. Background Improving the Growth Rate of Human Adipose-Derived Mesenchymal Stem Cells in Alginate/Gelatin Versus Alginate Hydrogels

The unique potential of the mesenchymal stem cells (MSCs) to modulate immune responses prompts their promising application in the regenerative medicine and tissue engineering. The multilineage differentiation potential of the human adipose-derived mesenchymal stem cells (hADSCs) together with the less invasive accessibility makes them a proper candidate for cell therapy (1, 2). Study on the application of several artificial extracellular matrices (ECMs) with different composites and their three-dimensional (3D) distribution patterns are considered as an interesting topic in attempt to improve their therapeutic capabilities (3). The exposed microenvironment of the 3D cultures that mimics in vivo conditions provides more effective interactions between cells and their microenvironment (4). Regarding the fact that the expansion and differentiation of adult stem cells depends on the Background: Expansion and differentiation of stem cells relies on the soluble materials as well as the physical conditions of their microenvironment. Several methods have been studied in attempt to enhance the growth and differentiation rates of different adult stem cells extracted from different sources. Objectives: The purpose was to improve the three-dimensional (3D) culture condition of the semi-permeable polymeric beads for encapsulation of the human adipose-derived mesenchymal stem cells (hADSCs) by modifying the ratio of the alginate-gelatin composition. Materials and Methods: Following isolation and characterization of hADSCs by flow cytometry and their functional differentiation, encapsulation in the alginate and alginate/gelatin compositions were performed. Moreover, the stability, swelling, size frequency, growth kinetics, and cytotoxicity of the beads were measured to meet proper condition in the designed experimental and control culture conditions. Finally, the growth rates of the cells in different experimental groups and control were measured and analyzed statistically. Results: Viability decreased in 2 and 3 percent alginate once compared to 1% alginate in beads (p≤0.05). Moreover swelling of the beads in the alginate/gelatin compositions (50:50 and 70:30) were higher than the pure alginate beads (p≤ 0.05). Finally, the cell growth rate in alginate/gelatin (50:50) beads was significantly higher than alginate and alginate/gelatin (70:30) beads (p≤0.05). Conclusions: These findings suggested for the first time that the composite of alginate/gelatin beads with the ratio of 50:50 might provide a suitable culture condition for the encapsulation and in vitro expansion of the hADSCs