Three-Dimensional Microstructured Azobenzene-Containing Gelatin as a Photoactuable Cell Confining System.

In materials science, there is a considerable interest in the fabrication of highly engineered biomaterials that can interact with cells and control their shape. In particular, from the literature, the role played by physical cell confinement in cellular structural organization and thus in the regulation of its functions has been well-established. In this context, the addition of a dynamic feature to physically confining platforms aiming at reproducing in vitro the well-known dynamic interaction between the cells and their microenvironment would be highly desirable. To this aim, we have developed an advanced gelatin-based hydrogel that can be finely micropatterned by two-photon polymerization and stimulated in a controlled way by light irradiation thanks to the presence of an azobenzene cross-linker. Light-triggered expansion of gelatin microstructures induced an in-plane nuclear deformation of physically confined NIH-3T3 cells. The microfabricated photoactuable gelatin shown in this work paves the way to new "dynamic" caging culture systems that can find applications, for example, as "engineered stem cell niches".