| This study reports the design, development, and characterization of 85/15 poly (dl-lactide-co-glycolide) acid (PLGA 85/15) scaffolds for tissue engineering applications. In this respect the effects of different processing parameters on the PLGA 85/15 scaffold's physical and mechanical properties were investigated. Porous PLGA 85/15 scaffolds were prepared using a gas foaming/salt leaching technique. The processing parameters under examination included gas saturation pressure, gas saturation time, and NaCl/polymer mass ratio. The physical properties of the scaffold considered were the density, the porosity, the average pore size, and the pore density. The mechanical property studied was the Young's modulus in compression. The results demonstrated that all the processing parameters worked in concert to produce a scaffold with a high level of interconnectivity. From the parameteric study, key processing parameters were identified and selected parameters led to optimal physical and mechanical properties of the scaffold. The experimental results obtained from the mechanical properties of scaffolds were compared with a theoretical model from Gibson and Ashby relating the scaffold's mechanical properties to the density. The predicted elastic responses of opened pores structure from the theoretical model showed agreement with the experimental results.; Subsequently, the effect of the optimized PLGA 85/15 scaffolds on the cell growth and the cell viability of the human promyelocytic leukemia cell line (HL-60) were reported. The investigation showed that the cell growth and viability were not impaired by the presence of PLGA 85/15 scaffolds for the time period under investigation.; Finally, the effects of different degradation media on the optimized PLGA 85/15 scaffold's physical and mechanical properties were also elucidated. The three different media were distilled water (dH2O), a phosphate buffered saline (PBS) solution, and HL-60 cells. In general, the average macropore size and the average molecular weight decreased as the degradation time increased in each medium. However, the scaffolds maintained mechanical and structural integrity throughout the study in all three media over the degradation period studied. Overall, PBS solution most strongly affected physical and mechanical properties, followed by dH2O and HL-60 cells. The distinct variations of the scaffold's properties using different media, demonstrated the importance of carefully selecting the medium to perform in vitro studies. The medium must replicate the actual environment where the scaffold would be used, in order to represent accurately the changes in properties that the scaffold would be undergoing. |
