Joris van Dongen

286 Chapter 12 harvested after 24h served as controls (2.9 and 2.11). For fibroblast proliferation, the mean cell proliferation of fibroblast after using the respective concentrated ASC-CMe was set at 100% (2.10). Moreover, hydrogels were not cytotoxic (data not shown). Figure 1. (A) Overview of the generation of ECM-derived hydrogels incubated with concentrated ASC- CMe. (B) Pre-gel solution prior to warming to 37°C. (C) Hydrogel after after gelation at 37°C. HCl = hydrogen chloride, NaOH = sodium hydroxide, ASC-CMe = adipose stromal cell conditioned medium, ECM = extracellular matrix, ASC = adipose stromal cell, PBS = phosphate buffered saline. Characterization of viscoelastic relaxation properties of the hydrogels NAM and DAM hydrogels (n=3) were formed in 0.8 mm polydimethylsiloxane rings and placed on a glass slide derived from three different pre-gel solutions per donor in duplicates (three technical replicates per donor) (Table 1). However, due to technical errors single data was obtained of pre-gel solution C of donor one and two. Then stress relaxation tests were performed on the NAM and DAM hydrogels with the help of a low-load compression tester in a non-hydrated environment at RT 26 . A stainless steel plunger with a diameter of 0.25 cmwas lowered towards the hydrogels at 5 µm/s till the plunger came in contact with the gel (touch load defined as 10 mg). This position was recorded and similarly the positionof the topof the glass slidewas determined.Hydrogel