Basement membrane structure and function: Relating biology to mechanics

Basement membranes are key mediators of many biological processes such as epithelial morphogenesis, kidney filtration, and muscle function among others. Basement membranes provide structural support to tissues so understanding their mechanical properties is important for determining how they contribute to tissue form and function. Further, basement membranes are altered in many diseases including cancer, diabetes, and fibrosis, and these changes may contribute to disease pathogenesis and progression. Understanding how basement membrane mechanics integrate with tissue function is the work of both biologists and engineers/material scientists, yet these disciplines have very different foundations. This review discusses basement membrane macromolecular structure with a view to illuminate how this structure confers basement membranes with unique mechanical properties adapted to resisting physiological stresses. The pathological implications of altered basement membrane mechanics are discussed in the context of different diseases. Additionally, we survey methods used to measure basement membrane mechanical properties, including atomic force microscopy, tensile stiffness assays, and non-quantitative assays such as cell bursting, assessing their strengths and limitations and their accessibility for different types of in vivo studies. We focus on explaining and illuminating the complexities of basement membrane material properties for biologists, and explaining the biological aspects for engineers, with the goal of making interdisciplinary science more accessible to experimentalists and readers.