In a paper published in June 2021, researchers at the Imperial College London have explored the future of wearable technologies. The wearable technology industry is expanding rapidly. The most obvious example is the growth of the Apple Watch. First launched in 2015, it sold 31 million units in 2019 alone, 10 million more than the entire Swiss watch industry. Globally, the wearable technology market was valued at $32.63bn in 2019, and is forecast to expand at an annual growth rate of 15.9% to 2027.
With the emergence of fitness monitors, such as Fitbit and smartphone apps, driven by low-cost microelectromechanical systems (MEMS) and optical sensors, wearable wellness monitors have become mainstream.
Up until now, wearable devices have predominantly been used to measure heart activity or patterns of respiration. One example of a widely used wearable device in healthcare is the Holter monitor. Dating back to the 1960s, it measures the electrical activity of the heart, termed an electrocardiogram (ECG), over a longer period of time than the traditional resting ECG that typically collects just a few beats for analysis.
Wearable sensors for animals
Apart from human applications, wearable devices have huge potential in both livestock farming and domestic pets. In animal farming, the lack of an ability to distinguish sick animals from healthy ones has led to mass antibiotic usage or culling, resulting in antimicrobial resistance and economic issues, respectively. High-intensity farming has also contributed to the spread of many pathogens of animal origin to humans, for example, the highly pathogenic avian influenza (bird flu), and may also be associated with the COVID-19 pandemic.
Wearables in healthcare
A good example of how wearable devices are currently improving medical care is with the treatment of diabetes. Constant monitoring of blood glucose is required to keep levels within a safe range. Conventional methods Conventional methods require a “finger stick test” to obtain a blood sample for analysis, known as self-monitoring of blood glucose (SMBG), reports Imperial College London.
COVID-19 and infectious diseases
Another important potential use for wearable technology is when a patient has an infectious disease and direct contact with healthcare workers is not desirable. In this scenario, rudimentary surrogate measures of health provided by wearables could be useful for the clinician. This has become much more relevant during the COVID-19 pandemic. One example of how wearables have been utilized by healthcare providers during the pandemic is the use of wireless pulse oximeters to detect early deterioration of COVID-19 patients.28 Patients are able to remain at home, monitored by the oximeter, which notifies healthcare providers should the patient require hospitalization.
The next generation of wearables
At Imperial College London, numerous new avenues to bring chemical and biochemical wearables to their full potential are currently being researched. One example includes employing biochemical engineering and optical outputs to design simple medical devices capable of diagnosing and monitoring medical conditions.
Wireless auscultation of dogs
Researchers at Imperial College London have developed a stretchable wearable device made of a polymer composite which can be used for wireless auscultation of dogs. The wearable sensor takes the shape of the body and removes air bubbles among the fur to improve the conduction of signals on the contact surface, allowing the recording of 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 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.