Cellular Response to Ordered Collagen Layers on Mica

Extracellular microenvironment, including its components and biophysical parameters such as matrix structure and stiffness, is a crucial determinant of cellular function. There exists interdependency between cellular behaviors and the extracellular matrix (ECM), whereby cells are constantly sensing and modifying their surroundings in response to physical stress or during processes like wound repair, cancer cell invasion, and morphogenesis, to create an environment which supports adaptation. To date, knowledge of the distinct regulatory mechanisms of this complex relationship is little, while the urge is evident as it plays a significant role in understanding tissue remodeling. Cells are observed to align with the parallel arrays of collagen fibrils found in tissues such as bone, tendon, and cornea, suggesting the importance of ordered matrices in defining cell functions. In this study, epitaxial growths of ordered two-dimensional collagen matrices were created, with parallelly aligned fibrils on muscovite mica, and novel triangular pattern matrix on phlogopite mica. Using Fluorescence and Atomic Force Microscopy, we were able to observe cell polarization along with stress fiber formation and matrix deformation at high resolution. Cells were observed to be able to penetrate between collagen fibrils and generate traction anisotropically to polarize. These ordered collagen matrices serve as an excellent model to study cellular remodeling of ECM in vitro, in which this fundamental apprehension of cell-matrix relationship is of crucial importance to manipulate the system and obtain desired cell functions.