Cell behavior on the alginate-coated PLLA/PLGA scaffolds.

Here, we investigated the effect of preparation temperature and alginate-coating on L929 fibroblast behavior on lyophilized microporous PLLA/PLGA (95:5, w/w) scaffolds. The lower freezing temperature used during lyophilization (-80 °C) resulted in smaller pores (around 50 μm) and higher compressive modulus (1500 kPa) than those prepared at the higher temperature (-20 °C) (pore size: 120 μm, compressive modulus: 600 kPa) (p < 0.01). Cell proliferation was significantly lower on the alginate-coated scaffolds (p < 0.05), probably due to weak cell adhesion on alginate, rapid degradation/dissolution of the alginate hydrogel (40% weight loss after 2 weeks of incubation) (p < 0.05), which resulted in loss of material and cells, and the decrease in the pH (p < 0.05), which probably resulted in decreased cell metabolic activity. Cells tended to get less round on the scaffolds prepared at -20 °C, which had lower compressive modulus and larger pores, and upon coating with alginate, which resulted in a hydrophilic surface that had lower stiffness. When the scaffolds had closer stiffness to the cells, the cells tended to get more branched. The most branched morphology of the fibroblasts was obtained in the presence of alginate, a natural polymer having a similar stiffness with that of the L929 fibroblasts (4 kPa).