Q800 ta instrument

Cell-free samples (n = 3) were prepared by injecting the different polymer solutions (Figure 1) into custom-made cylindrical Teflon molds (diameter: 6 mm; height 2 mm). Next, samples were UV cross-linked by exposure to 365 nm UV light (2.6 mW/cm², UVP CL-1000) for 15 minutes. After removing the hydrogels from the molds, they were incubated in DMEM/F-12+GlutaMax-1 (Dulbecco’s Modified Eagle Medium, 31331, Invitrogen, Carlsbad, California, USA) supplemented with 5% heat-inactivated fetal bovine serum (FBS, Biowhittaker, Breda, the Netherlands) and pen/strep (final concentration 100 units/ml penicillin and 100 μg/ml streptomycin, Gibco) for 24 hours at 37°C. A stress/strain curve was obtained for each hydrogel construct under unconfined compression using a Dynamic Mechanical Analyzer (DMA, Q800 TA-Instrument) to determine the Young’s modulus. The hydrogel constructs (three for each condition) were subjected to a preload force of 0.001 N and subsequently compressed with a force ramp rate of 0.5 N/min and an upper force limit of 1.5 N. The Young’s modulus was calculated as the initial slope (around 2% strain) of the stress/strain curve.