The aim of this study was to evaluate the effects of chitosan coating on the attachment, proliferation, functional and morphological change of periodontal ligament cells.

Primary human periodontal ligament cells were cultured in Dulbecco's modified Eagle's medium with 10% fetal bovine serum and 1% antibiotics. In experimental group, cells of 4th to 7th passage were inoculated in the multiwell plates coated with chitosan in concentration of 0.02, 0.2, and 2 mg/ml. Cell counting and MTT assay were done after 0.5, 1.5, 3, 6 and 24 hours of incubation to evaluate the cell attachment, and then after 2 and 7 days of culture to evaluate the cell proliferation. The alkaline phosphatase activity was measured after 4 and 7 days of culture and the ability to produce mineralized nodules was evaluated after 21 days of culture.

The results were as follows:

The morphology of periodontal ligament cells on the chitosan coating was round or spheric. Round cells were aggregated after 6 hours of culture. Aggregated cells on the chitosan coated surface showed nodulelike appearance after 24 hours of culture and not achieved confluency at 7 days.

During early period of culture, the attachment of periodontal ligament cells were inhibited by chitosan coating. Inhibition of cell attachment tended to increase with the concentration of chitosan.

At the chitosan concentration of 0.02 and 0.2 mg/ml, periodontal ligament cells were more rapidly proliferated at 7 days, compared to the control group. At the concentration of 2 mg/ml, the proliferation of periodontal ligament cells was inhibited(p<0.01).

Alkaline phosphatase activity of periodontal ligament cells was increased in chitosan coated group, especially at the concentration of 0.02 mg/ml after 4 days of culture.

Periodontal ligament cells produced mineralized nodules on chitosan coated wells without the addition of mineralized nodule forming materials (ascorbic acid, β-glycerophosphate, dexamethasone). With the addition of mineralized nodule forming materials, periodontal ligament cells produced more mineralized nodules at the concentration of 0.02 mg/ml, compared to the control.

In summary, the attachment, proliferation, cell activity, and alkaline phosphatase activity of periodontal ligament cells depended on the concentration of coated chitosan. Chitosan stimulated mineralized nodule formation by periodontal ligament cells. At the appropriate concentration(0.02 mg/ml), chitosan could increase alkaline phosphatase activity and stimulate the formation of mineralized nodule by periodontal ligament cells. These results suggest that chitosan can be used as an adjunct for bone graft material, and the matrix of tissue engineering for periodontal regeneration, especially bone regeneration.