2.2. Preparation of FG-KGN Complex

KGN (Sigma-Aldrich, Catalog #SML0370) was dissolved in dimethyl sulphoxide (DMSO) to make a stock solution at a concentration of 100 mmol/l and diluted to 5 mmol/l with PBS as working solutions. Fibrin glue served as the carrier of KGN. To prepare the FG-KGN complex, 20 μl of the 5 mM KGN solution was mixed well with the two components of fibrin glue (total volume 1 ml) and rested for 30 seconds at room temperature. The mixture formed a transparent hydrogel, termed the FG-KGN complex.