Differentiation of biologic scaffold materials through physicomechanical, thermal, and enzymatic degradation techniques

OBJECTIVE: The objective of this study was to characterize the physicomechanical, thermal, and degradation properties of several types of biologic scaffold materials to differentiate between the various materials. BACKGROUND: As more biologic scaffold materials arrive on the market, it is critical that surgeons understand the properties of each material and are provided with resources to determine the suitability of these products for specific applications such as hernia repair. METHODS: Twelve biologic scaffold materials were evaluated, including crosslinked and non-crosslinked; those of bovine, human, and porcine origin; and derivatives of pericardium, dermis, and small intestine submucosa. Physicomechanical, thermal, and degradation properties were evaluated through biomechanical testing, modulated differential scanning calorimetry, and collagenase digestion assays, respectively. Biomechanical testing included suture retention, tear strength, uniaxial tensile, and ball burst techniques. RESULTS: All scaffolds exhibited suture retention strengths greater than 20 N, but only half of the scaffolds exhibited tear resistance greater than 20 N, indicating that some scaffolds may not provide adequate resistance to tearing. A wide range of burst strengths were observed ranging from 66.2 ± 10.8 N/cm for Permacol to 1,028.0 ± 199.1 N/cm for X-Thick AlloDerm, and all scaffolds except SurgiMend, Strattice, and CollaMend exhibited strains in the physiological range of 10% to 30% (at a stress of 16 N/cm). Thermal analysis revealed differences between crosslinked and non-crosslinked materials with crosslinked bovine pericardium and porcine dermis materials exhibiting a higher melting temperature than their non-crosslinked counterparts. Similarly, the collagenase digestion assay revealed that crosslinked bovine pericardium materials resisted enzymatic degradation significantly longer than non-crosslinked bovine pericardium. CONCLUSIONS: Although differences were observed because of cross-linking, some crosslinked and non-crosslinked materials exhibited very similar properties. Variables other than cross-linking, such as decellularization/sterilization treatments or species/tissue type also contribute to the properties of the scaffolds.