2.7. In vitro studies
2.7.1. In vitro collagenase degradation
The PVABG/ChiCol composite disks (diameter ~1.3 cm, thickness~1.5 mm) were immersed in 5 mL of phosphate-buffered saline (PBS,pH 7.4) containing 100 μg mL−1 of collagenase at 37 °C for 3, 6, 9 and 12 h as described previously in ref. [33]. At pre-designed time intervals, the processes which were occurring were stopped by the addition of 0.2 mL of 0.2 M ethylenediaminetetraacetic acid (EDTA) (Sigma, USA) solution. The samples were removed from the PBS solution, washed
with water and then dried in desiccators at room temperature for one
day. The remaining weight of each sample was measured. Three duplicate
specimens were prepared and analyzed for each sample (n= 3).