The molecular weight and crystallinity of systems based on poly(L-lactic acid) PLLA is
an important issue as it can influence, besides the general physical properties of the polymer, the
patterns of cell adhesion, proliferation and cell morphology. The objective of the present study was
to evaluate how crystallinity and molecular weight of PLLA influence the referred parameters. Four
conditions were tested: low molecular weight amorphous and semi-crystalline PLLA disks, and
high molecular weight amorphous and semi-crystalline PLLA disks, obtained from hot press. The
thermal properties of the studied materials were accessed by differential scanning calorimetry. For
the cell culture studies a human osteosarcoma cell line (SaOS-2) was chosen. Disks were immersed
in a cell suspension containing 5x104 cells/ml and kept in culture for periods up to two weeks. Cell
viability and proliferation of SaOS-2 cells was assessed by MTS test and a total protein assay,
respectively. The adhesion and morphology of SaOS-2 cells on PLLA disks was assessed by
scanning electronic microscopy. Results showed that cell viability was not affected by the different
tested conditions. However, cell proliferation was increased in the high molecular weight
amorphous samples and cells seemed to have higher adhesion patterns on semi-crystalline samples.
This is probably happening due to different rates of integrin interaction with the substrate leading to
different patterns of focal adhesion points formation.(undefined