First Approach of Direct Ink Writing for a Sensorized Arterial Surrogate

The present study is a preliminary investigation into the feasibility of Direct Ink Writing (DIW) technology for fabricating stretchable resistive strain sensors intended for pulse wave velocity (PWV) measurements in elastomeric arterial surrogates. Conductive carbon-based ink sensors featuring an S-wave geometry were printed onto four specimens made of polyurethane. The sensorized specimens were subjected to quasi-static uniaxial tensile tests at a constant displacement rate of 1 mm/min. The electrical resistance variation was continuously monitored as a function of the applied engineering strain. The electromechanical response of all specimens is described by a second-order polynomial regression, with correlation coefficients exceeding 0.999. All sensors sustained strains up to 40%, satisfying the maximum elongation requirement of 30% for the target application. The achievable resolution, evaluated through inter-specimen variability analysis, ranged from 1.1% to 2.8%, meeting the required threshold of 5%. An Intraclass Correlation Coefficient of 0.986 confirmed inter-specimen consistency. These preliminary results suggest that DIW-printed sensors are a promising solution for strain-based PWV detection in arterial simulators, although further dynamic testing and manufacturing optimization are required.