A flexible optoelectronic patch, or ePatch, that is worn on a patient’s skin can continuously monitor blood pressure without the need for compressible cuffs or wired devices. 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.
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 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.
