Calahan Kristin N, Qi Yuan, Johannes Karl G, Rentschler Mark E, Long Rong
Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, USA.
BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80309, USA.
Sci Adv. 2022 Jun 24;8(25):eabn2728. doi: 10.1126/sciadv.abn2728.
Micropatterned surfaces exhibit enhanced shear traction on soft, aqueous tissue-like materials and, thus, have the potential to advance medical technology by improving the anchoring performance of medical devices on tissue. However, the fundamental mechanism underlying the enhanced shear traction is still elusive, as previous studies focused on interactions between micropatterned surfaces and rigid substrates rather than soft substrates. Here, we present a particle tracking method to experimentally measure microscale three-dimensional (3D) deformation of a soft hydrogel in normal and shear contact with arrays of microscale pillars. The measured 3D strain and stress fields reveal that the lateral contact between each individual pillar and the deformed hydrogel substrate governs the shear response. Moreover, by comparing pillars with different cross-sectional geometries, we observe experimental evidence that the shear traction of a pillar on the hydrogel substrate is sensitive to the convex features of its leading edge in the shear direction.
微图案化表面在柔软的水性组织样材料上表现出增强的剪切牵引力，因此有潜力通过改善医疗设备在组织上的锚固性能来推动医学技术发展。然而，增强剪切牵引力的基本机制仍然难以捉摸，因为先前的研究集中在微图案化表面与刚性基底之间的相互作用，而非与柔软基底的相互作用。在此，我们提出一种粒子跟踪方法，以实验方式测量软质水凝胶在与微尺度柱阵列进行法向和剪切接触时的微观三维（3D）变形。所测得的3D应变和应力场表明，每个单独的柱与变形的水凝胶基底之间的横向接触决定了剪切响应。此外，通过比较具有不同横截面几何形状的柱，我们观察到实验证据表明，柱在水凝胶基底上的剪切牵引力对其在剪切方向上前沿的凸起特征敏感。
