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3D Hyaluronic Acid Hydrogels for Modeling Oligodendrocyte Progenitor Cell Behavior as a Function of Matrix Stiffness

“…Norbornene groups preferably crosslink with thiyl radicals instead of with themselves, creating a phototunable hydrogel system where the degree of crosslinking is controlled by the molar ratio of thiol to norbornene groups. 24 Gramlich et al demonstrated the positive correlation between NorHA hydrogel stiffness and thiol to norbornene crosslinking ratio up to 0.8. 24 We also previously demonstrated the suitability of NorHA hydrogels for 3D cell culture across a range of Young's moduli from ~ 1-15 kPa.…”

“…24 Gramlich et al demonstrated the positive correlation between NorHA hydrogel stiffness and thiol to norbornene crosslinking ratio up to 0.8. 24 We also previously demonstrated the suitability of NorHA hydrogels for 3D cell culture across a range of Young's moduli from ~ 1-15 kPa. 28 In this work, the molar ratio of thiol to norbornene groups was kept constant at 0.315 while the NorHA macromer concentration was varied between 1 and 2 wt% to enable fabrication of hydrogels spanning a range of CNS-relevant stiffnesses.…”

“…HA-TBA synthesis: Research grade sodium hyaluronate (Lifecore Biomedical, 61.8 kDa) was converted to its tetrabutylammonium (TBA) salt (HA-TBA) to prepare for dissolution in DMSO. 24 Sodium hyaluronate was dissolved in DI water at 2 wt% and Dowex resin (50W x 200) was added at a ratio of 3 g resin/1 g HA. 24 The resin exchanges sodium ions for hydrogen ions, making the solution strongly acidic.…”

“…24 Sodium hyaluronate was dissolved in DI water at 2 wt% and Dowex resin (50W x 200) was added at a ratio of 3 g resin/1 g HA. 24 The resin exchanges sodium ions for hydrogen ions, making the solution strongly acidic. The solution was stirred for ~ 2 hrs.…”