Development of 3D microenvironment for engineering of glioblastoma brain tumor

Abstract

The aim of this work was to develop a 3D microenvironment for glioblastoma brain tumor engineering based on alginate hydrogels as a matrix for cell immobilization followed by cultivation in a biomimetic perfusion bioreactor. Alginate microfibers with immobilized cells were obtained by a simple extrusion technique. We have examined the influence of the needle diameter (22G - 28G), cell density in alginate solution (1 x 106 - 8 x 106 cells/ml) and different cancer cell lines (rat C6 and human U251 and U87) on cell immobilization efficiency and viability. The best alginate microfibers (500 µm in diameter) with all immobilized cells were obtained by applying a 25G needle with a minimal cell density of 4 x 106 cells/ml. The obtained microfibers with immobilized cells (C6 and U87) were cultivated in a perfusion bioreactor at the continuous medium flowrate in the range 0.05-0.30 ml/min over short- and long-term cultivation periods. The results have shown that the flowrate of 0.30 ml/min, corresponding to the superficial velocity of 100 µm/s, in combination with the C6 cell density of 8 x 106 cells/ml in short-term studies yielded higher cell viabilities and proliferation as compared to the control static culture. In addition, U87 cells immobilized in alginate microfibers at the density of 4 x 106 cells/ml after long-term cultivation at the medium flowrate of 0.05 ml/min (superficial velocity of 15 µm/s) stayed viable. The overall results have shown potentials of the applied approach for tumor engineering provided optimization of cultivation conditions for each cell type.