New Generation of Wearable Sensors to Perform Biochemical Analysis of Body Fluids

Wearable devices are already capable of monitoring vital body functions, such as pulse with a smartwatch or blood pressure with a smartphone app. While these sensors can provide reliable real-time data and even be used in clinical diagnostics, biochemical analyses still require bodily fluid samples like blood and urine, which are sent to labs for testing. This process can be invasive, time-consuming, and expensive. However, the next generation of wearable sensors promises to extend beyond basic vital sign tracking to include biochemical analysis. In the future, these sensors could offer valuable health insights by analyzing body fluids such as sweat, breath, saliva, tears, and urine. While many of these advancements are not yet market-ready, they are entirely feasible.

Researchers at Collegium Helveticum (Zurich, Switzerland) and ETH Zurich (Zurich, Switzerland) joined their leading counterparts in the field of wearable sensors to conduct a comprehensive review that was recently published in the journal Nature. These sensors offer significant advantages: they enable continuous health monitoring without requiring visits to medical facilities. For elderly individuals suffering from heat stress, a wearable device could remind them to stay hydrated or alert them when their electrolyte levels become critical. Additionally, such sensors are either non-invasive or minimally invasive, providing a less distressing alternative for young patients. For example, taking blood samples or inserting a catheter into infants can be difficult, leading to delays and discomfort. A wearable sensor on the infant's skin or in their diaper could perform necessary tests, such as urine analysis, with greater ease. Similarly, face masks capable of detecting viruses, like SARS-CoV-2, without invasive nasal swabs would have been especially valuable during the pandemic.

The potential applications for these devices are diverse, including innovations such as dummy sensors to detect infant dehydration, tattoos that monitor blood sugar levels, and contact lenses that gather data from the wearer’s tears. However, the challenge is clear: the devices must be practical and comfortable enough for patients to wear regularly. Additionally, the clinical benefits of the data these devices collect must be carefully considered. Not all measurable data translates into useful clinical information. For instance, C-reactive protein (CRP) is a marker of inflammation, but a high CRP reading only provides useful insight if compared to previous values, helping to assess if a patient’s condition has improved or worsened.

The development of wearable sensors also faces several technical challenges, such as how long the devices can function continuously, how they should be cleaned and stored, their energy consumption, and most importantly, the reliability of the data they collect. Validating this data is crucial, as only trustworthy readings will lead to widespread acceptance in clinical settings. Furthermore, the data from these wearables must be processed, interpreted, and presented in a user-friendly way for both patients and healthcare providers. As artificial intelligence (AI) continues to advance, it will play an increasing role in data analysis, accelerating the development of these devices. Although significant progress has been made, the researchers acknowledge that much work remains in terms of research, development, and clinical applications. Once these new devices are thoroughly tested and validated, they could gain regulatory approval, offering substantial benefits to patients and healthcare providers alike.