Collagen Fibril Structure and Strength in Acellular Dermal Matrix Materials of Bovine, Porcine, and Human Origin

Abstract

Strength is an important characteristic of acellular dermal matrix (ADM) materials used for surgical scaffolds. Strength depends on the material's structure, which may vary with the source from which the product is produced, including species and animal age. Here, variations in the physical properties and structures of ADM materials from three species are investigated: bovine (fetal and neonatal), porcine, and human materials. Thickness normalized, the bovine materials have a similar strength (tear strength of 75−124 N/m) to the human material (79 N/m), and these are both stronger than the porcine material (43 N/m). Thickness-normalized tensile strengths were similar among all species (18−34 N/mm 2 for bovine although higher in fetal material, 18 N/mm 2 for human and 21 N/mm 2 for porcine). Structure is investigated with synchrotron-based small-angle X-ray scattering (SAXS) for collagen fibril orientation index (OI) and scanning electron microscopy (SEM). SEM reveals a more open structure in bovine ADM than in the porcine and human material. A correlation is found between OI and thickness-normalized tear strength in neonatal bovine material measured with the X-rays edge-on to the sample, but this relationship does not extend across species. The collagen fibril arrangement, viewed perpendicular to the surface, varies between species, with the human material having a unimodal distribution and rather isotropic (OI 0.08), the porcine being strongly bimodal and rather highly oriented (OI 0.61), the neonatal bovine between these two extremes with a bimodal distribution tending toward isotropic (OI 0.14−0.21) and the fetal bovine material being bimodal and less isotropic than neonatal (OI 0.24). The OI varies less through the thickness of the porcine and human materials than through the bovine materials. The similarities and differences in structure may inform the suitability of these materials for particular surgical applications.

Clinically available reinforcing materials for soft tissue reconstruction

“…The mechanical properties of strength and stiffness are directly correlated with the organisation and alignment of the collagen fibre network of the source tissue, rather than the processing methodology. A study using synchrotron-based small-angle X-ray scattering to investigate collagen fibre organisation of extracellular matrix biomaterials derived from the dermis of three different species found significantly increased tear resistances and suture retention strengths in bovine and human dermis, compared to porcine dermis, that were correlated to a strongly bimodal and isotropic distribution of fibres in porcine dermis (Wells et al, 2015). Additionally, increasing thickness of an extracellular matrix biomaterial is correlated with increased load-bearing capacity (Adelman et al, 2014) and should be considered for more challenging surgical applications (Clemens et al, 2013).…”

Decellularized ECM-Derived Hydrogels: Modification and Properties

“…In addition, it is not expected to see under the surface because the X-ray source is weak and cannot penetrate the sample. On the other hand, scattering X-ray techniques can be used to get the shape, length and width, pore size, and fiber orientation directly from the sample, wet or dry, without further manipulation [55][56][57]. Depending on the distance to determine, normal X-ray diffraction equipment can also be used [58].…”

Deer leather: analysis of the microstructure affecting pebble

“…Figure 1 shows an overview of the SAXS experimental set-up. 11 In this experiment, diffraction patterns were recorded edge-on to the surface beginning at the grain (top) surface to the corium (bottom).…”