Promising patch for blood pressure monitoring

KAUST bioengineers have developed a flexible optoelectronic patch, or ePatch, that is worn on a patient’s skin and can continuously monitor blood pressure without the need for compressible cuffs or wired devices ^[1].

Continuous blood pressure monitoring could offer significant benefits across multiple health conditions, helping both patients and medical professionals. Deterioration in conditions such as cardiovascular disease and diabetes could be caught and treated more quickly if there were a comfortable, real-time method of monitoring blood pressure throughout patients’ daily lives.

“Wearable electronics enable 24/7 monitoring and deliver comprehensive data for health analysis without patients needing to attend multiple medical appointments,” says Yizhou Zhong, who worked on the project under the supervision of KAUST’s Sahika Inal as part of an international team from KAUST that included scientists from the United Kingdom, United States, and Spain.

The thin-film patch integrates multiple components to provide accurate blood pressure readings. Its robust polymer substrate houses various functional elements, including an organic electrochemical transistor, an organic photodiode, LEDs, and biosensor electrodes.

“Our breakthrough moment was achieving simultaneous measurement of two critical types of physiological information in a combined hybrid signal,” says Zhong.

Existing blood pressure monitoring relies on electrocardiography (ECG), which measures heart rhythm and rate. At the same time, blood volume changes in microvascular tissues are determined using photoplethysmography (PPG), which involves shining light into the skin and measuring the amount of light transmitted or reflected back. This enables calculation of blood transit time from the aortic valve to peripheral sites. The new ePatch integrates these two signals into a single hybrid signal, known as an electrocardio-photoplethysmogram (EC-PPG).

“The transistor collects signals from both the PPG-recording photodiodes and the ECG electrodes, combines them, and then amplifies the output so that we can resolve the signals properly. This is unique to our design,” says Zhong. “The EC-PPG data is then analyzed externally via a deep learning model to estimate blood pressure.”

“This is a tool with very exciting potential,” adds Inal. “Our approach enables continuous monitoring at 10-second intervals and outperforms existing dual-signal approaches. Separately, biosensor electrodes in the ePatch also measure sweat ion and glucose concentrations — vital signs unrelated to blood pressure but useful metrics in cardiovascular health assessment.”

The ePatch also reduces hardware expenses, and computational demands are low because the deep learning models are trained on a single hybrid signal. However, the manufacturing process is currently time-consuming, so the researchers need to optimize it before the patch can be mass-produced.

The team is planning several ePatch improvements as it moves into prototype trials. Further miniaturization and encapsulation will enhance user comfort and durability, while integrating a compact, efficient power source will support long-term, self-powered operation.

“We also hope to incorporate a reliable wireless communication interface that will improve real-time data transmission and offer consistent remote monitoring capabilities,” concludes Zhong.

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