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.