An optimized 3D-printed perfusion bioreactor for homogeneous cell seeding in bone substitute scaffolds for future chairside applications

A clinical implementation of cell-based bone regeneration in combination with scaffold materials requires the development of efficient, controlled and reproducible seeding procedures and a tailor-made bioreactor design. A perfusion system for efficient, homogeneous, and rapid seeding with human adipogenic stem cells in bone substitute scaffolds was designed. Variants concerning medium inlet and outlet port geometry, i.e. cylindrical or conical diffuser, cell concentration, perfusion mode and perfusion rates were simulated in silico. Cell distribution during perfusion was monitored by dynamic [18F]FDG micro-PET/CT and validated by laser scanning microscopy with three-dimensional image reconstruction. By iterative feedback of the in silico and in vitro experiments, the homogeneity of cell distribution throughout the scaffold was optimized with adjustment of flow rates, cell density and perfusion properties. Finally, a bioreactor with a conical diffusor geometry was developed, that allows a homogeneous cell seeding (hoover coefficient: 0.24) in less than 60 min with an oscillating perfusion mode. During this short period of time, the cells initially adhere within the entire scaffold and stay viable. After two weeks, the formation of several cell layers was observed, which was associated with an osteogenic differentiation process. This newly designed bioreactor may be considered as a prototype for chairside application.

Information technology for the analysis of CT perfusion in assessing the effectiveness of treatment for glioblastoma

Purpose of the study. To develop an information technology for calculating perfusion computed tomography parameters and to evaluate the effectiveness of using the proposed program in the differential diagnosis of continued glioblastoma growth and post-radiation necrosis. Materials and methods. We examined 53 patients who were treated at the Samara Clinical Oncological Dispensary. All patients underwent CT scan in perfusion mode. The results of using the program were compared with the data that were calculated on the workstation of the GE Discovery CT750 HD computed tomograph. Results. Significant differences were found in CBV and CBF perfusion indices in groups with continued growth and post-radiation necrosis, verified by biopsy. The parameters calculated using the developed program did not differ significantly from the results obtained on a standard workstation. Conclusion. The application of the developed computer program for the analysis of CT perfusion does not depend on the equipment manufacturer, works with standard DICOM data, which increases the availability of a valuable diagnostic method. The results obtained using the proposed information technology make it possible to differentiate the continued growth of glioblastoma from post-radiation necrosis.