Medical Devices
5 min read
By BioBuilt Editorial
For most of medical history, healthcare has been reactive. Patients develop symptoms, schedule an appointment, undergo testing, and receive treatment. In many cases, valuable physiological changes have already been occurring long before the first symptom appears.
Biomedical engineers are working to change that paradigm.
Through the development of wearable biosensors—devices capable of continuously measuring biological signals from the human body—researchers hope to shift medicine from occasional snapshots of health toward continuous monitoring. Instead of asking what your body looks like during a yearly physical, wearable technologies aim to reveal how it changes every minute of every day.
More Than a Fitness Tracker
Modern smartwatches can already measure heart rate, estimate sleep quality, and even alert users to irregular heart rhythms. While these consumer devices have introduced millions of people to wearable health technology, they represent only a fraction of what biomedical engineers envision.
Researchers are designing flexible sensors capable of analyzing chemical biomarkers found in sweat, tears, saliva, and interstitial fluid—the liquid surrounding the body's cells. These biomarkers may provide information about hydration, metabolism, inflammation, stress, and disease progression without requiring a blood draw.
The ultimate goal isn't simply collecting more health data. It's collecting information continuously, allowing physicians to observe trends that might otherwise go unnoticed.
Why Continuous Monitoring Matters
Imagine checking your heart rate only once every six months.
That single measurement would reveal almost nothing about how your cardiovascular system functions throughout daily life. The same principle applies to many other aspects of human physiology. Blood sugar, hormones, temperature, and numerous biochemical markers fluctuate throughout the day in response to exercise, sleep, nutrition, stress, and illness.
Continuous monitoring provides context that isolated measurements cannot.
As researchers explain in Nature Reviews Materials, wearable devices can enable "high-resolution and time-resolved historical recording of the health status of an individual," potentially allowing clinicians to detect disease progression earlier than traditional approaches.
Rather than reacting after symptoms become severe, physicians may eventually identify subtle physiological changes before patients realize anything is wrong.
Engineering Around the Human Body
Building a wearable biosensor is far more difficult than attaching electronics to the skin.
Human skin stretches, bends, perspires, and constantly sheds cells. A successful sensor must remain comfortable enough to wear for days while maintaining reliable contact with the body. It must consume little power, withstand moisture, and collect accurate measurements despite movement during everyday activities.
Perhaps the greatest scientific challenge, however, lies in interpreting the data.
Many wearable devices analyze sweat because it can be collected noninvasively. Yet researchers caution that the concentration of molecules in sweat does not always mirror their concentration in blood. Understanding these relationships—and determining which biomarkers provide clinically useful information—remains an active area of biomedical engineering research.
As Kim and colleagues note, "a better understanding of the correlations between analyte concentrations in the blood and noninvasive biofluids is needed to improve reliability."
The Future of Personalized Medicine
Wearable biosensors are becoming increasingly sophisticated as advances in materials science, electronics, artificial intelligence, and biomedical engineering converge.
Flexible electronics can conform to the body's surface. Machine-learning algorithms can identify patterns in massive streams of physiological data. Microfluidic systems can precisely collect tiny volumes of sweat or interstitial fluid for analysis.
Together, these technologies could make healthcare more personalized than ever before.
Instead of comparing every patient against population averages, physicians may one day monitor how each individual's biology changes over time, detecting deviations from that person's own healthy baseline.
Looking Ahead
Wearable biosensors are unlikely to replace physicians or laboratory diagnostics anytime soon. Many technologies remain under development, and researchers continue to study their long-term accuracy, reliability, and clinical usefulness.
Yet the direction of the field is becoming increasingly clear.
Healthcare is moving beyond isolated measurements toward continuous observation. The next major advance in medicine may not come from a larger machine inside a hospital—it may come from a nearly invisible device worn on the wrist, embedded in clothing, or adhered to the skin.
For biomedical engineers, the challenge is no longer simply building better sensors. It is learning how to transform an uninterrupted stream of biological information into earlier diagnoses, more personalized treatments, and healthier lives.
References
Kim J., Campbell A. S., Esteban-Fernández de Ávila B., Wang J. Wearable Biosensors for Healthcare Monitoring. Nature Biotechnology (2019).
Ates H. C. et al. End-to-End Design of Wearable Sensors. Nature Reviews Materials (2022).