible option, according to Matt Ream, vp, marketing, at Blue Spark Technologies. His company has developed 1.5V/cell carbon-zing MnO₂ base chemistry for the production of thin recyclable batteries with capacities ranging from 4 to 80mAh that can be customised in terms of voltage, shape, width and length and do not contain and metal parts of packaging.

Meanwhile, German major Bayer has developed a new polycarbonate/polyester blend, Makroblend M525, specifically for wearable devices, offering a high level of chemical resistance against body lotions and other chemicals while meeting the testing requirements for biocompatibility. The new blend is said to exhibit good toughness, mouldability and dimensional stability, and can be colour-matched to meet design criteria.

Researchers at Kansai University and chemical major Teijin in Japan have developed the world’s first polylactic acid (PLA) – and carbon-fibre-based piezoelectric fabrics.

The fabrics comprise a piezoelectric poly-L-lactic acid (PLLA) and carbon fibre electrode. Plain, twill and satin weave versions were produced for different applications: plain weave detects bending, satin weave detects twisting, and twill weave detects shear and three-dimensional motion, as well as bending and twisting.

The sensing function, which can detect arbitrary displacement or directional changes, incorporates Teijin’s weaving and knitting technologies. The function allows fabric to be applied to the actuator or sensor to detect complicated, even three-dimensional, movements.

Meanwhile, Kansai University and Teijin are continuing to working on ideal weaves and knits for fabric applications that enable elaborate human actions to be monitored simply via clothing. Applications are expected in areas from elderly care to surgery, artisanal techniques to space exploration, and many others.