Micro-composite substrates for the study of cell-matrix mechanical interactions.

Abstract

The chemical and physical gradients in the native cell microenvironment induce intracellular polarization and control cell behaviors such as morphology, migration and phenotypic changes. Directed cell migration in response to substrate stiffness gradients, known as durotaxis or mechanotaxis, has drawn attention due to its significance in development, metastasis, and wound healing. We developed a microcomposite substrate (μCS) platform with a microfabricated base and collagen hydrogel top to generate physiological linear stiffness gradients without any variation in chemical or transport properties. This platform is compatible with both 2D and 3D cell culturing and can be assembled with common supplies found in most biology labs. Ligament fibroblasts (LFs) and mesenchymal stem cells (MSCs) both respond to the mechanical gradient with directed migration. Interestingly, LFs exhibit higher mechanosensitivity compared with MSCs. Polarized nonmuscle myosin IIB distribution was also found on the μCS gradient, confirming previous reports. This robust system provides an easily accessible platform to study cell mechanosensing and a more physiological microenvironment for cell studies.