In a paper published in June 2021, researchers at Imperial College London explored the future of wearable technology. The wearable technology industry is rapidly expanding. The most obvious example is the growth of Apple Watch. It was first launched in 2015 and sold 31 million in 2019 alone, 10 million more than the entire Swiss watch industry. Globally, the wearable technology market is valued at US$32.63 billion in 2019 and is expected to grow at an annual growth rate of 15.9% by 2027.
With the advent of fitness monitors such as Fitbit and smartphone apps, wearable health monitors have become mainstream, driven by low-cost microelectromechanical systems (MEMS) and optical sensors.
So far, wearable devices are mainly used to measure heart activity or breathing patterns. The Holter monitor is an example of a wearable device widely used in the healthcare field. Dating back to the 1960s, it measures the electrical activity of the heart, called an electrocardiogram (ECG), which takes longer than a traditional resting electrocardiogram (usually only a few heartbeats are collected for analysis).
Wearable sensors for animals
In addition to human applications, wearable devices have great potential in both animal husbandry and domestic pets. In the animal husbandry industry, the lack of the ability to distinguish between diseased animals and healthy animals has led to the use or culling of a large number of antibiotics, leading to antibiotic resistance and economic problems, respectively. High-intensity farming has also led to the spread of many animal-borne pathogens to humans, such as highly pathogenic avian influenza (avian influenza), which may also be related to the COVID-19 pandemic.
Wearable devices in healthcare
A good example of how wearable devices are currently improving healthcare is the treatment of diabetes. Continuous monitoring of blood glucose is required to keep the level within a safe range. The conventional method Imperial College London reports that the conventional method requires a "fingertip test" to obtain a blood sample for analysis, called self-blood glucose monitoring (SMBG).
COVID-19 and infectious diseases
Another important potential use of wearable technology is when the patient has an infectious disease and does not want direct contact with medical staff. In this case, the basic health surrogate indicators provided by wearable devices may be useful to clinicians. This becomes even more important during the COVID-19 pandemic. An example of how health care providers can use wearable devices during a pandemic is the use of wireless pulse oximeters to detect the early deterioration of COVID-19 patients. 28 The patient is able to stay at home, monitored by the oximeter, which informs the healthcare provider that the patient needs to be hospitalized.
Next-generation wearable devices
At Imperial College London, many new ways to make chemical and biochemical wearables reach their full potential are currently being studied. One example includes the use of biochemical engineering and optical output to design simple medical devices that can diagnose and monitor medical conditions.
Wireless auscultation for dogs
Researchers at Imperial College London have developed a stretchable wearable device made of polymer composite materials that can be used for wireless auscultation of dogs. The wearable sensor adopts the shape of the human body to remove air bubbles in the fur to improve signal conduction on the contact surface, thereby recording heart sounds.
Wearable chemical and biochemical devices
By utilizing microfluidic channels these patches non-invasively sample minute volumes of sweat released from the skin. Passing analytes over sensing components probes allows for real time readout of biomarkers such as electrolytes.
Microneedles penetrate the outer layer of skin to gain access to the interstitial fluid. This minimally invasive technique allows for more in-depth analysis of the body homeostasis. Microneedles act as electrodes for simple electrochemical analysis of biomarker concentrations. These patches are worn in a similar way to a plaster and leave little imprint upon removal making them ideal for point-of-care analysis.
An illustration of how smart tattoo technology works. In this example, the tattoo is able to change color depending on the concentration of glucose within the blood. (Illustration courtesy of: Imperial College London)
An interesting technique to monitor analytes is smart tattoos. In normal tattoos, the ink is in contact with analyte solution under the skin. By including pigments that are sensitive to changes in biomarkers (such as pH, glucose, ions and enzymes), the tattoo responds to changes in biomarkers by changing color.
What are the main barriers to progress?
As the internet of things becomes more widespread, the public are becoming more conscious of how much of their life is quantified in data, and may feel uncomfortable with sharing large quantities of personal data collected by wearable devices. This issue is also compounded by the suspicion users have about where their data is going. For wearable sensors to reach their full potential, protecting user information is paramount.
An Imperial College London led startup Spyras spun out of the Güder Research Group at Imperial College London. It has developed a technology that analyses breathing patterns using sensors integrated into disposable facemasks. Respiration rate is one of the four vital signs of health, however, it is generally not measured using high-precision instruments. Spyras measures patterns of breathing, and breath biochemistry, which can play an important role in the early detection and monitoring of diseases and inform treatments.38,39 Real-time respiratory monitoring is also expected to play a growing role in the wellness segment in sport, meditation, and sleep.
Flow Bio – Imperial expertise in industry
The flowPATCH is a wearable, non-invasive patch that captures an athlete’s sweat and interprets key bio-markers in real-time, starting with electrolytes and total body fluid loss. This system provides users with personalized recommendations that allows them to improve their performance. Ali Yetisen, from the Department of Chemical Engineering, is the Science Advisor to Flow Bio, the company that developed the flowPATCH.