Mechanical evaluation of decellularized porcine thoracic aorta

Decellularized tissues are expected to have major cellular immunogenic components removed and in the meantime maintain similar mechanical strength and extracellular matrix (ECM) structure. However, the decellularization processes likely cause alterations of the ECM structure and thus influence the mechanical properties. In the present study, the effects of different decellularization protocols on the (passive) mechanical properties of the resulted porcine aortic ECM were evaluated.

Decellularization methods using anionic detergent (sodium dodecyl sulfate), enzymatic detergent (Trypsin), and non-ionic detergent [tert-octylphenylpolyoxyethylen (Triton X-100)] were adopted to obtain decellularized porcine aortic ECM. Histologic studies and scanning electron microscopy were performed to confirm the removal of cells and to examine the structure of ECM. Biaxial tensile testing was used to characterize both the elastic and viscoelastic mechanical behaviors of decellularized ECM.

All three decellularization protocols remove the cells effectively. The major ECM structure is preserved under sodium dodecyle sulfate (SDS) and Triton X-100 treatments. However, the structure of Trypsin treated ECM is severely disrupted. SDS and Triton X-100 decellularized ECM exhibits similar elastic properties as intact aorta tissues. Decellularized ECM shows less stress relaxation than intact aorta due to the removal of cells. Creep behavior is negligible for both decellularized ECM and intact aortas.

SDS and Triton X-100 decellularized ECM tissue appeared to maintain the critical mechanical and structural properties and might work as a potential material for further vascular tissue engineering.