Dr Chee: ‘Not only is better care equipment needed; it is really needed for older people who will be at home and unmonitored.’
A COLD silvery-white or grey lump of gooey metallic substance immediately brings mercury to mind.
Toxic and poisonous to the touch. Exposure to it can lead to severe health and neurological issues, including degrading motor skills, particularly in developing youngsters.
Gallium, on the other hand, looks identical to mercury, except you can hold it with bare skin without issue.
Gallium added with Indium becomes an alloy that promises a novel approach to wearables that use liquid metals (LM) inside them for purposes ranging from health monitoring to human-machine interactions, even remotely controlled ones.
Healthcare wearables in particular stand to benefit from a mass market introduction of products integrated with LM, and this is what research being done at Universiti Tunku Abdul Rahman (UTAR) is trying to achieve.
Not all wearables are created equally
Not all modern wearables are built the same.
Most conventional wearables are electronic gadgets that are inflexible and constructed in a rigid form as opposed to ‘conformer wearables’.
‘Conformer’ wearables cannot be powered through cables, so researchers at Utar designed an antenna pattern on a temporary tattoo using liquid metal which can harvest energy from WiFi signals and provide the information of a patient’s physiological change to an attached smart gadget.
A smartwatch, which can read one’s heart rate and track other physiological metrics, is not categorised as a ‘conformer’ wearable. Wearing it to sleep takes some getting used to, for instance.
“We want to solve this rigidness and improve patient experience and make it more suited to long-term wear,” says UTAR associate professor of mechatronics and biomedical engineering Dr Chee Pei Song.
“Conformer wearables are, for example, shirts and comfortable patches that you can wear and have it conform to your body.”
The need for better living quality is spurring demand for high-performance conformal healthcare devices, according to the research.
The manufacturing of efficient, comfortable and stretchable biomedical wearables also faces huge challenges using traditional materials.
Unlike mercury, gallium is a liquid metal that is safe to handle with your bare skin.
Liquid metals (LMs) show remarkable potential to solve this problem due to their extraordinary biocompatibility, stretchability, and thermal and electrical conductivity. In recent years, tremendous explorations have attempted to make stretchable biomedical devices with LM.
LM-based microfluidics demonstrate excellent performance in soft, flexible, and wearable electronics, soft robotics, and biomedical sensors among other applications.
It is the core of an emerging field of wearable products that Dr Chee has been studying in partnership with China’s Northwestern Polytechnic University, culminating in a joint research published on Feb 20 (2024) in the leading NPJ Flexible Electronics journal.
“LMs are good because used as sensors, they can easily show change in properties they are measuring,” he says, adding that it has the benefit of being able to be integrated into most materials and textiles that are used as wearables.
An example is a shirt coated in LMs will be able to measure heart activity, such as ECG signal, and other physiological signal in a patient’s body with greater accuracy and even ‘communicate’ to remote machines monitoring the patient.
Another key factor in the functional and sustainable use of wearables is powering the device.
“You cannot plug in cables to charge the device when wearing it,” Dr Chee says. “Our approach is to design an antenna pattern on a temporary tattoo using eutectic gallium–indium liquid metal.”
Essentially, this ‘tattoo’ can harvest energy from WiFi signals and provide the information of a patient’s physiological change to an attached smart gadget, he told Sunday Star.
The antenna will be able to communicate a patient’s status to various smart devices such as smartphones and tablets, which the patient, a caretaker, or a medical centre would monitor.
Dr Chee’s group developed an ‘electronic skin’, with electronic connections printed on a stretchable film, which is breathable and conforms to human skin.
“Our developed electronic skin includes a unique AI recognition function that could help to identify the type of heart disease of the wearer.”
This innovation won the Gold Award in the 35th International Invention, Innovation, Technology Competition and Exhibition (ITEX) 2024, held in May this year at the Kuala Lumpur Convention Centre.
Smart gloves built with LM too have the potential to assist the elderly and disabled patients in movement, increase their strength, and even help them perceive the world through sensors.
Dr Chee’s research found that LM could be key to bettering the artificial joints in such gloves made of textile material and human function augmenting.
Beyond healthcare, Dr Chee says that LM-based wearables would be useful in entertainment, virtual reality, and even manufacturing using soft robotics.
“We can use gallium with pliable rubber material that can give robotics more muscle-like movements compared to conventional servo-mechanisms,” he says.
Wearables taking hold
Wearables are gaining traction among Malaysians, particularly in the health and fitness space. A 2022 study by Universiti Teknologi Malaysia indicates that 65.5% of Malaysians surveyed tend to use them daily. The estimated number of wearable healthcare users in Malaysia touched 1.6 million at the end of 2022.
A 2023 study by UKM’s Graduate School of Business indicates that Malaysians “are more inclined towards wearable technologies than other South-East Asian residents”, adding that 65% of Malaysian consumers say they use wearable technologies for fitness and healthcare purposes.
The global market for wearable healthcare devices is also expected to reach US$16.2bil (RM75.7bil) in 2021 and US$30.1bil (RM140.6bil) by the end of 2026.
With Malaysia’s ageing population at 11.1% currently, and projected by the United Nations to officially become an ageing nation by 2030 when the percentage reaches 15%, there is a growing need for sustainable, lasting, and accurate healthcare wearables that are also easy to wear.
“Not only is better care equipment needed but it is needed for older people who will be at home and unmonitored,” Dr Chee says.
At the moment, unless produced at scale, wearables made with liquid metals are still more expensive, compared to carbon or silver-based ones but Dr Chee believes with further development, costs are expected to come down substantially for LM-based wearables.
