National University of Singapore researchers announce prototype of battery‑free skin patch for round‑the‑clock blood pressure tracking

SINGAPORE, June 15 — Researchers at the National University of Singapore (NUS) have built a prototype skin patch that can monitor blood pressure continuously without relying on a battery, a development that could reshape how hypertension and cardiovascular risks are tracked in daily life.

The Straits Times reported that the lightweight patch is designed to capture blood pressure changes throughout the day and night, eliminating the need for bulky cuffs or frequent recharging.

The system uses two sensors — one placed over the heart to detect electrical signals as blood is pumped out, and another on the wrist to measure changes in blood volume. By calculating the time it takes for blood to travel from the heart to the wrist, the device can infer blood pressure levels. Researchers say this timing, measured in milliseconds, is inversely related to blood pressure.

Lead researcher Selman Kurt from NUS’ Electrical and Computer Engineering department noted that blood pressure patterns during sleep and immediately upon waking are often missed by conventional monitors, even though these fluctuations can be strong indicators of stroke and cardiovascular risk. He added that peak blood pressure during exercise is also clinically significant.

Traditional cuff‑based devices remain accurate but capture only resting readings because users must remain still. Wrist wearables offer convenience but often compromise on clinical precision and require regular charging — a limitation the NUS team sought to overcome.

To avoid interference from moving parts, the researchers removed all bulk, including batteries. Instead, the sensors draw power wirelessly from a smartphone strapped to the user’s upper arm. Conductive fabric stitched into a long‑sleeved shirt links the sensors to the phone, which supplies energy via near‑field communication. Data is then transmitted back to the phone through Bluetooth.

The textile‑based conductive track, made from a copper‑nickel alloy, is patented by NUS. The prototype was tested on five users, with findings published in Nature Electronics.

Kurt said the project was partly inspired by his father’s experience with white coat syndrome, which required him to wear a 24‑hour portable cuff monitor that inflated repeatedly — including during sleep — causing discomfort.

While the team hopes the technology will eventually be commercialised for people at risk of hypertension or heart disease, they are currently focused on improving usability. Planned refinements include real‑time blood pressure displays via a mobile app and enhancing the durability of the conductive fabric, which currently withstands about 10 wash cycles before performance declines.