Evaluating the effects of glutaraldehyde concentration and incubation time on the structural integrity of the human...

Glutaraldehyde (GA) fixation of pericardial tissue is widely used in bioprosthetic heart valves. However, how GA concentration and incubation time jointly influence structure-function relationships remains incompletely understood. This study systematically evaluates the effects of GA concentration and incubation time on collagen architecture and mechanical behavior in human pericardial tissue.

Human pericardium was treated with GA concentrations of 0%-2.5% for 5-90 min. Collagen structure was quantified using Picrosirius red imaging and image analysis, while mechanical behavior was assessed via strain-controlled uniaxial tensile testing. Increasing incubation time was associated with reduced collagen waviness and evidence of fiber bundling. Mechanical analysis revealed a significant interaction between GA concentration and incubation time for maximum strain and transition strain (p < 0.05), indicating a non-linear, non-additive treatment effect. Repeated-measures correlation analysis showed strong internal consistency among mechanical parameters (e.g., maximum stress vs. high-strain modulus, r_rm = 0.92), whereas structural descriptors such as waviness and fiber orientation exhibited minimal association with mechanical outcomes (r_rm = 0.06).

GA treatment effects arise from a coupled, non-additive interaction between concentration and incubation time rather than a simple dose-response relationship. Importantly, commonly used structural metrics do not directly predict mechanical performance, underscoring the need for integrated structure-function assessment. These findings provide a framework for future evaluation of GA-treated pericardium in bioprosthetic applications.