Flexible thermal array sensor for imperceptible monitoring of multidimensional vascular dynamics.

Wearable electronics for monitoring vascular dynamics are crucial in assessing cardiovascular health. However, current vascular sensors hold challenges in limited perceptive dimension and accuracy and poor interface robustness. Here, we report 18-channel flexible thermal array sensor using active thermal penetration sensing principle for imperceptible monitoring of deep and superficial vasculature. Leveraging contact-free thermal penetration and natural piezo-thermic transduction of human skin, the sensor implements spatiotemporal mapping of vascular dynamics with high sensitivity, good-linearity, fast-response, low cross-talk, and excellent interfacial robustness. It enables real-time and in situ measurements of multimodal vascular characteristics including deep arterial pulsation, superficial capillary perfusion, relative blood flow velocity, skin temperature, and continuous blood pressure via data-efficient vascular feature extraction method. Imperceptible and comprehensive cardiovascular dynamics tracking by wearable electronics provides a promising avenue for advancing personal health care and clinic medicine.