FIGURE LEGENDS
FIGURE 1. Pancreatic cell culture on cellulose scaffolds with chemical surface modifications. A) Cellulose scaffold modifications: unmodified (U), amine-modified (A) and NaOH-modified (N), without and with gelatin (G) coating. B) Cell seeding on cellulose scaffold showing phase image of pancreatic progenitors in dish (top), scanning electron microscopy image of cellulose scaffold prior to cell seeding with 20 to 50 µm fibers (middle), and fluorescent image of DAPI-labeled cells on amine-modified scaffold (bottom). Scale bars are 50 µm, 50 µm and 20 µm respectively. C) Schematic of multi-well analysis of variously modified cellulose scaffolds cut into 2 x 3 x 5 mm3 pieces. D) Schematic of wicking matrix bioreactor.
FIGURE 2. Viability and expansion of pancreatic cells on chemically modified cellulose scaffolds. A) Fluorescence microscopy images of pancreatic progenitors prior to seeding onto the cellulose scaffold. Cells are stained with antibodies against specific biomarkers of the pancreatic lineage and counterstained with DAPI (blue). Top panel scale bar = 50 µm, bottom panel scale bar = 10 µm. B) MTT assay of pancreatic cells on different surface-modified cellulose scaffolds during 10 days incubation.
FIGURE 3. Scanning electron microscopy (SEM) images of pancreatic cells on chemically modified cellulose scaffolds. Cells were maintained on the scaffolds and fixed at days 1, 3, 5 and 10 to evaluate cell attachment and growth throughout the scaffold. Black circles show cell aggregates on scaffold. Scale bar = 10 µm.
FIGURE 4. Differentiation of hiPSCs to pancreatic cells. A) Differentiation timeline. B) Phase images of differentiating hiPSCs at selected stages. Scale bar = 100 µm. C) Immunocytochemistry of differentiating cells at selected stages. Scale bar = 50 µm.
FIGURE 5. Viability and functionality of hiPSC-derived pancreatic cells on scaffold. A) MTT assay of pancreatic single cells (12 days) and aggregates (10 days) on amine-modified scaffolds. B) MTT assay of pancreatic single cells (12 days) and aggregates (10 days) on gelatin-coated, NaOH-modified scaffolds C) Scanning electron microscopy of pancreatic single cells and aggregates seeded onto amine-modified scaffolds. Scale bar = 20 µm. C) Insulin release by pancreatic single cells (12 days) and aggregates (10 days) on amine-modified scaffolds. D) Insulin release by pancreatic single cells (12 days) and aggregates (10 days) on gelatin-coated, NaOH-modified scaffolds. E) Scanning electron microscopy of pancreatic single cells and aggregates seeded onto amine-modified scaffold. Scale bar = 20 µm. F) Scanning electron microscopy of pancreatic single cells and aggregates onto gelatin-coated, NaOH-modified scaffolds. Scale bar = 20 µm.
FIGURE 6. Growth and insulin secretion of pancreatic cells on amine-modified scaffolds in a miniature bioreactor. A) Bioreactor setup in the incubator. B) Scaffold incubated in MTT overnight at end of culture. Arrows indicate purple formazan crystals formed by viable cells on the scaffold. C) Scanning electron micrographs of pancreatic cells on the scaffold after 13 days in the bioreactor. Scale bar = 20 µm. D) Insulin secretion from pancreatic cells in the bioreactor during the 13-day culture period. Left panel, reactor seeded with 5 x 106 cells; right panel, reactor seeded with 1 x 107 cells. E) Metabolic profile of pancreatic cells seeded on the bioreactor during the 13-day culture period.