2.10. Swelling kinetics

The swelling properties of the UD gel film (Gel Film-2) were determined by immersion of the dried gels (average weight: 80 (±6) mg, size: 2 cm × 2 cm) in simulated wound solutions (adjusted pH to 2.0, 7.4, or 9.2) at 37 °C. The recipe of the simulated wound solutions was adopted from Bradford et al (Bradford et al., 2009). At pre-determined time points (0, 15, 30, 45, 60, 120, 240, 360, 1440 min), the swollen hydrogels were removed (n = 3), and weighed after blotting the excess water on the surface. The swelling ratio (Qs) was calculated by dividing the weight of the gels in the wet state by the initial gel weights in the dried state. Also, to compare the swelling capacity of different gel film formulations (Gel Film-1–6), additional swelling studies were carried out using simulated wound solutions at pH 7.4 with incubation for 1 h, and the Qs values of the gel films were calculated.