A polymer canvas with the stiffness of the bone matrix to study and control mesenchymal stem cell response

: The possibility to reproduce in vitro the complex multiscale physical features present in the human tissues creates novel opportunities for biomedical advances and fundamental understanding of cell-environment interfaces and interactions. While stiffness has been recognized as a key property in influencing cell behavior, so far systematic studies on the role of stiffness have been limited to values in the KPa-MPa range, significantly below the stiffness of bone. Here, we report a platform enabling the tuning and control of the stiffness of a biocompatible polymeric interface up to values characteristic of the bone tissue, which are in the GPa range. The ability to fine tune the stiffness up to these large values is achieved by using extremely thin polymer films on glass and cross-linking the films using UV light irradiation. We show that a higher stiffness is related to better adhesion, proliferation, and osteogenic differentiation, and that it is also possible to switch on/off cell attachment and growth by solely tuning the stiffness of the interface, without any surface chemistry or topography modification. Since the stiffness is tuned directly by UV irradiation, this platform is ideal for rapid and simple stiffness patterning, and stiffness gradients fabrication. This materials platform represents an innovative tool for combinatorial studies of the synergistic effect of tissue environmental cues on cell behavior, and creates new opportunities for next generation biosensors, single-cell patterning, and lab-on-a-chip devices. This article is protected by copyright. All rights reserved.