Cytocompatibility of aliphatic polyesters--in vitro study on fibroblasts and macrophages

A resorbable copolymer of glycolide and L-lactide (PGLA), a terpolymer of glycolide, L-lactide, and epsilon-caprolactone (PGLCL), and a copolymer of glycolide and epsilon-caprolactone (PGCL) were synthesized by ring opening polymerization using zirconium acetylacetonate (Zr(acac)(4)) as an initiator. The structure and physicochemical surface properties of the materials were studied by NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. On the basis of contact angle measurements and the Owens-Wendt approach, the surface free energy was calculated. The effect of polymeric films produced by solvent casting on morphology and activity of L929 fibroblasts, and two types of macrophages (macrophages from peritoneal exudates and RAW 264.7 monocytes/macrophages), was analyzed. It was found that viability, adhesion, and morphology of fibroblasts on PGLA were very similar to control glass. On PGLCL more adhering cells were round, while on PGCL only single, poorly spread cells were seen, and their viability was significantly reduced. This may suggest that the interaction of fibroblasts with PGCL was due to its hydrophobicity and a very low polarity. Adhesion and viability of RAW 264.7 cells was significantly enhanced on PGLA but reduced on both PGLCL and PGCL. The increased synthesis/release of chemoattractants and metalloproteinases-2 and -9 was observed in the macrophages from peritoneal exudates cultured on PGLA and PGLCL. The viability of cells decreased in the following order: PGLA > PGLCL > PGCL. It is worth noting that glass transition temperature and susceptibility to mechanical deformation of the polymeric materials also decreased in the same order. It may imply that those physical parameters should be also considered as potential factors affecting cell behavior.