Bioceramic hollow microspheres for 3-D bone tissue formation in rotating bioreactors

摘要

Novel bioceramic hollow microspheres with apparent density in the range 0.8-1.0g/cm~3 have been developed as microcarriers for 3-D bone tissue formation in rotating-wall bioreactors (RWV). The hollow ceramic microspheres have an inner shell with composition of 58-72percent SiO_2, 28-42percent Al_2O_3 (in percent by weight) and a porous calcium phosphate (CaP) surface. This CaP surface was deposited using a fine particle sedimentation method. Subsequently, the hollow microspheres were sintered for 1 hour at 600, 800 and 1000 deg C. A comparative analysis using FTIR indicated that crystalline calcium hydroxyapatite (HA) was present in the porous surface sintered at 600 and 800 deg C. The trajectory analysis in both an inertial frame and a rotating frame demonstrated that these microspheres remained suspended in a RWV during the entire cell culture period and experienced a low shear stress (approx0.6 dyn/cm~2). Cell culture studies in a RWV showed that osteoblastic cells (ROS 17/2.8) formed 3-D aggregates with hollow microcarriers in a RWV. Extracellular matrix and mineralization were observed in the aggregates. These data suggest that the bioceramic hollow microspheres can be used as microcarriers for 3-D bone tissue formation and for the study of the effects of microgravity on bone cell function in a rotating-wall bioreactor.