Effect of Controlled Rate Freezing on the Microstructural Properties of Poly (L-lactic Acid) Scaffolds

Bio-degradable poly (l-lactic acid) (PLLA) scaffolds were prepared by using thermally induced phase separation (TIPS) method. A solution of PLLA-Dioxane was formed by dissolving PLLA in dehydrated 1,4-Dioxane at three wt/vol percentages, specifically 3, 7 and 10%. This PLLA-Dioxane solution was then frozen in borosilicate glass vials (5mL) at three cooling rates (1, 10 and 40 °C/min) in a commercially available controlled rate freezer (CRF). The frozen solution was freeze-dried to sublimate the dioxane. The microstructural properties of the resulting PLLA scaffolds were determined utilizing Scanning Electron Microscopy (SEM) images and uniaxial compressive testing. The relationship between the wt/vol ratio of PLLA and Dioxane and the imposed cooling rates on the structural properties of PLLA scaffolds was determined.