Validation of a Modified Esophageal pH Probe for Monitoring Colon Health

An accelerated tensile fatigue protocol was performed using a CellScale BioTester 5000 biaxial test machine to verify the structural integrity of a modified Medtronic Bravo® pH capsule under simulated in-vivo peristaltic loading. The capsule was mounted between the BioTester terminals using suture thread: a binder clip was attached to the probe end and tied to one terminal, while the opposite end was tied through a drilled suture hole to the other terminal. The BioTester applied cyclic tensile loading to approximate cecal peristalsis over a 14-day study period (targeting ~120,960 cycles), accelerated to one cycle every ~2 seconds and including a 100 mN preload, with peak loading intended to represent peristaltic forces up to ~520 mN. Following completion of cycling, the capsule’s epoxy seam (original-to-new epoxy interface) was visually inspected under magnification for cracking, separation, or deformation, and capsule pH accuracy was checked before/after mechanical cycling using buffer solutions (pH 4, 7, 10.01).