SusCHEM: Fundamental Studies on Lyopreservation of Adult Stem Cells

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1605425 He, Xiaoming Lyopreservation of living cells for banking in a state of suspended animation at ambient temperature makes it possible to achieve low-cost maintenance and convenient distribution of the cells. The ready availability of cells is crucial for the wide application and eventual success of cell-based therapies involving tissue engineering, regenerative medicine, cell transplantation, blood transfusion, and stem cell therapy. The objective of this project is to perform a systematic investigation to understand the protective effect of trehalose, a nontoxic sugar, during freezing and drying of trehalose-laden human adipose-derived stem cells (hADSCs) and in banking the dried cells at ambient temperature. As trehalose has been used for many lower organisms to survive extreme cold and drought in nature, it is hypothesized that trehalose-laden stem cells will behave similarly. This project will have a significant impact on improving healthcare by facilitating the development of cell lyopreservation as an enabling technology for the success of cell-based medical treatments. The use of a nontoxic sugar (trehalose) to replace toxic chemicals (e.g., dimethyl sulfoxide or DMSO) for cell banking is well aligned with the NSF SusCHEM initiative to replace toxic chemicals with earth-abundant, inexpensive, and benign materials. To understand the fundamental science of drying living cells for banking in a state of suspended animation at ambient temperature, three specific research tasks are proposed. These include (i) investigation of the effect of freeze-drying parameters on the kinetics of drying trehalose solutions important for lyopreservation of primary hADSCs and on the microscopic morphology of the dried products, using freeze-drying microscopy and a benchtop freeze-dryer for small and large samples, respectively; (ii) simulation and experimental quantification of the biophysical responses of the trehalose-laden hADSCs to freezing and drying including cell dehydration and intracellular ice formation important for cell survival; and (iii) analysis of the morphology, survival, long-term proliferation, and stem cell properties and functions of the primary hADSCs after freeze-drying and banking at ambient temperature. The stem cell properties and functions will be assessed by the expression of stem cell gene and protein markers and their capability of adipogenic, osteogenic, and chondrogenic differentiation. A high survival and intact function of the primary hADSCs are anticipated after freeze-drying and long-term storage at ambient temperature under optimal conditions.This award by the Biotechnology and Biochemical Engineering Program of the CBET Division is cosponsored by the Biomaterials Program of the Division of Materials Research.