Papers by Author: L. Zhao

Abstract: To investigate the influence of initial copolymer compositions of poly (lactic-co-glycolic acid) (PLGA) on mechanical properties, degradation behavior and biological properties of the scaffolds, porous PLGA scaffolds with different initial copolymer compositions (lactide/glycolide (PLA/PGA) molar ratio: 50:50, 70:30 and 80:20) were prepared by solvent casting/particulate leaching method. Mechanical properties were measured by testing the tensile strength and degradation rate was detected by soaking the scaffolds in phosphate buffered solution at 37 °C for various time points. Human dermal fibroblasts were seeded on PLGA scaffolds with different copolymer compositions. The morphology, adhesion efficiency, proliferation rate, and total collagen contents of cells on the scaffolds were analyzed. The results showed that the ratio of PLA/PGA is one important factor which influences the degradation of scaffolds. The mechanical strength of PLGA scaffolds with the ratio of 70:30 and 80:20, was higher than that of PLGA scaffolds with the ratio of 50:50.. Compared to 70:30 and 80:20 PLGA scaffolds, 50:50 PLGA had a quicker degradation. The three PLGA scaffolds had no obvious difference for cell response and all of them had excellent cytocompatibility, indicated by their high efficiency for human dermal fibroblast adhesion, fast proliferation rate and stretched cell morphology. A large amount of extracellular matrix was secreted and after 7 days of culture, and cell nearly covered the entire surface of the scaffolds. Overall, our results indicate that the copolymer compositions of PLGA have important effect on degradation and mechanical strength, but have no obvious effect on the biological properties of the scaffolds.

Abstract: Poly(butylenes succinate) (PBSU) had good biocompatibility and biodegradability, but it is left unexplored for the possible application of PBSU in tissue engineering. The aim of this study was to compare PBSU and poly (lactide-co-glycolide) (PLGA) scaffolds prepared by electrospinning technique as vascular tissue engineering materials. Both scaffolds were characterized by fiber morphology, pore structure and mechanical properties. Smooth muscle cells (SMCs) and endothelial cells (ECs) were seeded on the electrospun PBSU and PLGA scaffolds and cultured for different time periods. Cell adhesion and proliferation on the scaffolds were measured by MTT assay, while SEM was used for observing cell morphology on the scaffolds. The results showed that fiber diameter of the electrospun scaffolds ranged from 300nm to 800nm and their porosities were higher than 90%. The electrospun PBSU scaffolds showed a high tensile strength of 2.06±0.11MPa, whereas the ultimate tensile strength of the electrospun PLGA scaffolds reached 14.31±5.24MPa. Cell adhesion efficacy had no significant difference between PBSU and PLGA scaffolds, but cell proliferation rate on PLGA scaffolds was significantly higher than that on PBSU scaffolds after 7 days of culture. Cell morphology was similar on both scaffolds with the polygonal shape for ECs and spindle-like shape for SMCs. From these results, the present in vitro study revealed that as compared to PLGA scaffolds, the electrospun PBSU scaffolds showed lower tensile strength and slower proliferation rate, but as regards the biocompatibility and pore structure, the electrospun PBSU scaffolds had a potential application in vascular tissue engineering.