Acellular dermal matrix (ADM) materials are used as scaffold materials in reconstructive surgery. The internal structural response of these materials in load-bearing clinical applications is not well understood. Bovine ADM is characterized by small-angle X-ray scattering while subjected to strain. Changes in collagen fibril orientation (O), degree of orientation as an orientation index (OI) (measured both edge-on and flat-on to the ADM), extension (from d-spacing changes) and changes to intermolecular spacing are measured as a result of the strain and stress in conjunction with mechanical measurements. As is already well established in similar systems, when strained, collagen fibrils in ADM can accommodate the strain by reorienting by up to 50° (as an average of all the fibrils). This reorientation corresponds to the OI increasing from 0.3 to 0.7. Here it is shown that concurrently, the intermolecular spacing between tropocollagen decreases by 10% from 15.8 to 14.3 Å, with the fibril diameter decreasing from 400 to 375 Å, and the individual fibrils extending by an average of 3.1% (D-spacing from 63.9 to 65.9 nm). ADM materials can withstand large strain and high stress due to the combined mechanisms of collagen reorientation, individual fibril extension, sliding and changes in the molecular packing density.

无细胞真皮基质（ADM）材料在重建手术中用作支架材料。这些材料在承重临床应用中的内部结构响应尚不十分清楚。牛ADM的特征是在受到应变时会出现小角度X射线散射。胶原蛋白原纤维取向（O）的变化，作为取向指数（OI）的取向程度（在ADM的边缘和平面上均测得），延伸率（从d间距变化）和分子间间距的变化测量为应变和应力以及机械测量的结果。正如在类似系统中已经确立的那样，当拉伸时，ADM中的胶原原纤维可以通过重新定向多达50°（作为所有原纤维的平均值）来适应应变。这种重新定向对应于OI从0.3增加到0.7。此处同时显示，原胶原蛋白之间的分子间间距从15.8Å减小了10％，原纤维直径从400减小到375Å，单个原纤维平均延伸了3.1％（D间隔从63.9扩展）至65.9nm）。由于胶原蛋白重新定向，单个原纤维延伸，滑动和分子堆积密度变化的综合机制，ADM材料可以承受较大的应变和高应力。