Pyriphenone modification of glutaraldehyde pretreated bovine pericardium mitigates advanced glycation end products, calcification, and platelet adhesion

Biaxial mechanical testing was performed using a commercial CellScale BioTester to determine whether ethanol, UV exposure, and Pyriphenone modification altered the mechanical properties of glutaraldehyde-fixed bovine pericardium. The study tested six groups: unmodified bovine pericardium with and without UV exposure, ethanol-incubated bovine pericardium with and without UV exposure, and ethanol-incubated bovine pericardium followed by Pyriphenone treatment with and without UV exposure. Each group included six samples, for a total of 36 biaxial test specimens. Samples were cut to 10 mm × 10 mm, with visible collagen fibers aligned to one specimen axis and to the BioTester x-axis. Sample thickness was measured with a digital caliper, then specimens were mounted using four sets of BioRake tines with an effective test region of 7 mm × 7 mm. Four fiducial markers were placed in the central one-third of each sample for non-contact strain measurement. Samples were submerged in deionized water, preloaded to 10 mN, preconditioned for 10 equibiaxial cycles to an 800 mN target peak force, and then characterized under seven biaxial force ratios: 1:1, 1:0.75, 1:0.50, 1:0.25, 0.75:1, 0.50:1, and 0.25:1. Each ratio used 10 loading/unloading cycles with a 20 second cycle duration, while images and load-cell forces were recorded at 5 Hz. The BioTester results showed no significant changes in stretch along the fiber direction, stretch across the fiber direction, or anisotropy ratio across modification groups, supporting the conclusion that Pyriphenone modification did not measurably compromise biaxial tissue mechanics.