Circuit-free cardiovascular monitoring via skin-interfaced nanophotonics

TL;DR

This paper introduces a novel, circuit-free optical method for continuous cardiovascular monitoring using skin-interfaced nanophotonics, enabling real-time pulse detection with a smartphone camera without complex electronics.

Contribution

A fully optical, smartphone-compatible approach for cardiovascular monitoring that eliminates the need for electronic sensors and spectrometers.

Findings

Accurately detected arterial pulse waves in human studies.

Identified benign arrhythmic events consistent with clinical references.

Captured features related to arterial stiffness, a cardiovascular risk marker.

Abstract

Continuous cardiovascular monitoring is essential for managing circulatory health and disease, yet most wearable sensors are constrained by reliance on electrical transduction and built-in electronics. We present a circuit-free, wholly optical approach using diffraction from a skin-interfaced nanostructured surface to detect minute skin strains from the arterial pulse. A smartphone camera records the shifting diffraction pattern in real time, removing the need for spectrometers or other optical hardware. In phantom and human studies, we recovered high-fidelity arterial pulse waves and detected benign arrhythmic events in close agreement with a clinical reference. Derived waveforms captured features linked to arterial stiffness, a key cardiovascular risk marker. Our approach uses battery-free, cost-effective, and disposable platforms enabling scalable monitoring for healthcare and broad consumer applications.