Adipogenic differentiation of stem cells in three-dimensional porous bacterial nanocellulose scaffolds.

There is an increased interest in developing adipose tissue for in vitro and in vivo applications. Current two-dimensional (2D) cell-culture systems of adipocytes are limited, and new methods to culture adipocytes in three-dimensional (3D) are warranted as a more life-like model to study metabolic diseases such as obesity and diabetes. In this study, we have evaluated different porous bacterial nanocellulose scaffolds for 3D adipose tissue. In an initial pilot study, we compared adipogenic differentiation of mice mesenchymal stem cells from a cell line on 2D and 3D scaffolds of bacterial nanocellulose. The 3D scaffolds were engineered by crosslinking homogenized cellulose fibrils using alginate and freeze drying the mixture to obtain a porous structure. Quenching the scaffolds in liquid nitrogen resulted in smaller pores compared to slower freezing using isopropanol. We found that on 2D surfaces, the cells were scarcely distributed and showed limited formation of lipid droplets, whereas cells grown in macroporous 3D scaffolds contained more cells growing in clusters, containing large lipid droplets. All four types of scaffolds contained a lot of adipocytes, but scaffolds with smaller pores contained larger cell clusters than scaffolds with bigger pores, with viable adipocytes present even 4 weeks after differentiation. Scaffolds with lower alginate fractions retained their pore integrity better. We conclude that 3D culturing of adipocytes in bacterial nanocellulose macroporous scaffolds is a promising method for fabrication of adipose tissue as an in vitro model for adipose biology and metabolic disease.