Validation of a Novel Microscale Mold Patterning Protocol Based on Gelatin Methacrylate Photopolymerizable Hydrogels

Native tissues are composed of functional three-dimensional (3D) units on the scale of 100–1000μm. The 3D architecture of these repeating units underlies the coordination of multicellular processes such as proliferation, differentiation, migration and apoptosis[1]. The requirement for 3D biomimetic matrices to mimic in vitro the ECM microarchitecture found in vivo becomes relevant in complex and vascularized tissue engineered models[2]. Among others, photopolymerizable hydrogels offer tunable geometrical features similar to the macromolecular-based components of soft ECM [3], can be crosslinked either in vivo or in vitro in the presence of a photoinitiator agent (PI) using visible or ultraviolet (UV) light irradiation, and have shown good compatibility with several protocols for cell embedding at different size-scales. In the present study, a new protocol to obtain cell-laden hydrogel micropatterns with highly controlled geometrical features is presented, based on the combination of polydimethylsiloxane (PDMS) replica molding and UV photopolimerization of methacrylate gelatin (GelMA).