Following this pioneering work, sensor integration is now shifting towards the combination of different sensor modalities. The importance of integrating multiple sensors on a single device has been demonstrated 16, where multiple chemical sensors were integrated into a single wrist band. Monitoring of single physical parameters, such as the electrocardiogram 5, 6, 7 and blood pressure (BP) 8, 9, 10, as well as biochemical parameters, such as glucose 11, 12, 13, 14, 15, using non-invasive wearable sensors has been reported. Wearable sensors can generate data continuously without causing any discomfort 1, 2 or interruptions to daily activity, thus enhancing the self-monitoring compliance of the wearer and improving the quality of patient care 2, 3, 4. Intertwined with concepts of telehealth, the internet of medical things, and precision medicine, wearable sensors offer features to actively and remotely monitor physiological parameters. Continuous and simultaneous acoustic and electrochemical sensing via integrated wearable devices should enrich the understanding of the body’s response to daily activities, and could facilitate the early prediction of abnormal physiological changes. In human volunteers, the device captured physiological effects of food intake and exercise, in particular the production of glucose after food digestion, the consumption of glucose via glycolysis, and increases in blood pressure and heart rate compensating for oxygen depletion and lactate generation.
We optimized the integrated device so that it provides mechanical resiliency and flexibility while conforming to curved skin surfaces, and to ensure reliable sensing of glucose in interstitial fluid and of lactate, caffeine and alcohol in sweat, without crosstalk between the individual sensors. Here we describe a non-invasive skin-worn device for the simultaneous monitoring of blood pressure and heart rate via ultrasonic transducers and of multiple biomarkers via electrochemical sensors.
Monitoring the effects of daily activities on the physiological responses of the body calls for wearable devices that can simultaneously track metabolic and haemodynamic parameters.