The Mechanical and Biological Performance of Photopolymerized Gelatin-Based Hydrogels as a Function of the Reaction Media.

From the first experiments with biomaterials to mimic tissue properties, the mechanical and biochemical characterization have evolved extensively. A number of properties can be described, however, what should be essential is to conduct a proper and physiologically relevant characterization. Herein, we describe the influence of the reaction media and buffer media -phosphate buffer saline (PBS) and Dulbecco's modified Eagle's medium (DMEM) with two different glucose concentrations- in GelMA hydrogel mechanics and in the biological behavior of two tumoral cell lines (Caco-2 and HCT-116). All scaffolds were photocrosslinked using UV light under identical conditions and evaluated for mass swelling ratio and stiffness. Our results indicate that stiffness is highly susceptible to the reaction media, but not to the swelling media. In addition, PBS-prepared hydrogels exhibited a higher photopolymerization degree as confirmed by HR-MAS NMR. These findings correlate with the biological response of Caco-2 and HCT-116 cells seeded on the substrates, which demonstrated flatter morphologies on stiffer hydrogels. Overall, cell viability and proliferation were excellent for both cell lines, and Caco-2 cells displayed a characteristic apical-basal polarization as observed in F-actin/Nuclei fluorescence images. These characterization experiments highlight the importance of conducting mechanical testing of biomaterials in the same medium as cell culture. This article is protected by copyright. All rights reserved.