In Vitro Release Kinetics of Hydrogel Formulations
The release of AgNPs-PVP from the hydrogel formulations was detected using a similar diffusion system as described in the literature51. Transwell membrane inserts (3-µm pore size and 1.1 cm2 area; Costar, USA) and 24-well plates were used as the donor and acceptor cells, respectively. A 200 µL aliquot of the formulation containing 18% P407 and 50 or 100 µM AgNPs-PVP was pipetted onto the prewarmed inserts’ membrane to get a solid-like hydrogel. Transwell inserts with solid-like hydrogel were placed into the 24-well plates with each well containing 1000 µL prewarmed phosphate-buffered saline (PBS). Then the plates were incubated at 37°C. The 1000 µL aliquots of the PBS were collected at each time point (0.5, 1, 3, 6, 24, and 48 hours), and the inserts were moved to a new well with 1000 µL fresh and prewarmed PBS. Collected aliquots were analyzed with UV-Vis Spectrophotometer; a standard curve was made to determine the AgNPs-PVP concentrations. Experiments were performed in triplicates.