Effects of three dimensional structure of tissue scaffolds on animal cell culture

Surface chemistry of the scaffold material, the fiber diameter, pore size, structure and configuration and porosity can regulate tissue development. The overall objective was to study the effect of the three dimensional structure of tissue scaffolds on animal cell culture. To achieve this, the growth of human astrocyte cells, secreting Glial-cell-line Derived Neurotrophic Factor (GDNF), in non-woven polyethylene terephthalate (PET) matrices was specifically targeted. The ability of GDNF to selectively nourish and regenerate dopaminergic neurons makes it an ideal candidate for the treatment of Parkinson's disease. On the basis of cell morphology, density and GDNF secretion, compressed PET matrices (porosity 88.8%, mean pore diameter 64 microns), treated with boiling sodium hydroxide, were found to be very effective in supporting high density growth of astrocytes. Most scaffolds used thus far, are anisotropic in their architecture and have a wide pore size distribution, making the task of identifying optimum values of the parameters important for tissue development even more difficult. However, microfabricated poly(lactic co-glycolic acid) (PLGA) scaffolds with a uniform structure supported a higher cell density, longer cell proliferation times than in non-uniform fibrous matrices, and induced less apoptosis, implying that uniformity in scaffold microstructure was a more important parameter than the mean pore size of the scaffolds. Cytocompatibility studies on PLGA scaffolds also revealed that cells could span in three-dimensional space over distances greater than four times their average length. To develop a fast convenient cell based model to study cell culture in three dimensional (3D) scaffolds, cells were transfected with an Enhanced Green Fluorescent Protein (EGFP) based reporter system. This allowed fast, sensitive and noninvasive monitoring of cell growth in suspension and could be used to detect the spatial distribution of these cells in 3D scaffolds. The fluorescence of these cells was linked to the S-phase of the cell cycle and decreased in a dosage dependent manner when the cells were treated with chemotherapeutic drugs 5-fluorouracil and doxorubicin, making these cells an ideal and reliable model for reporting cellular proliferation and drug effects on cell growth.