Fig. 2.

The supernatant solution was assessed by safranin O after crosslinking processes. A safranin O is red (left) and after adding heparin, it turns to yellow (right) due to metachromatic property of the dye in the presence of heparin. B The optical density of the control (non-crosslinked scaffold with the same heparin concentration) had the significant lower optical density than the experiment samples. This indicated the presence of a less amount of heparin in the supernatant solution and as a result, crosslinking of heparin with the scaffold. * Significant difference with control (p < 0.05). (Color figure online)