Preparation of biodegradable polymer scaffolds with dual pore system for tissue regeneration

Biodegradable polymer scaffolds that have dual pores on the matrix were successfully prepared using a combination of gas foaming and phase separation methods. PLLA and PLGA were dissolved in dioxane/water at the ratios of 90/10, 87/13, or 85/15 (v/v), respectively. Sodium bicarbonate was then added to the polymer solution and freezed-dried, then subjected to a gas foaming process. Dual pore scaffolds have two distinct pore sizes: large pores in 200 similar to 300 mu m and small ones in 5 similar to 20 mu m, with the interconnected structure. Their porosities were ranged from 92 to 98%, significantly higher than those of unipore scaffold (90%). Two variables, water content (10, 13, and 15%) and freeze-drying temperature (FDT; -196, -70, and -20 degrees C), were introduced during the scaffold preparation. Mechanical compressive strength decreased as the polymer solution was gradually diluted with water (100/0 to 85/15, v/v). Earlier weight loss of the different scaffolds was found with FDT at -20 degrees C but the final result was the same, regardless of different FDTs used. These dual pore polymer scaffolds may thus be useful in tissue engineering applications.