Method for the Direct Fabrication of Polyacrylamide Hydrogels with Controlled Stiffness in Polystyrene Multiwell Plates for Mechanobiology Assays.

Polyacrylamide (PAA) hydrogels are now widely used in mechanobiology because the well-defined available protocols allow a robust and reproducible control of substrate stiffness within a physiological range. However, several assays require hydrogels inside traditional plastic substrates and the current methods remain relatively tedious. Here, we present a simple and direct fabrication technique that successfully attaches PAA hydrogels inside polystyrene multiwell plates and Petri dishes of different sizes. It permits a control of the Young's modulus of the gels, within the desired range for mechanobiology. Some critical steps, that had to be overcome to guarantee protein conjugation and cell attachment, are detailed, as they differ from the standardized preparation on glass substrates. To validate our process, we demonstrated that HepG2 and 3T3L1 cell lines as well as primary hepatocytes seeded on PAA gels of different stiffnesses in plastics showed a mechanical response identical to the cells cultured on traditional gels.