Researchers at the Technion – Israel Institute of Technology have developed a miniature sensor that could enable continuous blood pressure monitoring without an inflatable cuff. The experimental technology combines light-based sensing, ultrasound and computational modelling to track changes in arterial diameter. The research represents another step towards wearable devices capable of measuring blood pressure during everyday activities. However, further validation is needed before the technology can be considered suitable for routine clinical use.
Blood pressure is an important indicator of cardiovascular health, particularly for people with hypertension and other cardiovascular conditions. Conventional measurements generally rely on inflatable cuffs, providing readings at specific moments rather than a continuous picture of blood pressure fluctuations.
Wearable technologies are increasingly being investigated as alternatives. Their potential advantage lies in capturing changes throughout the day, including during activities that are not normally monitored in clinical settings. Researchers Amir Rosenthal and Daniel Lange, together with doctoral student Gil Gelbert, have developed a miniature sensing system designed to address some of the technical limitations of existing cuffless approaches.
Measuring arterial changes with light
The new technology combines silicon photonics with optoacoustic sensing. Short pulses of light generate ultrasound waves within an artery, allowing a miniature sensor called SPADE to detect changes in its dimensions. Unlike approaches that measure only relative changes in arterial behaviour, SPADE is designed to determine both the absolute diameter of an artery and the small variations that occur with each heartbeat. These measurements provide information that can be used to reconstruct the arterial pressure waveform and estimate blood pressure continuously.
The researchers combine the sensor measurements with AI-based modelling of arterial behaviour to calculate blood pressure. A key feature is that the system uses a single sensing component rather than multiple sensors positioned at different locations. According to the researchers, it is also relatively tolerant of variations in sensor position and angle. This could simplify integration into wearable devices, where maintaining precise sensor placement during daily activities presents a technical challenge.
Proof-of-concept testing
In initial experiments involving volunteers, the system captured characteristics of arterial pressure waveforms at a sampling rate of 100 measurements per second. The researchers report promising results from these proof-of-concept tests, demonstrating the feasibility of monitoring arterial changes using a miniature optoacoustic sensor. However, measuring arterial dimensions and estimating blood pressure are not equivalent to demonstrating reliable clinical performance across different patient populations.
The technology still requires further evaluation to establish its accuracy under varying physiological conditions and during prolonged everyday use. The researchers envisage applications in smartwatches, medical patches and other wearable devices. These remain potential future uses rather than established clinical applications.
Cuffless monitoring
The Technion research is part of a wider effort to develop continuous blood pressure monitoring technologies that do not rely on inflatable cuffs. Earlier this year, researchers from the University of Utah and the University of Illinois Chicago presented another approach. Their experimental smartwatch uses bioimpedance measurements, which detect changes in the electrical properties of blood and surrounding tissues, combined with physics-informed AI.
Unlike the Technion sensor, which uses light-generated ultrasound to measure arterial dimensions, the American system analyses electrical signals associated with blood flow. Both approaches aim to reconstruct continuous blood pressure waveforms rather than provide only intermittent systolic and diastolic readings The American researchers tested their technology in approximately 150 individuals, including intensive care patients and outpatients. They also reported that their system does not require individual user calibration.
Clinical validation remains essential
Continuous blood pressure monitoring could provide additional information about cardiovascular changes during physical activity, rest and everyday life. For patients with hypertension or cardiovascular disease, such measurements may eventually complement conventional monitoring.
However, the development of cuffless devices presents important challenges. Sensor accuracy must be established across different blood pressure ranges, patient populations and conditions of use. Researchers must also determine whether continuous measurements provide clinically useful information beyond existing monitoring methods. For clinical adoption, the decisive question will be whether these technologies can provide sufficiently accurate, reliable and interpretable measurements during routine use.
References
Nature Communications (Research)
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