2.2 Synthesis of Chitosan-PEG Nanocomposite
The chitosan-PEG nanocomposite was synthesized according to Liu and Kim (Liu & Kim, 2012). Firstly, aqueous medium molecular weight chitosan (Bio Basic) of 0.4% (w/v) was prepared in 2% (v/v) acetic acid solution. Next, 0.1 g of PEG (Merck) and 0.1 g of phomopsidione were added into the chitosan solution to obtain a Chitosan/PEG/Phomopsidione (C/PEG/Ph) solution. Then, 3 mL of 0.4% genipin (Sigma) cross-linker solution was added into the C/PEG/Ph solution. The final solution was then homogenized for 30 min at room temperature using a homogenizer (Heidolph Silent Crusher M) to allow proper mixing and bridging of the polymeric components, then cast onto sterile Petri dishes. The hydrogels were dried at room temperature for 48 hours. Lastly, the resulting nanocomposite hydrogels were then stored at room temperature for further experiments. Besides, a standard GC/PEG nanocomposite hydrogel was also prepared as the negative control.