High-Resolution Strain Measurement for Biomechanical Parameters Assessment in Native and Decellularized Porcine Vessels

Abstract

Decellularized vascular scaffolds are promising materials for vessel replacements. However, despite the natural origin of decellularized vessels, issues such as biomechanical incompatibility, immunogenicity risks, and the hazards of thrombus formation still need to be addressed. In this study, we assess the mechanical properties of two groups of porcine carotid blood vessels: (i) native arteries and (ii) decellularized arteries. The biomechanical properties of both groups (n = 10, sample size of each group) are determined by conducting uniaxial and circumferential tensile tests by using an ad hoc and lab-made device comprising a peristaltic pump that controls the load applied to the sample. This load is regularly incremented (8 grams per cycle with a pause of 20 seconds after each step) while keeping the vessels continuously hydrated. The strain is measured by an image cross-correlation technique applied on a high-resolution video. The mechanical testing analyses of the arteries revealed significant differences in burst pressure between the native (1345.08 +/- 96.58 mbar) and decellularized (1067.79 +/- 112.13 mbar) groups. Moreover, decellularized samples show a significantly lower maximum load at failure (15.78 +/- 0.79 N) in comparison with native vessels (19.42 +/- 0.80 N). Finally, the average ultimate circumferential tensile also changes between native (3.71 +/- 0.37 MPa) and decellularized (2.93 +/- 0.18 MPa) groups. This technique is able to measure the strain in the regime of large displacements and enables high-resolution image of the local strains, thus providing a valuable tool for characterizing several biomechanical parameters of the vessels also applicable to other soft tissue presenting hyperelastic behaviours.