ion, differentiation, and signal transduction of cultured cells. The efficacy of two commercially available bioreactors (rotating-vessel miniPERM and static INTEGRA CL 350) to support long-term bone marrow cell cultures (LTBMCC) and three-dimensional growth of Hodgkin's lymphoma HD-MY-Z cells was investigated. In the miniPERM system, the growth of LTBMCC spheroids (containing 30-40 cells) was obtained. An essentially higher content of hematopoietic precursor cells (colony-forming units-granulocyte macrophage) was registered in the rotating-vessel system. In this bioreactor, a growth of large HD-MY-Z spheroids (containing 100-200 cells) was achieved. The composed mathematical models of the physicomechanical behavior of spheroids enabled the evaluation of the revolution frequency increase schedule. The differential equations took into account all inertial effects caused by the production module rotation movement as well as those caused by the relative movement of the spheroid in the fluid. The models aimed at the optimization of the rotation frequency increase schedule for different types of cells to reduce shear stress, augment productivity, and tolerate the growth of large spheroids. The models were numerically tested using MATLAB-SIMULINK software, and the trajectories of prestained HD-MY-Z spheroids were filmed. The coincidence of the theoretical and experimental trajectories was sufficient.
The use of murine embryonic stem cells, alginate encapsulation, and rotary microgravity bioreactor in bone tissue engineering
The application of embryonic stem cells (ESCs) in bone tissue engineering and regenerative medicine requires the development of suitable bioprocesses that facilitate the integrated, reproducible, automatable production of clinically-relevant, scaleable, and integrated bioprocesses that generate sufficient cell numbers resulting in the formation of three-dimensional (3D) mineralised, bone tissue-like constructs. Previously, we have reported the enhanced differentiation of undifferentiated mESCs toward the osteogenic lineage in the absence of embryoid body formation. Herein, we present an efficient and integrated 3D bioprocess based on the encapsulation of undifferentiated mESCs within alginate hydrogels and culture in a rotary cell culture microgravity bioreactor. Specifically, for the first 3 days, encapsulated mESCs were cultured in 50% (v/v) HepG2 conditioned medium to generate a cell population with enhanced mesodermal differentiation capability followed by osteogenic differentiation using osteogenic media containing ascorbic acid, β-glycerophosphate and dexamethasone. 3D mineralised constructs were generated that displayed the morphological, phenotypical, and molecular attributes of the osteogenic lineage, as well mechanical strength and mineralised calcium/phosphate deposition. Consequently, this bioprocess provides an efficient, automatable, scalable and functional culture system for application to bone tissue engineering in the context of macroscopic bone formation.