Poster Presentation 25
Producing Engineered Self-assembled Aggregates of
Mesenchymal Stem Cells in WAVE BioreactorTM
for Cell Therapy
Ang-Chen Tsai, Yijun Liu, Ravindran Chella, Teng Ma*
Department of Chemical and Biomedical Engineering, Florida State University
Abstract
Human mesenchymal stem cells (hMSCs) are primary candidates in cell therapy and regenerative
medicine and have been tested in clinical trials for a wide range of diseases. Recent studies showed that hMSC
have natural ability to self-assemble into 3D aggregates that enhance their therapeutic functions with higher
multi-lineage potential expression, increased migration ability, up-regulated secretion of anti-inflammatory and
angiogenic factors, and improved resistance to ischemic conditions after transplantation. Presently, various
laboratory methods have been developed for hMSC aggregates production, including manual hanging drops,
centrifugation with microfabricated surface, low attachment surface treatment, thermal lifting, and microfluidic
technologies. However, these method have limited scalability and/or poor control in aggregate size. Our
current study presented the accessibility to culture hMSCs as size-controlled aggregates scalably in WAVE
bioreactorTM by adjusting the rocking angle and speed. Our experimental results combined with simulation
modeling suggested that the aggregate size is reverse to the rocking angle and speed which are proportional to
the calculated shear stress. According to the Smoluchowski coagulation equation, suspended hMSCs formed
aggregates because of the balance of valid cell-cell collision and aggregate disaggregation, and hydrodynamics,
in particular the shear stress, plays an important role. We also shifted the aggregate size distribution in varying
the collision frequency by altering seeding density and in modifying the cell-cell binding kinetics by adding
small molecules, such as EDTA and Collagenase. Therapeutic functional tests also supported that hMSCs
derived from engineered aggregates in WAVE bioreactorTM have higher therapeutic gene and protein expression
compared with those from monolayer culture.
A.
B.
C.
Fig. A. Experimental result. Fig. B. Simulation modeling. Fig. C. Two-variable regression
References
1. Sart, S., et al., Three-dimensional aggregates of mesenchymal stem cells: cellular mechanisms, biological properties, and
applications. Tissue Engineering Part B: Reviews, 2013. 20(5): p. 365-380.
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