Low-Shear Circulation and Layered Regeneration: Coupled Analysis of RCCS-CFD for In Vitro Construction of Active Osteochondral Tissues.

The rotating cell culture system (RCCS) is widely used in 3D in vitro culture due to its ability to provide a low shear environment and optimal mass transfer. However, current understanding of the shear stress and fluid flow distribution within the RCCS remains limited. In this study, a dynamic culture environment of RCCS was constructed in vitro. The three-dimensional spatial structure of chitosan7/gelatin3/Nano-hydroxyapatite (Cs7/Gel3/nHAP) multilayer composite scaffold constructs and bone-derived scaffold structures was used to guide the directional differentiation of human adipose-derived stem cells (ADSCs). Then, computational fluid dynamics was used to simulate and predict the stress and fluid flow distribution of ADSCs-Cs7/Gel3/nHAP constructs and ADSCs-derived-bone scaffold constructs under different rotational speeds in RCCS. It was confirmed that the flow field environment in RCCS was a relatively stable annular laminar flow. Moreover, during the cultivation process in RCCS, the complex was subjected to a uniformly distributed shear force. Finally, the optimal operating conditions of RCCS were selected when two kinds of cell-scaffold bone constructs were placed in RCCS, and it has been experimentally verified that culturing bionic osteochondral scaffolds in the RCCS demonstrates significantly higher ADSCs proliferative activity and differentiation marker expression compared to static culture conditions.