Host: J.M. Pitarke

Almost every third person worldwide dies from cardiovascular diseases, and even more than 40 % in high income countries. Today?s practice of measuring systolic and diastolic blood pressure does not give any information about the biomechanics of the arterial system. The idea of the presented research focuses on a novel photonic method to measure the small arterial distensions in vivo, which encode the stiffness of the arterial wall. The measurement principle is based on transmission photoplethysmography, and transfers this technique to a new field of application ? large arteries. To understand photon propagation through arteries, we solved the Radiative Transfer Equation by Monte Carlo methods for the first time on multilayered cylinders. The simulations are in excellent compliance with ex vivo as well as in vivo experiments. To match the mechanical properties of biological tissue, the implantable sensor is realized by integration of chiplevel optoelectronics into polymeric substrates. The achieved precision of 5 ??m and sub-micron resolution outperforms all state-of-the-art techniques in sensing arterial distension. In the near term, this new approach offers a tool for clinical research, and as a perspective, a 24/7 monitoring system that makes key vital parameters, such as heart rate, arterial stiffness and more generally thedynamics of the arterial system, continuously accessible.