Magnetic sensing modules for in-vivo blood pressure monitoring in anastomosed arteries

This paper presents the development of magnetic sensing modules designed to conformally encircle arteries for in-vivo blood pressure monitoring. The modules incorporate multiple off-the-shelf Hall sensors and permanent magnets arranged on a flexible substrate to transform arterial distention due to blood pressure into voltage. The novelty of the design lies in the multitude of components and their circular collocations that yields significant improvement in pressure sensitivity as revealed by finite element simulations. The sensors and magnets were encapsulated in biocompatible materials and assembled on a flexible PDMS substrate with metal interconnects, which are fabricated through microfabrication techniques. Test results on a latex pipe serving as the artery model demonstrated sensitivity values reaching 0.42 mV/mmHg, representing a 3.8-fold improvement over traditional single sensor-magnet pair design. Long-term tests both in air and in PBS solution showed no degradation in the sensitivity, and a high linearity with R 2 exceeding 0.98. The average sensitivity is projected to reach 3.2 mV/mmHg in-vivo due to the higher compliance of the arterial tissue. The reported results underscore the viability of this implantable device for continuous blood pressure monitoring in large arteries. This is particularly crucial in organ transplantation, where the main artery supplying blood to the transplanted organ is anastomosed and requires continuous monitoring to ensure adequate blood flow after the surgical operation. • Magnetic sensing modules for in-vivo blood pressure monitoring are presented. • The modules consist of multiple Hall sensors and magnets to encircle an artery. • Various designs in biocompatible packaging were tested on latex pipes. • The average sensitivity is projected to reach 3.2 mV/mmHg on an artery. • Devices can be used for continuous blood pressure sensing in anastomosed arteries.