Mechanical characterisation of unidirectional and cross-directional multilayered urinary bladder matrix (UBM) scaffolds.

Multilayered biological scaffolds derived from mammalian extracellular matrix (ECM) have shown promising long-term clinical results when reconstructing damaged tissues and organs. Despite their established clinical applicability, experimental studies that describe the effects of alternate manufacturing protocols on an ECM's mechanical properties are lacking. In the present study the mechanical properties of multilayered 'unidirectional' porcine urinary bladder matrix (UBM) scaffolds were determined in favour of its longitudinal and circumferential axes. The scaffold's unidirectional mechanical properties were then compared with 'cross-directional' UBM scaffolds. The results showed significant variations when alternate manufacturing protocols for multilayered UBM were applied. Unidirectional longitudinal UBM remained the strongest biomaterial on a consistent basis. Its failure strength occurred at 4.79±0.85MPa compared to 3.36±0.53MPa for unidirectional circumferential and 2.91±1.05MPa for cross-directional UBM respectively (p<0.0001). Distensibility was greatest in unidirectional circumferential UBM with failure extension occurring at 14.77±1.66mm. In comparison, failure extension occurred at 12.88±0.94mm and 13.04±4.35mm for unidirectional longitudinal and cross-directional UBM respectively (p=0.0024). The present study demonstrates that predefined manufacturing protocols for UBM should be considered when reconstructing anatomical structures with specific mechanical requirements.