Implantable blood flow sensor integrated on flexible circuit for vascular graft application

This paper reports an implantable blood flow sensor system integrated on flexible circuit that consists of pressure sensor and inductively powered wireless sensor interface Application Specific Integrated Circuit (ASIC) for early graft failure detection application. The proposed system was embedded within the vascular graft to have continuously monitoring the differential blood pressure change as an indication of stenosis build- up in the graft. The fabricated pressure sensor is showed the step of 0.5psi of pressure changes is clearly visible with the resistance change. The resolution of pressure change 8mmHg was achieved. [1] The whole system was successfully integrated on designed flexible circuit by optimizing method of flip-chip bonding with gold stud bump and underfill encapsulant at lower temperature. The assembled system was successfully demonstrated wirelessly.