The gelation process of
the hydrogels has been analyzed by means of linear oscillatory rheology
using a control stress
HAAKE RheoStress 1 (Thermo Fisher Scientific,
Waltham, MA, US). The rheometer was connected to an external thermostatic
bath. The measurements were carried out using a cone–plate
sensor with a 35 mm radius and 1° angle. Once the hydrogel was
prepared, it was placed in the lower plate at 20 °C. Then the
upper cone was lowered to the measurement position, and the temperature
is gradually raised to 37 °C. Once the sample has been equilibrated
at this temperature, the hydrogel gelation was analyzed by applying
a very low stress of γ = 0.45 Pa at a frequency of 0.1 Hz with
a cyclic strain of 0.5% amplitude, which guarantees a torque of 5
μNm and a linear viscoelastic regime. To mitigate the evaporation
of water from the hydrogel, a liquid trap was used. Storage moduli
(
G′) were recorded as a function of time using
HAAKE Rheowin software (Job and Data Manager). Three samples were
used for each test condition.
Alamán-Díez P., Borau C., Guerrero P.E., Amaveda H., Mora M., Fraile J.M., García-Gareta E., García-Aznar J.M, & Pérez M.Á. (2023). Collagen-Laponite Nanoclay Hydrogels for Tumor Spheroid Growth. Biomacromolecules, 24(6), 2879-2891.