2.4. Preparation of PVABG/ChiCol composite scaffolds
Composite scaffolds of different amounts of PVABG and ChiCol (atweight ratios of 0.5:1, 1:1 and 2:1)were prepared by three mechanical freeze–thawing steps (12 h at−20 °C and 12 h at roomtemperature (25 °C) each step). The porous scaffolds were obtained by freeze drying in the steps shown in Scheme 1. The necessary amounts of the PVABG powders were poured into the gel-like solutions of the chitosan–collagen. The resultant mixture was stirred for 4 h in an ice bath. The resulting milky white solution then underwent three freeze/ thawing cycles which were carried out (12 h at −20 °C and 12 h at
room temperature (25 °C) each cycle). The samples were then frozen
at −80 °C for 48 h and lyophilized with a freeze dryer to form porous
scaffolds. In this way, PVABG/ChiCol scaffolds with a well developed porous
structure were obtained.